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Effect of Coatings of Silver Nanoparticles and Gum Arabic on Physicochemical and Microbial Properties of Green Bell Pepper ( C apsicum annuum ): Effect of Nanosilver and Gum Arabic Coatings on Bell Pepper
Journal of Food Processing and Preservation
Abstract
The main objective of this work was to study the effects of gum Arabic and silver nanoparticles on the quality of green bell peppers during 21 days of storage. Gum Arabic in aqueous solution of 10%, silver nanoparticles and silver nanoparticles–gum Arabic solution blend, coatings were formed directly on the surface of green bell peppers (Capsicum annuum) and were placed in incubators at 7 and 20C with a relative humidity of about 85%. Fruit quality was evaluated by weight loss, firmness retention, ascorbic acid content, surface color development and microbial decay. Gum Arabic coating presented lower ascorbic acid degradation, weight loss and textural damage but did not affect total aerobic count. Silver nanoparticles hindered microbial decay while did not prevent ascorbic acid decomposition, weight loss and firmness loss. Gum Arabic combined with silver nanoparticles significantly hindered microorganisms' growth and physicochemical losses and showed the best performance for enhancing the shelf life of green bell peppers.Practical ApplicationsThis study indicated that gum Arabic coating hinders water loss, texture softening and vitamin C decomposition, and silver nanoparticles have antimicrobial effects; thus, combination of these two materials results in development of a coating, which improves the nutritional value and marketability of green bell peppers.
... Inhibitory effects of the coating formulations on microbial growth in ghost chill samples was determined as described by Hedayati and Niakousari, 2015, with slight modification (Hedayati & Niakousari, 2015). Serial dilutions of the chilli samples in sterile peptone water were done up to 10 − 2 for viable cell counts. ...
... Inhibitory effects of the coating formulations on microbial growth in ghost chill samples was determined as described by Hedayati and Niakousari, 2015, with slight modification (Hedayati & Niakousari, 2015). Serial dilutions of the chilli samples in sterile peptone water were done up to 10 − 2 for viable cell counts. ...
... mg/100 g) coatings efficiently preserved ascorbic acid content than the control (89.66 mg/100 g). This is might be due to reduced oxidation in the coated samples, as reported in some other similar studies on green bell peppers, king chillies, green chillies, and sweet pepper (Malakar et al., 2020;Hedayati & Niakousari, 2015;Valiathan & Athmaselvi, 2018;Nair et al., 2018). ...
Ghost chilli (Capsicum chinense) is an indigenous variety of capsicum in the northeast region of India, which contains considerable amounts of vitamin C and antioxidants. The short shelf-life of the fruit causes significant postharvest losses, a major hurdle against supply chain resulting in financial losses for growers and suppliers. The primary goal of this study was to improve postharvest shelf-life of ghost chilli by applying composite coating formulations prepared from silk protein (SP), chitosan (CH), and Aloe vera gel (AVG). The coating on ghost chilli was applied by dip-coating method, and it extended the shelf-life of the coated fruits for up to 15 days during storage in ambient conditions. The result showed reduced weight loss in the coated fruit (less than 15%) compared to the uncoated control (almost 20%), maintained firmness, total soluble solids, and titratable acidity in the coated chilli (more than 15 N, 2% and 0.52%, respectively) compared to the uncoated control (6 N, 3%, and 0.42%, respectively). Moreover, the microbial counts in the SP/CH/AVG coated chillies was significantly less (1.5 log CFU/g compared to the uncoated control (almost 4 log CFU /g) after 15 days of ambient storage. The developed composite coatings can be effective alternative to synthetic wax based coatings for shelf-life enhancement of fruits and vegetables, however, future studies on toxicity of the developed coating formulation, cost analysis, etc. are needed for their future scale-up and commercialization.
... Inhibitory effects of the coating formulations on microbial growth in ghost chill samples was determined as described by Hedayati and Niakousari, 2015, with slight modification (Hedayati & Niakousari, 2015). Serial dilutions of the chilli samples in sterile peptone water were done up to 10 − 2 for viable cell counts. ...
... Inhibitory effects of the coating formulations on microbial growth in ghost chill samples was determined as described by Hedayati and Niakousari, 2015, with slight modification (Hedayati & Niakousari, 2015). Serial dilutions of the chilli samples in sterile peptone water were done up to 10 − 2 for viable cell counts. ...
... mg/100 g) coatings efficiently preserved ascorbic acid content than the control (89.66 mg/100 g). This is might be due to reduced oxidation in the coated samples, as reported in some other similar studies on green bell peppers, king chillies, green chillies, and sweet pepper (Malakar et al., 2020;Hedayati & Niakousari, 2015;Valiathan & Athmaselvi, 2018;Nair et al., 2018). ...
... Recently, the production and processing of fruits and vegetables have increased with the growing population and exchanging diet habits. Several preservation technologies such as active packaging (Lin et al., 2018;Moradinezhad et al., 2020;Zhang et al., 2020;Min et al., 2021), modified atmosphere packaging (Pinto et al., 2020), irradiation (Panou et al., 2020), and edible coating (Hedayati & Niakousari, 2015) have been developed to slow down the metabolic processes of fresh fruits and achieve a proper preservation. Antimicrobial packaging is an effective method to increase the shelf life of food products while retaining the nutritional and sensory quality of food (Zhang et al., 2019). ...
... Titratable acidity (TA) was evaluated by titrating the diluted juice (5 to 95) up to pH 8.2 using 0.1N NaOH (Hedayati & Niakousari, 2015). The antioxidant capacities of fruits were measured using 2,2-diphenyl-1picrylhydrazyl (DPPH) radical scavenging assay (Dong & Wang, 2017). ...
... As citric acid is the predominant organic acid present in strawberry fruit, titratable acidity is expressed in terms of the total quantity of citric acid (Hedayati & Niakousari, 2015). The results indicated that titratable acidity was affected by both active packaging treatments and storage time ( Table 1). ...
Strawberry is highly perishable with a short shelf life mainly due to physiological deterioration and microbiological decay. Thyme essential oil (TEO), which is a natural antimicrobial and antioxidant agent, encapsulated in zein (Z) nanofiber could be used by electrospinning to examine the ability of the nanofiber for strawberry quality preservation. Test groups were designated as zein nanofiber film, and zein loaded with TEO nanofiber film (Z/TEO). The fruit packed in PET container without film on its lid was used as the control group. Packages of fruits were then stored in a cool room at 4 ± 0.5 °C and 85 ± 5% RH for 15 days. Results indicated that the scanning electron microscopy images of nanofibers had a linear morphology, smooth surface and bead‐free structure. Fourier transform infrared also showed that the encapsulation of TEO in the zein was a physical process and no chemical interactions occurred between ingredients during electrospinning. Moreover, differential scanning calorimetry data confirmed the thermal stability of TEO encapsulated in zein nanofibers. Active packaging including nanofiber films significantly preserved the biochemical and microbial properties of fruit. Indeed, stored fruit in packages containing nanofiber Z/TEO (Zein loaded with TEO nanofiber film) significantly (p˂0.05) lowered total bacterial counts, fungi and yeast, and maintained the total phenols content, antioxidant activity and titratable acidity of the strawberries during 15 days of storage at 4 °C. In conclusion, this study revealed the benefits of incorporating TEO into zein films, which may have a great potential in active packaging and preservation of strawberry fruits.
... Green bell peppers have a limited shelf life, making them perishable products. Their postharvest quality is primarily affected by several physiological factors, such as disease-related issues, moisture loss, and chilling injury [3]. ...
... Area under the ROC (receiver operating characteristic) curve (AUC), 2 classification accuracy (CA),3 the measure of the harmonic means of precision and recall (F1), 4 precision (Prec), 5 the times the model correctly identifies positive instances (Recall),6 Matthews correlation coefficient (MCC). ...
Citation: Fatchurrahman, D.; Castillejo, N.; Hilaili, M.; Russo, L.; Fathi-Najafabadi, A.; Rahman, A. A Novel Damage Inspection Method Using Fluorescence Imaging Abstract: Fluorescence imaging has emerged as a powerful tool for detecting surface damage in fruits, yet its application to vegetables such as green bell peppers remains underexplored. This study investigates the fluorescent characteristics of minor mechanical damage, specifically 5 × 5 mm cuts in the exocarp of green bell peppers, which conventional digital imaging techniques fail to classify accurately. Chlorophyll fluorescence imaging was combined with machine learning algorithms-including logistic regression (LR), artificial neural networks (ANN), random forests (RF), k-nearest neighbors (kNN), and the support vector machine (SVM) to classify damaged and sound fruit. The machine learning models demonstrated a high classification accuracy, with calibration and prediction accuracies exceeding 0.86 and 0.96, respectively, across all algorithms. These results underscore the potential of fluorescence imaging as a non-invasive, rapid, and cheaper method for assessing mechanical damage in green bell peppers, offering valuable applications in quality control and postharvest management.
... In the present study, the reduction in weight loss, especially in fruit coated with 10% GA+10 g L -1 of turmeric was due to the synergistic effect of the composite coating where the 10% GA served as a semipermeable barrier against oxygen, carbon dioxide, and moisture, thus reducing respiration, water loss, and oxidation reactions [63,64], while 10 g L -1 was fungistatic against the fungus, hence reducing disease incidence. Composite coating of GA combined with other natural products (cinnamon oil and propolis) or synthetic chemicals (calcium chloride) or silver nanoparticles delayed senescence by decreasing weight loss in banana, mango, green bell pepper, and papaya [19,20,46,48,65]. ...
... Nerd and Mizrahi [67] reported that the change of peel color to pale green and then to reddish of pitaya fruit was due to changes in peel chlorophyll content during fruit development. Our study confirms the research by Hedayati and Niakousari [65] where 10% GA combined with silver nanoparticles as a composite coating significantly delayed color changes in green bell pepper for 21 days. Similarly, Ali et al. [17] also reported that composite coating of ethanolic extract of propolis (1.5%) and 10% GA reduced the occurrence of anthracnose and delayed color changes in papaya. ...
Several natural preservative techniques including plant extracts are used to minimize postharvest losses caused by pathogens. Our recent findings elucidated that the application of crude extracts of ginger, turmeric, and “dukung anak” (Phyllanthus niruri Linn.) alone causes phytotoxicity and adversely affects the postharvest quality of dragon fruit, especially at high concentrations. This study investigated the effect of a composite coating of 10% gum arabic (GA) and crude extracts of ginger, turmeric, and “dukung anak” separately at 5, 10, and 15 g L-1 on postharvest quality of dragon fruit stored at 11 ± 2 ° C , 80% RH for 28 days. After 28 days of cold storage, anthracnose was significantly reduced in fruit coated with 10% GA plus 10 or 15 g L-1 of any of the crude extracts and resolved the problem of phytotoxicity while maintaining the postharvest quality of fruit for 28 days. The reduction of anthracnose was pronounced at 10% GA+10 g L-1 of turmeric extract (38.6%) which was not significantly different at 10% GA+10 g L-1 of ginger extract compared to control (41.3%). Composite coating of 10% GA+10 g L-1 of turmeric extract maintained the postharvest quality of dragon fruit as was evident with a reduction in weight loss (2.53%), delayed degradation of titratable acids (0.15%), and maintained fruit firmness (28.72 N) and the overall acceptability of the fruit after 28 days. We conclude that incorporation of 10% GA with turmeric extract at a high concentration can serve as a potential biofungicide in postharvest management of fresh produced by reducing phytotoxicity while improving the overall acceptability of fruit.
... Earlier, 2 Journal of Food Quality tomatoes coated with gum arabic and kept at 20 ∘ C up to 20 days showed improved quality without production of any spoilage or off-flavors [19]; meanwhile, gum arabic coating in sweet cherries delayed the ripening process and off-flavor development [20]. In another study, gum arabic coating reduced textural damage and decay of green bell pepper [21], whereas gum arabic in combination with silver nanoparticles inhibited microbial growth and increased shelf life of green bell peppers [22]. A recent report showed that gum arabic along with calcium chloride enhanced low temperature tolerance in mango by improving the antioxidant defense system and reducing oxidative damage of mango fruit [23]. ...
... Previously, gum arabic application maintained higher ascorbic acid content in tomato slices [50]. Our results are also in agreement with the findings of Hedayati and Niakousari [22] who reported that gum arabic significantly reduced loss in ascorbic acid contents in green bell pepper. Moreover, the linear increase in pH might be ascribed to biochemical, structural, and physiological alterations taking place during respiration. ...
The present study was carried out to investigate the influence of food grade coatings on fruit quality and storage life of bell pepper cv. “Yolo Wonder” at 8±1 °C with 90–95% RH for 24 days. Coating treatments were given to bell pepper fruits by dipping in aqueous solutions of gum arabic (6, 9, and 12%), Aloe vera gel (4, 5, and 6%), and cinnamon oil (0.5, 0.75, and 1%). Physicochemical characteristics as well as quality of bell pepper fruits improved in all coating treatments. Results revealed that 12% gum arabic coating exhibited significantly reduced weight loss, membrane leakage, chilling injury, and decay incidence with less increase in pH, total soluble solids, and sugar percentage, whereas appealing fruit color ( L⁎ , a⁎ , and b⁎ ) along with higher values of ascorbic acid (1.84 mg/100 g), titratable acidity (0.19%), and firmness (4 N) was observed in cold storage environment. Our results clearly suggested that coating of bell pepper fruits with 12% gum arabic can maintain postharvest storage quality of bell pepper fruits.
... To inhibit the interaction between the core of particles and mucus components [174] Poloxamer 407-coated fluorescently tagged PLGA nanoparticles 60-80% of the surfactant-coated nanoparticles were dispersed in the mucus layer by coating with poloxamer 407, regardless of the type of nanoparticles [175] Gum arabic containing silver nanoparticles and a nonionic surfactant (glyceryl monostearate Protected the antioxidant (vitamin C) in the green bell pepper from dehydration and microbial spoilage and maintained marketable quality even after 21-days of storage [176] Silver nanoparticles coated with SDS or polysorbate 80 Increased antimicrobial activity of silver against 10 strains of bacteria [177] Surfactant modified nanoparticles as softening agent: Flexible zwitterionic ligands, which give nanoparticles exceptional functionality and stability [178]. These zwitterionic ligands form hydrogen bonds and electrostatic interactions have the capacity to bind numerous water molecules, thereby constraining non-specific relationships to biomolecules in the environment. ...
Surfactants play a major role in the formation of nanoparticles due to their strong dispersion-enhancing properties. Nano-emulsions are non-equilibrium systems, their characteristics properties rely on both their synthesis process and composition. Research on optimization strategies for the synthesis of nanomaterials is currently increasing. Surfactants are a flexible class of materials that emphasize surface energy levels, chemical properties, regularity, pH sensitivity, activity and the performance of nanoparticles. The broad spectrum of surface improvements and applications, such as sensors, catalytic activity, the conversion of energy and storage capacity, biological acceptance and therapeutics, dispersion behaviour of nanoparticles in fundamental composite materials, cement, traditional detergents, purification systems and particular applications in environmental sensing have become inevitable. The exploration of design concepts for surfactants that enhance the efficacy of specific nanostructures has been increasingly prominent in recent discussions.
... Chlorophyll breakdown is initiated by the presence of oxygen and enzymes such as chlorophyllase (Gong and Mattheis, 2003). Lower temperatures inhibit enzymatic functions, leading to a postponement in color alteration (Hedayati and Niakousari, 2015). In fact, this study observed a high retention of green color at 4 • C. ...
... The present study showed that the BPFs coated with 1% GT were more effective in reducing the loss of AsA as compared to other treatments. Our results are consistent with those of other researchers who showed that ECs were effective in reducing the loss of AsA inBPFs (Adetunji et al., 2019;Hedayati & Niakousari, 2015;Ullah et al., 2017). The use of ECs may reduce the release of oxygen, thus reducing the speed of fruit ripening; thus, it preserves AsA content and delays fruit senescence(Adetunji et al., 2019;Xing et al., 2011). ...
Bell pepper fruits (Capsicum annuum L.) are prone to both physiological and pathological deterioration following harvest, primarily due to their high metabolic activity and water content. The storage of bell peppers presents several challenges, including weight loss, softening, alterations in fruit metabolites and color, increased decay, and a decline in marketability. The application of edible coatings (ECs) is one of the environmentally friendly technologies that improves many post‐harvest quantitative and qualitative characteristics of products. This research investigated the impact of different levels of gum tragacanth (GT) coating (0, 0.25, 0.5, 1, and 2%) on the physiological and biochemical traits of stored bell pepper fruits (BPFs) (8 ± 1°C, 90–95% RH) for 28 days. The results showed the positive effect of coating treatments with higher concentrations of GT, up to 1%. Increasing the concentration of GT to 2% decreased the marketability and quality characteristics of fruits compared to 1% GT. After storage, the physiological weight loss of the fruits treated with 1% GT (10.46%) was lower than that of the uncoated fruits (18.92%). Furthermore, the coated fruits (1% GT) had more firmness, total phenol content, ascorbic acid, and titratable acidity content than uncoated fruits during storage. At the end of storage, the coated BPFs with 1% GT showed higher SOD (97.02 U g⁻¹), CAT (24.38 U g⁻¹) and POD (0.11 U g⁻¹) activities and antioxidant capacity (81.74%) as compared to other treatments. Total soluble solids, total carbohydrates, total carotenoids, pH, malondialdehyde, and electrolyte leakage content increased in coated fruit during storage but were significantly lower than in uncoated fruits. Moreover, the samples coated with GT (1%) maintained good marketability (about 75%), while the marketability of the control (about 40%) was unacceptable. The study shows that GT (1%) coating can be a promising novel treatment option for increasing the storage quality of BPFs.
... Tis outcome can be attributed to the degradation of chlorophyll resulting from factors such as oxygen presence and chlorophyllase enzymes. Te reduction in enzyme activity at lower temperatures contributes to the delayed alteration in color [29]. Regarding the yellow-blue (b * * ), the control group slightly decreased throughout the storage period, while the treatment group showed an increase followed by a decrease. ...
The utilization of natural preservatives presents a promising avenue for mitigating the spoilage of fresh-cut fruits and vegetables induced by microorganisms, enzymatic browning, and water loss. We have developed an innovative method for preserving fresh-cut green peppers using the combined effects of ε-polylysine (ε-PL) and p-Coumaric acid (p-CA). Through concentration screening experiments, we determined that the optimal concentrations of ε-PL and p-CA were 25 mg/L and 10 mg/L, respectively (ε-p-CA). Treatment with ε-p-CA significantly improved the quality of fresh-cut green peppers. It effectively reduced hardness and weight loss, preserving the texture and appearance of the peppers. Furthermore, ε-p-CA treatment delayed the increase in respiratory rate, electrolyte leakage, and ethylene production, thereby maintaining the structural integrity. Meanwhile, ε-p-CA treatment effectively inhibited the malondialdehyde (MDA) content increase and maintained DPPH radical scavenging activity. The microbial analysis demonstrated the ε-p-CA-treated peppers also showed lower total bacterial, mold, and yeast counts, which prolonged the freshness of fresh-cut peppers. In addition, ε-p-CA treatment improved the retention of phenolics and vitamin C without significantly affecting the color and soluble sugar content of green peppers. Overall, the ε-p-CA treatment showed promise as a natural preservative for extending the shelf life of fresh-cut green peppers.
... For over 3 months it has demonstrated excellent dispersion with no agglomeration development (Bankura et al., 2012). Hedayati and Niakousari (2015) evaluated the effectiveness of silver nanoparticles distributed in a gum arabic coating whose effect was seen on enhancing the shelf life of bell peppers (peppers). When a comparison was made with the uncoated samples, the coating greatly prevented the development of aerobic bacteria after 21 days storage period at different temperatures. ...
Recent advances in nanoscience and nanotechnology aim for
fresh and inventive uses in the food industry, which is relatively
new in comparison to their usage in the biological and pharmaceutical
industries. Nanotechnology is focused on material over a
molecular as well as atomic level. Other characteristics of a nanostructure
often include physicochemical characteristics, which
include surface area, surface hydrophobicity, heat resistance, and
antimicrobial activities. Recent progress in food packaging has lied
heavily on nanotechnology construction (Sharma et al., 2017). The
introduction of nanostructures into packaging materials has substantially
enhanced the performance and expanded the functions
of these materials due to various unique features of nanostructures
that are missing in their bulk forms. The use of nanostructures
(nanotechnology) in food technology has demonstrated
several benefits in terms of increasing food quality and extending
its shelf life (Cerqueira et al., 2018). Food preservation entails preventing
all elements of food degradation, which are ultimately the
source of nutritional loss and food safety loss. The most important
and common example of this is the oxidative reaction, which
results in vitamin degradation, flavor change, and visual damage
to food, such as the browning reaction in vegetables, fruits, and
meat. Utilizations of nanotechnology have been stressed in the
portrayal, manufacture, and control of nanostructures or nanomaterials
(Chen et al., 2021). Nanostructured materials are being
used in a variety of areas of food science, including nanosensors,
... The increased respiration and oxidation of acids into sugars could be to blame for the drop in vitamin C concentration. The present findings are similarly consistent with those of Hedayati et al. [40], who found that the coating of SGBP with arabic gum dramatically reduced ascorbic acid loss. Moreover, the linear increase in pH might be ascribed to biochemical, structural, and physiological alterations taking place during respiration. ...
... Se han empleado diversas estrategias de envasado para prolongar la vida de anaquel de algunos tipos de chiles del género Capsicum annuum. Entre estas estrategias se han implementado recubrimientos de ácido giberélico, goma arábiga, quitosano o envasados en atmósferas modificadas (Chitravathi, Kallepalli, Chauhan & Kizhakkedath, 2020;Hedayati & Niakousari, 2015;Hernández-López, Ventura-Aguilar, Correa-Pacheco, Bautista-Baños & Barrera-Necha, 2020;Panigrahi, Gheewala, Patel, Patel & Gantait, 2017;Singh, Giri & Kotwaliwale, 2014;Xing et al., 2011). Sin embargo, la mayoría de los agricultores, transportistas y consumidores no pueden pagar los costos de mantenimiento de las instalaciones de almacenamiento atmosférico controlado o implementar el empleo de recubrimientos o películas comestibles, por lo que es necesario desarrollar sistemas económicos y viables para 2021 https://doi.org/10.22201/fesz.23958723e.2021.365 ...
The growing interest in conserving the environment is motivating the development of biodegradable packaging for food from agro-industrial waste. Corn crops and Mexican pinion generate considerable amounts of lignocellulose waste that can be used as feedstock to make paper packaging. The objective of this work was to elaborate and characterize a paper packaging from cellulose of fibrous residues of Mexican pinion (CCJ) and corn stem/leaves (CTM), and to determine its functionality in prolonging the useful life of serrano peppers stored at room temperature. Paper was made from different concentrations (100-0 to 80-20%) of CTM and CCJ by alkaline method with NaOH. Paper formulation P5 was selected corresponding to a relation 95-5% of CTM-CCJ respectively with the purpose to use it to preserve quality in Serrano pepper (grammage 97.0 g/m 2 , hardness 3112 MPa, thickness 0.25 mm). The use of P5 as packaging for Serrano pepper favors the values of firmness, moisture, color and vitamin C with respect to the control pepper during the days of storage at room temperature. The properties of texture and color are extremely important in the qualitative quality of Serrano pepper, since being a variety of fresh consumption, are criteria for consumption or acquisition of this product.
... 346 Hedayati et al prepared surfactantcoated nanoparticles (gum Arabic containing silver nanoparticles and a nonionic surfactant (glyceryl monostearate [ Figure 1]). 347 They reported that coating green bell pepper with this product protected the antioxidant (vitamin C) in the green bell pepper from dehydration and microbial spoilage and maintained marketable quality even after 21-days of storage. Since silver nanoparticles need to be in a dispersed state to exert their antibacterial effect, the approach of coating their surface with a non-ionic surfactant and dispersing them in a system is widely used. ...
Surfactants, whose existence has been recognized as early as 2800 BC, have had a long history with the development of human civilization. With the rapid development of nanotechnology in the latter half of the 20th century, breakthroughs in nanomedicine and food nanotechnology using nanoparticles have been remarkable, and new applications have been developed. The technology of surfactant-coated nanoparticles, which provides new functions to nanoparticles for use in the fields of nanomedicine and food nanotechnology, is attracting a lot of attention in the fields of basic research and industry. This review systematically describes these “surfactant-coated nanoparticles” through various sections in order: 1) surfactants, 2) surfactant-coated nanoparticles, application of surfactant-coated nanoparticles to 3) nanomedicine, and 4) food nanotechnology. Furthermore, current progress and problems of the technology using surfactant-coated nanoparticles through recent research reports have been discussed.
... Fruit post-harvest: edible coatings of 10% Gum Arabic signifi cantly delayed changes in fi rmness, weight, soluble solids, ascorbic acid, titratable acidity, percentage decay and colour development of tomato during 20 days storage (Asgar et al., 2013). Gum Arabic in aqueous solution of 10% combined with silver nanoparticles signifi cantly hindered the growth of microorganisms and physicochemical losses, and showed the best performance for enhancing the shelf life of green bell peppers (Hedayati and Niakousari, 2015). Application of GA 10% coating combined with CA 3% might be a simple and eff ective technique for preserving mango fruit quality during low temperature storage (Ghulam et al., 2015). ...
... Green bell peppers are perishable products and their keeping quality is relatively low. The main physiological factors that negatively affect the postharvest quality of pepper are pathological factors, water loss and chilling injury (Hedayati and Niakousari, 2015) There are many methods commonly used for bell pepper physical quality inspection: grading machine based on imaging and near infra red which can grade bell peppers based on their size, color, shape and their biological properties including cultivar, season, maturity level and geographical origin . As well as for nutritional monitoring of green pepper during storage: quantification of total acidity, total soluble solid content, protein content, proline content, catalase activity, peroxidase activity, total antioxidant activity, chlorophyll content and capsaicin content (Patel N. et al., 2019) those methods somehow having disadvantages of being destructive, time consuming and expensive. ...
Determining the index for monitoring the freshness of green pepper during storage is still a challenge to be solved in research to avoid food loss, linked to the economical loss. The aim of the present study was to investigate the potentiality of fluorescence spectroscopy for the determination of the freshness index. Time series fluorescence characteristics from different parts of green pepper (Capsicum annuum L.) at different temperatures of storage were determined. Three replicate measurements of Excitation and Emission Matrix (EEM) fluorescence were conducted on every single evaluation during 20 days of storage with a 1-day interval starting from day 4 after harvest. Physical evaluation of color change, firmness, and weight loss were observed to have a correlation with the EEM fluorescence intensity. It was observed that fluorescence components could be extracted from green pepper, the intensity of chlorophyll-a EEM significantly dropped after day 16th from 2822 a.u and 2810 a.u to 2038 a.u and 2106 a.u in day 20th stored at 20 • C and 4 • C respectively as well as the color change behaved the same as the R/G value increased from 0.541 and 0.535 to 0.655 and 0.610 at 20 • C and 4 • C respectively. Finally, it is suggested that two suspected flavonoids substances with EEM 230-nm/310 nm and 270-nm/310 nm are potential to be a probe for freshness index in green pepper as the ratio of these EEMs increased linearly during storage with R2 0.96 and R2 0.91 for both temperatures 20 • C and 4 • C respectively.
... GA coating decreases the rate of change of color and loss of total phenolics, total flavonoids, and ascorbic acid in fruits (Alali et al., 2018;Khaliq, Muda Mohamed, Ghazali, Ding, & Ali, 2016). GA incorporated with silver nanoparticles significantly retarded growth of microorganisms and physicochemical losses and improved the shelf life of green bell peppers (Hedayati & Niakousari, 2015). Given the extensive use of GA in fresh and processed food industry, to our knowledge, no study has been carried out to investigate its capability to improve postharvest quality of stored persimmon fruits. ...
Hydrocolloid gums are extensively used in food industry. Recently, hydrocolloid gums such as gum arabic have been widely researched as edible coatings to extend post-harvest life of fruits and vegetables. Therefore, in this study, the efficacy of gum arabic (GA)-based edible coating was investigated for maintaining quality of persimmon fruits during ambient storage. Persimmon fruits were coated with 0 and 10% GA and stored at 20 ± 1°C and 80 ± 2% RH for 20 days. The 10% GA-coated fruits showed significantly lower weight loss, membrane leakage, H2O2, and malondialdehyde content than control. GA application suppressed increase in activities of polygalacturonase, pectin methylesterase, and cellulase enzymes. GA-coated fruits exhibited substantially higher superoxide dismutase, peroxidase, ascorbate peroxidase, andcatalase activities. Moreover, coated persimmons showed markedly higher total phenolics, ascorbic acid, antioxidant activity, and titratable acidity, but reduced total carotenoids, total soluble solids, and ripening index throughout the storage.
... They reported that using a combination of active coating with PP bags prolonged the shelf-life of carrots for about 70 days compared with 4 days for the uncoated samples. In another study, Hedayati et al. [66] investigated the efficiency of AgNPs dispersed in gum arabic-based coating to extend the shelf-life of green bell peppers. After 21 days of storage at both tested temperatures 7 °C and 20 °C, the coating significantly inhibited the growth of aerobic microorganisms when compared to uncoated samples. ...
Packaging is an integral part of food products, allowing the preservation of their quality. It plays an important role, protecting the packed product from external conditions, maintaining food quality, and improving properties of the packaged food during storage. Nevertheless, commonly used packaging based on synthetic non-biodegradable polymers causes serious environmental pollution. Consequently, numerous recent studies have focused on the development of biodegradable packaging materials based on biopolymers. In addition, biopolymers may be classified as active packaging materials, since they have the ability to carry different active substances. This review presents the latest updates on the use of silver nanoparticles in packaging materials based on biopolymers. Silver nanoparticles have become an interesting component of biodegradable biopolymers, mainly due to their antimicrobial properties that allow the development of active food packaging materials to prolong the shelf life of food products. Furthermore, incorporation of silver nanoparticles into biopolymers may lead to the development of materials with improved physical-mechanical properties.
The unregulated and extensive application of synthetic compounds, such as preservatives, pesticides, and drugs, poses serious concerns to the environment, food security, and global health. Essential oils (EOs) are valid alternatives to these synthetic chemicals due to their therapeutic, antioxidant, and antimicrobial activities. Lavender essential oil (LEO) can be potentially applied in food, cosmetic, textile, agricultural, and pharmaceutical industries. However, its bioactivity can be compromised by its poor stability and solubility, which severely restrict its industrial applications. Encapsulation techniques can improve the functionality of LEO and preserve its bioactivity during storage. This review reports recent advances in the encapsulation of LEO by different methods, such as liposomes, emulsification, spray drying, complex coacervation, inclusion complexation, and electrospinning. It also outlines the effects of different processing conditions and carriers on the stability, physicochemical properties, and release behavior of encapsulated LEO. Moreover, this review focuses on the applications of encapsulated LEO in different food and non-food products
The biodegradable activity antibacterial materials have been widely applied on food preservation because they not only protect foods from pathogenic attacks but also relieve environmental pollution. Biodegradable melt-blown nonwovens (MB) have several advantages over the other materials in terms of a simpler and more environmentally friendly fabrication process, higher specific surface area, and lower cost. Herein, polylactic acid (PLA) MB is first modified by polydopamine (PDA) to activate the surface. Then, chitosan (CS) and cinnamon essential oil (CEO) are used to decorate the surface of the modified PLA MB via a simple one-pot method to prepare CEO/CS@PLA MB with different CEO contents. Compared with PLA MB, CEO/CS@PLA MB had a rougher surface and larger average fiber diameter, while the average pore diameter and air permeability reduced. The input of CEO led to a decrease in the tensile strength of CEO/CS@PLA MB and an obvious increase in the elongation at break. The combination of CS and CEO shows excellent synergistic antibacterial effect. The antibacterial efficiencies of CEO/CS@PLA MB against Escherichia coli and Staphylococcus aureus enhance with the increase of the CEO content. When the weight ratio of CS to CEO is 1:2, the antibacterial efficiencies of CEO2/CS@PLA MB against E. coli and S. aureus are 99.98 and 99.99%, respectively. When being applied to the preservation of fresh strawberry, CEO2/CS@PLA MB can effectively inhibit the microbial growth in strawberry and reduce decay, which extends the shelf time of strawberry.
Nanoparticles (NPs) have acquired significance in technological breakthroughs due to their unique properties, such as size, shape, chemical composition, physiochemical stability, crystal structure, and larger surface area. There is a huge demand for packaging materials that can keep food fresher for extended periods of time. The incorporation of nanoscale fillers in the polymer matrix would assists in the alleviation of packaging material challenges while also improving functional qualities. Increased barrier properties, thermal properties like melting point and glass transition temperatures, and changed functionalities like surface wettability and hydrophobicity are all features of these polymers containing nanocomposites. Inorganic nanoparticles also have the potential to reduce the growth of bacteria within the packaging. By incorporating nano-sized components into biopolymer-based packaging materials, waste material generated during the packaging process may be reduced. The different inorganic nanoparticles such as titanium oxide, zinc oxide, copper oxide, silver, and gold are the most preferred inorganic nanoparticles used in food packaging. Food systems can benefit from using these packaging materials and improve physicochemical and functional properties. The compatibility of inorganic nanoparticles and their various forms with different polymers make them excellent components for package fortification. This review article describes the various aspects of developing and applying inorganic nanoparticles in food packaging. This study provides diverse uses of metals and metal oxides nanoparticles in food packaging films for the development of improved packaging films that can extend the shelf life of food products. These packaging solutions containing nanoparticles would effectively preserve, protect, and maintain the quality of the food material.
Nanomaterials have so far earned huge acceptance due to its promising applications in food packaging industry. Most of the shortcomings of conventional packaging has been succeeded with the introduction of nanotechnology in the packaging sector. Nanotechnological interventions in packaging field with the development of antimicrobial nanocomposites shows promises in protecting food from microbial spoilage and extending food shelf-life for longer duration. Among the various nanomaterials applied in packaging materials, silver nanoparticles (AgNPs) has renowned as the best candidate with immense applications, because of its varied and unique features. Today, silver-based nanomaterials find varied applications in food packaging sector, which include functionalized packagings with antimicrobial and improved physicochemical properties; edible nanocoatings, which can protect and retain food freshness, and moreover, thermal resistant high performance packages. In spite of the increasing exploitation and acceptance of AgNPs in various food contact materials, the possible issues associated with its release into food has to be properly and carefully addressed.
A novel synthesis of tin sulfide film was used for the first time when the film was prepared directly from abundant and biodegradable precursors via a simple SILAR (successive ionic layer adsorption and reaction) method at 40 °C. The structural, optical and electrochemical properties of tin sulfides are explored by changing the number (20 or 30) of SILAR cycles and the quantity of L-ascorbic acid (0.6-1.3 g). X-ray diffraction data showed the multiphase composition consisting of SnS and Sn2S3 in obtained films on fluorine doped tin oxide coated glass slides and Raman spectroscopy confirmed this. The most intensive peaks are assigned to mineral herzenbergite. Scanning electron microscopy showed that the films consist of densely packed irregular clusters of nanoparticles. The crystallite size was in the range of 9 - 15 nm and was dependent on the number of SILAR deposition cycles. The average size of the thickness of films varied from 310 to 1050 nm. The bandgap values calculated using ultraviolet-visible light spectroscopy data are very close to the theoretical values of herzenbergite (0.9- 1.3 eV). Electrochemical measurements showed that among all the films tested in this study, a tin sulfide film prepared with the lowest quantity of ascorbic acid is able to generate the highest specific capacitance of 6.35 F⋅g⁻¹ with the best specific energy value of 3.53 Wh⋅kg⁻¹. These results confirmed that the samples are promising candidates to be used as supercapacitors.
Packaging is the last stage of food processing and a successful package is one that protects a product or contents from environment for a period of time with a reasonable cost. The package affects the quality of foods by controlling the degree of factors connected with processing, storage and handling that can act on components of food. Use of nanotechnology in science brings great opportunities to many industries including food packaging industry. Recently, various engineered nanomaterials such as nanoclays and metallic nanoparticles have been introduced to food packaging as functional additives. Their positive effects on developed packaging materials have been extensively reported. Nanoclays and metallic nanoparticles are also promising in active packaging technology, an innovative technology for food preservation based principally on mass transfer interactions between systems “food/packaging”. These nanoparticles have been applied to packaging system using different ways. This chapter aims to give an overview about the use of nanoparticles for food packaging and introduce the nanoclay and metallic nanoparticle types. Recent developments on active packaging produced by the use of nanoparticles are summarized. Migration studies and their safety issues are also discussed.
Selenium (Se)-rich binary Cu-Se and In-Se nanoparticles (NPs) were synthesized by a modified heat-up method at low temperature (110 °C) using the gum exudates from a cherry blossom tree. Coating of CISe absorber layer was carried out using Se-rich binary Cu-Se and In-Se NPs ink without the use of any external binder. Our results indicated that the gum used in the synthesis played beneficial roles such as reducing and capping agent. In addition, the gum also served as a natural binder in the coating of CISe absorber layer. The CISe absorber layer was integrated into the solar cell, which showed a power conversion efficiency (PCE) of 0.37%. The possible reasons for low PCE of the present solar cells and the steps needed for further improvement of PCE were discussed. Although the obtained PCE is low, the present strategy opens a new path for the fabrication of eco-friendly CISe NPs solar cell by a relatively chief non-vacuum method.
Tin monoselenide (SnSe) nanoparticles (NPs) have great potential to replace the conventional absorbers used in the fabrication of thin film solar cells. However, the studies pertain to the synthesis and fabrication of SnSe NPs based solar cells are still lacking. This article presents the eco-friendly synthesis of SnSe NPs by a chemical precipitation method in a short reaction time of 10 min. The effect of different reducing agents (such as NaOH, ethylenediamine, Na2SO3, and NaBH4) on the reactivity of Se-precursor and phase formation of SnSe NPs was investigated in detail. Our study indicated that the reaction between Sn2+ ions complexed by ascorbic acid and Se2- ions provided by the reduction with NaBH4 was resulted into the formation of single phase SnSe NPs. For the first time, SnSe NPs thin film inorganic solar cell with device structure of SLG/Mo/ SnSe NPs/CdS/i-ZnO/Al:ZnO/Ni/Ag was fabricated and tested, which showed an efficiency of 0.43%.
This study investigated a freshness assessment method utilizing electronic nose (e-nose) for fresh-cut green bell pepper (Capsicum annuum var. grossum) stored at 7 ± 1 °C. Physicochemical results showed that the fresh-cut green bell peppers were fresh until 5 days and became spoiled at 7 days, particularly as evidenced by a surge in aerobic plate count and malondialdehyde content on subsequent days. The e-nose data combined hierarchical cluster analysis (HCA) can preliminarily distinguish between fresh (days 0, 1, 3 and 5) and spoiled (days 7 and 9) samples. Principal component analysis (PCA) result showed that days 0 and 1 samples were mixed together in PCA plot, and the other different groups can be obtained according to the different sampling days. Partial least squares (PLS) statistical model (R² = 0.9783, RMSE = 0.3317) was used to correlate the e-nose data with the aerobic plate counts. The results suggested the promising possibility of e-nose system for monitoring freshness of fresh-cut green bell pepper.
Edible films and coatings are thin layers of edible materials applied on food products that play an important role on their conservation, distribution and marketing. Some of their functions are to protect the product from mechanical damage, physical, chemical and microbiological activities. Their use in food applications and especially highly perishable products such as horticultural ones, is based on some particular properties such as cost, availability, functional attributes, mechanical properties (flexibility, tension), optical properties (brightness and opacity), the barrier effect against gases flow, structural resistance to water and microorganisms and sensory acceptability. In this piece of work, the lastest advances on their composition (polymers to be used in the structural matrix), including nanoparticles addition, and properties have been reviewed, as well as the trends in the research about their different applications, including oil consumption reduction in deep-fat fried products, their use in combination with bioactive compounds that bring foodstuff additional functions and shelf life extension of highly perishable products.
Edible coatings can represent an alternative for extending post-harvest life of perishable fruits, as strawberries. In this
work, the effect of cassava starch edible coatings, added or not of potassium sorbate, on mechanical properties, surface color,
sensory acceptance, and respiration rate of strawberries was evaluated in order to choose the best coating conditions to minimally
processed strawberries. Integrity and water-vapor resistance of the coatings were also evaluated. Three different concentrations
of cassava starch (1%, 2%, and 3%) and two concentrations of potassium sorbate (0.05% and 0.10%) were used in the coatings
formulations. Minimally processed strawberries without coating were used as control samples. The strawberries treated with
different coatings and control fruits did not present differences regarding mechanical properties, surface color, and all
the sensory attributes evaluated. A good integrity of cassava edible coatings on strawberries surface was observed for 2%
and 3% starch concentration and the use of coatings, in these concentrations, reduced the strawberries respiration rate, representing
a possibility to extend the shelf life of fruits. All coatings showed beneficial effects on increasing the water vapor resistance
of the samples, but a significant increase was obtained only with the use of coating with 3% of starch. The potassium sorbate
improved significantly the resistance to water vapor, but no differences were observed between the two concentrations studied.
Based these results, the coatings with 3% of cassava starch and 3% of cassava starch +0.05% of potassium sorbate were those
selected for future shelf life study of minimally processed strawberries.
KeywordsStrawberry-Respiration rate-Edible coating-Cassava starch-Potassium sorbate-Minimal processing
To investigate the mechanism of inhibition of silver ions on microorganisms, two strains of bacteria, namely Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus), were treated with AgNO3 and studied using combined electron microscopy and X-ray microanalysis. Similar morphological changes occurred in both E. coli and S. aureus cells after Ag⁺ treatment. The cytoplasm membrane detached from the cell wall. A remarkable electron-light region appeared in the center of the cells, which contained condensed deoxyribonucleic acid (DNA) molecules. There are many small electron-dense granules either surrounding the cell wall or depositing inside the cells. The existence of elements of silver and sulfur in the electron-dense granules and cytoplasm detected by X-ray microanalysis suggested the antibacterial mechanism of silver: DNA lost its replication ability and the protein became inactivated after Ag⁺ treatment. The slighter morphological changes of S. aureus compared with E. coli recommended a defense system of S. aureus against the inhibitory effects of Ag⁺ ions. © 2000 John Wiley & Sons, Inc. J Biomed Mater Res, 52, 662–668, 2000.
Quality of bell peppers after harvest is largely influenced by water loss from the fruit. The objective
of this study was to determine the effect of fruit fresh weight, size, and stage of ripeness on the rate of water
loss and permeance to water vapor. Fruit diameter was correlated with fresh weight, and surface area was
associated with fresh weight and diameter. Fruit surface area decreased logarithmically with increases in fruit
size, with smaller fruit showing larger changes in surface area than larger fruit.Mean water loss rate for individual
fruit and permeance to water vapor declined with increases in fruit size and as fruit ripeness progressed. Fruit
surface area/fresh weight ratio and rate of water loss were both highest in immature fruit and showed no
differences between mature green and red fruit. In mature fruit, permeance to water vapor for the skin and calyx
were 29 μmolm−2 s−1 kPa−1 and 398 μmolm−2 s−1 kPa−1, respectively. About 26% of the water loss in mature fruit
occurred through the calyx. There was a decline in firmness, water loss rate, and permeance to water vapor of the
fruit with increasing fruit water loss during storage
In this work, the effects of both active coating loaded with silver-montmorillonite (Ag-MMT) nanoparticles and film barrier properties on shelf life of fresh-cut carrots are presented. In particular, sensory and microbiological quality has been monitored during the storage period. While for microbiological quality the main spoilage microorganisms (mesophilic and psychrotrophic bacteria, Enterobacteriaceae spp., Pseudomonas spp., yeasts and moulds) were monitored, colour, odour, firmness and product overall quality were judged for the sensory evaluation. Results highlighted that statistically significant differences in microbial populations were found between coated and active coated samples. For the products with active coating microbial cell loads remained always below the selected microbial threshold. Moreover, samples packaged with the active coating appeared to be better preserved from a sensory point of view. As regards packaging mass transport properties, the film made up of oriented polypropylene with a thickness of 20 μm was found to be the most suitable for fresh-cut carrots. Thus, experimental results demonstrated that a significant shelf life prolongation up to more than two months can be achieved by using the developed active coating before packaging the fresh-cut carrots in a proper system.
The effects of an edible coating, i.e. SemperfreshTM and cold storage on shelf-life and quality of cherries were studied. Two groups of cherries (Prunus avium) were coated just after harvest with 10 and 20 g/L SemperfreshTM fruit coating which is composed of sucrose esters of fatty acids, sodium carboxymethyl cellulose and mono-diglycerides of fatty acids. Half of the cherries from each of the above groups was stored at ambient temperature (∼30±3 °C) and at 40–50% relative humidity, the other half of the cherries was stored at cold storage (0 °C) and at 95–98% relative humidity. Each group was analysed for the following quality parameters: firmness, weight loss, titratable acidity, soluble solid content, sugar content, ascorbic acid content, and external color. It was demonstrated that SemperfreshTM was effective to reduce the weight loss and increase firmness, ascorbic acid content, titratable acidity and skin color of cherries during storage time. However, soluble solid content and sugar content were not affected by coating. The results of this study suggest that SemperfreshTM increased the shelf-life of the cherries by 21% at 30±3 °C and by 26% at 0 °C without perceptible losses in quality.
Silver nanoparticles have recently gained increasing interests due to their antimicrobial activities in food processing applications. The aim of this study was to evaluate the effect of silver nanoparticles-PVP coating on weight loss, ascorbic acid, total chlorophyll, crude fiber, color, firmness and microbial qualities of asparagus spears stored at 2 and 10°C. Asparagus samples were first sanitized with 100mgl−1 sodium hypochloride solution for 15min. They were then immersed in coating solution containing silver nanoparticles for 3min at room temperature. During 25-day storage at 2 or 10°C, the coated asparagus demonstrated lower weight loss, greener color and tender texture compared with the control samples. The growth of microorganism was significantly hindered by the coating. Based on comprehensive comparison and evaluation, asparagus spears coated by silver nanoparticles could be kept in good quality for 25 days at 2°C and for 20 days at 10°C.
Physicochemical responses and microbial characteristics of shiitake mushroom (Lentinus edodes) to gum arabic (GA) coating incorporating natamycin (NA) during storage were investigated. Mushroom weight loss, firmness, total soluble solids, total sugar, reducing sugar, ascorbic acid, and microbial and sensory quality were measured. Mushroom coated with gum arabic+natamycin (GANA) maintained tissue firmness and showed reduction in microbial counts from yeasts and moulds compared with the control. In addition, GANA coating also delayed changes in the soluble solids concentration, total sugar and ascorbic acid. Sensory evaluation proved the efficacy of GANA coating by maintaining the overall quality of shiitake mushroom during the storage period. The efficiency was better than that of GA or NA treatment alone. Our study suggests that GANA has the potential to improve the quality of shiitake mushroom and extend its shelf-life up to 16d.
Coating of tomato fruit with gum arabic has been found to enhance their shelf-life and postharvest quality. Gum arabic in aqueous solutions of 5, 10, 15 and 20% was applied as a novel edible coating to green-mature tomatoes which were stored at 20 °C and 80–90% RH for 20 d. Fruit coated with 10% gum arabic showed a significant (P ≤ 0.05) delay in changes of weight, firmness, titratable acidity, soluble solids concentration, ascorbic acid content, decay percentage and colour development compared to uncoated control fruit. Sensory evaluation proved the efficacy of 10% gum arabic coating by maintaining the overall quality of tomato fruit during the storage period. The results suggest that by using 10% gum arabic as an edible coating, the ripening process can be delayed and the storage life of tomatoes stored at 20 °C and at the breaker stage can be extended up to 20 d without any spoilage and off-flavour.
Green bell pepper fruits (Capsicum annuum L., cv. “Jupiter”) were coated with a mineral-oil-based coating or a cellulose-based coating. Three different milk-protein-based edible coatings (whey protein isolate, sodium caseinate, and sodium caseinate beeswax emulsion) plasticized with glycerol were also tested. The effects of these coatings were followed by measurement of changes in respiration, internal gases, color, firmness, and water loss during storage at 10°C, 80–85% RH for 20 days. None reduced respiration or affected color. Only the mineral-oil-based coating significantly reduced moisture loss, thus maintaining fruit firmness and thereby prolonging fruit freshness.
Firmness and soluble solids content (SSC) of Red Fuji apples were examined by Vis/NIR transmittance to find out factors to be considered in online detection. Four arrangements of light source and fruit-orientation were investigated. The wavelength range of 650–920 nm was selected and two types of data pre-processing were used to enhance the precision of calibration models based on partial least square (PLS). The results show the precision of determination can be improved by using second derivate. The best fruit-orientation was the stem–calyx axis was vertical and the fruit surface was illuminated from the upper side. The precision of determination was enhanced by using multi lamps. According to the high grade of apple to export (SSC ⩾ 14 °Brix, firmness ⩾ 8.0 kg/cm2), the classifying correctness was 86%. Validation models for SSC and firmness had a r2 of 0.9532 and 0.8136, as well as, SEP of 0.3838 and 0.5344, respectively.
This paper presents a simple method that shows how digital imaging and software analysis can be combined for color measurement. The results showed that L∗, a∗ and b∗ values from Hunter colorimeter and the digital imaging method had appropriate correlation with R2 of greater than 0.98, however color values obtained from digital imaging method can be used only to monitor the trend of color changes and relative comparison and there is a noticeable difference between L∗, a∗ and b∗ from digital imaging and values of Hunterlab colorimeter. By using equations presented in this paper, L∗, a∗ and b∗ values obtained from digital imaging method can be successfully converted to Hunterlab color values. Changes in color of Mazafati date during ripening by hot acetic acid solution were monitored by use of this method. L∗, a∗, and b∗ values of the samples decreased during ripening.
Quality of bell peppers after harvest is largely influenced by water loss from the fruit. The objective of this study was to determine the effect of fruit fresh weight, size, and stage of ripeness on the rate of water loss and permeance to water vapor. Fruit diameter was correlated with fresh weight, and surface area was associated with fresh weight and diameter. Fruit surface area decreased logarithmically with increases in fruit size, with smaller fruit showing larger changes in surface area than larger fruit. Mean water loss rate for individual fruit and permeance to water vapor declined with increases in fruit size and as fruit ripeness progressed. Fruit surface area/fresh weight ratio and rate of water loss were both highest in immature fruit and showed no differences between mature green and red fruit. In mature fruit, permeance to water vapor for the skin and calyx were 29 µmol m−2 s−1 kPa−1 and 398 µmol m−2 s−1 kPa−1, respectively. About 26% of the water loss in mature fruit occurred through the calyx. There was a decline in firmness, water loss rate, and permeance to water vapor of the fruit with increasing fruit water loss during storage. Copyright © 2006 Society of Chemical Industry
Branchlets of broccoli (Brassica oleracea L.) were used to examine ethylene-stimulated chlorophyll catabolism. Branchlets treated with: 1) air (CK); 2) 1 LL–1 1-methylcyclopropene (1-MCP) for 14 hr at 20 C; 3) 1000 LL–1 ethylene (C2H4) for 5 hr at 20 C; or 4) 1-MCP then C2H4, were stored in the dark at 20 C for up to 3 d. Chlorophyll (Chl) content and branchlet hue angle decreased during the storage period and 1-MCP treatment delayed this change. Chl degradation in broccoli was accelerated by exposure to C2H4, especially for Chl a. Prior treatment with 1-MCP prevented degreening stimulated by C2H4. Lipoxygenase activity was not altered by any of the treatments, however, 1-MCP with or without ethylene resulted in reduced activity of chlorophyllase (Chlase) and peroxidase (POD). Exposure to C2H4 stimulated Chlase activity and extended the duration of high POD activity. Treatment with 1-MCP followed by C2H4 resulted in reduced POD activity and delayed the increase in Chlase activity. The results suggest chlorophyll in broccoli can be degraded via the POD – hydrogen peroxide system. Exposure to C2H4 enhances activity of Chlase and extends the duration of high POD activity, and these responses may accelerate degreening. Treatment with 1-MCP delays yellowing of broccoli, an effect that may be due to the 1-MCP-induced reduction in POD and Chlase activities.
Silver nanoparticles (AgNP) are among the fastest growing product categories in the nanotechnology industry. Despite the importance
of AgNP in consumer products and clinical applications, relatively little is known regarding AgNP toxicity and its associated
risks. We investigated the effects of AgNP on gene expression in the mouse brain using Affymetrix Mouse Genome Arrays. C57BL/6
mice were exposed to AgNP (geometric mean diameter, 22.18±1.72nm; 1.91×107 particles/cm3) for 6h/day, 5days/week using the nose-only exposure system for 2weeks. Total RNA isolated from the cerebrum and cerebellum
was subjected to hybridization. From over 39,000 probe sets, 468 genes in the cerebrum and 952 genes in the cerebellum were
identified as AgNP-responsive (one-way analysis of variance; p<0.05). The largest groups of gene products affected by AgNP exposure included 73 genes in the cerebrum and 144 genes in
the cerebellum. AgNP exposure modulated the expression of several genes associated with motor neuron disorders, neurodegenerative
disease, and immune cell function, indicating potential neurotoxicity and immunotoxicity associated with AgNP exposure. Real-time
PCR data for five genes analyzed from whole blood showed good correlation with the observed changes in the brain. Following
rigorous validation and substantiation, these genes may assist in the development of surrogate markers for AgNP exposure and/or
toxicity.
KeywordsBrain-Inhalation-Mice-Microarray-Silver nanoparticles-Toxicity-EHS-Nanomedicine
Effect of chitosan–oil coating on qualitative properties of sweet pepper (Capsicum annuum L.) stored at 8 °C for 35 days was investigated. The chitosan–oil coating treatment exhibited the best control effect on decay (below 5%). At the end of storage, samples treated with chitosan-oil coatings maintained good sensory acceptability, whereas the sensory quality of control samples became unacceptable. The higher activities of scavenger antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), in treated peppers at the 35th day should be contributed to the chitosan–oil coating. Malondialdehyde (MDA) and electrolyte leakage contents in chitosan–oil-coated peppers were increased but were still lower than in control samples. Atomic force microscopy images showed that the surface of sweet pepper without coating treatment was rougher than that of peppers treated with chitosan–oil coating. Our study suggests that chitosan–oil coating might be a promising candidate for enhancing the keeping quality of sweet peppers.
Edible coatings of varying composition were applied on fresh apricots and green peppers. The water and vitamin C losses of these coated fresh foods were followed and compared with those of uncoated ones. The main components of the coating were methyl cellulose (MC) and polyethylene glycol (PEG). Stearic acid (SA) and ascorbic acid (AA) or citric acid (CA) were added to the coating formulation to control the barrier properties toward water and oxygen. It was found that coatings of any composition studied lower the water loss rate of fresh apricots and green peppers. Coating formulation of MC–PEG–SA was the most effective in reducing the water loss. Inclusion of AA or CA in the coating formulation as antioxidants lowered the vitamin C loss.
A novel non-ionic surfactant nanoemulsion designated 8N8 has been tested for its biocidal activity. One percent 8N8 produced effective bactericidal activity against Bacillus cereus, Bacillus subtilis, Haemophilus influenzae, Neisseria gonorrhoeae, Streptococcus pneumoniae, and Vibrio cholerae in 15 minutes. In contrast, most enteric Gram-negative bacteria were resistant to 8N8. One percent 8N8 was also virucidal within 15 minutes for all tested enveloped viruses, including Herpes simplex type 1, influenza A and vaccinia viruses. One percent 8N8 also demonstrated fungistatic activity on Candida albicans. The rapid and non-specific inactivation of vegetative bacteria and enveloped viruses, in addition to its fungistatic activity and low toxicity in experimental animals, makes 8N8 a potential candidate for use as a topical biocidal agent.
Gum arabic, an exudate from Acacia trees, has a unique combination of excellent emulsifying properties and low solution viscosity. These properties make gum arabic very useful in several industries but especially in the food industry where it is used as a flavor encapsulator and stabilizer of citrus oil emulsion concentrates in soft drinks. Gum arabic is a mixture of principally polysaccharides and proteoglycans, the latter being arabinogalactan proteins (AGPs). Gum arabic also contains trace levels of lipids. Our hypothesis is that these lipids are attached to the gum arabic AGPs as glycosylphosphatidylinositol (GPI) lipids, as found in rose and other AGPs, and that these lipids make important contributions to the emulsifying activity of gum arabic. To test this hypothesis, chemical treatments expected to cleave GPI lipid anchors have been applied to gum arabic, and the resulting effects on structure and emulsifying activity have been examined. Treatment of gum arabic with nitrous acid resulted in diminished emulsifying activity, loss of some glucosamine and nitrogen, but very little effect on the principal carbohydrate composition. Treatment with 50% aqueous HF at 0 °C resulted in diminished emulsion properties but also significant loss of arabinosyl residues. The approximately 1–3% subfraction of gum arabic components that adsorb at the surface of oil droplets has higher abundance of GPI linker components, much higher relative lipid content, much higher nitrogen content, and somewhat higher emulsifying action than the whole gum. These results are consistent with roles of both lipid and protein in the emulsifying activity of the gum.
Silver nanoparticles have been formed in fluff pulp and nanostructured Lyocell fibres by immersion in silver nitrate, and a subsequent transformation of the adsorbed silver ions into elementary silver nanoparticles by physical (thermal/UV) or chemical (sodium borohydride) methods. Microscopy revealed that nanoparticles generated by physical methods were regular in shape and efficiently dispersed, while the chemical reduction produced highly aggregated nanoparticles. Nanoparticle size has been found relevant to guarantee high antimicrobial activity, being the samples with big aggregated silver nanoparticles almost inefficient. Indeed a satisfactory correlation between silver ion release and the antimicrobial efficiency against Escherichia coli and Staphylococcus aureus could be confirmed, and furthermore, the highest concentrations tested were efficient to reduce the microbial load in poultry exudates. This work demonstrates that especially designed absorbent materials could be optimised to preserve aseptic conditions during manipulation, leading to feasible applications of a silver based nanotechnology in food technology.
Edible coatings can provide an additional protective coating for fresh products and can also give the same effect as modified atmosphere storage in modifying internal gas composition. Recently, several edible coatings for preserving fruits such as oranges, apples, and grapefruits were successfully applied. But, in some cases, edible coatings were not successful. In fact, fruit quality was worse. The success of edible coatings for fresh products totally depends on the control of internal gas composition. This article is designed to help develop a systematic means of selecting edible coatings to maximize quality and shelf life of fresh fruits and vegetables. Methods will be introduced to select edible coatings based on their gas permeation properties relative to controlling internal gas composition of target products.
The principal physiological factors that negatively impact pepper fruit during shipment and storage and subsequent marketing are water loss and chilling injury. The current study evaluated the effect of harvest methodology on postharvest water loss from sweet bell pepper fruit and the potential relationship between water loss and chilling injury in cold-stored fruit. The influence of cultivar, epicuticular wax, and AOX gene expression on water loss and chilling injury were examined. Our results demonstrated that the degree of water loss in pepper fruit is subject to effects of genotype and pre- and postharvest environments as evidenced by year to year variation in fruit storage attributes. A comparison of pepper fruit harvest methods, wherein peduncles were either torn or cut, showed that harvest method had little effect on percent water loss. Observations on fruit water loss in relation to fruit size suggested that fruit cuticles are the primary barrier to water loss. A clear relationship between epicuticular wax content and fruit water loss was not evident. Cultivars varied in their susceptibility to chilling injury and fruit water loss was positively correlated with the severity of chilling injury. No correlation was found between endogenous AOX transcript levels and cultivar-specific susceptibility to chilling injury. The results illustrate the difficulty of identifying indices correlated with water loss that could be used to develop or identify cultivars with improved storability. We did, however, find that there are significant differences in storage attributes of pepper cultivars and that routine screening for water loss and chilling injury are advantageous for selection of cultivars most suitable for cold-storage.
The aim of this study was to evaluate the effects of a bio-based coating containing silver-montmorillonite nanoparticles combined with modified-atmosphere packaging (MAP) on microbial and sensory quality decay of Fior di latte cheese. Different concentrations of silver nanoparticles (0.25, 0.50, and 1.00 mg/mL) were dispersed in a sodium alginic acid solution (8% wt/vol) before coating the cheese. Modified-atmosphere packaging was made up of 30% CO(2), 5% O(2), and 65% N(2). The combination of silver-based nanocomposite coating and MAP enhanced Fior di latte cheese shelf life. In particular, product stored in the traditional packaging showed a shelf life of about 3 d, whereas coated cheese stored under MAP reached a shelf life of more than 5 d, regardless of the concentration of silver nanoparticles. The synergistic effects between antimicrobial nanoparticles and initial headspace conditions in the package could allow diffusion of dairy products beyond the local area.
To investigate the mechanism of inhibition of silver ions on microorganisms, two strains of bacteria, namely Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus), were treated with AgNO(3) and studied using combined electron microscopy and X-ray microanalysis. Similar morphological changes occurred in both E. coli and S. aureus cells after Ag(+) treatment. The cytoplasm membrane detached from the cell wall. A remarkable electron-light region appeared in the center of the cells, which contained condensed deoxyribonucleic acid (DNA) molecules. There are many small electron-dense granules either surrounding the cell wall or depositing inside the cells. The existence of elements of silver and sulfur in the electron-dense granules and cytoplasm detected by X-ray microanalysis suggested the antibacterial mechanism of silver: DNA lost its replication ability and the protein became inactivated after Ag(+) treatment. The slighter morphological changes of S. aureus compared with E. coli recommended a defense system of S. aureus against the inhibitory effects of Ag(+) ions.
Inhibition of Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes by grape seed extract (ActiVin) and pine bark extract (Pycnogenol) and the effect of these natural extracts on the oxidative stability of raw ground beef were studied. In an agar dilution test, the MICs of ActiVin and Pycnogenol were determined to be 4.0 mg/ml for 4.43 log CFU per plate of E. coli O157:H7 and 4.0 mg/ml for 4.38 log CFU per plate of L. monocytogenes. In an inhibition curve test, populations of E. coli O157:H7, Salmonella Typhimurium, and L. monocytogenes fell to below the detection limit (10 CFU/ml) after 16 h of incubation. The numbers of E. coli O157:H7, L. monocytogenes, and Salmonella Typhimurium declined by 1.08, 1.24, and 1.33 log CFU/g, respectively, in raw ground beef treated with 1% Pycnogenol after 9 days of refrigerated storage. ActiVin (1%) and oleoresin rosemary (1%) resulted in an approximately 1-log CFU/g reduction in the populations of all three pathogens after 9 days. The addition of 1% ActiVin and Pycnogenol contributed to the maintenance of an acidic pH of 5.80 and 5.58, respectively, in raw ground beef. Compared to the control, all treatments increased in L* (lightness), with the exception of ActiVin. ActiVin and oleoresin rosemary had the highest a* (redness) and b* (yellowness) values, respectively. ActiVin most effectively retarded lipid oxidation, followed by Pycnogenol. The results suggest that these natural extracts have potential to be used with other preservative methods to reduce pathogenic numbers, lipid oxidation, and color degradation in ground beef.
The development of new edible coatings with improved functionality and performance for fresh and minimally processed fruits is one of the challenges of the post harvest industry. In the past few years, research efforts have focused on the design of new eco-friendly coatings based on biodegradable polymers, which not only reduce the requirements of packaging but also lead to the conversion of by-products of the food industry into value added film-forming components. This work reviews the different coating formulations and applications available at present, as well as the main results of the most recent investigations carried out on the topic. Traditionally, edible coatings have been used as a barrier to minimize water loss and delay the natural senescence of coated fruits through selective permeability to gases. However, the new generation of edible coatings is being especially designed to allow the incorporation and/or controlled release of antioxidants, vitamins, nutraceuticals, and natural antimicrobial agents by means of the application of promising technologies such as nanoencapsulation and the layer-by-layer assembly.
Official Methods of Analysis
AOAC. 2000. Official Methods of Analysis, 16th Ed.,
Association of Official Analytical Chemists, Washington, DC.
Genomics-based screening of differentially expressed genes in the brains of mice exposed to silver nanoparticles via inhalation Edible coating effects on postharvest quality of green bell peppers
- H Y Choi
- J U Jung
- E J Yin
- H Q Kwon
- J T Kim
- J E Im
- H T Cho
- M H Kim
- J H Kim
- B H Lerdthanangkul
LEE, H.Y., CHOI, J.U., JUNG, E.J., YIN, H.Q., KWON, J.T., KIM,
J.E., IM, H.T., CHO, M.H., KIM, J.H., KIM, H.Y. and LEE,
B.H. 2010. Genomics-based screening of differentially
expressed genes in the brains of mice exposed to silver
nanoparticles via inhalation. J. Nanopart. Res. 12, 1567–1578.
LERDTHANANGKUL, S. and KROCTHA, J.M. 1996. Edible
coating effects on postharvest quality of green bell peppers.
J. Food Sci. 61, 176–179.
Edible coating effects on postharvest quality of green bell peppers
- S Lerdthanangkul
- J M Kroctha
LERDTHANANGKUL, S. and KROCTHA, J.M. 1996. Edible
coating effects on postharvest quality of green bell peppers.
J. Food Sci. 61, 176-179.