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Revealing the relationship between vegetable oil composition and oxidative stability: A multifactorial approach
Abstract
A detailed composition analysis was performed for 22 diverse oils and fats and included determination of tocopherols (α, γ and δ), β-carotene, chlorophyll, total phenolic compounds (TPC) and fatty acid (FA) composition, as well as the determination of their oxidative stability (Rancimat test). Principal components analysis was applied to obtain an overview of the sample variations and to identify behavioural patterns. Linear regression correlations and a multiple linear regression model were performed to quantify the relationship between the composition of oils and fats and their oxidative stability. The TPC and saturated FA were the main individual factors that correlated positively with oxidative stability (r ² = 0.417, r ² = 0.321 respectively, p < .01), whereas unsaturated FA, polyunsaturated FA and total tocopherols correlated negatively (r ² = 0.304, r ² = 0.264, r ² = 0.223 respectively, p < .01). Saturated, monounsaturated and polyunsaturated FA together accounted for 67% of variability and are considered the most important parameters to affect oxidative stability. Results of this study provide a better understanding of the complex relationship between oil and fat composition and their oxidative stability, which is an essential step for designing strategies to increase stability and shelf-life of culinary oils.
... These oils can be purified by washing them with water, then settling, filtering, and centrifuging them. Chemical and physical refining processes, such as degumming, neutralisation, bleaching, and deodorisation, as well as supplementation of CPOs with synthetic additives, are banned [2,3]. For this reason, CPOs are rich sources of minor constituents, such as the Oil contamination by PAHs may be attributed to the contact of the oilseeds with polluted air, the uptake by the oilseed plants through soil, and any contaminated element present in the production line or mineral oil residues from packaging [19]. ...
... On the other hand, the fatty acid profile of oil can affect its vulnerability to oxidation and deterioration reactions. Polyunsaturated fatty acids (PUFA) such as linoleic acid (C18:2) and linolenic acid (C18:3) are much more prone to oxidation than monounsaturated (MUFA) oleic acid (C18:1) and saturated (SFA) stearic acid (C18:0) [3,[21][22][23]. ...
... The results of TTC and individual tocopherols in the investigated oils demonstrated a wide variability. Evidence from large observational studies indicates that the climate during the growth and ripening of oilseeds, their genetic varieties, cold-pressing parameters, and oil storage conditions can affect amounts of tocopherols in CPOs [3,32,33]. ...
The consumption of cold-pressed oils (CPOs) has continuously increased due to their health-promoting compounds, such as polyunsaturated fatty acid (PUFA), tocopherols, sterols, and polyphenols. This study focused on the estimation and comparison of the physicochemical properties and sensory quality of six CPOs: linseed oil (CPLO), pumpkin oil (CPPO), milk thistle oil (CPMTO), rapeseed oil (CPRO), camelina oil (CPCO), and sunflower oil (CPSO), which are the most popular in the Polish market. These oils were analysed for their fatty acid composition (FAC), their tocopherol, sterol, polycyclic aromatic hydrocarbon (PAHs), water, and volatile matter (WVM) contents, as well as their antioxidant activity (AA) and oxidative stability parameters. Moreover, quantitative descriptive analysis (QDA) was performed to obtain detailed information on the sensory profiles and quantitative data on the CPOs' attributes that affected consumer acceptability and purchase intent. All of the analysed CPOs were rich in PUFA (27.94-68.42%). They were characterised by the different total amounts of health-beneficial compounds, such as tocopherols (TTC = 44.04-76.98 mg/100 g), sterols (TSC = 300-684 mg/100 g), and polyphenols (TPC = 2.93-8.32 mg GA/100 g). Additionally, their AA was determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and ferric reducing antioxidant power (FRAP) methods, with results ranging between 185.36-396.63, 958.59-1638.58, and 61.93-119.21 µmol TE/100 g, respectively. However, the deterioration parameters of CPOs, such as peroxide values (PV = 0.24-4.61 meq O2/kg), p-anisidine values (pAnV = 0.39-4.77), acid values (AV = 0.31-2.82 mg KOH/g), and impurity amounts (Σ4PAHs = 1.16-8.76 μg/kg and WVM = 0.020-0.090%), did not exceed the level recommended by the Codex Alimentarius Commission. The obtained results indicated that all of the investigated CPOs are valuable sources of health-promoting bioactive compounds.
... Generally, pressed oils are processed without involving organic solvents and under a low temperature, possessing advantages of a low production of heat-induced chemical contaminants (1)(2)(3), preservation of more-beneficial minor components (4), and protection of unique flavors and odors for wide applications (5). Cold-pressed oils may be clarified by washing with water, settling, filtering, and centrifuging (6); however, they do not undergo a refining process of purification to eliminate minor compounds that are considered impurities and can potentially destabilize the oil (e.g., free fatty acids) or enhance oxidative stability (e.g., tocopherols) (7). Thus, safety concerns may arise from unintentionally consuming oxidized pressed oil, since it is not properly labeled and its shelf-life has not been evaluated. ...
... The existence of a correlation between tocopherols and fatty acids in vegetable oils has been discussed but still considered non-causal (15). Though the type of fatty acids is critically important for the oxidative stability of edible oils, substantial deviations were observed from the expectation that the higher the content of unsaturated fatty acids the lower the corresponding oxidative stability (6). Nevertheless, the negative trend of correlations between degree of unsaturation and oxidative stability was found to be absolute in previous studies (6,15). ...
... Though the type of fatty acids is critically important for the oxidative stability of edible oils, substantial deviations were observed from the expectation that the higher the content of unsaturated fatty acids the lower the corresponding oxidative stability (6). Nevertheless, the negative trend of correlations between degree of unsaturation and oxidative stability was found to be absolute in previous studies (6,15). Furthermore, the relative contribution of natural compounds to oxidative stability has proved elusive in edible oils and fats (6). ...
Introduction: Due to the enhanced awareness of consumers concerning healthy foods, homemade expeller-pressed oils have become popular worldwide. However, an extended storage period may lead to oxidization of the oil and exposure to hazardous byproducts by consumers.
Methods: In this study, 10 pressed oil samples prepared from common oilseeds using a small-scale expeller oil press were analyzed by OXITEST with a sample amount of 5 g of oil and an oxygen pressure of 800 kPa under accelerated conditions for shelf-life projections. The oil properties were investigated, including the recovery, smoke point, acid value, iodine value, “fatty acid composition, and contents of pigments and tocopherols”.
Results: The autoxidation reaction of various expeller-pressed oils under an accelerated testing system followed zero-order Arrhenius kinetics ( R ² > 0.99). Shelf-lives of the pressed oils at 25°C were estimated by extrapolation to range 105~1,089 days. The obtained shelf-lives were significantly correlated with log induction period (IP) values ( r > 0.81, p < 0.05) and unsaturated fatty acids (UFAs) ( r < −0.69, p < 0.05), but not with the iodine value, acid value, or smoke point. Scatter diagrams between shelf-lives and UFAs suggested that these pressed oils could be grouped by two linear regression curves ( r > 0.98, p < 0.05). The predictive equations using multiple linear regression are presented herein, with predictor variables of UFAs and an unspecified item involving potential influencing factors such as tocopherol contents ( r > 0.88, p < 0.05).
Conclusions: Our findings first revealed that the UFA portion was partially correlated with the shelf-lives of selected expeller-pressed seed oils as estimated by the OXITEST. The derived equations can be applied for shelf-life predictions of expeller-pressed oils stored under dark ambient conditions based on the fatty acid profile.
... The results obtained according to literature data [32,61] evidenced that the oil composition strongly affects its antioxidant activity and oxidative stability. Consequently, the effect of fatty acids on oil oxidative stability was studied using principal component analysis based on the stability time data reported in Table 7 and the data concerning fatty acid composition (Table 3). ...
... The results obtained according to literature data [32,61] evidenced that the oil composition strongly affects its antioxidant activity and oxidative stability. Consequently, the effect of fa y acids on oil oxidative stability was studied using principal component analysis based on the stability time data reported in Table 7 and the data concerning fa y acid composition (Table 3). ...
Citation: Rodríguez-Blázquez, S.; Gómez-Mejía, E.; Rosales-Conrado, N.; León-González, M.E.; García-Sánchez, B.; Miranda, R. Valorization of Prunus Seed Oils: Fatty Acids Composition and Oxidative Stability. Molecules 2023, 28, 7045. https://doi.org/10.3390/ molecules28207045 Academic Editors: Petko Denev, Abstract: Prunus fruit seeds are one of the main types of agri-food waste generated worldwide during the processing of fruits to produce jams, juices and preserves. To valorize this by-product, the aim of this work was the nutritional analysis of peach, apricot, plum and cherry seeds using the official AOAC methods, together with the extraction and characterization of the lipid profile of seed oils using GC-FID, as well as the measurement of the antioxidant activity and oxidative stability using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging method. Chemometric tools were required for data evaluation and the obtained results indicated that the main component of seeds were oils (30-38%, w). All seed oils were rich in oleic (C18:1n9c) and linoleic (C18:2n6c) acids and presented heart-healthy lipid indexes. Oil antioxidant activity was estimated in the range IC 50 = 20-35 mg·mL −1 , and high oxidative stability was observed for all evaluated oils during 1-22 storage days, with the plum seed oil being the most antioxidant and stable over time. Oxidative stability was also positively correlated with oleic acid content and negatively correlated with linoleic acid content. Therefore, this research showed that the four Prunus seed oils present interesting healthy characteristics for their use and potential application in the cosmetic and nutraceutical industries.
... Recent studies by members of the research group that heads this project, used 22 oils of vegetable origin for the study of oxidative stability at different temperatures. The results were different according to the oil used and improved when a portion of rosemary powder was added [10,11]. These considerations lead us to propose a study on the influence of the addiction of different aromatic plants or food spices with a high content of polyphenols, on the oxidative stability of different margarines with different fatty acid composition. ...
... Figure Loadings plot of margarines PC1 vs. PC2 shows eight groups of each margarine with all species as it is expected. Fig 5B presents PC1 vs. PC3, where margarines are distributed in two major clusters: Cluster A exclusively includes all margarines with Rosmarinus officinalis with highest IP values (1-8), Cluster B, the rest and includes four subgroups: Subgroup 1 (11,19,27,35,43) formed by Flora pro-activ colesterol original with the rest of herbs. Subgroup 2 (16,24,32,40,48), Consum mantequilla with the rest of herbs with the lowest IP. ...
Margarines are W/O emulsions with minimal fat and are heat treated when used for baking. Lipid oxi-dation has been identified as the major deterioration process of margarines and addition of antioxidants is necessary. Consumers are increasingly demanding that chemical antioxidants in foods be replaced by natural preservatives. A multivariate statistical study gave us oxidative stability depending on the com-position of 20 different commercial margarines and an analysis of the principal components allowed us to classify and select eight of them. This study analyzes the antioxidant capacity of six different natural ground herbs (Curcuma longa, Illicium verum, Rosmarinus officinalis, Taraxacum officinale, Thymus piperella and Thymus vulgaris) on the oxidative stability of eight selected margarines. In order to evalu-ate the oxidative stability, we determine the induction period (IP) with Rancimat assays at 120 ºC with 1.5 hours of suppression. As results, Rosmarinus officinalis increases the IP value by 73.17% with respect to its basal values, Curcuma longa, Thymus vulgaris and Thymus piperella increases it between 17% and 26% and Taraxacum officinale together with Illicium verum reduces it between 19% and 34% respec-tively. A multiple linear regression model approach shows that IP has a positive correlation with SFA, PUFA, acids, MUFA/PUFA ratio and antioxidant activity.
... The antioxidants in oils improve their oxidative stability and prevent their oxidative degradation, either by delaying the oxidation reaction by reacting with free radicals or by inhibiting the propagation step by reacting with alkoxy and alkyl peroxy radicals [29]. The results of this study further showed the DPPH clearing capacity of 2.5% peanut oil was 42.02~52.34%, ...
... In the process of roasting, the oxide (O-heterocyclic (r: −0.986), aldehyde (r: −0.950), and alcohol (r: −0.890)) compounds generated were transformed into N-heterocyclic compounds as the temperature increased due to the Maillard reaction. Other studies have indicated that unrefined oils naturally contain antioxidant compounds that provide oil oxidation stability [10,18,29]; especially, polyphenol has an ef-fective approach to mitigating the heat-oxidation formation of oxidative free radicals, mainly by inhibiting oxidative pathways and trapping reactive intermediates [14]. ...
... Lipid oxidation during processing and storage has long been recognised as a major reason that causes oil deterioration in the edible oil industry because such oxidation not only reduces nutrition of the oil, but also leads to off-flavours and rancid taste (Mcclements & Decker, 2018;Redondo-Cuevas et al., 2018). Encapsulation of oils (essential oils and high oxidation oils) (Hadad & Goli, 2019;Kumar et al., 2020), adding antioxidants to oils and packaging are major techniques applied to protect unsaturated fatty acids against hydroperoxides formation through termination of the free radical chain reaction or protect oil from environmental pro-oxidants (oxygen, heat, light, etc.). ...
... Although the oxidative stability data confirmed the effectiveness of the TA fibrous mat, it was still unclear what variations in the pattern of fatty acid oxidation cause these differences among the treatments. Regarding overall changes, PCA was used to simplify the number of descriptors into a few interdependent principle components (PCs) that represent the most important variables and identifying behavioural patterns (Mildner-Szkudlarz & Jele n, 2008;Siroli et al., 2015;Redondo-Cuevas et al., 2018). The following eight major fatty acid components of FO extracted under different antioxidant treatments were considered as the data matrix and subjected to PCA: palmitic acid, palmitoleic acid, stearic acid, arachidic acid, behenic acid, oleic acid, linoleic acid, linolenic acid. ...
Encapsulation of tannic acid (TA) in an edible guar gum (GG)‐ the nanofibrous delivery system was applied to improve antioxidant efficacy relative to butylated hydroxytoluene (BHT) and non‐encapsulated TA under accelerated oxidation of flaxseed oil (FO). The TA fibrous mat (average fibre diameter of 96 ± 22 nm) significantly improved oxidative stability compared to BHT‐ and non‐encapsulated TA‐treated samples during the oil accelerated oxidation test (peroxide value, p‐anisidine, p < 0.05). Principal component analysis (PCA) for eight fatty acids: palmitic acid, stearic acid, arachidic acid, behenic acid, oleic acid, linoleic acid, linolenic acid, and palmitoleic acid, explained 80.0% of the total variation. Linolenic acid, palmitoleic acid, and stearic acid were essential to the discrimination of fatty acid changes in the PLS model among all the studied variables. After 30 days of oxidation, TA fibrous‐mat treated FO was separated from the control‐, BHT‐, and non‐encapsulated TA‐treated sample, mainly due to the changes in linolenic acid. Our original study provides a novel method to improve the oxidative stability of FO and may support further exploration of the interaction between active nano‐delivery systems and fatty acids.
... This indicator allows for determining the resistance of a given oil to the oxidation processes, which significantly reduces the fats' quality. Temperature is also a factor determining oxidative stability, so the oxidation induction time of oils shortens with increasing temperature [6,7]. ...
... Oxidative stability depends on the composition of fatty acids, especially unsaturated ones, which are susceptible to oxidation. The content of antioxidants, primary and secondary oxidation products, or oil impurities is also important [6,7]. Temperature also determines oxidative stability because the oils' oxidation induction time decreases with increasing temperature. ...
The aim of the study was to analyse the chemical composition and oxidation stability of selected cold-pressed oils and oil mixtures. The oils were tested for their initial quality, fatty acid composition, total phenolic compounds, DPPH, and ABTS free radical scavenging activity. The Rancimat method was used to assess oxidative stability. The obtained results were subjected to principal component analysis (PCA) to determine the influence of selected chemical properties on the oxidative stability of the oil. It has been found that different factors of oil quality influence the stability of cold-pressed oils. The highest correlation coefficient was noted between the induction time, peroxide value, and TOTOX indicator (r = 0.89). Fatty acid composition, including the percentage of SFA, MUFA, PUFA, and the ability to scavenge ABTS captions radicals, did not significantly affect the oxidative stability of the oils. Black cumin seed oil was the most resistant to the oxidation processes in the Rancimat apparatus, mainly due to the high content of phenolic compounds (384.66 mg GAE/100 g). On the other hand, linseed oil and its mixtures were the least stable. Their fatty acid composition was dominated by a polyunsaturated α-linolenic fatty acid, significantly reducing the antioxidant resistance.
... Leaf blight of greengram caused by M. phaseolina was first reported from Jabalpur, (M. P.), India [20]. Earlier workers recorded leaf spot caused by M. phaseolina in mungbean crop from Madhya Pradesh causing considerable losses [21,22,23]. ...
... Antioxidants (AOs) of natural products (NPs) from herbs and spices improved the oxidative stability and frying performance of vegetable oils (VOs) [19]. The relationship between VO-composition and oxidative stability was revealed via a multifactorial approach [20]. It was informed chemical and biological screening approaches to phytopharmaceuticals [21], cultural interbreeding in indigenous and scientific ethnopharmacology [22], ...
This volume brings together innovative research in natural products chemistry.
... Sesame seed has been reported to contain a high level of unsaturated fatty acids which are oleic acid, 38.86%, and linoleic acid, 46.18% [11]. However, the fatty acid composition of vegetable oils varies and is dependent on several parameters such as extraction process, seed variety, climatic condition, the extent of fruit ripening, harvesting period, and harvesting technique [12][13][14]. This edible oil has been grown from ancient times as a cooking oil and flavour enhancer in many continental and intercontinental dishes [15]. ...
... The 13 C NMR spectra of the unsulfonated sesame oil and sulfonated sesame oil are depicted in Fig. 4. The 13 C NMR spectrum of the unsulfonated oil (Fig. 4a) [33]. The methyl group at the end of the acyl chains in the glyceride moiety is seen in both spectra (Fig. 4a & b) at around 14.1 ppm. ...
Fatliquor is an oil-in-water emulsion that improves the physical properties of leather such as tensile strength, flexibility, and softness by lubricating the leather fibres. Sulfonated Sesamum indicum oil was synthesized, characterized, and examined for consideration as a substitute for imported fatliquor in Nigeria. The sulfonation of the oil was confirmed by the significant observations made in the FTIR, ¹ H NMR, ¹³ C NMR, and ¹³ C NMR DEPT analysis results. A remarkable difference was observed in the physicochemical properties results of both unsulfonated and sulfonated oils. The sulfonated sesame fatliquor was applied onto goatskin and compared with a commercial sulfated fatliquor in the processing of shoe upper leather using standard methods. The average results for tensile strength, double edge tear, elongation, and softness results for the commercial and synthesized fatliquors are as follows: 14.27 N/mm ² ; 13.77 N/mm ² , 50.61 N; 60.11 N, 38.06%; 54.28%, 25.2; 25.0. A comparable level of lubrication of the leather treated with the sulfonated Sesamum indicum oil and that treated with the commercial leather fatliquor was revealed by the Sudan IV stain test as well as scanning electron microscopy analysis results. Experimental analyses, therefore, show that the as-synthesized sulfonated Sesamum indicum oil could be considered as a substitute for imported fatliquor in the leather industry.
Graphical abstract
... The lowest induction times were recorded with corn oil supplemented with curcumin at 80 µg/mL (5.66 h). The induction time of corn oil increased with the addition of natural antioxidants [23][24][25] Redondo-Cuevas et al. [26] recorded the induction time of corn oil equal to 0.84 h. ...
Curcumin (40, 80, and 120 μg/mL), β-carotene (5, 10, and 20 μg/mL), and TBHQ (200 μg/mL) were
used to test how well they protected corn oil from oxidation under accelerated oxidation conditions.
Linoleic acid has the highest amount (51.1 %), while linolenic acid has the lowest content (1.3%). Corn
oil supplemented with 200 μg/mL TBHQ was shown to have the longest induction time (12.9 h) of the
oils studied, followed by corn oil supplemented with 20 μg/mL β-carotene (11.78 h) and 40 μg/mL
curcumin (11.53 h). Curcumin, and β-carotene showed greater antioxidant potential in all tested samples
compared to the control in the accelerated storage experiment. Curcumin and β-carotene can potentially
improve the shelf life of corn oil compared with TBHQ-200 μg/mL. It can be concluded that curcumin,
and β-carotene were found to be effective antioxidants activity at 40, 80, and 120 μg/mL for curcumin
and 5, 10, and 20 μg/mL for β-carotene, so TBHQ was not required.
... The content of antioxidants in oils improves oxidative stability and prevents oxidative degradation. Antioxidants can slow the propagation phase when reacting with alkoxy and alkyl peroxy radicals or postpone the oxidation reaction when reacting with free radicals (30). Therefore, preserving the oil's natural composition and oxidation stability involves extracting vegetable oil at low temperatures and without the use of organic solvents. ...
In the last years, the consumption of vegetable oils has increased in comparison with those obtained from animal sources, due to their high nutritional value. These oils can be extracted from seeds, fruits, and nuts by solvent extraction and physical methods. Unrefined vegetable oils are of particular interest because during their obtention chemical compounds are not used. This study aimed the evaluation of the physicochemical properties [peroxide value (PV), free acidity (AF), and total phenols content (TPC)], and oxidation stability by Differential Scanning Calorimetry (DSC) of cold extracted oils from avocado pulp, almond, peanut, and pumpkin seeds. Because of this, oil from avocado pulp, almond, and peanut was obtained by centrifugation; whereas, pumpkin oils were obtained by mechanical pressing. PV and AF values ranged from 3.56 to 9.06 meq O2/kg oil and 0.55 to 0.81% expressed as oleic acid, respectively. These values were within the established international standards. The higher TPC determined was in peanut oil (2177.56 ± 2.92 mg GAE/kg oil), due to its great important considering the biological activities associated with them. Oxidation temperatures estimated by DSC were 162.84 and 185.15 ºC for avocado pulp and pumpkin seed (Cucurbita moschata) oils, respectively. In addition, pumpkin seed oils showed a higher oxidation induction time (> 15 min at 160 ºC). These results confirm that DSC is a technique that facilitates the analyses of the oxidation stability of oils, requiring small samples and short-time analyses. The high oxidative stability of pumpkin, peanut, and almond oils suggested that can have promised for applications in processing foods with heat (including the frying process). Centrifugation and mechanical pressing methods are great alternatives for the obtention of vegetable oils that complies with international standards. Additionally, using mechanical or physical methods to extract oil reduces the need for chemicals that are bad for both human health and the environment.
... In general, results from the Rancimat test evidencing oil stabilization have been positively correlated with the total polyphenol content of oils [30]. On the other hand, in several instances mentioned above, a PF < 1 evidenced the expression of prooxidant effects of polyphenol-containing extracts, depending on the level of enrichment. ...
The current project aimed at examining the effect of the enrichment of commercial seed oils with waste orange peel (WOP) extracts on their polyphenolic profiles and resistance against oxidation. Polyphenol-containing WOP extracts were produced using a novel combination of ethanol and triacetin, and they were incorporated into seed oils (sunflower, soybean, corn oil), at a level of 36.87 mg per kg of oil. The oils were then stored at 60 • C, for 58 days. By performing a Rancimat test, it was shown that enrichment of sunflower, soybean, and corn oils with WOP extracts did not provoke any prooxidant effects, but, to the contrary, exerted an antioxidant action, with protection factors varying from 1.01 to 1.61. Furthermore, in all cases examined, it was demonstrated that, during the storage period, the stabilizing effect of WOP extract against oxidation was comparable to that observed in oil samples containing 200 mg BHT per kg oil. This outcome was ascertained by measuring the onset of peroxide value, thiobarbituric-acid-reactive substances, and the TOTOX value. Furthermore, it was revealed that the Trolox-equivalent antiradical activity of the enriched oils exhibited a decline at the end of the examination period, a fact most probably attributed to the depletion of the antioxidants occurring in the oils. It was concluded that the method proposed might be a means of stabilizing commercial seed oils against oxidation, and of enhancing their nutritional value by enriching them with natural polyphenols.
... These alterations have remarkable effects on the shelf life and consumption of vegetable oils. Moreover, the end products of lipid oxidation reactions are highly reactive and could have undesirable effects on human health such as cancer, atherosclerosis, heart diseases and allergic responses [3]. ...
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Oxidative stability is one of the most important quality parameters of vegetable oils. This study aims to determine oxidative stability of five different vegetable oils by means of infrared spectroscopy combined with DFT calculations and to compare experimental and theoretical results. The oxidation induction times of hazelnut, corn, canola, safflower and sunflower oils were determined by the Rancimat method and fatty acid profile of the oils was analyzed by gas chromatography. Moreover, the middle infrared spectra of the samples was obtained by using Fourier transform infrared spectroscopy. The oxidative stability of the vegetable oils was analyzed by considering two mechanisms regarding to oxidation process in the theoretical parts of the study. The chemical hardness of fatty acids, a key characteristic of Conceptual Density Functional Theory, was calculated and discussed. It was evaluated that there was a remarkable correlation between oxidative stability and chemical hardness of fatty acids. The harder fatty acids had stronger oxidative stability. A new, accurate, cost-effective, and ecologically friendly technique was developed for determination of oxidative stability of vegetable oils.
... Oxidative stability is one of the most important parameters that affects the oil quality and it is closely related to the fatty acids compositions of oils, as well as some minor antioxidant components and numerous external factors [1,2]. The fatty acids composition of sunflower oil is greatly influenced by the location and climatic conditions during vegetation [3,4]. ...
Background:
In this work, the chemical composition analysis was performed for cold pressed oils obtained from the 15 sunflower hybrids grown in Serbia and Argentina, as well as the determination of their oxidative quality. The fatty acid composition and bioactive compounds including total tocopherols, phenols, carotenoids, and chlorophyll contents were investigated. The oxidation products were monitored through the peroxide value (PV), anisidine value (AnV), conjugated dienes (CD) and conjugated trienes (CT) content, and total oxidation index (TOTOX) under accelerated oxidation conditions by the oven method.
Results:
Linoleic acid was the most abundant fatty acid in investigated oil samples, followed by oleic and palmitic acids. The mean contents of total tocopherols, phenols, carotenoids, and chlorophyll were 518.24, 9.42, 7.54 and 0.99 mg/kg, respectively. In order to obtain an overview of sample variations according to the tested parameters Principal Component Analysis (PCA) was applied.
Conclusion:
PCA indicated that phenols, chlorophyll, linoleic and oleic acid were the most effective variables for the differentiation of sunflower hybrids grown in Serbia and Argentina. Furthermore, based on the fatty acid composition and bioactive compounds content in the oils, a new Artificial Neural Network (ANN) model was developed to predict the oxidative stability parameters of cold pressed sunflower oil.
... Soybean and cottonseed oil had more polyunsaturated fatty acid, which is essential for skin and hair health and cardiovascular and cerebrovascular diseases [21]. Although oils containing high amounts of linoleic and linoleinic acid are prevalent in daily life, the saturation degree of fatty acids not only determines the nutritional value of vegetable oils but can also affect their oxidative stability; the higher the degree of unsaturation, the more easily that fatty acids can be oxidized [34,35]. ...
Rosemary (Rosmarinus officinalis L.) extract (RE) is one of the most efficient natural antioxidants and can significantly inhibit oil oxidation during storage or heating. The present study determined the protective capacity and mechanism of RE on the thermal oxidative stability of different vegetable oils by adding RE (70% carnosic acid) to five types of vegetable oils (soybean oil, rapeseed oil, cottonseed oil, rice bran oil, and camellia oil) and measuring the physicochemical indices (fatty acid composition, tocopherol content, total phenolic content, and free radical scavenging capacity), induction period, and thermal oxidative kinetic parameters. The relationships between the antioxidant capacity and thermal stability parameters were determined. The results show that, compared with artificial antioxidants, RE significantly increased the free radical scavenging capacity, induction period, and activation energy (Ea) of thermal oxidation, decreasing the thermal oxidation reaction rate (k) of all vegetable oils, especially rice bran oil. A Spearman correlation analysis showed that the induction period (IP) and Ea showed a significant positive correlation, the combination of which effectively reflected the efficiency of antioxidants and explained the inhibition mechanism of RE towards oil thermal oxidation.
... Moreover, control kernels of 'A4 and 'Beaumont' had significantly (p < 0.001) high ∑ SFAs (136.40 and 137.48 µg/g) and lower ∑ PUFA: ∑ SFA (0.43 and 0.38 µg/g), respectively. Our findings are similar to [50], who reported a low ratio of ∑ USFA: ∑ SFA (0.11%) and high ∑ SFA (8.42%), attributed to the low content of linoleic acid content, probably as the result of its peroxidation [51]. ...
Depending on the temperature regime used during roasting, the biochemical and sensory characteristics of macadamia nuts can change. ‘A4′ and ‘Beaumont’ were used as model cultivars to examine how roasting temperatures affected the chemical and sensory quality of macadamia nuts. Using a hot air oven dryer, macadamia kernels were roasted at 50, 75, 100, 125, and 150 °C for 15 min. The quantity of phenols, flavonoids, and antioxidants in kernels roasted at 50, 75, and 100 °C was significant (p < 0.001); however, these kernels also had high levels of moisture content, oxidation-sensitive unsaturated fatty acids (UFAs), and peroxide value (PV), and poor sensory quality. Low moisture content, flavonoids, phenols, antioxidants, fatty acid (FA) compositions, high PV, and poor sensory quality—i.e., excessive browning, an exceptionally crunchy texture, and a bitter flavor—were all characteristics of kernels roasted at 150 °C. With a perfect crispy texture, a rich brown color, and a strong nutty flavor, kernels roasted at 125 °C had lower PV; higher oxidation-resistant UFA compositions; considerable concentrations of flavonoids, phenols, and antioxidants; and good sensory quality. Therefore, ‘A4′ and ‘Beaumont’ kernels could be roasted at 125 °C for use in the industry to improve kernel quality and palatability.
... This suggests that the increase in α-tocopherol, as shown in Figure 2, does not increase the stability of milk fat against oxidation, but may acts as pro-oxidants at high concentrations. Redondo-Cuevas, Castellano, Torrens and Raikos (2018) found that the USFA and total tocopherols were the main individual factors that correlated negatively with oxidative stability (r² = 0.304, r² = 0.223, respectively). Zhao et al. (2013) indicated that cows fed long-chain FA exhibit positive effects on milk FA composition, but may decrease oxidative stability of milk fat. ...
The experiment was carried out to evaluate the quality of anhydrous milk fat (AMF) of cows and buffaloes supplemented with flaxseed oil (FO), soybean oil (SO), or their mixture (FSO). Lactating crossbred cows and buffaloes were fed with control diet or with one of three supplements: 2% FO, 2% SO, and 2% FSO according to a double 4 x 4 Latin Square Design. The diets with FO, SO, or FSO reduced saturated FA, mainly C4:0, C14:0 and C16:0, while increased the unsaturated FA C18:1 and C18:2 in milk from cows and buffaloes. Cholesterol content decreased in cow's AMF while increased in buffalo's AMF when a diet supplemented with FO, SO, or FSO. The diet with SO or FSO increased the content of vitamin E in AMF obtained from cows (25.06 and 17.89 mg 100 g-1) and buffaloes (28.48 and 30.32 mg 100 g-1) compared with the control diet (11.02 and 15.68 mg 100 g-1), respectively, which correlated positively with scavenging activity for DPPH• (r2 = 0.66) and ABTS• (r2 = 0.67) radicals. Solid fat content (SFC) was high for cow’s AMF, with 58.12-60.37% at 5°C compared to that of buffalo's AMF, with 52.37-56.98%, but was low for cow's AMF at >15°C. Finally, supplementing a diet with vegetable oils, particularly SO, improves the quality of AMF; increases USFA/SFA ratio, vitamin E content, and antioxidant activities
... The quality of oils and fats for consumption depends on their source, influencing their composition. It relates to the amount of saturated and unsaturated fatty acids content (van den Bremt et al., 2012), which ranges from the extraction process to ingestion (Redondo-Cuevas et al., 2018). After consumption, this quality will interfere with the body fat distribution, negatively affecting the metabolism (Hammad & Jones, 2017). ...
... One of the main problems in food preservation is rancidity, which is linked partially to the oxidation of unsaturated fatty acids in edible oils during processing, transportation, storage, and final preparation of edible Vos [52,53]. Many methods have been developed in order to control the rate and extent of lipid oxidation in foods, and then ensure the proper preservation of food products containing fats, which remains a fundamental objective for the food industry [54]. ...
Oil oxidation is the main factor limiting vegetable oils’ quality during storage, as it leads to the deterioration of oil’s nutritional quality and gives rise to disagreeable flavors. These changes make fat-containing foods less acceptable to consumers. To deal with this problem and to meet consumer demand for natural foods, vegetable oil fabricators and the food industry are looking for alternatives to synthetic antioxidants to protect oils from oxidation. In this context, natural antioxidant compounds extracted from different parts (leaves, roots, flowers, and seeds) of medicinal and aromatic plants (MAPs) could be used as a promising and sustainable solution to protect consumers’ health. The objective of this review was to compile published literature regarding the extraction of bioactive compounds from MAPs as well as different methods of vegetable oils enrichment. In fact, this review uses a multidisciplinary approach and offers an updated overview of the technological, sustainability, chemical and safety aspects related to the protection of oils.
... Furthermore, non-saponifiable components, such as tocopherols or phenol compounds, could also significantly affect oxidative stability. The oxidation of vegetable oils is the main cause of deterioration due to the loss of their nutritional value and the formation of undesirable volatile compounds (Redondo-Cuevas et al., 2018). The oxidative stability of crude jatropha oil was found to be higher than refined soybean oil even though it contains Vitamin E, which acts as an antioxidant to extend its shelf life. ...
The biodiesel production is typically conducted around 65 °C (methanol's boiling point), this study describes a catalytic process at room temperature (25 ± 3 °C) to shrink energy consumptions. In order to achieve this, potassium ferrate (K2FeO4) is used as a heterogeneous pseudo-catalyst in the transesterification reaction of two different vegetable oils: refined soybean oil (SBO) and crude Jatropha curcas L. oil (JCO). Transesterification variables are optimized using a Box-Behnken design (BBD) to maximize the oil conversion to fatty acid methyl esters (FAMEs). Process variables such as stirring rate (125–700 RPM), K2FeO4 dosage (0.15–6 wt.%), and methanol to oil molar ratio (6:1 to 16:1) are varied to obtain maximum conversion. The experimental results revealed that maximum conversion of 98.17% and 98.35% are produced in 1 h using the optimized conditions determined with the response surface methodology (RSM) for JCO (357 RPM, 5.29 wt.% K2FeO4 dosage, 14.89:1 MeOH: oil molar ratio) and SBO (700 RPM, 4.82 wt.% K2FeO4 dosage, 14.28:1 MeOH: oil molar ratio), respectively. The conversion percentage is quantified by Fourier Transform Infrared Spectroscopy (FTIR) and corroborated by proton nuclear magnetic resonance (¹H NMR). The fatty acid methyl esters produced under optimized reaction conditions are characterized to obtain their density, viscosity, acid number, oxidative stability, flash point, heating value, cloud point, and pour point to determine the quality compliance with the standard ASTM D6751. Additionally, conversion percentage is monitored at 0, 1, 5, 10, 15, 30, 45, 60, and 90 min of reaction. It is found that after 5 min of transesterification reaction, a conversion of 98.31% is reached without significant variation over time using SBO. A similar conversion (98.07%) is generated at 30 min for JCO, reaching its maximum conversion (98.65%) at 90 min. These fast reactions might occur due to the methoxy radicals formed on K2FeO4, unlike the methoxy ions produced by other heterogeneous catalysts. X-ray diffraction (XRD) and scanning electron microscopy (SEM) spectroscopy are used to characterize the K2FeO4 material.
... A total of 40 samples were analysed and four types of edible oils were used to investigate how fatty acid composition affects furan production ( Table 4). Palm oil was used as saturated fatty acid-rich oil, olive oil as oleic acid-rich oil, and soybean and corn germ oil as linoleic acid-rich oil (18,31,32). After frying, the results showed that increasing the heating time increased the furan concentration regardless of the sample and edible oil types. ...
In this study, furan analysis was conducted on dried red pepper powder treated by three cooking methods (boiling, roasting, and frying). A total of 144 samples were prepared and their furan levels were analysed using automated solid-phase micro-extraction gas chromatography-mass spectrometry. The furan concentration in boiled soup ranged from 1.26 to 4.65 ng/g, and from 7.37 to 27.68 ng/g for boiled red pepper samples. For the roasting method, a furan concentration between 6.66 and 761.37 ng/g was detected. For the frying method, the furan level of edible oils ranged from 3.93 to 125.88 ng/g, and a concentration ranging from 4.88 to 234.52 ng/g was detected for the fried red pepper samples. The cooking method using edible oil obtained a higher furan concentration than the water-based method. Samples using corn germ oil (linoleic acid-rich oil) obtained the highest furan concentration among the four edible oils. In all cooking methods, the higher the heating temperature and time, the higher the furan concentration detected. A kinetic study was conducted using the roasting model system and the apparent activation energy was 60.5 kJ/mol. The results of this study could be useful as a database for furan concentration in dried red pepper powder according to various cooking methods.
... It should be noted that the oil content has an important role in grain or seed storage since it can be degraded, resulting in oxidative rancidity and altering its nutritional and organoleptic quality and its germination power (20,21). For instance, higher PUFA levels can lead to oil oxidation, reducing the oil quality (22). In contrast, lipid degradation into glycerol and free fatty acids (lipid hydrolysis) is carried out by a group of enzymes known as lipases, which can be triggered by lipid oxidation (21,23). ...
The nutritional quality of quinoa is often related to the high protein content of their seeds. However, and despite not being an oilseed crop, the oil composition of quinoa seeds is remarkable due to its profile, which shows a high proportion of polyunsaturated fatty acids (PUFAs), particularly in essential fatty acids such as linoleic (ω-6) and α-linolenic (ω-3). In line with this, this study aimed at evaluating the effect of elevated temperatures on the oil composition of different quinoa cultivars grown in the field in two consecutive years (i.e., 2017 and 2018). In 2017, heat stress episodes resulted in a reduced oil content and lower quality linked to decreased ratios of oleic acid:linoleic acid, larger omega-6 (ω-6) to omega-3 (ω-3) ratios, and lower monounsaturated fatty acid (MUFA) and higher PUFA contents. Furthermore, the correlations found between mineral nutrients such as phosphorous (P) and the contents of oleic and linoleic acids emphasize the possibility of optimizing oil quality by controlling fertilization. Overall, the results presented in this study show how the environmental and genetic factors and their interaction may impact oil quality in quinoa seeds.
... The ratio of mono-and polyunsaturated fatty acids is 1:2. The content of carotenoids reaches 31 mg/100 g [88], tocopherols 89 mg/100 g [61,89], sterols 482 mg/100 g [90], and phenols only 2 mg/100 g [61]. ...
Consumer’s awareness of the health-promoting aspects of food and their search for products with high nutritional value is driving increased interest in niche oils. Such oils are produced on a small scale due to limited access to raw material and its low oil content. The aim of this multi-criteria analysis was to position niche oils. Data for the study were collected based on a literature review regarding twenty-three niche oils available on the European Union market. Analysis of quality parameters, key production factors, waste reusability, and average annual consumption volume in 2015–2020 was performed. Based on the research, it was concluded that linseed (flaxseed) oil, hemp oil, mustard oil, raspberry seed oil, and sesame oil should be of the most interest to consumers. They are characterized by the highest content of tocopherols, sterols, polyphenols, and carotenoids, a favorable ratio of mono- and polyunsaturated fatty acids, and pro-ecological and sustainable production technology. Based on the results of the study, the need for empirical research was identified, the key to filling the knowledge gaps in the area of edible niche oils.
... Oleic acid (C18:1) is the most dominant fatty acid, corresponding with the data reported from the various studies [14,15,31]. MUFA content of Irish rapeseed oils varied from 40.95% to 82.38%, with oleic acid (C18:1) content ranging from 34.17% to 66.03% (Table 1), corresponding with the data reported in various studies [32][33][34]. The oleic acid (C18:1) content variation was considered a statistically significant difference (p = 0:05). ...
The low saturated fatty acid content of rapeseed oil has resulted in it being classed as one of the most health-benefiting culinary oils. This study determines whether Irish rapeseed oils contain identical fatty acid profiles or whether distinct profiles exist between producers and producers’ successive oil batches. The fatty acid content of Irish rapeseed oils was determined in terms of the desirable MUFA and PUFA and saturated content of these oils. The fatty acid composition demonstrated significant differences in individual unsaturated fatty acid content, while total saturation had insignificant differences. Saturated fatty acid content ranged from 6.10 to 15.8%, while unsaturated fatty acids ranged from 84.20 to 90.10%. Moreover, individual fatty acid content exhibited significant differences (p<0.05). Oleic acid (C18:1), linoleic acid (C18:2), and stearic acid (C18:0) contents were considered significantly different from other fatty acids detected. The third successive batch from each producer exhibited lower oleic acid content, and the third batch contained higher linoleic acid content, at the same time maintaining a desirable unsaturated fatty acid composition. Studies suggest that differences in the fatty acid composition may be due to cultivation practices such as climate, soil composition, sowing and harvesting, processing techniques, and oxidation reactions.
... PO, RO, and HORO oils, in comparison to the literature data [40,41], had a low concentration of chlorophylls, which was advisable in view of the intended use for frying. However, the tested oils had an average content of carotenoids, about half as much as the oils analyzed by Symoniuk et al. [40], and several times higher than the oils studied by Redondo-Cuevas et al. [42]. The frying process has significantly affected the pigment content of oils. ...
One of the commonly used food preparation methods is frying. Fried food is admired by consumers due to its unique taste and texture. Deep frying is a process of dipping food in oil at high temperature, usually 170–190 °C, and it requires a relatively short time. The aim of this study was to analyze the thermo-oxidative changes occurring during the deep frying of products such as potatoes and tofu in cold pressed rapeseed oils and palm olein. Cold pressed rapeseed oil from hulled seeds (RO), cold pressed high oleic rapeseed oil from hulled seeds (HORO), and palm olein (PO) (for purposes of comparison) were used. Characterization of fresh oils (after purchase) and oils after 6, 12, and 18 h of deep frying process of a starch product (potatoes) and a protein product (tofu) was performed. The quality of oils was analyzed by determining peroxide value, acid value, p-anisidine value, content of carotenoid and chlorophyll pigments, polar compounds, smoke point, color (CIE L*a*b*), fatty acids content and profile, calculation of lipid nutritional quality indicators, and oxidative stability index (Rancimat). Cold pressed high oleic rapeseed oil was more stable during deep frying compared to cold pressed rapeseed oil, but much less stable than palm olein. In addition, more thermo-oxidative changes occurred in the tested oils when deep frying the starch product (potatoes) compared to the deep frying of the protein product (tofu).
... Several studies related to the fatty acid composition of VOs have been presented Giakoumis, 2018). It has been used to select premium quality VOs (Ai et al., 2014), in different biodiesel related studies (Alviso et al., 2020b(Alviso et al., ,c, 2019Alviso and Romano, 2021), and for the characterization of several physicochemical properties of VOs such as the density (Esteban et al., 2012), the viscosity (Fasina et al., 2006;Oliveira et al., 2016), the oxidative stability (Li et al., 2018;Redondo-Cuevas et al., 2018), and the electrical and ultrasonic properties (Corach et al., 2014(Corach et al., , 2015Lizhi et al., 2008). Moreover, a very interesting study on dielectric properties of VOs as a function of their composition, temperature, moisture, and frequency has been presented by Lizhi et al. (2008), where it was pointed out that their results could be used for the evaluation of the quality of VOs. ...
The dielectric constant (DC) and speed of sound (SoS) have been measured in many studies on vegetable oils (VOs). These measurements can be applied for quality control, for the detection of contaminants, and in works related to heated and frying VOs. There are several hundreds of VOs with potential use in the food industry, and for most of them, the DC and SoS values are not yet available. This paper proposes regression models of the DC and SoS of VOs as a function of their composition (saturated and unsaturated fatty acids) and the temperature. A regression study was conducted using available experimental databases including a total of 57 and 56 data in the range of 20−50 °C for the DC and SoS, respectively. The equations are obtained using genetic programming (GP). The goal is to minimize the mean absolute error (MAE) between the values of the measured and predicted DC and SoS for several VOs. The resulting GP regression equations reproduce correctly the dependencies of the DC and SoS of VOs on the saturated and unsaturated fatty acids. The validation of these equations is carried out by comparing their results to those of the experimental databases. The MAE values of the regression equations concerning the databases for DC and SoS of VOs are 0.02 and 1.0 m/s, respectively.
... In addition, polyunsaturated, saturated, and monounsaturated fatty acids required in human diets are also found in SBO in good proportions (de Almeida Chuffa et al., 2014). Although unsaturated fatty acids bring out several benefits for human hearts and bodies, their high levels result in accelerated oxidative susceptibility in vegetable oils, causing undesirable effects in the taste, aroma, and color, as well as in the chemical and nutrient values of the oils (Chen et al., 2014;Roszkowska et al., 2015;Maszewska et al., 2018;Redondo-Cuevas et al., 2018). Therefore, the addition of the appropriate type and quantity of antioxidants to these vegetable oils is crucial to improving their shelf-life and overall quality. ...
This study examined the effectiveness of different antioxidative compounds, namely 0.2% BHA (Butylated hydroxyanisole) + BHT (butylated hydroxytoluene), 0.03% α – tocopherol, and 3% and 6% tea seed oil (TSO) on the oxidative stability of vegetable oils. Four commonly used oils, viz. rapeseed oil (RSO), peanut oil (PNO), sunflower oil (SFO), and soybean oil (SBO), were assessed by the Schall Oven test method and monitored during the 12-day preservation period under 60°C. The total oxidation values (TOTOX) of the samples treated with 6% TSO were lower than those treated with 0.2% BHA+BHT. The results indicated the potential of TSO as a novel natural antioxidant for dietary vegetable oils. Our study also suggested that TSO could serve as an effective substitution for currently used synthetic antioxidants such as BHA and BHT.
... In particular, storing can greatly affect the oxidation stability of EVOO, one of the primary causes of its degradation, which can progress in the dark (autoxidation), and can be accelerated in the presence of light (photo-oxidation) and enzymes (enzymatic oxidation) [6]. The high oleic acid content and the natural antioxidants present in EVOOs, including phenolic compounds, tocopherols (mainly α-tocopherol), squalene, chlorophyll, carotenoids, and vitamins, are tied to oil stability by providing an effective defense against free radicals by different mechanisms [7][8][9][10][11]. Minor polar phenolic compounds are constituted by simple phenols, such as tyrosol and hydroxytyrosol, and by their combination with other moieties to form oleuropein and ligstroside and their derivatives, cinnamic acids, as well as lignans and flavonoids [12]. ...
The extent and conditions of storage may affect the stability and quality of extra virgin olive oil (EVOO). This study aimed at evaluating the effects of different storage conditions (ambient, 4 °C and −18 °C temperatures, and argon headspace) on three EVOOs (low, medium, and high phenols) over 18 and 36 months, analyzing the main metabolites at six time points. The results showed that low temperatures are able to maintain all three EVOOs within the legal limits established by the current EU regulations for most compounds up to 36 months. Oleocanthal, squalene, and total phenols were affected by storage temperatures more than other compounds and degradation of squalene and α-tocopherol was inhibited only by low temperatures. The best temperature for 3-year conservation was 4 °C, but −18 °C represented the optimum temperature to preserve the organoleptic properties. The present study provided new insights that should guide EVOO manufacturers and traders to apply the most efficient storage methods to maintain the charac-teristics of the freshly extracted oils for a long conservation time.
... The reason for the low oxidative stability of VO is unsaturated fatty acids, ie. C=C in acid compositions (Redondo-Cuevas et al., 2018). For the unsaturated acids in the cis form, they cannot form a straight chain. ...
Friction and wear are inevitable in machine parts in motion. The industrial sector uses various kinds of lubricants, which include engine oils, CFs, hydraulic fluids, greases, etc. to control friction and wear. The main purpose of using CF is to remove heat produced during machining and to reduce cutting forces, tool wear and energy associated with it. Thus, it increases the productivity and quality of the manufacturing process. But more than 80% of the CFs used in the industries now are mineral oil-based. These mineral oils and additives are highly undesirable because of their toxicity, nonbiodegradability, pollution and ecological problems. Hence, these petroleum-based oils in the lubrication system can be substituted with alternatives such as vegetable-based CF. Several studies are being conducted in the field of eco-friendly CFs. Because of the variance in fatty acid profile and availability, the selection of vegetable oils (VOs) is another problem faced nowadays. The present study is focused on bio-based oils and many eco-friendly additives. Various machining processes and comparisons relating to the same have also been made. The aim is to minimize the use of mineral oil and thereby introduce sustainability in production.
... Gruzdiene and Anelauskaite (2011) and Roszkowska, Tańska, Czaplicki, and Konopka (2015) corroborated a positive correlation between their content and induction time in rapeseed oils. In turn, Redondo-Cuevas, Castellano, Torrens, and Raikos (2018) found that the total phenolic compounds were the main factors that correlated positively with the oxidative stability of 22 commercial oils and fats studied. Also, Dąbrowski, Konopka, Czaplicki, and Tańska (2017) explained the higher oxidative stability of acetone-extracted chia oil with a higher amount of phenolics compared to the pressed and hexane-extracted oils. ...
Background
Phenolic compounds from different plant sources, like fruits, vegetables, cereals, and herbs, have been excessively studied and widely used in different industrial areas, including food, medicine, and pharmaceuticals. Recently, special attention has been paid to the phenolic compounds of plant oils that have recently been found to vastly affect the oxidative stability of these products.
Scope and approach
This paper reviews the contents and types of phenolic compounds in their initial forms in plant oils and methods of their determination. Also, their impact on the oxidative stability of oils is discussed.
Key findings and conclusions
The total free content of phenolic compounds and the phenol profile in plant oils are very diverse and depend on the oil source and production method. Generally, the main oily source of these compounds is rice brans and olive fruits. Their high amounts can also be found in rapeseed, flaxseed, grapeseed, and pumpkin oils. The main groups of phenolic compounds in oils are phenolic acids and flavonoids. Additionally, lignans, secoiridoids, and phenolic derivatives are identified in some oils. The two main methods for the determination of phenolic compounds in oils include the spectrophotometric and chromatographic ones. The general principles of these assays are often modified by various authors to adapt them to research conditions. Available literature data confirmed the strong antioxidative activity of some phenolic compounds found in oils. However, further studies are needed to better understand the mechanism of their protective action on oils, especially under natural storage.
... Figure 2b shows clear segregation of H20, H21, and RSO samples which indicates significantly better oxidative characteristics compared to other tested samples, due to the lower degree of fatty acid unsaturation. Similar results were obtained by Redondo-Cuevas et al. (2018). They applied PCA to oil samples originating from different raw materials (corn, olive, sunflower, rapeseed, sesame, coconut, palm, butter, ghee) and obtained new PCs accounting for 66.6% of the total variance (PC1 accounts for 46.3% and PC2 20.3%). ...
Refined sunflower oil has dissimilar shelf life compared to cold-pressed sunflower oil, which increases the use of refined oil, and it is more abundant in the diet. On the other hand, the production of cold-pressed oils does not require chemical processing. Moreover, these oils contain significant amounts of bioactive components with a beneficial health effect. Breeders are trying to create new sunflower hybrids for the production of cold-pressed oil with improved oxidative characteristics. This study aims to examine the rancidity of 24 cold-pressed sunflower oils of new hybrids under accelerated thermal stability test conditions (Rancimat and Schaal oven tests) and to compare the obtained results with refined sunflower oil. According to investigated oxidative parameters, the most similar to refined sunflower oil was the H20 sample with the induction period determined by the Rancimat test of 9.55 ± 0.00 h, compared to 9.49 ± 0.00 h, obtained in refined sunflower oil. The total oxidation value of the H20 sample amounted to 3.26 ± 0.12, while in refined sunflower oil this value was 2.12 ± 1.73.
... Despite unquestionable benefits, cold-pressed oils present a major issue on two fronts, i.e., a decrease of their (1) stability and (2) sensory quality during storage and thermal treatment [6]. Oil stability is one of the most important factors that affect the oil quality since instable oils have an undesirable taste and flavor [3,11]. One way to improve the stability of oils is by blending with ingredients containing high antioxidant levels [12]. ...
The aim of this study was to monitor sensory quality, stability, selected nutritionally interesting properties and their changes in cold-pressed oil blends after fortification with chia and sesame seeds and seed oils during repeated thermal treatments. Rapeseed (cv. Sidney) and sunflower (cv. Velox) seeds from the Czech Republic were used to produce cold-pressed oils, which were fortified with chia and sesame seeds and seed oils in the concentrations of 1% and 5%. In all oil blends, sensory evaluation (quantitative descriptive analysis and hedonic analysis) and chemical analyses (oxidation degree, hydrolytic stability, chlorophyll and carotenoid content) were carried out in order to perform separation of samples degraded by thermal treatment. Assessors representing consumers were able to differentiate between individual thermal treatments from the viewpoint of pleasantness. Interestingly, the overall pleasantness of all fortified oil samples was still acceptable until the second thermal treatment. On the other hand, the results of the study emphasized the problematic oxidation degree of cold-pressed oil blends. The fortification of cold-pressed oils with chia and sesame seeds and oils did not unambiguously lead to better stability during thermal treatment. The application of elevated temperatures during the culinary use of these types of products should be limited to only one thermal treatment since sensory and chemical changes occur after repeated heating.
Sesame (Sesamum indicum) seeds are highly valued for their culinary applications and for producing a premium-quality oil. This study investigated the polyphenol content and fatty acid composition of a set of sesame accessions and examined their association with seed colors. Among the different colors, black-seeded accessions exhibited the highest total lignan content, while white-seeded accessions had average lower levels. Brown-seeded accessions showed relatively lower concentrations of sesamol and intermediate levels of sesamolin and sesamin than other colors. The oil derived from these seeds contained unsaturated fatty acids (UFAs) and saturated fatty acids (SFAs), nutritionally crucial for human consumption. Brown varieties exhibited higher concentrations of these fatty acids. Roasting black and white sesame seeds at increasing temperatures (180 and 250 °C) significantly affected lignan and UFAs concentrations. Higher temperatures resulted in elevated levels of detrimental t-oleic and t-linoleic acids. Furthermore, sesamolin content notably decreased at 180 °C and became undetectable at 250 °C. The temperature also caused a marked increase in sesamol, regardless of seed color. PCA analysis highlighted clusters between white and black varieties according to roasting temperature, displaying the potential application of chemometrics to assess processing effects and ensure sesame quality and safety. This research provides valuable insights for exploiting sesame within agrosystems in Mediterranean climates.
Vegetable oils (VOs) comprise 90%–98% triglycerides (three fatty acids esters and glycerol), with trace amounts of mono-glycerides and di-glycerides. The content of glycerides in VOs can vary depending on the specific type of oil, the processing methods used, and other factors such as the cultivar and harvest date. VOs have been examined for usage in different applications due to their physicochemical properties, including stationary engines, big ships, and Diesel engines of low and medium speed. There are around 350 VOs that have the potential to be used as fuel sources, the vast majority of which have yet to have their physicochemical properties investigated. Regression models based purely on VOs fatty acid content are beneficial in this context. This study conducts a regression analysis of VOs density (DE), kinematic viscosity (KV), flash point (FP), and low and high heating values (LHV and HHV) as a function of their fatty acids. Several experimental databases were selected, including the values of VOs fatty acid composition and physico-chemical properties. Optimal non-linear polynomials were chosen for the regression procedure. Scheffé polynomials offer different fitting alternatives to adjust the VOs experimental databases using their five main fatty acids: from simple linear polynomials (including five terms) to full cubic polynomials (including 35 terms). The polynomials are validated by showing how well their results correspond with the experimental databases. The standard error values for the proposed full polynomials concerning the databases for DE, KV, FP, LHV, and HHV are 0.70%, 7.79%, 7.86%, 1.66%, and 0.19%, respectively.
Los aceites son parte importante de la dieta de las personas, este producto es empleado de diversas formas en las preparaciones culinarias para proveer cualidades organolépticas en los alimentos. Actualmente el procedimiento más utilizado para cocinar los alimentos es la fritura con aceite o para ser utilizado en frío para condimentación de ensaladas, por lo que hoy en día se encuentran disponibles en el mercado gracias a las nuevas tecnologías de las empresas, pero no siempre estas nuevas propuestas son las mejores para la salud. En el presente artículo se evaluó la evidencia existente sobre las características de los aceites con la finalidad de conocer cuáles son los ideales para este tratamiento térmico en la preparación de alimentos. Se realizó una búsqueda en diferentes bases de datos (Google Scholar, Dialnet, PubMed, Elsevier, biblioteca digital de la UAEH), teniendo como resultado un total 51 referencias sobre información nutrimental y estabilidad para el freído. Con apoyo de estas referencias se evaluaron 8 aceites vegetales (oliva, oliva extra virgen (EV), girasol, sésamo, coco, soja, aguacate y canola) y se realizó una tabla comparativa con sus características nutricionales y parámetros de calidad. Los mejores aceites encontrados de acuerdo a las características nutricionales fueron el de oliva, oliva EV, soya y girasol, mientras que por estabilidad ante las altas temperaturas resultaron ser el de canola, girasol y soya, por lo que, se debe preferir el consumo de aceites que presentan menores cambios estructurales durante este procesamiento para evitar la formación y consumo de compuestos que dañan la salud, se deben de seguir estudiando los cambios ocurridos durante la fritura ya que aún no se cuenta con información disponible suficiente.
Using sunflower oil as the oil matrix, the antioxidant effects and types of interactions of three natural components, α-tocopherol, β-carotene and epigallocatechin gallate (EGCG), were investigated and the kinetic model of oxidation reaction was established. The results showed that the ability of the three antioxidants to scavenge DPPH radicals was ranked as EGCG > β-carotene > α-tocopherol in the concentration range of 0~100 mg/kg. 15 samples were obtained by combining two of three natural components. When the concentration ratios of β-carotene and EGCG were 1:20 and 1:7.5, α-tocopherol and EGCG were 1:13.3, 1:6, and 1:2, and α-tocopherol and β-carotene were 1:0.2 and 1:0.05, the type of interaction was synergistic, while the rest of the samples showed antagonistic effects. The sample with a 1:13.3 concentration of α-tocopherol and EGCG showed the longest induction period, the lowest oxidation rate constant, the highest activation energy, the best oxidative stability, and the longest shelf life at different temperatures. This compounded natural antioxidant was the most favorable for the stability of sunflower oil. This provides some theoretical basis for the development and application of compounded natural antioxidants in vegetable oils.
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In the food industry, oil blending represents a simple method for the generation of products with desired nutritional and technological properties. The objective of this work was to blend anchoveta oil (AO) with virgin olive oil (VOO) to modify the ω-6/ω-3 ratio of the product for nutritional purposes and to evaluate its oxidative stability index (OSI) for technological purposes. Four AO/VOO blends were formulated: 50/50, 40/60, 30/70 and 20/80 (w/w), generating a ω-6/ω-3 ratio between 0.610–2.129, nutritionally recommendable. The Rancimat method allowed determining the OSI of the formulations at temperatures of 100, 110 and 120 °C, finding OSI ranges between 0.963–3.410 h, 0.430–1.730 h and 0.183–0.813 h, respectively. The kinetic behavior of the formulations with respect to activation energy (89.622 to 93.414 kJ/mol), entropy (−13.248 to −17.657 kJ/mol), enthalpy (86.455 to 90.248 kJ/mol), Gibbs energy (91.928 to 96.348 kJ/mol) and Q10 (2.090 to 2.153) has been described. The formulations are proposed as an alternative to increase the shelf life of AO and increase the nutritional value of VOO.
Vegetable oils are subjected to heat treatments during processing and changes during storage. Thus, it is required, for usage as a food source, the evaluation of their thermo-oxidative stability and physicochemical characteristics. In this context, the objective of this paper was to evaluate the oil of catole coconut (Syagrus cearensis), aiming to characterize its identity and quality, as well as its antioxidant capacity and thermo-oxidative stability. The catole coconut was collected in the city of Lagoa Seca-PB, Brazil, its almonds were dried in a stove and the catole oil was obtained by cold pressing. The results of the physicochemical parameters complied with the current legislation, with average values of 2.48 mg KOH g−1 oil for acid value, 0.14 meq peroxide kg−1 oil for peroxide value and 253 mg KOH g−1 oil for saponification value. Catole oil presented the profile of saturated fatty acids (84.42%), with the predominance of lauric acid (45.06%), besides major phenolic compounds such as salicylic acid [12.324 mg (100 g−1) of oil] and myricetin [1.405 mg (100 g−1) of oil]. The thermogravimetric profile remained stable to decomposition at temperatures up to around 240 °C and oxidative stability withstood at 110 °C for more than 48 h. Therefore, it was possible to identify and characterize this unexplored oilseed species of the Brazilian semiarid, diversifying its use in the food industry.
This work investigated the efficiency of pressurized liquid extraction (PLE) to obtain oil and active compounds from crambe seeds, using dimethyl carbonate (DMC) and ethanol as solvents. The Box-Behnken experimental design was used to evaluate the influence of experimental conditions (addition of ethanol to DMC, pressure and temperature) on extraction mass yield (EMY) and yield of phytosterols (PY) and γ-tocopherol (TY). In the condition that provided the maximum value of the evaluated response variables, the effect of the solvent to seed ratio and solvent was determined, as well as the comparison with the data from the application of conventional extraction by Soxhlet. From the results obtained, it was found that the temperature and the addition of ethanol to the DMC had a high influence on the removal and quality of the oil. The addition of 50% ethanol to the DMC, low pressure (50 bar) and high temperature (150 °C) allowed obtaining the highest values for the response variables and the validation of the model was verified by high correlation between the predicted (EMY: 36.43%; PY: 925.44 mg per kg of seeds; TY: 536.66 mg per kg of seeds) and experiments (EMY: 39.35%; PY: 914.57 mg per kg of seeds; TY: 533.29 mg per kg of seeds) values. PLE resulted in EMY higher than that obtained in the Soxhlet extraction, and for the different solvents tested, EMY followed the order DMC + ethanol > ethanol > DMC. The use of ethanol in PLE provided a high content of active compounds compared to the use of the solvent mixture, however, it presented greater extraction of non-lipid compounds. The main fatty acids present in crambe oil were erucic and oleic, the iodine value and the fatty acid composition were similar for the different solvents/extraction technique. In general, the presence of natural antioxidants and the high oxidative stability of the oil showed that it has the potential to be applied in the synthesis of biodiesel.
The ultrasound‐assisted extraction (UAE) was applied to enhance the extraction efficiency of oil from babassu kernel (BKO) using n‐hexane as solvent. For this purpose, the effects of temperature (30 to 60 °C), solvent to kernel ratio (6 to 10 mL g‐1) and time (10 to 30 min) on oil yield (YO) were determined, in addition to assessing the effect of these variables in the characteristics of the obtained oil. In the condition of maximum extraction, the chemical composition of the oil was determined and the results were compared with the Soxhlet extraction. In the evaluated experimental range, the amount of solvent used in the process influenced the YO, while time and temperature had no effect on the response variable. With this a high oil removal of kernels (89.5% of obtained by Soxhlet) was obtained in low conditions of time (10 min) and temperature (30 °C), in addition to using smaller amount of solvent (10 mL g‐1) in relation to conventional technique (30 mL g‐1). The lowest evaluated temperature (30 °C) was also indicated to obtain an oil with higher content of phenolic compounds and antioxidant activity. BKO showed a predominance of lauric (~49.9%) and myristic acids (~15.6%), and high oxidative stability. The quality of the oil extracted by UAE was superior in terms of phytosterols, phenolic compounds, antioxidant activity and color parameters.
The physical-chemical and organoleptic properties of vegetal oils are subject to frequent change caused by different degradation process. Hence, producers must provide accurate information on shelf-life prediction. Due to the complexity of chemical interactions between the oil phase and environment, multiple studies under real-time storage and forced conditions have been conducted. This paper reviews the application of methods based on multivariate data analysis, and its advantages, in shelf life and stability studies of edible both virgin and refined vegetable oils. Three multivariate approaches could mainly be differentiated regarding previous studies on foodstuff stability data: unsupervised methods; multivariate pattern recognition methods; and other chemometric resolution methods. Note that, multivariate approaches bring numerous opportunities, these applications currently show also limitations, especially for official control purposes in food surveillance. Future trends will rely on the practical implementation of such promising chemometric approaches combining high informative advanced techniques and comprehensive multivariate data analysis.
Effects of moisture content, degree of oxidation, degree of unsaturation of fatty acid compositions in C18-based edible oils were determined by a microwave resonator in the range of 0–4.4 GHz. Moisture content and degree of oxidation in corn oil made difference in signal intensity at 1.7–1.9 GHz and 1.0–1.2 GHz, respectively without uniform trend in signal intensity. Degree of unsaturation of C18-based edible oils including corn, sesame, soybean, olive, perilla, and flaxseed oils provided difference in 3.0-3.1 GHz with a dependent manner of degree of unsaturation. Average of signal intensity (ASI) in 3.0-3.1 GHz had high correlation (R² > 0.93) to the degree of unsaturation in edible oils. Oils with high oleic acid had relatively low ASI while those with high linolenic acid had high ASI value. Oxidative stability of C18-based edible oils can be categorized successfully without fatty acid analysis using a microwave resonator.
This new volume introduces readers to some of the latest research applications of physical chemistry.
Combretum collinum, Combretum micranthum, Combretum nigricans, and Combretum niorense are abundant unconventional seed oils of the African savannah. In this study, the proximate, mineral, amino acid, fatty acid, and triacylglycerol compositions of the four seed oils were quantified, and the oxidative and physicochemical properties were investigated. The amino acid, fatty acid, and triacylglycerol compositions were determined by using high performance liquid chromatography (HPLC) and gas chromatography respectively. Carbohydrates (57.35%–64.20%) followed by crude oils (20.07%–22.60%), proteins (11.95%–15.86%), and ashes (3.78%–6.19%) were the main constituents of the four seed species. The highest ash, crude fat, and protein contents were found in C. collinum, C. nigricans, and C. niorense, respectively. All four seed species were rich in Ca, K and Mg, and poor in methionine, cysteine, and lysine. The four seed oils had high saponification values (198.46–202.71 mgKOH/g), low acidity (1.12–2.26 mg of KOH/g of oil), and peroxide values (1.19–1.98 mEqO2/kg of oil). The seed oils of C. micranthum and C. collinum exhibited the highest thermal oxidative stability (8.10 and 9.79 h at 160°C). Oleic (40.49%–56.69%), palmitic (15.17%–24.27%) and linoleic (9.49%–14.50%) acids were the predominant fatty acids of the four seed oils. The results showed that the four seed species and seed oils had good chemical composition and physicochemical properties making them suitable for food and non‐food application.
In this study the use of pressurized ethanol to extract oil from radish seeds was investigated. The influence of the pretreatment of the seeds and the ethanol flow rate, static time, temperature and pressure applied during the extraction was evaluated to determine the effect on the yields of oil and active compounds. The application of thermal treatment after immersion promoted an increase in the oil yields. An ethanol flow rate of 3 mL min⁻¹ and a static time of 10 min increased the oil diffusion. The extraction at 150 °C provided a high oil fraction and higher yields of phytosterols and γ-tocopherol were obtained at 135 °C. In addition, 5 MPa was sufficient to achieve an oil yield of 36.6%, as higher pressures did not influence the process. The oil obtained was rich in oleic and erucic acids, with low acidity and high oxidative induction time.
Abstract
Polysaccharides were extracted from seven plants endemic to Gabon to study their potential immunological activities. Peripheral blood mononuclear cell (PBMC) (5 × 105 cells/mL) proliferation, cytokine and immunoglobulin G (IgG) assays were performed after stimulation with different concentrations of polysaccharide fractions compared with lipopolysaccharides (LPS) and concanavalin A (ConA) from healthy volunteers. The culture supernatants were used for cytokine and IgG detection by enzyme-linked immunosorbent assay (ELISA). The results show that pectin and hemicellulose extracts from Uvaria klainei, Petersianthus macrocarpus, Trichoscypha addonii, Aphanocalyx microphyllus, Librevillea klaineana, Neochevalierodendron stephanii and Scorodophloeus zenkeri induced production levels that were variable from one individual to another for IL-12 (3–40 pg/mL), IL-10 (6–443 pg/mL), IL-6 (7–370 pg/mL), GM-CSF (3–170 pg/mL) and IFN-? (5–80 pg/mL). Only hemicelluloses from Aphanocalyx microphyllus produce a small amount of IgG (OD = 0.034), while the proliferation of cells stimulated with these polysaccharides increased up to 318% above the proliferation of unstimulated cells. However, this proliferation of PBMCs was abolished when the pectin of some of these plants was treated with endopolygalacturonase (p < 0.05), but the trend of cytokine synthesis remained the same, both before and after enzymatic treatment or saponification. This study suggests that these polysaccharides stimulate cells in a structure-dependent manner. The rhamnogalacturonan-I (RGI) fragment alone was not able to induce the proliferation of PBMC. This study confirms the immunostimulatory properties of polysaccharides.
Keywords: Pectins hemicelluloses cytokines IgG human PBMCs endemic plants Gabon
Olive oils have been shown to be more resistant to oxidation than other vegetable fats, mainly due to their fatty acid (FA) profile which is rich in oleic acid and to their high content of antioxidants, principally phenols and tocopherols. This has situated virgin olive oils (VOOs) among the fats of high nutritional quality. However, it is important to stress that the oil’s commercial category (olive oil, virgin olive oil, extra-virgin olive oil), the variety of the source plant, and the extraction-conservation systems all decisively influence the concentration of these antioxidants and the oil’s shelf-life. The present work studied the fatty acid (FA) and phenolic composition and the oxidative stability (OS) of eight olive varieties grown in Extremadura (Arbequina, Cornicabra, Manzanilla Cacereña, Manzanilla de Sevilla, Morisca, Pico Limón, Picual, and Verdial de Badajoz), with the olives being harvested at different locations and dates. The Cornicabra, Picual, and Manzanilla Cacereña VOOs were found to have high oleic acid contents (>77.0%), while the VOOs of Morisca and Verdial de Badajoz had high linoleic acid contents (>14.5%). Regarding the phenol content, high values were found in the Cornicabra (633 mg·kg−1) and Morisca (550 mg·kg−1) VOOs, and low values in Arbequina (200 mg·kg−1). The OS was found to depend upon both the variety and the date of harvesting. It was higher in the Cornicabra and Picual oils (>55 h), and lower in those of Verdial de Badajoz (26.3 h), Arbequina (29.8 h), and Morisca (31.5 h). In relating phenols and FAs with the OS, it was observed that, while the latter, particularly the linoleic content (R = −0.710, p < 0.001, n = 135), constitute the most influential factors, the phenolic compounds, especially o-diphenols, are equally influential when the oils’ linoleic content is ≥12.5% (R = 0.674, p < 0.001, n = 47). The results show that VOOs’ resistance to oxidation depends not only on the FA or phenolic profile, but also on the interaction of these compounds within the same matrix
Virgin olive oil (VOO) represents a rich source of natural antioxidants, with tocopherols as the most effective group of lipophilic, phenolic antioxidants. α-Tocopherol represents more than 95% of the total tocopherols in virgin olive oil, and it possesses the highest biological activity among members of the vitamin E family. Content and composition of the tocopherols of virgin olive oil depend on several agronomic factors, as well as olive processing and oil storage conditions.
In this chapter, the tocopherol homologue activity in virgin olive oil and the biological importance are discussed. Research work is reported on the tocopherol content and composition variability in virgin olive oils of the most widespread Croatian cultivar “Oblica” and Italian cultivar “Leccino.” Factors studied such as year, growing area and olive fruit ripening and their influence on the tocopherol content and composition of virgin olive oils are discussed. The effect of filtration of the oil and storage conditions on tocopherols are also examined.
The objective of this study is to compare the influence of genotype, environmental conditions and processing methods after maturation and harvesting of four varieties of flaxseed (Altess, Biltstar, Niagara and Oliwin) on the levels of tocochromanols, carotenoids and chlorophyll in flaxseed oil. Samples were produced by cold pressing of dry seeds and seeds heated for 30 min at 60 °C. Temperature, sunshine and rainfall were primary environmental conditions included. Grand mean of mass fraction of γ-tocopherol was (522±29), of plastochromanol-8 (305±2) and total tocochromanols (831±3) mg per kg of oil. The highest levels of these compounds and strongest antioxidant activity were found in cold - -pressed oil of Biltstar variety. During seed maturation, levels of γ-tocopherol and plastochromanol- 8 increased with average temperature and total sunshine and decreased with total rainfall. Fifth week after flowering was identified as the maturation period with best climate conditions to achieve optimal tocochromanol content. Grand mean of mass fraction of carotenoids expressed as β-carotene was (1.83±0.01) and of chlorophyll expressed as pheophytin a (0.43±0.10) mg per kg of oil. Altess variety had the highest levels of pigments. Antioxidant activity decreased with the increase of chlorophyll, while correlations with carotenoids were not determined. Generally, oil obtained by cold pressing had higher levels of tocochromanols and lower levels of pigments but similar antioxidant activity to the oil after seed conditioning. The results of this study contribute to identifying the flaxseed variety that is the best for oil production with the highest antioxidant activity and nutritive value, and provide better understanding of tocochromanol biosynthesis depending on different climate conditions.
Present study includes evaluation of fatty acid composition, tocols profile, and oxidative stability of some fully refined edible oils. Fully refined sunflower, soybean, corn, hazelnut, peanut, and canola oils were analyzed for fatty acids by capillary gas liquid chromatography, tocols by normal phase-high performance liquid chromatography and oxidative stability by rancimat. Free fatty acid, peroxide value, and iodine value of investigated oils were determined by titrimetric methods. Saturated, mono-, and polyunsaturated fatty acids were found to be in the ranges between 2.03-18.58, 23.39-77.26, and 14.39-58.52%, respectively. Tocols and oxidative stability of the investigated oils were found to be in the ranges between 488.88-913.51 mg kg−1 and 3.05-4.99 h, respectively.
Operational parameters of Rancimat, including sample weight (3, 6, 9 g), airflow rate (10, 15, 20 L/h) and temperature (110, 120, 130°C) were evaluated to determine their effects on oxidative stability index, temperature coefficient, Q10 number, and shelf life prediction of ghee (anhydrous milk fat). These parameters showed statistically significant effects on the oxidative stability index. It was observed that when the sample weight and airflow rate at a given temperature were at saturated air condition, the oxidative stability indexes showed no significant differences (p Keywords: Ghee; Oxidative stability index; Q10 number; Rancimat; Temperature coefficient Document Type: Research Article DOI: http://dx.doi.org/10.1080/10942912.2012.680220 Affiliations: Dairy Chemistry Division, National Dairy Research Institute, Karnal, Haryana, India Publication date: October 21, 2014 $(document).ready(function() { var shortdescription = $(".originaldescription").text().replace(/\\&/g, '&').replace(/\\, '<').replace(/\\>/g, '>').replace(/\\t/g, ' ').replace(/\\n/g, ''); if (shortdescription.length > 350){ shortdescription = "" + shortdescription.substring(0,250) + "... more"; } $(".descriptionitem").prepend(shortdescription); $(".shortdescription a").click(function() { $(".shortdescription").hide(); $(".originaldescription").slideDown(); return false; }); }); Related content In this: publication By this: publisher By this author: Pawar ; Purohit ; Gandhi ; Arora ; Singh GA_googleFillSlot("Horizontal_banner_bottom");
The tocopherol content of Brazil nut oil from different Amazon regions (Manicoré-AM, Rio Preto da Eva-AM, São João da Baliza-RR, Caroebe-RR, Belém-PA, and Xapurí-AC) was investigated by normal-phase high-performance liquid chromatography. For all authentic oils, two isomers: α- and γ-tocopherols were observed (37.92-74.48 µg g-1, 106.88-171.80 µg g-1, respectively), and their levels were relatively constant among the oils having these geographic origins, which would enable to distinguish Brazil nut oil from other plant oils for authentication purposes. Commercial Brazil nut oils were also evaluated, and some of these oils demonstrated a tocopherol content that was very different from that of the authentic oils. Therefore, we suggest that the tocopherol profile of Brazil nut oil can be useful chemical marker for quality control and authentication.
Sesame (Sesamum indicum L.) seed and oil have long been used widely as healthy foods to supply energy and prevent aging. Some of the main active anti-oxidative constituents in sesame seeds are γ-tocopherol and phenols. The purpose of this study was to investigate the relationship between roasting temperature and time with γ-tocopherol and total phenolic compounds (TPC) of sesame seeds when roasted in a domestic electric oven.
Eight cultivars of sesame seeds in this study were Darab, Dezful, Karaj, Moghan, Naz- Branching, Naz-NonBranching, Siah and Varamin. Each cultivar was divided into ten group based on the roasting time (10, 15 and 20 min) and temperatures (180, 200 and 220 °C)andunroasted one. The high-performance liquid chromatography (HPLC) and spectrophotometeric methods were used for γ-tocopherol (n = 80) and TPC (n = 80) analysis, respectively.
The γ-tocopherol content ranged from 329 ± 5 mg/L in Naz-Branching sesame oil to 1114±7 mg/L in Siah sesame oil and 169±6 to 577±1 mg/kg in sesame seed respectively. γ-tocopherol content of six cultivars increased significantly (p < 0.05) as the roasting temperature and time; until 200 °C for 10 min, but they were decreased by roasting at 220 °C in longer time.
Also TPC increased significantly as the roasting temperature. The amount of TPC varied in different sesame cultivars from 20.109 ± 3.967 μM to 129.300±3.493 in Varamin and Naz- Branching sesame seed cultivars, respectively, also TPC increased from 70.953 ± 5.863 μM in unroasted Naz-Branching sesame seed to 129.300 ± 3.493 μM after roasting in 200 °C for 20 min.
The present study showed that Iranian sesame seed can be considered as a good source of natural antioxidant specially after roasting. The optimum temperature and time roasting to obtain the most γ-tocopherol and total phenolic content was 200 °C for 10 and 20 min, respectively.
The effect of commercial refining steps on the peroxide value (PV), acid value (AV), carbonyl value (CV), total polar compounds (TPC) content, polar compounds distribution, and oil/oxidative stability index (OSI) of soybean and canola oils was studied. The PVs were changed during the different refining steps. The AVs significantly decreased after the neutralisation step. The CVs continuously increased during the refining steps. The marked decrease observed in the TPC contents after the neutralisation step was mainly due to the decrease in the content of free fatty acids (FFA) and oxidised triglyceride monomers (oxTGM) than in the content of the other polar compounds. On the contrary, the study showed more significant changes in diglycerides (DG) and triglyceride dimers (TGD) contents than in the FFA and oxTGM contents during the deodorisation step. The OSIs significantly decreased after the neutralisation step and indicated no considerable changes during the further refining steps.
Oxidative stability of VOO is widely determined by Rancimat test, an accelerated method that shortens analysis time. The most usual temperature used for Rancimat analysis is 98C; however several authors have reported oxidative stability values at different temperatures higher than 98C (110C, 120C) in order to reduce the analysis time. In this study the effect of temperature on Rancimat method for VOO analysis, measuring the method reproducibility at each temperature, has been evaluated. Method precision expressed as the relative standard deviation (RSD) was ranged from 1.14 to 5.84%, indicating that analytical method was repeatable even at 140C. A mathematical model is presented to transform the induction period inter-temperatures (98–140C). The results suggested 110C as the more adequate temperature since the analysis time was shortened by 63% compared to induction period obtained at 98C; the inter-conversion 98–110C presented low differences between theoretical value obtained from mathematical model and experimental value obtained by Rancimat apparatus. To shorten analysis time, 84 and 92% respectively, 120 and 130C can be used too; although some samples can present higher differences between theoretical and experimental induction period values because of the different oxidation mechanism at each temperature.
An experimental investigation was performed on virgin olive oils from Coratina and Ogliarola salentina cultivars extracted from green, partially blackened and totally blackened olives in order to evaluate changes in the organoleptic
properties and in the shelf-life of the oil. The aim of the investigation was to identify the optimal stage of olive maturation
for each cultivar to produce higher quality oils. Routine analyses in accordance with EC regulation no. 2568/91, the determination
of phenols by HPLC and induction times were carried out. On the whole, the simple phenolic compounds increased as darker olives
were used whereas the hydrolysable phenolic compounds decreased. In both the cultivars, total phenols and induction times
were significantly higher in the oils obtained from green olives than in oils from totally blackened olives. Hence, it seems
advisable to delay olive harvesting for cultivars usually yielding bitter to pungent oils (e.g. Coratina), but to anticipate harvesting for olives producing sweet tasting oils (e.g. O. Salentina). This would produce less bitter Coratina oils, with organoleptic features which may better fulfil consumers' expectations, and O. Salentina oils more resistant to oxidation.
The changes of total and individual tocopherols were investigated during different sunflower oil processing stages by reverse-phase
high-performance liquid chromatography. The results revealed that the levels of total and individual tocopherol content were
decreased during the neutralization, bleaching, and deodorization processes. The overall loss of total tocopherols during
these stages was found to be 37.9%, although the general reduction trend of delta (δ), gamma (γ), and alpha (α) tocopherols
is very similar during neutralization (35.3%), bleaching (38.3%), and deodorization (37.8%). However, in contrast to the neutralizing
and deodorizing stages, the bleaching process caused relatively less reduction for individual tocopherol contents. Deodorizer
distillates were also analyzed and were found to be rich with tocopherols content (29,348.24μg/ml). The results of the study
indicated that most parts of the tocopherols are wasted during processing. Therefore, the proper concentration of nutritionists,
industrialists, and manufacturers is needed for the necessary improvements in processing technology to avoid the major loss
of tocopherols and to increase the shelf life, as well as the nutritive value of processed oil.
KeywordsSunflower oil–Tocopherols–Refining stages–Reverse-phase HPLC
Oxidative stability is an important parameter in the characterization of fats and oils. The determination of this parameter with the Active Oxygen Method (AOM; AOCS Method Cd 12-57) is both very costly and labor intensive, owing to the repeated peroxide value determinations involved. The alternative rancimat method is based on the conductometric determination of volatile degradation products and features automatic plotting of the conductivity against time. The evaluation is performed graphically after completion of the experiment. The labor required for this method is considerably less as it is not necessary to perform titrations at regular intervals. In the determination of the peroxide values of six samples at three temperatures, ca 151 mixed solvent and chemicals valued at SFr. 400 (ca $180 US) were consumed.
The induction times (tI
) determined with both methods using six different fats and oils show a good correlation (slope 1.005, correlation coefficient 0.987). The rancimat method thus yields results equivalent to the AOCS Method Cd 12–57, but offers a real alternative for the determination of oxidative stabilities owing to the appreciable saving in labor.
Problem statement: Some vegetable oils contains natural antioxidants such as beta
carotene and vitamin E namely tocopherol and tocotrienol. Different vegetable oils contained different
amount of vitamin E and β-carotene. Approach: Study was carried out to investigate the natural
antioxidants (vitamin E and beta carotene) composition in four different vegetable oils [Red Palm
Olein (RPO), palm plein (PO), Corn Oil (CO) and Coconut Oil (COC)]. Results: The results showed
that RPO contained the highest amount of vitamin E and β-carotene compared to the other three types
of vegetable oils studied. Conclusion: The RPO can be considered as a good source of natural
antioxidant (tocopherol, tocotrienol and β-carotene).
Electron spin resonance spectroscopy (ESR), based upon the spin trapping technique, was applied at 60 °C for evaluating the oxidative stability of 11 vegetable oil samples, including sunflower oil, rapeseed oil and their mixtures. The ESR results were compared with the oxidative stability values provided by the Rancimat method and differential scanning calorimetry (DSC) at 100 °C. High linear correlations were found between ESR and Rancimat (r=0.963), and between ESR and DSC (r=0.979), suggesting that ESR can predict the oxidative stabilities provided by the Rancimat method, as well as by DSC, within a wide range of stability values. In order to examine the capability of each method to evaluate antioxidant activity, different concentrations of α-tocopherol were tested in purified sunflower oil and purified rapeseed oil. Minor differences among the three methods were found when low concentrations of α-tocopherol were used, whereas similar responses were obtained at the highest antioxidant concentration assayed. In comparison with the Rancimat method and DSC, the ESR method is concluded to be useful as a method employing milder conditions and shorter time, and which can be applied for the evaluation of oxidative stability of oils containing volatile antioxidants and other lipid systems containing water.
Food oils are primarily composed of triacylglycerols (TAG), but they may also contain a variety of other minor constituents that influence their physical and chemical properties, including diacylglycerols (DAG), monoacylglycerols (MAG), free fatty acids (FFA), phospholipids (PLs), water, and minerals. This article reviews recent research on the impact of these minor components on lipid oxidation in bulk oils and oil-in-water emulsions. In particular, it highlights the origin of these minor components, the influence of oil refining on the type and concentration of minor components present, and potential physicochemical mechanisms by which these minor components impact lipid oxidation in bulk oils and emulsions. This knowledge is crucial for designing food, pharmaceutical, personal care, and other products with improved stability to lipid oxidation.
The chlorophylls are responsible for the characteristic green color of the olive fruits and their products. Virgin olive oil (VOO) is obtained from processing olives only by mechanical and physical means under conditions ensuring that the natural characteristics of the fruit composition are maintained as far as possible. In terms of the total chlorophyll content of oil, the extraction process entails a loss of chlorophyll of up to 80%. Many factors, both agronomical and technological, can affect the presence of green pigments in VOO. The analysis of green pigments in olives and/or oil requires an initial phase of extraction of these compounds from the solid and fluid matrix, followed by the selective separation and subsequent identification of the different components of the chlorophyll fraction. The aim of this review article is to summarize and critically analyze the available information about chlorophylls in VOO.
The profile of phenolic compounds, antioxidant capacity, oxidative stability, and chemical characteristics (free acidity, peroxide value, specific extinction K232 and K270 values, and DeltaK) of 22 commercial extra virgin olive oil (EVOO) samples coming from the denomination of protected origin (DPO) Monti Iblei and obtained from olives harvested in the period September-December 2005 in the production area of the province of Siracusa (Sicily, Italy) were evaluated. The content of total phenols, expressed as gallic acid equivalents, ranged from 14.80 to 121.20 mg/100 g, with a mean value of 53.72 mg/100 g, mainly attributable to deacetoxyligstroside aglycone, deacetoxyoleuropein aglycone, oleuropein aglycone, and ligstroside aglycone. The mean values of Trolox equivalent antioxidant capacity (TEAC) and of oxidative stability were 54.76 and 11.99 hours, respectively. Both TEAC and oxidative stability were positively correlated to the phenol content and to the percentage of inclusion of the olive cultivar "Tonda Iblea." The high mean content of phenols, besides conferring prolonged oxidative stability, likely confers to the DPO Monti Iblei EVOO marked potential beneficial effects for human health.
The discovery of vitamin E will have its 100th anniversary in 2022, but we still have more questions than answers regarding the biological functions and the essentiality of vitamin E for human health. Discovered as a factor essential for rat fertility and soon after characterized for its properties of fat-soluble antioxidant, vitamin E was identified to have signalling and gene regulation effects independent of its antioxidant properties only in the 1980 s. In the same years the cytochrome P-450 dependent metabolism of vitamin E was characterized and a first series of studies on short-chain carboxyethyl metabolites in the 1990 s paved the way to the hypothesis of a biological role for this metabolism alternative to vitamin E catabolism. In the last decade other physiological metabolites of vitamin E have been identified, such as α-tocopheryl phosphate and the long-chain metabolites formed by the ω-hydroxylase activity of cytochrome P-450. Recent findings are consistent with gene regulation and homeostatic roles of these metabolites in different experimental models, such as inflammatory, neuronal and hepatic cells, and in vivo in animal models of acute inflammation. Molecular mechanisms underlying these responses are under investigation in several laboratories and side-glances to research on other fat soluble vitamins may help to move faster in this direction. Other emerging aspects presented in this review paper include novel insights on the mechanisms of reduction of the cardiovascular risk, immunomodulation and antiallergic effects, neuroprotection properties in models of glutamate excitotoxicity and spino-cerebellar damage, hepatoprotection and prevention of liver toxicity by different causes and even therapeutic applications in non-alcoholic steatohepatitis.
Oxidative Stability and Shelf Life of Foods Containing Oils and Fats focuses on food stability and shelf life, both important factors in the improvement and development of food products. This book, relevant for professionals in the food and pet food industries, presents an evaluation of methods for studies on the oxidative stability and shelf life of bulk oils/fats, fried oils and foods, food emulsions, dried foods, meat and meat products, and seafood in food and pet food. Focuses on the application of various evaluation methods to studies of oxidative stability and shelf life in oils and fats and oils and fats-containing foods in the food and pet food industries. Discusses oxidative stability and shelf life of low-moisture (dry) food, including dry pet food. Discusses lipid co-oxidation with protein because a number of food products contain both lipids and proteins. Directed mainly toward readers working in the food and pet food industries. © 2016 AOCS Press. Published by Elsevier Inc. All rights reserved.
Chumphon Horticultural Research Centre (CHRC) is Thailand's main coconut research unit. CHRC has developed three coconut cultivars: Sawi Hybrid No. 1 (Malayan Yellow Dwarf x West African Tall: MYD x WAT), Chumphon Hybrid No. 60 (Thai Tall: THT x WAT) and Chumphon Hybrid No. 2 (MYD x THT). This study compared some chemical components in virgin coconut oil (VCO) from coconut hybrids with their parents. The VCO was extracted by cold pressing and fermentation methods, and was analyzed for fatty acid profiles, triacylglycerol profile, acid value, tocopherol content, total phenolic content, and antioxidant activity against DPPH (1,1-diphenyl-2-picrylhydrazyl) radicals. The findings showed that hybrids contained lauric acid ranging from 46.63 to 48.34% of total fatty acid. Chumphon 60 had the highest lauric acid content, 48.34% of total fatty acids, which was not significantly different (p > 0.05) from that of the parents. In contrast, the cultivars from MYD, Sawi 1 and Chumphon 2, had significantly greater lauric acid content than the parent MYD (p ≤ 0.05). Cold pressing and fermentation provided an oil extraction yield of 25 and 20%, respectively. The proportions of lauric acid in VCO from these two methods were not significantly different (p > 0.05), but the cold pressing method resulted in higher tocopherol content (p ≤ 0.05). The VCO of Chumphon 60 from the cold pressed method had tocopherol content close to that of the parent WAT (p > 0.05) but significantly higher than that of the other parent THT (p ≤ 0.05). In addition, it contained the highest total phenolic contents among the three cultivars, 57.89 mg GAE/100 g oil, leading to antioxidant activity with a low EC50 of 0.53 mg GAE/ml. Overall, the hybrid of WAT x THT, Chumphon 60, was outstanding among the cultivars; it had the highest levels of lauric acid, total phenolic compounds, and antioxidant activity.
Although fatty acid (FA) composition is known to be of fundamental importance to oxidative stability in lipids, consistent quantifications of the magnitude of this association have proved elusive. The objective of this study was to quantify the relationship between FA composition and stability on a large scale within comparable lipid systems, with the numerical effects of individual outcome factors (e.g. output of a singular assay, oxidative products after a brief period of time, etc.) attenuated by incorporation into a comprehensive summation of stability. The stability of 50 plant-based oils and fats was modeled according to FA composition, utilizing a quantification of stability that encompassed the complete oxidation curves of four distinct classical assays (two 1° and two 2° oxidation assessments) throughout 2 months of accelerated storage (60 °C). In our models, the concentrations of monounsaturated FA (MUFA), diunsaturated FA (DiUFA), and triunsaturated FA (TriUFA) together demonstrated a very strong correlation with our consolidated measure of stability (r
2 = 0.915; greater than observed with our assessments by individual assays). The resultant model also indicated the relative effect upon magnitude of oxidation of MUFA:DiUFA:TriUFA to be approximately 1:3:12—substantially greater than the 1:2:3 ratio of their relative unsaturation.
Total antioxidant capacity (TAC) may be a comprehensive oil quality index because of its potential association with chemical composition, oxidative stability, and fresh oil quality. We aimed to investigate the chemical determinants of the oxidative stability and TAC of oils using multivariate statistical analyses and the use of the TAC assay as a predictor of oil stability. Fatty acids, tocols, phenolic compounds, peroxide value, acid value, induction period (by the Rancimat test) and TAC (by the TEAC assay) were determined in refined canola, corn, soybean, and sunflower oils as well as cold‐pressed nut oils. Principal component analysis was used for data reduction and variable extraction. Generalized linear models successfully estimated the TAC ( R ² = 90.3%, p < 0.005) and oxidative stability ( R ² = 91.6%, p < 0.001) of the oils, and γ‐tocopherol was the most important predictor in both of the models. The peroxide value and induction period were linearly associated with antioxidant capacity ( R ² = 0.65, p < 0.01 and R ² = 0.70, p < 0.01, respectively), allowing the prediction of the initial quality and oxidative stability of the oils by the TEAC assay. Additionally, the proposed minimum TAC value for good quality refined oils was 2.2 mmol TE/kg.
Practical Applications : Lipid oxidation is one of the major causes of vegetable oil degradation, affecting its global quality and limiting its shelf life. Therefore, a quality index applicable for estimating oxidative stability and initial quality of refined and cold‐pressed vegetable oils might be an important tool for quality control of oils in the food industry. We show that the TEAC assay, a simple and rapid spectrophotometric assay of antioxidant capacity, may be a useful tool for the determination of the global quality of oils due to its significant associations with the induction period and peroxide value. A minimum TAC value is advisable for good quality refined plant oils, especially when the initial quality and the shelf life are of concern.
Antioxidant capacity is a surrogate measure of the quality and stability of vegetable oils. 2.2 mmol trolox equivalents/kg was proposed as a minimum total antioxidant capacity value for good quality refined oils.
Cited By (since 1996):1, Export Date: 18 October 2014
Virgin olive oil consumption, as final seasoning or within cooked foods, is increasing worldwide, mainly due to its recognized nutritional benefits. However, the maintenance of its quality and health attributes after thermal processing is frequently questioned. The aim of this article was to provide a careful review of published studies on the assessment of olive oil thermal processing, in order to ascertain the optimal settings for maximization of olive oil quality, while delaying the onset of oxidation products with detrimental health impacts.
Through the selection of a particular olive grade, such as extra-virgin, virgin or refined olive oil, distinct starting compositions may be achieved, particularly regarding bioactive and antioxidant compounds, with a direct effect on thermal performance and nutritional value of cooked foods. Furthermore, different cooking practices, from common frying to boiling and including microwave cooking, along with operating conditions, as time, temperature and food amounts, undoubtedly modify the olive oil chemical profile.
According to the compiled studies, in order to preserve virgin olive oil bioactive components heating time should be reduced to the minimum. Nevertheless, olive oil performance under prolonged thermal processing is usually equal or superior to other refined vegetable oils, due to its balanced composition regarding both major and minor components. However, as most of its bioactive components, including phenolic compounds, are gradually loss, it is economically advantageous to use lower olive oil grades and frequent replenishment under prolonged thermal processing. Future studies dealing with thermal degradation paths of minor olive oil components and their implication in human health will be of particular value to further clarify this issue.
The aim of the present investigation is to discriminate five minor Tunisian olive cultivars (Hor Kesra, Sredki, Chladmi, Betsijina and Aloui) by studying their sterol and phenol compositions. This is the first study of the chemical composition of virgin olive oils (VOO) from these cultivars. The majority of analytical parameters presented statistically significant differences (P < 0.01). The examined varieties produce excellent oils with a chemical composition within the regulatory limits and an appreciable amount of natural antioxidants. Our results showed that Betsijina oil was characterized by high mean values of total phenols (1400 mg kg−1) and oxidative stability (113 h). VOOs studied demonstrate that the differences in phenols (min: 253–max: 1400 mg kg−1), tocopherol (139–402 mg kg−1), sterols (1039–1567 mg kg−1), triterpene dialcohols (19.1–32.4 mg kg−1) and triacylglycerols profiles may be explained by genetic factors. Results of PCA and HCA analyses show a good discrimination between varieties according to phenol, triacylglycerol and sterol data. These components seem to be an effective tool to discriminate between the varieties.
