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Effect of Sample Preparation on the Measurement of Sugars, Organic Acids, and Polyphenols in Apple Fruit by Mid-infrared Spectroscopy
Abstract
The objectives of this study were (i) to test different conditions of freezing, thawing, and grinding during sample preparation and (ii) to evaluate the possibility of using mid-infrared spectroscopy for analyzing the composition of sugars, organic acids, and polyphenols in apples. Seven commercial apple cultivars were chosen for their large variability in composition (total polyphenols from 406 to 1033 mg kg(-1) fresh weight). The different conditions of sample preparation affected only the phenolic compounds and not sugars or organic acids. The regression models of the mid-infrared spectra showed a good ability to estimate sugar and organic acid contents (R(2) ≥ 0.96), except for citric acid. Good predictions were obtained for total phenolic, flavan-3-ols, and procyanidins (R(2) ≥ 0.94) provided oxidation was avoided during sample preparation. A rapid and simple procedure was then proposed for phenolic compounds using sodium fluoride during sample homogenization at ambient temperature and freeze-drying before spectra acquisition.
... It can be observed that the absorbance at different frequencies increases as maturity advances. The MIR peaks at 2960 cm -1 , 2919 cm -1 , and 2850 cm -1 are associated with asymmetric and symmetric C-H stretching of CH 2 (Bureau et al. 2009(Bureau et al. , 2012Trevisan et al. 2012;Giovanelli et al. 2014;Ruiz et al. 2008). In the fingerprint region, peaks that are changing with the advance of maturity were observed around at 1711 cm -1 , 1615 cm -1 , 1539 cm -1 , 1514 cm -1 , 1448 cm -1 , 1321 cm -1 , 1206 cm -1 , 1162 cm -1 , 1031 cm -1 , 870 and 761 cm -1 . ...
... In the fingerprint region, peaks that are changing with the advance of maturity were observed around at 1711 cm -1 , 1615 cm -1 , 1539 cm -1 , 1514 cm -1 , 1448 cm -1 , 1321 cm -1 , 1206 cm -1 , 1162 cm -1 , 1031 cm -1 , 870 and 761 cm -1 . In the MIR fingerprint region absorbance values at 1711 cm -1 , 1615 cm -1 , 1539 cm -1 , 1514 cm -1 are associated with amide I and II bands (Bureau et al. 2009(Bureau et al. , 2012Trevisan et al. 2012;Giovanelli et al. 2014;Ruiz et al. 2008). These frequencies indicated the changes in compounds containing nitrogen (e.g. ...
... These frequencies indicated the changes in compounds containing nitrogen (e.g. proteins, amino acids) (Bureau et al. 2009(Bureau et al. , 2012Trevisan et al. 2012; Giovanelli et al. 2014;Ruiz et al. 2008). In addition, absorbance or peaks around 1615 cm -1 might be associated with the C═O stretching of flavonoids, whereas the peak around 1711 cm -1 is associated with carbonyl stretching of carboxylic acids. ...
Knowledge about the inherent complexity of the composition, nutrition, and physiology of different plant tissues and parts is required as this will allow for the discovery of new or improved properties (e.g. new bioactive compounds with health-benefitting activities, antimicrobial substances to reduce food spoilage activity). This paper reports the use, analysis and interpretation of the mid-infrared spectra of different plant parts (fruits and leaves) from an Australian native tropical plant, Terminalia ferdinandiana Exell [Combretaceae]. The use of infrared spectroscopy together with chemometric techniques will allow to obtain different levels of information about the chemical composition of leaf and fruit samples associated with maturity. Freeze-dried powder and puree of Terminalia ferdinandiana is commercially available as a functional food ingredient, whereas leaves or any other tissues are not considered as functional ingredients. The use of mid-infrared spectroscopy can provide an initial screening tool for the discovery and development of new ingredients and products. This technology can be an easy to use, cost-effective and high throughout method to ensure quality and authenticity of food products throughout the value chain. The incorporation of these techniques might be considered the base of bio spectroscopy analysis as proxies to study tropical species with distinctive bioactive properties and nutritional value such as Terminalia ferdinandiana.
... Direct ATR-FTIR estimations on fruit fresh homogenates have obtained good results to predict soluble solids content, dry matter content, titratable acidity, some individual sugars and organic acids (Bureau, Ścibisz, Le Bourvellec, & Renard, 2012;Ayvaz et al., 2016). As infrared spectroscopy is extremely sensitive to changes of hydrogen bonding (Jackson & Mantsch, 1995), the main drawback of spectral measurements is the low sensitivity and limited specific signals of chemical compositions under strong water interactions in fresh fruit suspensions, such as citric acid in apples (Bureau et al., 2012), lycopene and β-carotene in tomato (Baranska et al., 2006). ...
... Direct ATR-FTIR estimations on fruit fresh homogenates have obtained good results to predict soluble solids content, dry matter content, titratable acidity, some individual sugars and organic acids (Bureau, Ścibisz, Le Bourvellec, & Renard, 2012;Ayvaz et al., 2016). As infrared spectroscopy is extremely sensitive to changes of hydrogen bonding (Jackson & Mantsch, 1995), the main drawback of spectral measurements is the low sensitivity and limited specific signals of chemical compositions under strong water interactions in fresh fruit suspensions, such as citric acid in apples (Bureau et al., 2012), lycopene and β-carotene in tomato (Baranska et al., 2006). Moreover, classical measurements of rheological properties and particle size distribution of fruit products require costly rheometer, particle sizing equipment and experienced staffs. ...
... i) the first subset was dedicated to apples characterization: 3 replicates of 10 apples were selected and separated into two aggregate samples as described by Bureau (Bureau et al., 2012). One sample corresponding to the NF sample was stored at −80°C and then homogenized at 11000 rpm with an Ultraturrax T-25 (IKA, Labortechnik, GmbH, Staufen, Germany) after 1.5 h of thawing at 22.5°C for biochemical and spectral characterizations. ...
Attenuated total reflectance Fourier transform spectroscopy (ATR-FTIR) was applied on fresh (NF), freeze-dried (FD) and cell wall materials (AIS) of raw and processed apples. These samples prepared from 36 apple sets and the corresponding 72 purees, issued from different varieties, agricultural practices, storage periods and processing conditions, were used to build models including exploratory analysis, supervised classification and multivariate calibration. Fresh and freeze-dried samples presented similar fingerprint spectral variations due to processing. ATR-FTIR directly on fresh purees satisfactorily predicted textural properties such as particle average size and volume (RPD> 3.0), while freeze-drying improved assessment of chemical (RPD> 3.2) and rheological (RPD> 3.1) parameters using partial least-squares regression. The assessment of texture and macrocomponents of purees can be obtained with a limited sample preparation. For research applications because of a need of sample preparation, changes of cell wall composition during fruit processing could be assessed in relationship with pectin degradation.
... According to Coates (2000) and Bureau et al. (2012), the region from 900 cm −1 to 1500 cm −1 was characterized by the typical bands of phenolic compounds such as CeCeC of aromatic ring stretch the phenol OeH bend, the aromatic C-H in-plane bend, and the C]O stretch of phenol (Table 2). In addition, Rubio-Diaz et al. (2011) reported that the region between 950-980 cm −1 was characterized by the transe-CHe]CHe absorption of carotenoids in tomato. ...
... The best FT-MIR calibration and validation models developed to predict TPC of apricot genotypes were obtained when the first derivative coupled with SNV algorithm spectra processing in the range of 1000-1800 cm −1 was applied (Bureau et al., 2012), inside which PLS loading spectra showed high variability (Fig. 4A). Maximum absorption peaks identified in the frequency range of 1000-1200 cm -1 can be attributed to the fluctuations associated with the C-O-H group in some phenolic compounds typically found in fruit (Golubtsova, 2017;Coates, 2000). ...
... The RPD value, equal to 8.51, indicates an excellent model performance, which may therefore be effectively used for screening the new samples. Regarding TCC, the optimal wavelength region for MIR prediction ranged from 800 to 1800 cm −1 , in agreement with Bureau et al. (2012), and the best PLS model was obtained from first derivative spectra and SNV pre-treatment. ...
Vibrational spectroscopy is considered a green alternative to the traditional analytical methods for quantitative determination of antioxidants in agricultural products. In this study, the potential of NIR and MIR spectroscopy for the prediction of antioxidant compounds in seven early-to-late apricot genotypes from different locations was
reported. NIR and MIR calibration models were developed using Partial Least Squares Regression (PLS) withcross-validation, and the performance of final models was evaluated using Rp2, root mean square error of prediction (RMSEP) and relative predicted determinant (RPD). Five independent PLS models were developed,using both NIR and MIR spectra from 300 samples per year and their corresponding total phenols (TPs), total
flavans (FLs), total carotenoids (TCs), antiradical capacity (AC) reference values, yielding coefficient on averagealways>0.95. Very good models were obtained for TPs (Rp2 = 0.99, RMSEP = 0.73 g kg−1 GAE, RPD = 12.0; Rp2 = 0.99, RMSEP = 0.95 g kg−1 GAE, RPD = 9.9 for MIR and NIR models, respectively), and FLs (Rp2 =0.99, RMSEP = 0.99 g kg−1 CAT, RPD= 8.5; Rp2 =0.98, RMSEP = 1.10 g kg−1 CAT, RPD= 6.4, for MIR and NIR models, respectively). Besides, both MIR and NIR models for total carotenoids (TCs) quantification showed a satisfactorily predictive capability (Rp2 = 0.98, RMSEP = 0.01 g kg-1 β-carotene, RPD = 6.5; Rp2 = 0.95, RMSEP = 0.01 g kg-1 β-carotene, RPD = 4.5, for MIR and NIR models, respectively). Good model performances were also obtained for the prediction of antiradical potential of samples, developed herein for the first time on freeze-dried apricot samples. In general, ATR-MIR demonstrated advantages over NIR in predicting all nutraceutical parameters, whereas similar model performances were obtained for the antiradical potential tested versus ABTS+• using MIR and NIR spectral regions. Results reported in the present study suggest that vibrational spectroscopy, both in MIR and NIR range, is adequate to predict the nutraceutical properties of apricots for screening purposes quickly and sustainably.
... However, in most of these studies, a limited set of plant samples with a slight variability was used. Our previous works have been dedicated to the use of ATR-FTIR coupled with multivariate analyses such as PLS regression and PCA to assess the composition of sugars, organic acids and polyphenols in different fruit species and specially on apples using dry samples (Bureau et al., 2012) with a particular attention done on the sampling which should be representative of the observed and known variability. In this work, the objective was to use the same methodology and strategy to evaluate the most as possible all information on cell wall, quantity and composition, taking into account the fragmented cell wall characterization described in literature above. ...
... Both, RM and AIS, were passed through a 150 μm (100 Mesh) size screen sieve and stored in P 2 O 5 atmosphere before acquisition of ATR-FTIR spectral data (4000 cm −1 to 650 cm −1 ) using the Tensor 27 FTIR spectrometer (Bruker Optics) equipped with a single-reflectance horizontal ATR cell (Golden Gate equipped with a diamond crystal, Bruker Optics), as described by Bureau et al. (2012). Each sample was measured five times (by removing and putting different aliquots of powder to evaluate their heterogeneity) and each spectrum was the average of 16 scans. ...
... Total dietary fiber (TDF) is composed mainly of non-starch polysaccharides (cellulose, hemicelluloses and pectic substances), undigested cell wall proteins, lignin, phenolic compounds, phytates, resistant starches and other minor compounds not digestible by secretions of the gastrointestinal digestive tract (Jones, 2014). In the same way, a very good prediction is found for dry matter in tomato (340 samples, 39 cultivars) and in apple (168 samples, 7 cultivars, using ATR-FTIR (ATR ZnSe 6 reflections) associated to PLS cross-validation (Bureau et al., 2012;Ścibisz et al., 2011). However, to our knowledge, no paper has related the use of FTIR associated with multivariate analysis and calibration models on fruit and vegetables to predict the AIS yield directly on the freeze-dried samples. ...
Infrared spectroscopy coupled with multivariate analyses such as linear regressions was applied to assess the main cell wall components of a huge diversity of fruits and vegetables belonging to 29 plant species. The methodology was tested on the raw freeze-dried powders and on their corresponding AIS (Alcohol Insoluble Solids) dried by solvent exchanges. The most informative spectral region was 1750-1035 cm ⁻¹ . Excellent predictions (determination coefficient R2 ≥ 0.9 and residual predictive deviation RPD ≥ 3.0) were obtained for AIS yields and for arabinose, total glucose, non-cellulosic glucose, total neutral sugars, methanol and starch contents in the AIS samples. The key wavenumbers were: 1740 cm ⁻¹ for total neutral sugars; 1075, 1440–1450, 1616 and 1740 cm ⁻¹ for pectins; 895, 1035–1041 and 1160-1163 cm ⁻¹ for cellulose and 1035–1041 cm ⁻¹ for lignin. Limitations of the reference methods to analyze cell wall components (biochemical assays, spectrophotometry, chromatography) affecting the prediction accuracy were also discussed.
... 10 From a breeding perspective, it would be advantageous to use a technology that can determine individual free sugars, fructan and pungency in onion juice simultaneously. A possibility is Fourier-transform infrared (FTIR) spectroscopy, which has been successfully applied to analysis of juice and pulp from a variety of fruits and vegetables, [11][12][13][14][15][16] but not onion. Methanolic/aqueous extracts of lyophilised onion powder have been investigated by FTIR, although only to determine total phenolic content and antioxidant capacity. ...
... Where values have been reported on a w/w basis to facilitate direct comparison with onion data, they include pulps from apple, peach, raspberry and tomato. 11,14,15,41 Calibration errors in these investigations range between 0.83 and 1.8 mg g −1 FW, with RPDs between 2.5 and 7.1. The model for fructose in onion therefore falls amongst the better ones developed for this analysis. ...
... Analysis of glucose by FT-MIR has been reported previously in studies also measuring fructose. 11,14,15,41 Calibration errors for glucose in these investigations ranged between 0.36 and 2.0 mg g −1 FW, with RPDs between 2.4 and 10.0. The onion model for glucose falls mid-range within this group. ...
BACKGROUND
To facilitate faster phenotyping of onions (Allium cepa L.), Fourier‐transform mid infrared (FT‐MIR) spectroscopy with partial least squares (PLS) regression modelling was evaluated for determination of pungency (pyruvate), sweetness (free sugars) and fructan in juice samples (n = 605) expressed from bulbs from breeding populations.
RESULTS
FTIR spectra (1700–900 cm‐1 range) were from 30 μL droplets of unprocessed juice. Goodness‐of‐fit (R²) and prediction errors (SECV) for optimal PLS models were: soluble solids (0.997, 0.1°Brix), pyruvate (0.825, 0.8 μmol g‐1 FW), fructan (0.98, 1.9 mg g‐1 FW), glucose (0.941, 1.1 mg g‐1 FW), fructose (0.967, 1.0 mg g‐1 FW) and sucrose (0.919, 1.7 mg g‐1 FW). FTIR models for industry Sweetness Indices based on glucose or sucrose equivalents were also developed. Because of its very low concentration (0.8–12 μmol g‐1 FW) relative to other compounds, pyruvate was the weakest model developed. Fructan could be determined spectroscopically without the need for enzymatic digestion.
CONCLUSIONS
All chemometric models developed are acceptable for screening purposes. Those for soluble solids, fructan and fructose are also suitable for routine analysis. FT‐MIR can therefore be utilised for the simultaneous determination of pungency, sweetness and fructan in this crop.
... Qualitative and quantitative phenolics, individual sugar, and organic acids composition is well-documented in apple [14,[17][18][19][20][21][22][23][24]. The content of phenolics, sugars and organic acids in apple are influenced by several biotic and abiotic factors such as cultivar [18,20,[22][23][25][26], rootstock [27], climate [7], temperature, light, and water availability modulated by irrigation [28]. ...
... Qualitative and quantitative phenolics, individual sugar, and organic acids composition is well-documented in apple [14,[17][18][19][20][21][22][23][24]. The content of phenolics, sugars and organic acids in apple are influenced by several biotic and abiotic factors such as cultivar [18,20,[22][23][25][26], rootstock [27], climate [7], temperature, light, and water availability modulated by irrigation [28]. The available data on the effect of the orchard practices and management system on phenolic content of apple give controversial results. ...
... In the fingerprint region (1500 and 900 cm -1 ), i.e. the absorption range of different molecular vibrations such as OH-bending, C-O and C-C stretching, the MIR spectra differ in absorbance in relation to the variability of the apples composition [23]. This spectral range also contains quantitative information a.o. ...
La teneur totale en polyphénols et le profil phénolique de pommes issues d'une expérimentation système qui permet d'individualiser l'effet du système de culture (conventionnel, bas-intrants, agriculture biologique (AB)) et de la variété (Ariane, Melrose, Smoothee) ont été analysés pendant trois ans par analyse HPLC en phase inverse avec ou sans thiolyse. L'analyse multivariée pointe la variété et l'année comme principaux facteurs affectant le profil phénolique des pommes. Un focus sur Ariane en 2011 pour approfondir l'effet du système de culture montre que la teneur totale en polyphénols de l'épiderme ou du parenchyme ne diffère pas entre systèmes. Les procyanidines, composés majoritaires, présentent également des teneurs similaires entre systèmes. La teneur en composés de l'épiderme tels que la (-)-épicatéchine et l'acide 5'-caféoylquinique est significativement plus élevée dans les pommes en AB, mais c'est l'inverse pour la (+)-catéchine du parenchyme. La teneur en phloridzine dans l'épiderme est significativement différente entre systèmes (AB>bas-intrants>conventionnel). La teneur en cyanidine-3-O-galactoside est plus faible dans la peau de pommes bas-intrants. Les mêmes voies métaboliques étant en jeu dans l'élaboration des composés phénoliques, ces résultats soulignent la complexité des mécanismes à l'origine de la synthèse des polyphénols dans la plante. Enfin, considérer une gamme d'intensité des pratiques, déclinée pour trois variétés, plutôt que deux systèmes contrastés (e.g. AB vs. conventionnel), identifie principalement la variété puis l'année de récolte comme facteurs affectant la teneur en polyphénols des pommes. Mots-clés : Malus x domestica, variété, mode de production, qualité du fruit, métabolites secondaires Abstract: Polyphenols and orchard management: the case study of apple in BioREco experiment The total polyphenol content and their profile of apples from orchards differing in their management and cultivar were analyzed across three years using a reverse phase HPLC analysis with or without thiolysis. Studied management systems were conventional, low-input and organic. Each of them was planted with three apple cultivars: Ariane, Melrose and Smoothee. Multivariate analyses highlighted cultivar and year as main factors individualizing polyphenol profiles of fruit samples. When considering the Ariane cultivar and year 2011 to investigate the effect of the management system per se, the total polyphenol content of either the flesh or the peel of apples was not different between systems. Procyanidins, the prevailing compound, were also similar among systems. Some compounds of the peel ((-)-epicatechin and 5'-caffeoylquinic acid) showed the highest concentrations in organic apples, but the opposite was observed for (+)-catechin in the flesh. Phloridzin content of peel significantly decreased in apples from organic to low-input then conventional systems. Cyanidin-3-O-galactoside in the peel was the lowest in low-input apples. As far as the same metabolic processes are involved in the elaboration of phenolic compounds in the fruit, this highlights that mechanisms underlying polyphenol content in the plant are complex. Finally, when considering a range of management systems combined with three C. Le Bourvellec et al. 92 Innovations Agronomiques 42 (2014), 91-104 cultivars instead of the usual organic vs. conventional comparison, polyphenol content of apple appeared more determined by the cultivar and the year of cropping than the orchard practices.
... Qualitative and quantitative phenolics, individual sugar, and organic acids composition is well-documented in apple [14,[17][18][19][20][21][22][23][24]. The content of phenolics, sugars and organic acids in apple are influenced by several biotic and abiotic factors such as cultivar [18,20,[22][23][25][26], rootstock [27], climate [7], temperature, light, and water availability modulated by irrigation [28]. ...
... Qualitative and quantitative phenolics, individual sugar, and organic acids composition is well-documented in apple [14,[17][18][19][20][21][22][23][24]. The content of phenolics, sugars and organic acids in apple are influenced by several biotic and abiotic factors such as cultivar [18,20,[22][23][25][26], rootstock [27], climate [7], temperature, light, and water availability modulated by irrigation [28]. The available data on the effect of the orchard practices and management system on phenolic content of apple give controversial results. ...
... In the fingerprint region (1500 and 900 cm -1 ), i.e. the absorption range of different molecular vibrations such as OH-bending, C-O and C-C stretching, the MIR spectra differ in absorbance in relation to the variability of the apples composition [23]. This spectral range also contains quantitative information a.o. ...
Many biotic and abiotic parameters affect the metabolites involved in the organoleptic and health value of fruits. It is therefore important to understand how the growers' decisions for cultivar and orchard management can affect the fruit composition. Practices, cultivars and/or year all might participate to determine fruit composition. To hierarchize these factors, fruit weight, dry matter, soluble solids contents, titratable acidity, individual sugars and organics acids, and phenolics were measured in three apple cultivars ('Ariane', 'Melrose' and 'Smoothee') managed under organic, low-input and conventional management. Apples were harvested at commercial maturity in the orchards of the cropping system experiment BioREco at INRA Gotheron (Drôme, 26) over the course of three years (2011, 2012 and 2013). The main factors affecting primary and secondary metabolites, in both apple skin and flesh, were by far the cultivar and the yearly conditions, while the management system had a very limited effect. When considering the three cultivars and the year 2011 to investigate the effect of the management system per se, only few compounds differed significantly between the three systems and in particular the total phenolic content did not differ significantly between systems. Finally, when considering orchards grown in the same pedoclimatic conditions and of the same age, instead of the usual organic vs. conventional comparison, the effect of the management system on the apple fruit quality (Fruit weight, dry matter, soluble solids content, titratable acidity, individual sugars, organic acids, and phenolics) was very limited to non-significant. The main factors of variation were the cultivar and the year of cropping rather than the cropping system. More generally, as each management system (e.g. conventional, organic…) encompasses a great variability of practices, this highlights the importance of accurately documenting orchard practices and design beside the generic type of management in such studies.
... The three bands between 1402 and 1603 cm −1 were attributed to aromatic ring vibrations. Multiple bands between 1140 and 1319 cm −1 comprised intricate absorption of the C-O stretch and C-O-H bending of phenols, carboxylic acids, and carbohydrates (Silverstein et al. 1981;Coates 2000;He et al. 2007;Lopez-Sánchez et al. 2010;Bureau et al. 2012). The spectral region giving the best results for phenolic compound prediction was 1010-1700 cm −1 . ...
... 'M 1 ' differed from other A. arguta cultivars in the range of 1042-990 cm −1 and showed only one peak at 1015 cm −1 . Our results are similar to others, showing the polyphenols differences in the spectral region giving the best results for phenolic compound prediction of 1010-1700 cm −1 (Bureau et al. 2012). In the region of 865-775 cm −1 , 'M 1 ' is similar to 'Hayward' and 'Bidan.' ...
... Thus, for each cultivar, a unique phenolic fingerprint in the IR spectral region could be obtained. Most remarkable are the differences from 1232 till 777 cm −1 (He et al. 2007;Lopez-Sánchez 2010;Bureau et al. 2012). A shift in the difference between the standard and the investigated samples can be explained by the extraction procedures of the total phenols. ...
In this research, eight kiwi fruit genotypes (six hardy kiwis (Actinidia arguta and their hybrids), one of Actinidia deliciosa ‘Hayward,’ and one of Actinidia eriantha ‘Bidan’ were examined and compared by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), Fourier transform infrared (FT-IR) spectra, and nuclear magnetic resonance (NMR) spectroscopy. Proteins were extracted from lyophilized fruits, flesh with seeds, grinded seeds, and singular seeds and then separated by SDS-PAGE. Matrix similarity and dendrogram was generated using Nei coefficient and Unweighted Pair Group Method with Arithmetic mean (UPGMA) algorithm. Based on protein patterns, Actinidia species were clearly distinguishable, whereas differences between hardy kiwi fruit cultivars were minor or nondetectable. The electrophoretical separations were able to distinguish a half of hardy kiwi fruit cultivars, so cluster analysis revealed a limited number of cultivar groups. Intervarietal polymorphism was low and this affected the results of similarity analysis. One distinct cluster, composed of two pairs of cultivars and identical by protein patterns, was obtained. Cultivars ‘Ananasnaya’ and ‘Weiki,’ according to the morphological description, were similar. Oppositely, ‘M1’ cultivar significantly differed from other hardy kiwi cultivars by densitometrical bands intensity. All examined singular seeds of ‘Ananasnaya’ cultivar possessed identical protein patterns. The protein patterns of ‘Bingo’ and ‘Ananasnaya’ hardy kiwi fruits harvested in 2011 and 2013 were identical. Three weeks storage after harvest did not affect the protein composition of these cultivars. FT-IR and NMR spectrum of hardy kiwi fruits were presented and compared with ‘Hayward’ and ‘Bidan’ and showed slight differences in comparison with the protein profiles. SDS-PAGE is more applicable than FT-IR and NMR for comparison of different kiwi fruit cultivars. The used analytical methods can be applied to any food analysis in order to distinguish the main compounds and to present fingerprints of different cultivars.
Graphical Abstract
A, Actinidia arguta kiwi fruit cultivars; B, Actinidia deliciosa kiwi fruit ‘Hayward’; C,Actinidia eriantha kiwi fruit ‘Bidan’; D, Electrophoretical patterns of proteins extracted with urea bufferfrom: 1, ‘Bingo’; 2, ‘M1’; 3, ‘Ananasnaya’; 4, ‘Weiki’; 5, ‘Jumbo’; 6, ‘Geneva’; 7, ‘Hayward’; 8,‘Bidan’; E, FT-IR spectra of extracted polyphenols. Curves from the top kiwi fruit ‘Ananasnaya,’‘Bingo,’ ‘M1’; F, 1H-NMR spectra from the top of DMSO extracts of ‘Bidan’; ‘Hayward’;‘Ananasnaya’.
... The advantage toward PCA was confirmed by Liu et al. [58] and Lu et al. [59]. Lots of researchers have applied PLS in their studies, including Shan et al. [5] and Bureau et al. [60]. ...
... They offered two methods to enhance the accuracy: a temperature variable-eliminating calibration model and a global robust calibration model, both of which performed well, with RMSEP of 0.72 and 0.69, respectively. Bureau et al. [60] monitored the change in sugar content during sample preparation. Results showed that different conditions of sample preparation could not affect the sugar concentration. ...
... Bureau et al. [60] employed mid-IR spectroscopy in the 5882-9900 nm range to measure organic acids. Through monitoring its quantitative changes, the concentration of organic acids was proved to be unaffected by different conditions of sample preparation, such as storage temperature, sample grinding and sample oxidation. ...
An overview is presented with regard to applications of visible and near infrared (Vis/NIR) spectroscopy, multispectral imaging and hyperspectral imaging techniques for quality attributes measurement and variety discrimination of various fruit species, i.e., apple, orange, kiwifruit, peach, grape, strawberry, grape, jujube, banana, mango and others. Some commonly utilized chemometrics including pretreatment methods, variable selection methods, discriminant methods and calibration methods are briefly introduced. The comprehensive review of applications, which concentrates primarily on Vis/NIR spectroscopy, are arranged according to fruit species. Most of the applications are focused on variety discrimination or the measurement of soluble solids content (SSC), acidity and firmness, but also some measurements involving dry matter, vitamin C, polyphenols and pigments have been reported. The feasibility of different spectral modes, i.e., reflectance, interactance and transmittance, are discussed. Optimal variable selection methods and calibration methods for measuring different attributes of different fruit species are addressed. Special attention is paid to sample preparation and the influence of the environment. Areas where further investigation is needed and problems concerning model robustness and model transfer are identified.
... Hydroxycinnamic acids, flavan-3-ols (including monomeric catechins and procyanidins), and dihydrochalcones can be found in all parts of the fruit. 12 −14 In studying factors modifying leaching from fruit, most investigators have considered sugars and water diffusion, in the context of osmotic diffusion, i.e., when confronted with solutions of higher osmotic pressure. Few have considered polyphenol mass-transfer mechanisms. ...
... The homogenates were centrifuged at 9000g for 10 min at 4°C. The supernatant was collected to analyze sugars by a colorimetric enzymatic method as described by Bureau et al. 12 Quantification of Polyphenols by High-Performance Liquid Chromatography (HPLC) after Thioacidolysis. Polyphenols were quantified by HPLC after thioacidolysis as described by Bureau et al. 12 The average degree of polymerization (DP n ) was measured by calculating the molar ratio of all of the flavan-3-ol units (thioether adducts plus terminal units) to (−)-epicatechin and (+)-catechin corresponding to terminal units. ...
... The supernatant was collected to analyze sugars by a colorimetric enzymatic method as described by Bureau et al. 12 Quantification of Polyphenols by High-Performance Liquid Chromatography (HPLC) after Thioacidolysis. Polyphenols were quantified by HPLC after thioacidolysis as described by Bureau et al. 12 The average degree of polymerization (DP n ) was measured by calculating the molar ratio of all of the flavan-3-ol units (thioether adducts plus terminal units) to (−)-epicatechin and (+)-catechin corresponding to terminal units. A HPLC system equipped with a diode array detector (SPD-M20A, Schimadzu, Inc., Kyoto, Japan) and a Lichro 250 × 4 mm column, Lichrospher 100 RP-18.5 μm (25 cm × 4.6 mm), were used. ...
Fruits contain polyphenols, widespread antioxidants beneficial for human health. Their mass transfer was studied during the leaching of apple slices immersed in mannitol solutions with ranging concentrations (0, 0.2, 0.4, 0.6 M). The solution of Fick's law for unsteady mass transfer in planar configuration was used to calculate apparent diffusivity (De). Polyphenols were quantified by HPLC for each immersion time. Leaching from raw apple tissues occurred only when cell integrity was lost, here at certain level of difference in osmotic pressure. Different diffusivity values were found in the two apple varieties. Values of De either decreased from 0.2 to 0.1 × 10-9 m2 s-1 and 0.2 × 10-9 m2 s-1 respectively for Golden Delicious and Granny Smith or were not determined when mannitol concentration increased from 0 to 0.6 M. The osmotic strength of the solution strongly impacted the leaching rate of polyphenols from apple cells. The structure of the polyphenols also affected De, with low values for procyanidins. Keywords: Malus domestica Borkh, apparent diffusivity, mannitol, turgor, osmotic pressure.
... This model performed well with rp = 0.97 and RMSEP = 140 mg/g. A similar result was obtained by Bureau et al. (2012) [32], who applied mid-infrared spectroscopy in the range of 6378-9900 nm. The PLS model they created performed very well, with rp = 0.98 and RMSEP = 0.09. ...
... This model performed well with rp = 0.97 and RMSEP = 140 mg/g. A similar result was obtained by Bureau et al. (2012) [32], who applied mid-infrared spectroscopy in the range of 6378-9900 nm. The PLS model they created performed very well, with rp = 0.98 and RMSEP = 0.09. ...
The quality assessment and grading of agricultural products is one of the post-harvest activities that has received considerable attention due to the growing demand for healthy and better-quality products. Recently, various non-destructive methods have been used to evaluate the quality of agricultural products, which are very desirable and faster and more economical than destructive methods. Optical methods are one of the most important non-destructive methods that use the high speed of light detection and computer data processing and are able to evaluate the quality and classification of products with high accuracy. Among the optical methods, visible–near-infrared (Vis/NIR) spectroscopy is considered one of the most accurate methods. In this research, Vis/NIR spectroscopy technology was used in the spectral range of 350–1150 nm for non-destructive detection of some quality parameters including pH, TA, SSC, and TP of two varieties of Red Delicious and Golden Delicious apples. Various pre-processing models were developed to predict the parameters, which brought the desired results with high accuracy so that pH prediction results were for yellow apples (RMSEC = 0.009, rc = 0.991, SDR = 2.51) and for red apples (RMSEC = 0.005, rc = 0.998, SDR = 2.56). The results for TA were also (RMSEC = 0.003, rc = 0.996, SDR = 2.51) for red apples and (RMSEC = 0.001, rc = 0.998, SDR = 2.81) for yellow apples. The results regarding SSC were for red apples (RMSEC = 0.209, rc = 0.990 and SDR = 2.82) and for yellow apples (RMSEC = 0.054, SDR = 2.67 and rc = 0.999). In addition, regarding TP, the results were for red apples (RMSEC = 0.2, rc = 0.989, SDR = 2.05) and for yellow apples (RMSEC = 1.457, rc = 0.998, SDR = 1.61). The obtained results indicate the detection of the mentioned parameters with high accuracy by visible/infrared spectroscopic technology.
... Egyptian navel oranges are mostly exported to nations in the Arab Gulf and the European Union [1]. The required fruit quality range varies by market and includes fruit size, color, and some internal chemical characteristics such as total soluble solids (TSS), juice acidity, and TSS/acidity ratio [3][4][5]. ...
... There were three factors taken into consideration during training, namely the maximum depth (Md) of the tree, the minimum sample leaf (Ms), and the maximum leaf nodes (Mln). The parameters values were (1, 3,5,7,9), (2,4,6,8,10), and (none, 10,20,30,40,50) for Md, Ms, and Mln, respectively. The hyperparameter optimization was performed during the training, and the top-level model was generated using the best parameters. ...
Citation: Galal, H.; Elsayed, S.; Elsherbiny, O.; Allam, A.; Farouk, M. Using RGB Imaging, Optimized Three-Band Spectral Indices, and a Decision Tree Model to Assess Orange Fruit Quality. Agriculture 2022, 12, 1558. https://doi.
... Pedro and Ferreira (2007) applied the same methodology (NIR) to predict sugar content and acidity in tomato products. Bureau et al. (2009), Bureau, Scibisz, Bourvellec, andRenard (2012) used the MIR spectroscopy to determine sugar, organic acid and polyphenol contents in apricot and apples. Changes in carotenoid contents in maize were verified by Brenna and Berardo (2004) using near-infrared spectroscopy. ...
... Full spectra presented characteristic peaks. In Fig. 2a, MIR spectrum of lyophilized passion fruit pulp showed characteristic absorption zones (Bureau et al., 2012). Absorption zone in 1500-900 cm −1 corresponds to the major components, particularly sugars and organic acids (Bureau et al., 2009;Ruiz, Reich, Bureau, Renard, & Audergon, 2008). ...
... The homogenates were centrifuged at 9000g for 10 min at 4°C. The supernatant was collected to analyse sugars by the colorimetric enzymatic method as described in Bureau et al. (2012). ...
... Polyphenols were quantified by HPLC after thioacidolysis as described by Bureau et al. (2012). The average degree of polymerisation (DP n ) was calculated as the molar ratio of all of the flavan-3-ol units (thioether adduct plus terminal unit) to (À)-epicatechin and (+)-catechin corresponding to the terminal units. ...
Raw, heated and frozen-thawed apple parenchyma of the 'Golden Delicious' and 'Granny Smith' varieties were subjected to leaching and phenolic compounds were analysed by high performance liquid chromatography (HPLC). Fick's second law was applied for the determination of the apparent diffusivity (De) of individual polyphenols. Further information was obtained histochemically by means of toluidine blue O staining and image analysis. No difference in phenolic quantification existed between the biochemical and histochemical approaches. The histochemical analysis revealed cell structure changes and the interaction of procyanidins with the cell wall during the leaching process. The De values of the total polyphenols were 0.30 and 0.26 × 10-9 m2 s-1 for the 'Golden Delicious' and 'Granny Smith' raw apple matrix, respectively. The De values (and leaching yields) increased after treatments that degraded the plant tissue matrix. After freeze-thaw, the De values became 0.39 and 0.40 × 10-9 m2 s-1, while after heating they were 0.92 and 0.38 × 10-9 m2 s-1. There was also an influence of the phenolic compound nature.
... Pedro and Ferreira (2007) applied the same methodology (NIR) to predict sugar content and acidity in tomato products. Bureau et al. (2009), Bureau, Scibisz, Bourvellec, andRenard (2012) used the MIR spectroscopy to determine sugar, organic acid and polyphenol contents in apricot and apples. Changes in carotenoid contents in maize were verified by Brenna and Berardo (2004) using near-infrared spectroscopy. ...
... Full spectra presented characteristic peaks. In Fig. 2a, MIR spectrum of lyophilized passion fruit pulp showed characteristic absorption zones (Bureau et al., 2012). Absorption zone in 1500-900 cm −1 corresponds to the major components, particularly sugars and organic acids (Bureau et al., 2009;Ruiz, Reich, Bureau, Renard, & Audergon, 2008). ...
In this work, NIR and MIR spectroscopy was investigated and compared for predicting passion fruit ripening parameters as sugars, organic acids and carotenoids. Spectra of 56 samples of the lyophilized passion fruit were collected using an integrating sphere in NIR range and attenuated total reflectance accessory in MIR range. Individual sugars (sucrose, glucose and fructose), organic acids (malic and citric acids) and carotenoids (beta-carotene) contents were determined by reference methods. Spectral and reference data were analyzed by principal component analysis. Partial least square regression (PLSR) was used to establish calibration models. MIR technique was better than the NIR technique for glucose (R-v(2) = 0.942), fructose (R-v(2) = 0.855), sucrose (R-v(2) = 0.818), total sugar (R-v(2), = 0.914) and citric acid (R-v(2) = 0.913) content determination. On the other hand, NIR was superior for total acids (R-v(2) = 0.903) content determination. For malic acid and beta-carotene contents both methods were unsatisfactory due to low concentrations of these constituents in the passion fruits. (C) 2013 Published by Elsevier Ltd.
... The content of citric acid was also significantly higher in 'Baya Marisa' (0.898 g/kg FW) compared to 'Golden Delicious' (0.570 g/kg FW). The results of Bureau et al. [22], who measured the organic acids in different apple cultivars ('Golden Delicious', 'Fuji', 'Gala', 'Granny Smith', 'Canada', 'Chantecler', and 'Pink Lady') with different techniques of sample preparation, show that the content of organic acids ranges from 2800 to 7300 mg/kg FW for malic acid and from 0.0 to 180.0 mg/kg FW for citric acid. The results of Bars-Cortina et al. [13] showed a higher content of malic acid in red-fleshed apple cultivars compared to white-fleshed cultivars, with the exception of 'Granny Smith', which had a similar malic acid content compared to red-fleshed apple cultivars. ...
We analyzed the red-fleshed apple cultivar ‘Baya Marisa’ and compared it with the traditional, white-fleshed apple cultivar ‘Golden Delicious’. The objective of this study was to compare sugars, organic acids, and phenolic compounds of ‘Baya Marisa’ with the widely known and consumed white-fleshed apple cultivar ‘Golden Delicious’. In addition, flesh firmness, color, and soluble solid content was studied. A total of 46 phenolic compounds were quantified and identified, some for the first time in apples. The study showed that the total analyzed phenolic content (TAPC) was 1.6× higher in the skin of red-fleshed ‘Baya Marisa’ and 1.4× higher in the flesh of red-fleshed ‘Baya Marisa’. Organic acid (citric acid, malic acid, and ascorbic acid) content was higher in the red-fleshed cultivar ‘Baya Marisa’, whereas sugar content (sucrose, glucose, and sorbitol) was similar, except for fructose, which was 1.1× higher in ‘Golden Delicious’. The content of citric acid was 1.6× higher in ‘Baya Marisa’, whereas the content of malic acid was 1.2× higher in ‘Baya Marisa’ and the content of ascorbic acid was 2.8× higher in ‘Baya Marisa’. Among phenolics, total dihydrochalcones in the skin were 3.3× higher in ‘Baya Marisa’ and similar in the flesh compared to ‘Golden Delicious’. Flavonols were 1.4× higher in the skin of ‘Baya Marisa’ and 2.8× higher in the flesh of ‘Golden Delicious’. Anthocyanins were not identified in the white-fleshed cultivar ‘Golden Delicious’. Total hydroxycinnamic acids were 2.0× higher in the skin of ‘Golden Delicious’ and similar in the flesh compared to ‘Baya Marisa’. Total flavanols were 1.8× higher in the skin and 2.2× higher in the flesh of the white-fleshed cultivar ‘Golden Delicious’.
... Then, they are submitted to freeze-dry (or another equivalent technique). [58] Usually, for being straightforward and a common technique adopted, lyophilization can be chosen to remove water from the samples. [59,60] However, the longer time required in this procedure (generally between 12 and 72 hours) implies higher energy consumption in comparison to other drying techniques-plus the cost of the equipment, which makes this process not always feasible, especially for industrial applications. ...
Citrus fruits (CF) are highly consumed worldwide, fresh, processed, or prepared as juices and pies. To illustrate the high economic importance of CF, the global production of these commodities in 2021 was around 98 million tons. CF's composition is considered an excellent source of phenolic compounds (PC) as they have a large amount and variety. Since ancient times, PC has been highlighted to promote several benefits related to oxidative stress disorders, such as chronic diseases and cancer. Recent studies suggest that consuming citrus fruits can prevent some of these diseases. However, due to the complexity of citrus matrices, extracting compounds of interest from these types of samples, and identifying and quantifying them effectively, is not a simple task. In this context, several extractive and analytical proposals have been used. This review discusses current research involving CF, focusing mainly on PC extraction and analysis methods, regarding advantages and disadvantages from the perspective of Green Chemistry.
... As expected, there was a large variability in sugars and organic acids content among the 155 accessions. Values for the different traits varied significantly among accessions and years, as reported in previous studies [14,19,[57][58][59]. Since the only source of variability between years was the climatic characteristics during the growing season, these results highlight that both accession and inter-annual climate variability have a relevant role in the assessed traits. ...
Apple is widely cultivated in temperate regions. The beneficial properties of apple for preventing several illnesses are widely known. Nevertheless, qualitative variables such as sweetness or sourness may influence consumer satisfaction; they are critical factors for fruit consumption and essential in plant breeding. In the present work, 155 apple accessions were assessed during five consecutive years (2014–2018). Four individual sugars and seven organic acids were analysed by HPLC. A mixed-effects model was fitted with accessions and the years’ climatic features as independent variables. A cluster analysis was applied on the mixed-effects model coefficients. Four groups were considered as optimum. Genetics seemed to have the strongest effect and showed clear differences between accession groups, while climate effects were strong only for certain compounds and had a more horizontal behaviour equally affecting the different accession groups. In fact, non-Spanish cultivars tended to concentrate, while autochthone accessions had a much wider spread. Individual sugars and acids concentrations correlated negatively with precipitation and positively with temperature range and solar radiation in all accession groups. The geographic region where the orchard is grown is thus very important in the resulting metabolites profiles. Moreover, apple genetics would also play a decisive role as highlighted in the cluster analysis.
... The above wavebands included typical absorption bands for some chemical groups; for example, (Rodriguez-Saona et al., 2001). Additionally, Bureau et al. (2012) showed that different sample preparation conditions did not affect sugar concentrations. Moreover, midinfrared spectra showed excellent ability to predict sugar contents. ...
Peaches (Prunus persica L. Batsch) are commonly consumed fruits with high nutritional value. We evaluated the nutritive qualities of peach fruit during storage. Heatmap analysis showed that protein, ash, and crude fiber contents clustered together, whereas fat and reducing sugars clustered separately. We then classified the nutrients into two clusters; cluster 1 showed low fat and reducing sugar levels and high protein, crude fiber, and ash levels, whereas cluster 2 showed high fat and reducing sugar levels and low protein, cruder fiber, and ash levels. Partial least squares regression and random forest analyses showed accuracies of 67% and 61%, respectively. Spectra at 1,439 and 1,440 nm indicated reducing sugars, and the spectrum at 2,172 nm indicated protein. Thus, Fourier transform-near infrared spectroscopy could predict the two clusters based on five nutritive qualities. Our findings may help to establish guidelines for promoting the acceptability of peach fruits among consumers.
... Direct MIR characterizations of raw and processed fruits have shown considerable aptitudes to evaluate soluble solids content (SSC), dry matter content (DMC), titratable acidity (TA), some individual sugars, organic acids, rheological (viscosity and viscoelasticity) and structural (particle averaged size and volume) properties (Ayvaz, Sierra-Cadavid, Aykas, Mulqueeney, Sullivan, & Rodriguez-Saona, 2016;. These studied parameters are related to the taste (SSC, DMC, TA, malic acid), the texture (viscosity, viscoelasticity, particles and cell wall contents) and the basic nutrients (fructose, sucrose and glucose) impacting in a large amount puree quality (Bureau, Ś cibisz, Le Bourvellec, & Renard, 2012;Espinosa-Muñoz, Renard, Symoneaux, Biau, & Cuvelier, 2013;Fügel, Carle, & Schieber, 2005). ...
The potential of MIRS was investigated to: i) differentiate cooked purees issued from different apples and process conditions, and ii) predict the puree quality characteristics from the spectra of homogenized raw apples. Partial least squares (PLS) regression was tested both, on the real spectra of cooked purees and their reconstructed spectra calculated from the spectra of homogenized raw apples by direct standardization. The cooked purees were well-classified according to apple thinning practices and cold storage durations, and to different heating and grinding conditions. PLS models using the spectra of homogenized raw apples can anticipate the titratable acidity (the residual predictive deviation (RPD) = 2.9), soluble solid content (RPD = 2.8), particle averaged size (RPD = 2.6) and viscosity (RPD ≥ 2.5) of cooked purees. MIR technique can provide sustainable evaluations of puree quality, and even forecast texture and taste of purees based on the prior information of raw materials.
... All cell wall polysaccharide samples, in the form of dry powder, were stored in P 2 O 5 atmosphere before analysis to remove residual water. ATR-FTIR spectra data (4000 to 600 cm − 1 ) were acquired at room temperature in a Tensor 27 FTIR spectrometer (Bruker Optics®, Wissembourg, France), using a single-reflectance horizontal ATR cell (Golden Gate with a diamond crystal, Bruker Optics®) equipped with a system to press the dried homogenized samples on the crystal surface (Bureau, Ś cibisz, Le Bourvellec, & Renard, 2012). Each sample was analyzed three times (using after homogenization three different aliquots of the powders) to consider its heterogeneity, and each spectrum was the average of 16 scans. ...
The contribution of ATR-FTIR spectroscopy to study cell wall polysaccharides (CWPs) was carefully investigated. The region 1800-800 cm⁻¹ was exploited using principal component analysis and hierarchical clustering on a large range of different powders of CWPs based on their precise chemical characterization. Relevant wavenumbers were highlighted for each CWP: 1035 cm⁻¹ was attributed to xylose-containing hemicelluloses, 1065 and 807 cm⁻¹ to mannose-containing hemicelluloses, 988 cm⁻¹ to cellulose, 1740 and 1600 cm⁻¹ to homogalacturonans according to the degree of methylation. Some band positions were affected by macromolecular arrangements (especially hemicellulose-cellulose interactions). However, as arabinan and galactan did not reveal distinctive absorption bands, ATR-FTIR spectroscopy did not allow the discrimination of cell walls differing by the abundance of these polysaccharides, e.g., those extracted from apple and beet. Therefore, the application of ATR-FTIR could remain sometimes limited due to the complexity of overlapping spectra bands and vibrational coupling from the large diversity of CWP chemical bonds.
... The cylinders were put immediately in liquid nitrogen prior to storage at − 20 • C, giving 35-36 cylinders per apple, following the previous works of Mo et al. (2017) and Bureau et al. (2012). These cylinders were distributed with a systematic repartition for each apple from the top to the bottom and from the sunny to the shady faces. ...
The heterogeneity of apple fruit was highlighted by near-infrared hyperspectral imaging (NIR-HSI) using a data analysis in two successive steps. First, NIR-HSI images were acquired on the cut surface of six transverse slices per apple, which were then systematically sampled with 5 or 6 cylinders per slice. PCA carried out on the NIR-HSI images allowed to select 141 representative cylinders from the total dataset (1056 samples), in which the contents of dry matter (DMC), total sugars (TSC), fructose, glucose, sucrose, malic acid and polyphenols were quantified by spectrophotometry and chromatography. In a second step, leave-one-out PLS models were developed and successfully used to describe the distribution of DMC (R cv 2 = 0.83, RPD = 2.39) and TSC (R cv 2 = 0.81, RPD = 2.20) in each apple slice. A strong heterogeneity of DMC and TSC was detected inside each fruit. Such a simple and rapid method reduced the needs of numerous chemical characterizations to demonstrate the distribution of quality traits within and between fruit and contributed to better manage the fruit quality measurements.
... Native 178 cell walls and modified cell walls were stored in P 2 O 5 atmosphere before analysis to 179 remove residual water. ATR-FTIR spectra were acquired at room temperature on 180 sample powder using a single-reflectance horizontal ATR cell (Golden Gate equipped 181 with a diamond crystal, Bruker Optics) as described by Bureau et al. (2012), by 182 scanning from 4000 to 600 cm -1 and correcting against the background spectrum of air. ...
Cell wall (CW) degradation causes texture loss of plant-based products after processing. However, these losses differ in intensity, which could be due to cell wall structure or plant tissue internal pH conditions. To distinguish these two factors, CWs isolated from apple, beet and kiwifruit were subjected to boiling at pH 2.0, 3.5 and 6.0. Pectin depolymerization was the least pronounced at pH 3.5, while galacturonic acid contents of all CWs decreased at pH 6.0 due to the β-elimination. Pectins were solubilized, and their size decreased with increased pH during CW treatment. At pH 6.0, degrees of methylation decreased mostly in apple and beet CWs while galactose decreased more in kiwifruit CW. At pH 2.0, arabinan was lost in apple and beet CW due to acid hydrolysis. Apple CW was the most susceptible to degradation either at pH 2.0 or 6.0, while beet CW was more degraded at pH 2.0. In contrast, kiwifruit CW was the least susceptible to degradation whichever the pH. Acid hydrolysis and β-elimination appeared to be common mechanisms that cause loss of neutral sugars, often from pectin side chains, and galacturonic acid, respectively, but their effects were of different intensities. This work has a guiding significance for improving texture in the thermally canning process.
... MIR spectra of the soil-bound EPS were collected on freeze-dried aliquots of EPS extracts with a Tensor 27 FTIR spectrometer (Bruker Optics, Wissembourg, France) equipped with a single-reflectance horizontal ATR cell (Golden Gate equipped with a one internal reflection diamond crystal, Bruker Optics). The freeze-dried homogenized samples of soil extracts were placed at the surface of the diamond crystal and were pressed with a system press tip flap (Bureau et al., 2012). The samples were scanned between 4000 and 600 cm-1 and each spectrum was obtained by averaging 16 successive scans to have a good ratio of signal to noise. ...
Quantifying and characterizing Extracellular Polymeric Substances (EPS) and especially exopolysaccharides (EPSac) is an issue for understanding the hydro-physical and biological functioning of the rhizosphere. However, few comparative studies of extraction techniques have been carried out on soils and none on calcareous Mediterranean soils. Three soil-bound EPS extraction techniques, i.e. Cation Exchange Resin (CER), EDTA and NaOH + Formaldhyde (NaOH + F) were compared on three contrasted Mediterranean soils. CER presented the lowest extraction efficiency of EPSac, but also the lowest contamination of EPS by extractants and extracellular compounds. Contamination with intracellular compounds was low and similar with the three methods. Mid-Infrared (MIR) spectra enabled the best discrimination of the EPS extracts when they were prepared with CER. CER is then identified to be the suitable extraction technique of EPS (including EPSac) from soils, including calcareous soils. This technique was applied on rhizospheric and bulk soils harvested in an experimental field of tomato cultivation. A rhizospheric effect was highlighted during the growth of plants of two cultivars with both the soil-bound EPSac amounts (total sugar equivalent of extracted EPS) and the MIR spectra of extracted EPS. Extraction of soil-bound EPS and their further analysis by spectral and chemometric approaches is a promising way for relating EPS chemical characteristics to their biological and hydric impacts within the plant rhizosphere in a context of agro-ecological transition and climatic change.
... Vitamin C content varies from 2 to 25 mg per 100 g, depending on the variety, and the levels of this vitamin are four to six times higher in the peel than in the flesh. Many polyphenols have been detected in apple fruits: phenolic acids, mostly in the form of chlorogenic acid, coumaroylquinic and cafeoylquinic acids, flavanols such as catechins, epicatechins and B1, B2, B3, B5 and C1 procyanidins, flavonols such as quercetin, quercetin-3-rhamnoside, quercitrin, hyperin, isoquercitrin, reynoutrin, avicularin and rutin, dihydrochalcones such as phloretin, phlorizin, phloretin-2 ′ -O-xyloglucoside, anthocyanins such as cyanidin and ideain, and coumarins (Awad et al. 2000;Bureau et al. 2012;Colin-Henrion 2008;Massiot et al. 1994;Travers 2002;Veberic et al. 2005;Verdu 2013;Wu et al. 2007). Most (65%) of the polyphenols present are located in the fleshy receptacle, 24% in the epidermis, 10% in the lignified endocarp (core), and 1% in the seeds (Guyot et al. 1998). ...
Pesticides have been widely used since the middle of the twentieth century to protect crops and ensure productivity and safety foods. Herbicides and non‐herbicides, known as insecticides and fungicides are the main categories of used pesticides. In the north hemisphere countries, many fungicides are sprayed, particularly on apple orchards. If most wild apples of Malus sieversii from primeval forests in Tian Shan, China have become scab‐resistant through millions of years, this is not the case of domestic harvested apples from Malus domestica. Apple is the third consumed fruit worldwide. The global culture represents some 71 million tonnes. It was thus interesting to focus on this particular fruit, synonym of the social advancement of middle classes all around the world, and of the development of China. European and American studies pointed out that income, the level of education and the socio‐economic status are determining factors for apple consumption. All middle classes live in the same way, and use the same cultural and food products, claiming their belonging to a way of life different from struggling people. Emerging countries such as Vietnam, Thailand, and Bangladesh, have become important importers. Apple is considered as the perfect healthy fruit, that is worth consuming. In apple, more than 90% of the pesticides sprayed on the surface are located in the epidermis, particularly in the cuticle, a lipidic extracellular biopolymer, that acts as the outermost protective barrier on the surface of the fruit. The chemical composition and the structure of the cuticle are ones of the most important and complex parameters that handle the membrane transport of abiotic molecules such as pesticides. Because the cuticle is biosynthesized, the composition and structure depend mostly on the plant species and varieties, on the different biological development steps, and on diverse abiotic factors including climatic harvesting conditions, or storage conditions. Pesticide formulations contain one or more active molecules and additives whose aim is to promote their penetration and transport through the cuticle. Different chemical groups are responsible for the pesticide activity, and others provide the penetration into the plant target. The physico‐chemical properties of the plant components, active molecules and pesticide formulations, such as amorphous to crystalline ratio of the cuticular waxes, lipophilicity, molecular size, nature of substituents, plasticizers, etc. are key factors to comprehend the location and the transport through the cuticle. Pesticides dissolve and diffuse in a chemically and structurally heterogenous cuticle. As a result, chemical interactions between active molecules and components of the plant cuticle are complex, and as numerous and various as the multiplicity of active molecules, their decay products and plant matrix components.
... First, nondestructive measurements (NIR, color, ethylene releasing rate, fruit weight), and then texture tests (puncture mean load and puncture linear distance) were performed on each apple. After that, each apple was cored and divided as described by Bureau et al. (Bureau, Scibisz, Le Bourvellec, & Renard, 2012) in order to create, for each replicate of ten apples, three batches of 40 pieces representative of each apple. The pieces were immediately put in liquid nitrogen to avoid any oxidization. ...
... Acetic acid and lactic acid were the dominant organic acids in vinegars, which mainly generated during the stage of acetic acid fermentation and alcohol fermentation, respectively (Nie, Huang, et al. 2013;Nie, Zheng et al., 2013;Nie et al., 2017;Xu, Huang, et al., 2011;Xu, Xu, et al., 2011). In addition, fruits contain organic acids such as malic acid, citric acid, artaric acid, lactic acid and succinic acid, which provide the source of organic acids in fruit vinegars (Bureau, Scibisz, Le Bourvellec, & Renard, 2012;Soyer, Koca, & Karadeniz, 2003). The organic acids in the different types of vinegars are shown in Table 4. ...
Vinegar has been widely used as acidic condiment worldwide for thousands of years. Vinegar contains various nutrients and bioactive components, which are brewed by liquid-state and solid-state fermentation techniques. This review highlights the nutrients and bioactive components in different types of vinegars and their functional properties. Nutrients in vinegar include amino acids, sugars, vitamins, and minerals. The functions of these nutrients were providence energy, regulation of cell metabolism regulation, immunoregulation, antioxidation, anticoagulation and improvement of brain development. In addition, the bioactive components in vinegar include organic acids, polyphenols, melanoidins, and tetramethylpyrazine, which have the functions of antioxidative activity, regulation of lipid metabolism, liver protection, blood pressure and glucose control, anti-fatigue and anti-tumor. However, further studies are needed to explore the novel functional compounds in vinegars and their molecular mechanisms on health benefits in future.
... Alongside with the aforementioned and discussed spectra of the standard solutions of sugars, the FT-MIR spectra (650-4000 cm −1 ) of fruit juices obtained from the "Stanley", "Vânăt de Italia", Alongside with the aforementioned and discussed spectra of the standard solutions of sugars, the FT-MIR spectra (650-4000 cm −1 ) of fruit juices obtained from the "Stanley", "Vânăt de Italia", and "Tuleu Gras" varieties which were harvested throughout their growth and development, show three areas of relevant importance: 2800-3700 cm −1 , 1500-1800 cm −1ş i 900-1500 cm −1 . According to already published data [37], water molecules are assigned to the first two areas, the studied plum juice having a high level of water content. The characteristic feature for sugars is the area between 900-1500 cm −1 , showing their accumulation during the plum fruit growth and development. ...
Individual sugars were analyzed by High Performance Liquid Chromatography (HPLC) in plum juice samples obtained from “Stanley”, “Vânăt de Italia”, and “Tuleu Gras”. The samples were harvested from the inside and periphery of the crown during six development phases. The aim of the present study was to determine the individual sugars in plum juice by the HPLC and Fourier transform mid-infrared spectroscopy (FT-MIR) methods and to validate them. Our findings were as follows: levels between 0.26–3.73% for fructose, 1.43–1.10% for glucose, and 0.01–10.19% for sucrose. The FT-MIR analyses confirmed the differences between the juice samples, mainly in the spectral region characteristic to sugars which ranged from 900 to 1500 cm−1. FT-MIR coupled with Partial least squares (PLS) was used to develop calibration models for estimating individual plum juice sugars, the predictive characteristics being assessed. The optimal regions and spectral pretreatments were 800–1600 cm−1 and Savitzky Golay first derivative (d1) for fructose, 800–1600 cm−1 for glucose, and 915–1145 cm−1 and second derivative (d2) for sucrose. The selection of optimal spectral zones and pre-treatments led to PLS calibration models with acceptable predictive abilities for glucose, very good for sucrose, and less satisfactory for fructose. Moreover, the FT-MIR results were compared to the HPLC results in external validation tests and reference values included.
... Regarding physicochemical quality attributes, apples treated at 0.01 kJ kg −1 had higher TA but similar pH than the untreated ones, showing that even if concentration in dissociated protons did not change, there was an accumulation of undissociated acids (Lobit, Soing, Génard, & Habib, 2002). This fact, together with increased SSC at 24 h after treatment, suggested that very low specific energy PEF treatment stimulated an accumulation of organic acids and sugars in apple (Bureau, Ścibisz, Le Bourvellec, & Renard, 2012), which was more important at 24 h after treatment. In this sense, it is known that some organic acids and sugars, among other molecules, are involved in abiotic stress response in plants (Shulaev, Cortes, Miller, & Mittler, 2008). ...
Pulsed electric fields (PEF) have arisen as a promising tool for enhancing plant-based food bioactive compounds, although side effects on quality attributes might compromise consumer acceptance. This work was aimed at filling the gap in the understanding of whole effects of PEF on apple phenolic compounds profile and quality parameters. Treatment specific energy was a critical factor affecting phenolic profile and quality attributes, which in turn varied from 0 to 24 h after treatment. Treatments at 1.8 and 7.3 kJ kg⁻¹ (140 and 260 μs total treatment times, respectively) induced important quality changes, mainly discoloration and firmness loss, while overall phenolic contents decreased, except those of flavonols. However, 24 h after treatment at 0.01 kJ kg⁻¹ (20 μs total treatment time), the main apple phenolic compounds as determined by HPLC-DAD-MS had enhanced contents (28% 5-caffeoylquinic acid; 35% procyanidin B2). Accordingly, total phenolics and total flavan-3-ols contents increased (26% and 35%, respectively), while physicochemical quality attributes were not affected. Therefore, 0.01 kJ kg⁻¹ PEF treatment is proposed for obtaining apples with optimal quality and enhanced functional value.
... As previously observed (Miaw et al., 2018), the intense band near 3300 cm −1 and the sharp peak at 1640 cm −1 present in all samples are related to the OeH absorption of water ( He et al., 2007;Shen et al., 2016). The region between 1700 and 1000 cm −1 incorporates the typical bands for phenolic compounds, such as the C]CeC aromatic ring stretching, the phenol OH bending, the aromatic CeH in-plane bending, and the CeO stretching of phenol (Bureau, Ścibisz, Le Bourvellec, & Renard, 2012). Additionally, in this region, sugars and organic acids are present showing the characteristic bands (between 1500 and 950 cm −1 ) ( Shah et al., 2010;Shen et al., 2016). ...
... This is because bulk pressed juice is frequently used as the medium to characterise progeny, and attenuated total reflectance (ATR) FT-MIR is ideally suited to the analysis of fluids, even down to the smallest of volumes (~30 μL) obtained from single berries, if so desired. Applications involving use of FTIR spectroscopy for analysis of fruit composition include apple, apricot, citrus, peach and tomato (Beullens et al. 2006;Bureau et al. 2009bBureau et al. , 2012Bureau et al. , 2013Clark 2016;Irudayaraj and Tewari 2003). ...
Introduction of Fourier-transform infrared (FTIR) spectroscopy would enable breeders to screen phenotypic variability in multiple fruit from large numbers of progeny. Thus far, however, there has been no comprehensive attempt to develop chemometric models for determination of quality attributes of small berry species by this approach. FTIR spectra (1800–900 cm⁻¹) of juice from breeding populations of four genera (Actinidia, specifically red kiwifruit, Ribes, Rubus and Vaccinium) were analysed by partial least squares regression to determine the possibility of measuring soluble solids (SS), titratable acidity (TA) and total anthocyanin (ACY) concentration simultaneously using global prediction models. SS, TA and ACY concentrations across all berry juices ranged between 4.1 and 22.4 °Brix, 0.1–5.5% citric acid and 2–4697 ppm, respectively. R² (coefficient of determination in cross-validation) and SECV (standard error of cross-validation) statistics for global models were 0.996 (0.22 °Brix), 0.996 (0.08% citric acid) and 0.893 (280 ppm). Analysis of data sets for individual berry types separately demonstrated that it was possible to develop models with superior prediction statistics for each attribute. However, these were not necessarily robust when validated against data from different seasons, locations or breeding selections. These global models represent an advance for researchers wishing to screen substantial fruit populations more rapidly.
... This spectral sensor is known as robust, accurate, precise and reliable for field practical used and application in agriculture [3]. The application of this technology has been largely studied in many agricultural products such as: kiwifruit [4], apple [5], banana [6], peach fruit [7], strawberry [8], grapes [9], and mango [10]. Technically, NIRS uses electromagnetic spectrum from 350 to 2500 nm, which can be divided into Visible (350-750 nm), NIR (751-1000 nm), Short Wave Infra Red (SWIR) 1 (1001-1250 nm), SWIR 2 (1251-1750 nm), and SWIR 3 (1751-2500 nm). ...
Recently, the use of Near Infrared (NIR) spectral sensor in agricultural process is getting much attention, particularly for fruit quality evaluation. The sensor requires a spectrometer to produce some sufficient information called spectrum as interaction between physical matters of the sample with the electromagnetic spectrum. In fact, the presence of experimental error or/and measurement error due to the heterogeneous particle size, moisture content variability, sample density, the instrument noise and pretreatment experience are often cannot be avoided. These would damage the spectra collected which results to decrease the performance in model selection, and increases the prediction error as the harmful influence of possible outlier and leverage points in dataset. To encounter these, a robust pretreatment of NIR spectral data is needed to correct the spectra before it is used for post-processing using any statistical method. In this paper, several different classical pretreatment methods were evaluated and a new robust Generalized Multiplicative Scatter Correction (GMSC) algorithm was proposed to correct the additive and/or multiplicative baseline effects in the spectral data. A dataset of NIR spectral on oil palm (Elaeis guineensis Jacq.) fruit bunch was used in the simulation. In the simulation, a number of repetitions using the single and double cross validation with robust partial least square are also applied. The Desirability Indices as statistical measures are presented for evaluating the methods.
... Up-to-date research on the use of NIRS on apples has mainly focused on determining the soluble solids content, firmness and acidity (McGlone et al., 2002;Mehinagic et al., 2003;Park et al., 2003;Peirs et al., 2003;Sanchez et al., 2003;Zude et al., 2006;Paz et al., 2009;Bobelyn et al., 2010). Recently, the possibility of using mid-infrared spectroscopy for the determination of sugars, acids and polyphenols contents has been evaluated and a Vis-NIR portable system has been tested for the determination of apples' nutraceutic properties (Bureau et al., 2012;Beghi et al., 2013). ...
Description of the subject. The article deals with the use of near-infrared spectroscopy (NIR) on fresh apples to determine the phenolic compounds and dry matter content in peel and flesh powders. Objectives. The aim is the rapid and non-destructive determination of these nutritional parameters. Method. Two hundred twenty-nine fruits from 20 varieties were analyzed with NIR spectroscopy and reference methods. Results. Great variability of total phenolic compounds (TPC) in peel and flesh powders was observed among varieties. The dry matter (DM) content also differed greatly between peel and flesh. Calibration and validation models showed high coefficients of determination for the TPC content, which were slightly higher for the peel than for the flesh (R² val = 0.91 and 0.84 respectively). For the DM content, high coefficients of determination and ratios of prediction to deviation (RPDs) were also observed (R² val = 0.94, RPD = 4.8 and R² val = 0.94, RPD = 4.9 for the peel and flesh respectively). Conclusions. Calibration and validation models allow quantitative predictions to be made for TPC and DM content. They confirm the potential of NIRS for predicting the polyphenol content and highlight its potential for determining the DM content, a parameter often neglected in research into apple quality. © 2018, FAC UNIV SCIENCES AGRONOMIQUES GEMBLOUX. All rights reserved.
... Mid infrared spectroscopy is a simple, rapid and non destructive method used to characterize macromolecules as cell wall polysaccharides ( Brahem et al., 2017a;Coimbra et al., 1999;Ferreira et al., 2001;Kačuráková et al., 2000;Kačuráková & Wilson, 2001;Szymanska-Chargot et al., 2015) and polyphenols ( Bureau et al., 2012;Edelmann et al., 2001;Fragoso et al., 2011). In this study, MIR combined to multivariate data analysis was applied to evaluate if a non-destructive method is able to discriminate the samples composed of cell wall of different tissues and two maturity stages in presence or not of procyanidins. ...
In order to study overripening impact on cell wall–procyanidin interactions, perry pear cell walls and procyanidins were isolated and characterized at ripe and overripe stage. Their associations were quantified using Langmuir isotherms and isothermal titration calorimetry.Perry pears were rich in procyanidins with high degree of polymerization and their constitutive units were mainly (-)-epicatechin. Cell walls isolated from the whole flesh and parenchyma cells were characterized by extremely methylated pectin and highly branched rhamnogalacturonans whereas cell walls from stone cells and skin were more lignified and rich in hemicelluloses.Overripening did not modify procyanidin structure and molar mass distribution, but the distribution of the procyanidin-containg aggregates in the vacuoles was modified, from dispersed in ripe pears to close to the tonoplast in overripe pears. Between the ripe and overripe stage, pear cell walls lost pectic side chains, arabinans and galactan, mostly from cell walls isolated from parenchyma cells and the whole flesh.The affinity between procyanidins and cell walls decreased as follows: parenchyma cells > flesh > stone cells > skin as reported by Langmuir isotherms. The amount of bound procyanidins increased at the overripe stage notably for the cell walls from stone cells and whole flesh. Isothermal titration calorimetry indicated that overripening induced the modification of cell wall binding mechanism especially for parenchyma cells where interactions were driven by hydrophobic interactions.The increase of procyanidin binding capacity at the overripe stage was confirmed by juice pressing where overripe pear juices were poorer in procyanidins than ripe pear juices whereas fruit procyanidin contents did not change with overripening.
... NIR has been used to quantify pectins and their constituents in Japanese pear [25] as well as firmness in mangoes [26]. MIR spectroscopy has been applied to determine sugar, organic acid, and polyphenol contents in apricot and apples [27,28]. NIR radiation has penetrates more than MIR and has been more suitable for analyses of both the bulk and intact samples [29]. ...
Orange firmness, peel thickness, and total pectin content are associated with fruit quality and denote important parameters for the food industry. These attributes are usually determined through destructive methods that can be time-consuming and also unable to monitor fruit quality over time. Therefore, non-invasive methods such time-domain nuclear magnetic resonance (TD-NMR), near-infrared (NIR), and mid-infrared (MIR) spectroscopies may represent efficient alternatives to evaluate these quality attributes. In this work, partial least square regression (PLSR) models of TD-NMR relaxometry as well as NIR and MIR spectroscopic data were used to predict firmness, peel thickness, and total pectin content of fresh Valencia oranges. Principal component analyses (PCA) were applied to explain the correlations of orange ripening stage, flowering, and crop season with its physicochemical parameters. Data obtained through standard destructive methods were used to calibrate and validate the PLSR models. NIR and MIR showed the best PLSR models for orange firmness, with Pearson correlation coefficients (r) of 0.92 and 0.84 and squared errors of prediction (SEP) equal to 6.22 and 9.05 N, respectively. Orange peel thickness PLSR model was validated only by TD-NMR (r = 0.72; SEP = 0.49 mm). TD-NMR and NIR also presented potential to predict total pectin orange in orange (r = 0.76 and 0.70; SEP = 5.76% and 5.04%, respectively). Therefore, NIR presented a higher potential to predict orange firmness than MIR and TD-NMR. On the other hand, TD-NMR showed a higher prediction power concerning peel thickness than NIR and MIR. Both NIR and TD-NMR methods showed similar prediction powers for total pectin content.
A combination of FTIR- and NMR-based metabolomics approaches coupled to multivariate data analysis techniques was used for the first time to characterize and explore the metabolic changes along the ripening of two Spanish melon landraces (Jimbee N and Jimbee XL). Furthermore, the fatty acids profile and the antioxidant capacity were investigated by GC-FID and ORAC method, respectively. Despite FTIR was able to identify changes in the sugars content between fruits of different maturity stages, it failed to discriminate between both varieties, being exceeded by NMR in both situations. Increased fruit maturation led to an increase of sucrose, fatty acids and β-carotene, accompanied by a decrease of glucose, fructose, citrate, amino acids, and polyphenols (which were positively correlated with fruits antioxidant activity).
Samples of raspberry, mint, rape, sunflower, thyme, acacia and tilia honey were subjected to authentication using destructive (melissopalinological analysis and physicochemical parameters determination) and non-destructive (Fourier transform infrared spectroscopy – FTIR) methods. The melissopalinological analysis confirmed that all types of honey samples were authentic monofloral honey. To correlate the FTIR spectral information with the physicochemical parameters and therefore assess the usefulness of FTIR in the analysis of honey quality and authenticity, the spectral information was coupled with principal component analysis (PCA), linear discriminant analysis (LDA) and partial least square regression (PLS-R). PCA showed a clear separation can be observed for 5 groups of honey, namely: mint, rape, acacia, tilia and sunflower honeys, while thyme and raspberry honeys are mixing some samples. Moreover, the PLS-R model was found successful in predicting the physicochemical parameters of honey based on FTIR spectra. These results show that FTIR spectroscopy can be simultaneously used to confirm the authenticity of honey and also its quality and freshness.
The aim of this study was to identify optimal storage conditions able to preserving date palm quality and minimising their loss in the supply chain. Hence, the effect of storage at −18, 0, 2 and 4 °C for 3, 6 and 9 months during two harvest seasons (2017 and 2018) on sugars, organic acids, polyphenols and cell wall yields and composition of ‘Deglet Nour’ Tunisian dates, were studied. Mid Infrared Spectroscopy (MIR) as a non-targeted method allowed to highlight a year effect on chemical composition and to discriminate samples stored at 4 and 2 °C regarding to major components (moisture, sugars, organic acids.). Cell wall yields were stable during the time. However, galactose from pectin side chains decreased with time, causing an increase of lignin, cellulosic glucose, fucose and rhamnose. Procyanidins, accounting for 98% of total polyphenols, were not affected by storage. Regarding quality parameters stability, stored fruits at −18 °C could be the solution for a long term storage but due to its high energetic costs, 2 °C must be the optimal temperature with a lower time.
Apple trees (Malus domestica Borkh.) tend to exhibit a biennial cycle: a heavy-flowering year with an excessive amount of low-quality fruits is followed by a year with scarce flowering and low fruit load. Chemical thinning is currently the only viable solution in large commercial operations to ensure adequate yield. However, most thinners are effective only in the first few weeks following bloom and thinning efficiency depends on numerous factors and is difficult to predict. Forecasting the expected fruitlet drop after an initial thinner application would help perform corrections with the subsequent application. In this study, we used in-situ spectroscopy in the visible and near-infrared (Vis-NIR) range to forecast fruitlets drop rate. The study was carried out on “Golden Delicious” apple trees during two growing seasons – in April 2017 and April 2018. As commonly done in commercial orchards, the fruitlet drop was amplified by the application of synthetic auxins 1-naphthaleneacetic acid (NAA) and its amide (NAD). Fruitlets were tagged and monitored in situ every 2–4 days by measuring reflectance over the 400–1000 nm range. Special care was taken to assess sunlight interference during the measurement and correct it using a custom post-processing procedure. Measurements at 4–12 days after NAA/NAD treatment (days after treatment - DAT) were used to forecast fruitlet drop by 20–26 DAT (prediction dates). Principal component analysis (PCA(was carried out, followed by a classification algorithm (linear or quadratic discriminant analysis). Performing measurements on 4 DAT proved too early to predict fruitlet drop with satisfactory reliability (forecast accuracy 65%). Measurements at 6–12 DAT resulted in forecast accuracies of 80–97%, depending on the selected dates. The method offers a non-destructive prediction of apple fruitlet drop rate, which could lead to the development of a low-cost device that could help manage chemical thinning.
In this paper, Pseudomonas aeruginosa MTCC7815, a biosurfactant producing strain was studied for its ability to utilize waste cooking oil (WCO) as a sole carbon source for the production of biosurfactant. Culture conditions were optimized based on surface tension reduction and biomass concentration. The obtained biosurfactant was characterized using 1H NMR, FTIR, LC–MS, and MALDI-TOF techniques. The chemical properties of the produced biosurfactant were estimated by assessing the critical micelle concentration (CMC), emulsification index (E24) and oil displacement test. The optimal culture conditions were found to be similar to the natural domestic sewage such as basic pH value of 10, temperature of 25 °C and a very high WCO concentration of 40 gL−1 (C/N ratio of 40/1). The biosurfactant yield was found to be significant as 11 ± 0.2 gL−1 upon utilizing about 90% of WCO within 5 days of incubation. The biosurfactant produced was found to be a mixture of mono- and di-rhamnolipid in nature and comprised excellent surface active properties i.e. an extremely low CMC of 8.8 ± 0.3 mgL−1, E24 of 62.5 ± 0.3% and surface tension reduction up to 26.2 ± 0.5 mNm−1. These results suggest the suitability of Pseudomonas aeruginosa for the biosurfactant production at commercial scale along with waste remediation in an economic way.
In recent years, decreased cost, miniaturisation and advances in computing power and data processing software have led to widespread introduction of Fourier-transform (FT) spectrometers across different disciplines. In this review, applications of FT mid infrared (FT-MIR) spectroscopy are summarised covering the analysis of fresh fruit and vegetables, and some of their processed products (juices, jam, oil, wine). The paper also outlines basic principles of vibrational spectroscopy in the MIR region, using sugars and acids in fruit juices as exemplars of spectral interpretation. Laboratory-based spectrometers, FT-MIR microspectroscopy for high-resolution mapping and portable, hand-held units for field work are described. Applications involving these systems, which extend to more than 40 genera, and more than 40 different crop attributes, include; assessing the maturity or quality attributes of produce, screening progeny from breeding programmes, determination of bioactive contents and plant metabolites, determining the extent of adulteration and authenticating products for type or geographic location, and localisation of metabolites within plant cells. Principles outlining best-practice for developing calibration models in fruit and vegetable-based systems are also included.
Wild and cultivated Licorice (Glycyrrhiza uralensis FISCH.) are the main source of licorice. In recent years, wild Glycyrrhiza plants have been seriously damaged and this has reduced the population. The cultivation of Licorice has been the best way to solve the problem of its shortage. The contents of glycyrrhizic acid greatly differs in licorices cultivated at different region of China. However, the contents of glycyrrhizic acid in cultivated licorice in china is lower than that of wild licorice. To produce the high quality cultivated licorices, researchers studied the factors affecting the glycyrrhizic acid produced in licorice. It was found that manganese (Mn) application improved the medicinal material yieldand quality especially the contents of the glycyrrhizic acid. In this paper, we investigated the effects of Mn on the accumulation of glycyrrhizic acid in medicinal materials based on the material ingredients distribution and also explored the mechanism. The influence of Mn on the relative contents of glycyrrhizic acid were significant except for day 30 while the influence is significant to the absolute contents all the time. The relative contents of glycyrrhizic acid increased while the contents of crude protein, crude fiber and total material ingredients decreased. The absolute contents of glycyrrhizic acid rose when crude protein contents increased. This implies that the contents of glycyrrhizic acid are in a close relationship with material ingredients. Mn application of appropriate concentration could stimulate the formation of primary metabolites, and then promote the secondary metabolism of G. uralensis which could lead to the formation and accumulation of glycyrrhizic acid in G. uralensis.
Predictive models using attenuated total reflectance/Fourier-transform infrared (ATR-FTIR) spectra of citrus juices have been developed for determination of soluble solids (SSC), titratable acidity (TA) and the Californian–Australian citrus industry BRIMA index. Generic models, developed using partial least squares regression, included fresh juices (n = 326) from grapefruit, lemon, mandarin (plus hybrids tangelo and tangor), oranges and interspecific hybrids. The models cover the ranges 4.0–17.6 °Brix, 0.08%–6.96% TA and −332–212 BRIMA units. Root mean square errors of prediction were 0.18 °Brix, 0.055% TA and 4 BRIMA, respectively. Spectral data acquisition time was 52 s per sample. Further analysis of navel oranges (n = 1470) demonstrated that improved models that analyse juices from single species give better prediction errors (0.12 °Brix, 0.027% TA, 3.1 BRIMA units) than generic models. It is suggested that FTIR analysis is a suitable replacement for manual titration for TA in countries where regulations allow adoption of new technologies, while simultaneously measuring SSC and industry maturity standards.
Agricultural internet of things (Ag-IoT) is the highly integrated and comprehensive application of the new generation of information technology in agricultural field. Ag-IoT is playing an important leading role in the agricultural informationization of China. It has changed the traditional agricultural production mode, and it is also promoting the transformation from the traditional agriculture to intelligent and precision agriculture. The concept of Ag-IoT and its technical system framework were firstly introduced. Then the research status and advances of sensing technologies, communicating technologies and key application technologies used in Ag-IoT were reviewed in detail. The challenges and problems existing in the development of Ag-IoT in China were further analyzed. Based on the analysis, countermeasures for the applications and development of Ag-IoT of China in many aspects were proposed, such as research priorities, development layout, advancing directions, application models and mechanisms for sustainable development.
Chapter 4 offers an extensive description of the citric acid chemistry. It includes presentation of total syntheses of citric acid, preparations of labeled citric acid, typical reactions – neutralization, degradation, oxidation, esterification, formation of anhydrides, amides, citrate-based siderophores and other compounds.
The prediction of internal quality properties, such as sweetness and acidity, in peach fruit by mid-infrared spectroscopy is of interest for rapid determination. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) was tested here on two populations of peach fruits issued from contrasting genitors providing a large phenotypic variability. Over two successive years, 284 samples in 2006 and 483 samples in 2007 were characterized for soluble solids content (SSC), titratable acidity (TA), glucose, fructose, sucrose, malic acid and citric acid contents. Sugar and organic acid composition were determined by three methods: colorimetric enzymatic measurements (ENZ), high-performance liquid chromatography (HPLC) or proton NMR spectroscopy (1H-NMR), depending on the samples. For all samples, fruit homogenates were analysed in ATR-FTIR using the same methodology and the same spectrometer. The objective here was to evaluate the effect of reference methods on the prediction performance. The best results were generally observed for SSC and TA, the percentage of the root mean square error of cross validation (RMSECV%) ranging respectively between 5.8 and 8.7% and between 5.9 and 8.0%, depending on the samples. For individual sugars and organic acids, the best correlations were obtained between ATR-FTIR data and ENZ reference data followed by HPLC and 1H-NMR ones.
A Fourier transform infrared spectroscopy–Partial Least Squares (FTIR–PLS) strategy for the determination of the quality of olive fruits and the respective virgin olive oil (VOO) has been developed. This methodology has been demonstrated as able to correlate the level of fly attack in olive oils with their FTIR spectra. A multivariate calibration model was built by the PLS algorithm using the 4000–700 cm−1 spectral range on pretreated data and an evaluation of some of the usual quality parameters of VOO (free acidity, fatty acids composition, oxidative stability by OSI time and phenolic compounds obtained by capillary electrophoresis) and was performed to corroborate the real influence of fly attack on the quality of the oils. Furthermore, the evaluation of the FTIR data showed some differences in the regions of the fatty acids and phenolic compounds depending on the percentage of fly attack on the olives. This non-destructive method easily allows a non-destructive measure and, at the same time, establishes the level of Bactrocera oleae attack in olive fruit thus analysing directly the olive oil obtained without any previous treatment.
Classical liquid-state high-resolution (HR) NMR spectroscopy has proved a powerful tool in the metabonomic analysis of liquid food samples like fruit juices. In this paper the application of 1H high-resolution magic angle spinning (HR-MAS) NMR spectroscopy to apple tissue
is presented probing its potential for metabonomic studies. The 1H HR-MAS NMR spectra are discussed in terms of the chemical composition of apple tissue and compared to liquid-state NMR spectra of apple juice. Differences indicate that specific metabolic changes are induced by juice
preparation. The feasibility of HR-MAS NMR-based multivariate analysis is demonstrated by a study distinguishing three different apple cultivars by principal component analysis (PCA). Preliminary results are shown from subsequent studies comparing three different cultivation methods by means
of PCA and partial least squares discriminant analysis (PLS-DA) of the HR-MAS NMR data. The compounds responsible for discriminating organically grown apples are discussed. Finally, an outlook of our ongoing work is given including a longitudinal study on apples.
The objective of this study was to create a French database on the polyphenol content of fruit and vegetables as uncooked fruits and vegetables and then to evaluate polyphenol intake through fruit and vegetable consumption in France. To achieve this, we used the Folin-Ciocalteu method adapted to fruit and vegetable polyphenol quantitation (1). Vegetables with the highest polyphenol concentration were artichokes, parsley, and brussels sprouts [.250 mg of gallic acid equivalent (GAE)/100 g fresh edible portion (FEP)]; fruits with the highest concentrations were strawberries, lychees, and grapes (.180 mg of GAE/100 g FEP). Conversely, melons (Cantaloupe cv.) and avocados had the lowest polyphenol concentration for fruits and vegetables, respectively. Based on fruit consumption data, apples and strawberries are the main sources of polyphenols in the French diet, whereas potatoes, lettuces, and onions are the most important vegetable sources. Total polyphenol intake from fruit is about 3 times higher than from vegetables, due to the lower polyphenol concentration in vegetables. The calculation of polyphenol intake, based on both assessment methods used [(Socié té d#É tudes de la Communication, Distribution et Publicité (SECODIP) and Supplé mentation en Vitamines et Miné raux Antioxydants (SUVIMAX)], showed that apples and potatoes provide approximatively half of the total polyphenol intake from fruit and vegetables in the French diet.
Fluorescence spectroscopy has, over the last two decades, been frequently used for studies of biological cells and their molecular components. In combination with molecular biological methods that allow introduction of fluorescent labeling in vivo and in vitro, fluorescence spectroscopy methods, such as Förster resonance energy transfer (FRET), have made membrane proteins accessible to studies of their molecular structure and dynamics. In this article, we describe a variety of fluorescence spectroscopy techniques and focus on their use in the studies of the physiological role ion channels play, and the conformational rearrangements involved in the gating of ion channels, whose function as gated membrane pores underlies numerous cellular processes essential for the survival of living cells and organisms.
A combination of Fourier transform infrared spectroscopy (FTIR) and multivariate statistics (chemometry) was applied as a screening tool for the quantitative determination of carbohydrates, such as glucose, fructose and sucrose, in 11 processed commercial apple juices and 2 genuine juices obtained from squeezed apples. For calibration, a number of 24 mixtures of glucose, fructose and sucrose solutions (synthetic samples), at different concentrations were prepared and scanned in the 885 and 1500 cm -1 spectral range, using attenuated total reflectance (ATR) FTIR spectroscopy. Based on the mixtures spectra in the mid IR (MIR) region, we realized calibration models for each carbohydrate, using partial least squares (PLS) regression. The models were then used to predict the glucose, fructose and sucrose concentration in commercial apple juices, comparatively with concentrations in fresh, genuine juices, in order to assess the juice authenticity. The glucose concentrations (%, w/w) predicted for commercial juices ranged from 1.664 to 3.133 versus 3.1 for genuine fresh juices. The fructose concentrations (%, w/w) predicted for commercial juices ranged from 3.701 to 6.941 versus 9.2 for genuine fresh juices, while the sucrose concentrations (%, w/w) predicted for commercial juices ranged from 0.746 to 5.795 versus 1.38 for genuine fresh juices. The standard deviations of most predicted values are below 10%. Most juices exhibited glucose, fructose and sucrose concentrations in the expected range. However, several samples showed discrepancies from average concentration values, thus the authenticity of these juices could not be confirmed. Also, high sucrose concentration can flag adulterated juices, or indicates sucrose addition to maintain the juice sweetness intensity. Our results indicate ATR-MIR spectroscopy to be a rapid, accurate, non-destructive and cost-effective tool for routine monitoring of multiple constituents in apple juices, as quality and safety indicators.
This review examines the parameters of enzymatic browning in apple and apple products that is, phenolic compounds, polyphenoloxidases, and other factors (ascorbic acid and peroxidases), both qualitatively and quantitatively. Then the relationships between intensity of browning and the browning parameters are discussed, including a paragraph on the methods used for browning evaluation. Finally, the different methods for the control of browning are presented.
Apple is among the most consumed fruits worldwide. It is available on the market for the whole year being a major source of dietary polyphenols. Several studies suggested that apple polyphenols could play a role in prevention of degenarative diseases. The action of these compounds has been partially ascribed to their antioxidative ability, and fruit antioxidants profile is influenced by apple variety and by the postharvest storage. In this work, the polyphenols composition of the flesh of four apple varieties cultivated in southern Italy were investigated by HPLC, and a flow injection MS/MS procedure to quantify cholorogenic acid and catechins was set up. Phenolic composition and the radical scavenging activity were monitored during a postharvest storage of four months. The quantification by flow injection procedure gives results comparable to those obtained by HPLC, and the increase of the antioxidant activity during storage correlated with an increase of the concentration of catechin and phloridzin. This trend is particularly evident for the variety "Annurca" which is a typical product cultivated in the area around Naples. The genetic characteristics of the Annurca variety together with the anticipated harvest time and the peculiar postharvest conditions are likely responsible for this increase of the antioxidant activity.
According to epidemiological studies, fruits and vegetables are recognised to have protective effects against degenerative diseases such as cancer and cardiovascular diseases. These beneficial health effects are attributed mainly to diverse antioxidant compounds: vitamin C, carotenoids, sulphur compounds and polyphenols. However, it remains difficult to estimate the average daily intake of total polyphenols. In fact, polyphenols represent a wide variety of compounds belonging to different subclasses (flavonoids, phenolic acids, lignans, proanthocyanidins, etc.). Many of these compounds usually escape quantification, usually performed by HPLC/UV, because there is a lack of commercially available standards and because of the presence of unidentified compounds leading to an underestimation of the total polyphenol content. We proposed a rapid determination method for polyphenol quantification (Journal of Agricultural and Food Chemistry, 2005, 53, 1370-1373). This method was used to build a French database of the polyphenol content of fruits and vegetables. We estimated the French daily polyphenol intake based on food questionnaire (SU.VI.MAX). The highest polyphenol contents for vegetables were artichoke, parsley and Brussels sprouts (>250 mg of gallic acid equivalent (100 g fw)-1) and for fruits, strawberry, litchi and apricot (>180 mg of gallic acid equivalent (100 g fw)-1). Among fruits, the main source of polyphenols in the French diet is apple and for vegetables it is potato.
The influence of low temperature and storage time on the antioxidant capacity of standard solutions and apple and orange extracts was evaluated. In addition, the effects of ascorbic acid (AA) addition to the fruit extracts in terms of antioxidant capacity, AA content and soluble and hydrolyzable polyphenol contents were also analysed. Polyphenol contents in both apple and orange extracts were stable during storage period, which reflected also in the antioxidant capacity stability. Freezing at −18 °C did not result in different retention rates for polyphenols, AA and antioxidant capacity when compared to freezing at −70 °C. However, vitamin C content in orange juice, without AA addition, slightly increased along the experimental period (10 days). Thus, this study shows that it may not be necessary to measure the antioxidant capacity immediately after the preparation of fruit extracts or antioxidant standard solutions.
The oxidative activity of mushroom tyrosinase was optimized in chloroform, using catechin and vanillin as substrates. The presence of 1.75 and 5.00% (% vv) methanol, respectively, showed an activating effect (92.3%) with catechin, but an inhibitory one (87.1%) with vanillin. The addition of acetone to the reaction medium, 30% (% vv) for catechin and 25% for vanillin, reduced the enzymatic activity by 92.1 and 93.5%, respectively. The Vmax values of tyrosinase in chloroform were 0.1415 and 0.0250 dA/μg protein/s for catechin and vanillin, respectively; in addition, Km values were 0.7940 and 0.0825 μmol, respectively for the two substrates. The use of 0.25 μmol catechol activated the tyrosinase activity by 56.2% when catechin was used as substrate; however, no effect was found with vanillin. In addition, the use of 0.85 and 0.45 μmol of ethylenediaminetetraacetic acid, with catechin and vanillin as substrates, inhibited the tyrosinase activity by 44.3 and 84.7%, respectively. FT-IR analyses suggested that native mushroom tyrosinase is predominately of α-helical conformation; while that in chloroform the enzyme is mainly composed of β-sheet structure.
Polyphenol oxidase (PPO) was purified to homogeneity from loquat (Eriobotrya japonica Lindl. cv. Mogi) fruit. The enzyme was purified 422-fold with a total yield of 35.6%. The molecular weight was estimated to be about 58 000 and 55 000 by SDS−PAGE and FPLC gel filtration chromatography, respectively, indicating that PPO is a monomer. The optimum pH and temperature of the enzyme activity were found to be pH 4.5 and 30 °C, respectively, and the enzyme was stable in the range of pH 4−8. In substrate specificity, a maximum activity was shown with epicatechin, followed by chlorogenic acid, neochlorogenic acid, 4-methylcathechol, and pyrocatechol, and no activity was apparent toward monophenol and p-diphenol. The Km values for chlorogenic and neochlorogenic acids were 0.105 and 0.425 mM, respectively. The enzyme activity was markedly inhibited by sodium ascorbate, diethyldithiocarbamate, metabisulfide, dithiothreitol, mercaptoethanol, NaF, NaN3, l-cysteine, and reduced glutathione. Keywords: Polyphenol oxidase; loquat fruit; Eriobotrya japonica Lindl.; polyphenols; browning
Phenolic compounds have been determined by HPLC in the flesh and skin of three apple cultivars (Golden Delicious, Empire, Rhode Island Greening) during maturation and cold storage. The main phenolic compounds in all three apple cultivars were found to be epicatechin and procyanidin B2, rather than chlorogenic acid which previously had been reported as the major phenolic compound in apples. The concentration of individual phenolics in apple flesh decreased sharply during the early stage of development and then remained relatively constant during maturation and storage. There was a direct correlation between concentration of polyphenols in the flesh and in the skins. The tendency to brown decreased throughout the fruit development and maturation period.
The objective of this study was to investigate the possibility of predicting the quality parameters of tomato by mid-infrared spectroscopy For 2 years tomato samples representing a large variability in the chemical composition were scanned using the attenuated total reflectance accessory of a Fourier transform spectrometer in the wavenumber region between 4000 and 400 cm(-1) Calibration models were developed using partial least squares (PLS) regression method and were tested with internal validation sample set in the first year Different spectral preprocessing techniques were investigated and different spectral regions were selected to optimise the calibration models In addition the models obtained in 2007 were used to predict the soluble solids dry matter and total acidity in tomato harvested in 2008 The regression models of the spectra showed reasonable ability to estimate the dry matter soluble solids total acidity citric acid and individual sugars contents in tomatoes grown in 2007 with high coefficients of determination (from 0 98 for soluble solids to 0 92 for fructose) and low percentage errors of prediction (from 3% to 7% for soluble solids and citric acid respectively) By contrast the predictive capability of model for malic acid was unsatisfactory with error of prediction of 26% When the best calibration models from 2007 were used to predict the selected parameters in tomato picked in 2008 very high correlations were obtained confirmed by low errors of prediction from 4% to 7% for dry matter and total acidity respectively Mid-infrared spectroscopy is an attractive alternative for standard methods for determination of internal quality parameters in tomato (C) 2010 Elsevier Ltd All rights reserved
The aim of this work was to develop a fast, versatile, inexpensive and environmentally safe analytical method to quantify simple sugars, malic acid and total phenolic compounds in apple pomace, considering its potential use as a raw material with value instead of as an industrial waste. Diffuse reflectance infrared spectroscopy (DRIFTS) measurements of twenty-six samples of apple pomace were analysed by partial least squares regression (PLSR), using several signal pre-processing methods. Multivariate models developed with four to five latent variables (LVs) and based in the MIR (mid-infrared) region had good prediction for the determination of sucrose, fructose, malic acid and total phenolic compounds, with average errors between 3.9% and 6.6%. By contrast, glucose was better determined by models developed in the NIR (near-infrared) region and using six LVs, yielding an average error lower than 7.4%. These results confirmed the feasibility of the multivariate spectroscopic approach as an alternative for expensive and time-consuming conventional chemical methods.
Initial crushing and pressing operations have a major influence on the polyphenolic composition of apple juice, therefore, we have tested the impact of variations of this step using three cider apple cultivars of contrasting polyphenolic composition: Guillevic, Kermerrien and Dous Moen. Under inert atmosphere, increased temperature (between 5 °C and 24 °C), increased the extraction of procyanidins from fruit to juice. The crushed apples were also subjected to four conditions of oxidation: preserved from oxidation as above, short contact with air, short contact with air and mixing, long contact with air and mixing. Oxidation decreased the concentrations of native polyphenols in the juices, especially for flavan-3-ols. The golden colour of the juices was initially enhanced with increases in saturation C∗ and a shift of the hue angle from yellow to orange. However, for the highest oxidation state the colour became paler and more yellow. Bitterness and astringency decreased upon oxidation, probably due to increased retention of oxidised moieties.
This study provides the first report on the occurrence of the respiratory climacteric during cold storage of apple fruit (Malus domestica Borkh. cv. Reinette du Canada). The respiratory pattern at 4°C was very similar to that observed during postharvest ripening at room temperature, except that shelf life was considerably extended and the onset of the climacteric delayed. Increasing the calcium content of the apple fruit significantly reduced loss of firmness during cold storage, but showed no effect on respiration or on the other parameters determined. A gradual accumulation of soluble sugars occurred during the first 60 days after harvest and was effectively completed before the climacteric peak was reached. This increase in sugars correlated with an increase in the activity of sucrose-phosphate synthase (EC 2.4.1.14), and a marked change in the kinetic properties of the enzyme was observed after sucrose accumulation ceased. Changes in the hexose-phosphate pool and in glycolytic and gluconeogenic activities indicated an initial increase in the gluconeogenic flow at early stages of the climacteric, followed by activation of glycolysis, with the carbon flow being most likely regulated at the reversible phosphorylation of fructose-6-phosphate to fructose-1,6-bisphosphate (mostly via pyrophosphate:fructose-6-phosphate phosphotransferase, EC 2.7.1.90) and at the pyruvate kinase (EC 2.7.1.40) steps. The results presented indicate that the respiratory climacteric does not occur to accommodate extra ATP requirements during sucrose synthesis nor can it be a consequence of an increased supply of respiratory substrate.
Blueberries (family Ericaceae; genus Vaccinium corymbosum L.) are interesting fruit for potential health benefits due to their bioactive compounds (anthocyanins, flavonoids, polyphenols and ascorbic acid). Blueberry quality indices and nutritional properties are generally determined by instrumental techniques (LC–MS; HPLC) that are time and chemical consuming, laborious and expensive. The aim of this work was to examine the potential of MIR and near-infrared (NIR) spectroscopy to evaluate both ripening indices and nutraceutical properties of two blueberry cvs, ‘Brigitta’ and ‘Duke’, grown in Valtellina (northern Italy), harvest 2005 and 2006, collected weekly from mature green to full ripe berry stage. Fruit from each ripening class was analysed for total soluble solids (TSS), total phenols, total flavonoids and total anthocyanins, ascorbate and spectroscopic analysis, such as FT-IR and FT-NIR. The spectral datasets were correlated with technological ripening parameters and with nutraceutical compounds by using partial least squares (PLS) regression algorithms both in full cross-validation and test set validation. The PLS analysis for quantitative prediction of TSS gave good calibration models in near (root mean standard error in cross-validation (RMSECV) = 0.50% and root mean standard error in test set validation (RMSEP) = 0.65%) and mid-infrared regions (RMSECV = 0.30% and RMSEP = 0.36%). The calibration models developed in the near infrared region were able to evaluate the content of total phenols (RMSECV = 0.14 mg catechin/g and RMSEP = 0.18 mg catechin/g), total flavonoids (RMSECV = 0.20 mg catechin/g and RMSEP = 0.25 mg catechin/g) and total anthocyanins (RMSECV = 0.25 mg malvidin/g and RMSEP = 0.22 mg catechin/g). The models developed in the mid-infrared region proved to be well correlated with analytically determinated phenolic compounds. The predicted results by the regression models developed for ascorbic acid in near and mid-infrared regions were not as good as those obtained for the phenolic parameters. On the whole, near and mid-infrared spectroscopy gave promising results as they were rapid and non-destructive methods able to evaluate at the same time, technological ripening indices and nutraceutical compounds of blueberries. These techniques could be valid and simple tools to reduce the analytical time and cost of monitoring blueberry quality.
A simple, fast and accurate Fourier transform mid-infrared spectroscopy method was developed for simultaneously determining sugar and organic acid contents in apricot fruit slurries using the attenuated total reflectance. The potential of this method coupled with chemometric techniques based on partial least squares was assessed by comparison with currently used enzymatic determination of sucrose, glucose, fructose, malic acid and citric acid. Fruits of eight contrasted cultivars harvested at different ripening stages were used in this study and randomly divided in a calibration set (505 apricots) and in a validation set (252 apricots). The most suitable region was found in the range between 1500 and 900 cm−1. Good prediction performances were obtained (R2 ⩾ 0.74 and RMSEP ⩽ 18%). Results concerning the prediction of other quality traits such as firmness, skin colour, ethylene production, soluble solids content and titratable acidity were discussed.
The investigation concerned white and green cauliflowers: a traditional technology of freeze – blanched cauliflower, a modified technology of freeze – cooked cauliflower, and two temperatures of frozen storage at −20 and −30 °C for 0, 4, 8, and 12 months. Compared with the white cauliflower, the green variety was characterized by significantly greater contents of dry matter, vitamin C, carotenoids, β-carotene, polyphenols and a higher antioxidative activity at all the stages of evaluation. Depending on the investigated sample, after 12 months of refrigerated storage, cauliflower prepared for consumption retained 29–50% of vitamin C, 73–100% of carotenoids, 53–125% of β-carotene, 69–85% of polyphenols and 26–40% of antioxidative activity in comparison with the raw material. After a 12-month storage, the product obtained using the modified technology contained significantly more vitamin C and in general showed a higher antioxidative activity than did with the traditional product. The lower storage temperature resulted in significantly better retention of vitamin C and also – in some samples – a better retention of carotenoids, β-carotene, and polyphenols. A higher sensory quality was found in products of green cauliflower obtained according to the traditional technology.
The relationship between objective and sensory measurements of apple taste and flavour was investigated. The aim was to determine the objective parameters that were best correlated with sensory evaluation, and then to identify the minimum objective difference that was required before a trained sensory panellist could detect a difference in apple taste and/or flavour. Objective measures included titratable acidity, °Brix (soluble solids content), levels of individual volatiles, sugars and acids, as well as calculations of °Brix/titratable acid ratio. Sensory panellists were trained to assess sweet taste, acid taste, apple flavour, and overall flavour. Titratable acidity was the best predictor of acid taste (correlation of 0.86 for the median panellist), and differences between apples of 800 mg kg−1 (0.08% titratable acid) were required before the average trained panellist could detect a difference in acid taste (P=0.90). This value represented about a tenth of the range of titratable acidity values of the treatments presented to the trained panel. Sweet taste was difficult to predict using any of the objective methods. Indeed, the best objective predictor of sweetness was °Brix (correlation of 0.41 for the median panellist), which could predict a difference in taste when apples differed by more than 1 °Brix (P=0.90). This value represented about a third of the range of °Brix levels presented to the trained panel. Thus, while acid taste may be predicted on the basis of titratable acidity, we recommend that evaluation of sweet taste and flavour attributes continue to require assessment by trained sensory panels.
Micra RS tomatoes, frozen in the form of cubes, were stored during 12 months at −20 and −30°C, analyses being conducted after freezing and after 3-, 6-, 9- and 12-months' storage. The storage did not affect the level of dry matter, soluble solids, sugars, dietary fibre, total nitrogen, nitrates, nitrites, pH, ash or its alkalinity. However, differences in the contents of protopectins, pectins, total acidity, vitamin C, carotenoids, beta-carotene and lycopene and also in the activity of peroxidase, catalase and lipase were statistically significant. In frozen products at a temperature of −30°C in comparison with those at −20°C the contents of the following were: protopectins 33%, pectins 68%, vitamin C 90%, carotenoids 30%, beta-carotene 39% and lycopene 43%, while the activities of catalase and of lipase were 52% and 45% lower, respectively. Organoleptic ecaluation showed good conservation quality in tomato cubes stored at −20°C during 9 months and, in the case of −30°C, throughout the entire investigated period.
The optimum conditions for polyphenoloxidase (PPO) extraction from apple fruit were obtained with a buffer solution above pH 7 containing 15 mM ascorbic acid and 0.5% of Triton X100. In 12 cultivars grown in France, the PPO activity ranged from 3.1 to 0.62 in the cortex and from 3 to 0.3 mkat/kg in the peel. For both parts, the cultivar Red Delicious exhibited the highest activity, whereas the lowest activity was in Elstar. In the Red Delicious apples, the PPO activity steadily declined during the eight weeks around the commercial date of harvest, the total decrease being close to 30%. PPO from Red Delicious cortex has been purified 120-fold, with a total yield close to 40%, by ammonium sulphate precipitation and hydrophobic chromatography on Phenyl Sepharose CL4B. The pIs, obtained by isoelectrofocusing were at pH 4.5 and 4.8 for two major bands and near neutral for a minor one. The Mr determined by gel filtration was unique (ca46 000). The optimum pH of activity was between 4.5 and 5 for 4-methylcatechol, chlorogenic acid and (+) catechin. The Km values were almost independent of pH on the acid side of the pH optimum and were in the range of 5 mM for the three substrates studied. At pH 4 which is close to the pH of apple vacuoles, chlorogenic acid is a better substrate for apple PPO than (+) catechin.
Direct thiolysis of crude plant materials and HPLC analysis of the reaction media were used to quantify and to characterise procyanidins (condensed tanins) and other main polyphenols of three dessert apple varieties. Results showed evidence of the large predominance of the procyanidin class in the polyphenolic composition of dessert apple skin and flesh. The structure of procyanidins was wholly homogeneous with (-)-epicatechin representing more than 95% of the constitutive flavan-3-ol units and with average degrees of polymerisation in the 5–7 range.
The partial compositional characteristics were determined for apple juice from 175 non-commercial varieties of apples developed from scion wood collected from approximately 12 countries and several USA geographical areas. Juices from many of the varieties were high in malic acid and potassium. Mean values for many of the attributes did not match existing compositional database value means. However, some of the overall minimum and maximum values for the various attributes (i.e., Brix°, pH, ash, TA, sucrose, glucose, fructose, sorbitol, malic, citric, fumaric, sodium, and calcium) in this study compared reasonably well with existing compositional database values. Distribution of phenolics between the various varieties was highly variable with some juices containing little if any phenolic compounds. Chlorogenic acid and phloridzin were detected in all varietal samples while arbutin and HMF were not measurable. The data developed should be useful with other databases in describing authentic apple juice and in the development of future apple commercial varieties to target specific consumer requirements.
Cell wall materials were prepared from apple tissue by seven different procedures, some of which are methods in current use in laboratories. The yield, the composition and the fractionation patterns of the pectin content, following sequential extraction in water, chelating agent (CDTA) and a pectin lyase treatment, was compared for each CWM. Variability of the yields and compositions of the CWM were small and few differences were statistically significant. There were differences in the partitioning pattern of the pectin during fractionation but also a high standard deviation of the yields between repetitions.
This paper investigates the influence of cultivar (Annurca, Golden Delicious, Red Chief, and Stayman Neepling), rural practice (integrated and organic), and growing region (different Italian regions) on polyphenol composition and antiradical activity of the pulp and skin of apples, as presented to the consumer at the market. Antiradical activity of fruit was strongly related with the total polyphenolic content, determined both by the spectrophotometric Folin-Ciocalteu method ( R (2) = 0.90; P < 0.01) and by HPLC ( R (2) = 0.85; P < 0.01). Considering the edible portion of the fruit, polyphenolics contribute toward explaining approximately 90% of the overall antiradical activity, thus highlighting their important role in human health protection. Therefore, the data indirectly indicated that ascorbic acid and other antiradical molecules differing from polyphenols play a much less important role in explaining the health-protecting properties of apples. Cultivar effect was by far the most important, and Annurca and Golden Delicious were respectively the best and the worst apples from the point of view of the health-protecting attributes.
Apples (Malus domestica Borkh.) of two table and two cider cultivars were collected during fruit growth and maturation from the end of cell proliferation. Concentrations of flavonoids (flavan-3-ols, dihydrochalcones and flavonols) in the fruit flesh decreased sharply between circa 35 and circa 100 days after flowering. For hydroxycinnamic acids, the decrease appeared slower. In a second experiments apples of the cider cultivars Kermerrien and Avrolles were sampled every 2 weeks from 40 days after flowering to overripeness for a detailed characterisation of polyphenol accumulation kinetics in the fruit flesh. Most polyphenol synthesis had occurred at 40 days after full bloom, though it persisted at a low (Kermerrien) to very low (Avrolles) level during all the fruit growth. All qualitative characteristics of the polyphenols were remarkably stable. The degree of polymerisation of the procyanidins increased slightly in Avrolles and decreased in Kermerrien. This was accompanied by a relative increase in procyanidin B2, while size-exclusion chromatography of Kermerrien polyphenol extracts showed the disappearance of a highly polymerised fraction.
Plant polyphenols are extremely diverse, due to the occurrence of several basic structures, numerous substitutions and, for some groups, of polymers (tannins). Plant polyphenol composition depends on the plant species and organ, with some molecules specific of particular plant families while others are ubiquitous. The polyphenol content is classically assessed by global analysis methods, which lack specificity and accuracy. These methods have been replaced with high performance liquid chromatography (HPLC), that enables accurate determination of individual molecules, provided they can be unambiguously identified and calibration curves can be established. However, HPLC analysis is restricted to simple compounds and difficult to apply in the case of complex extracts. Further difficulties encountered in the case of polymers include irreversible adsorption on the stationary phases. Proanthocyanidin analysis by HPLC after acid-catalysed depolymerisation in the presence of a nucleophile permits to overcome these problems and shows that proanthocyanidins predominate in the polyphenol composition of most plants. Large varietal differences in tannin quantitative and qualitative composition were observed for all plant species studied. Moreover, analysis is usually performed after extraction, which may lead to significant underestimation of the polyphenol content, since a large proportion is not extracted by usual solvents. This may be due to covalent binding to other plant constituents and to non-covalent adsorption on plant solids. Such matrix effect also influences the taste perception of polyphenols and their fate in the digestive tract, from in-mouth interactions with salivary proteins to their metabolism by colon microflora, with potential influence on bioavailability.