Interfacial performance of gallic acid and methyl gallate accompanied by lecithin in inhibiting bulk phase oil peroxidation

Unveiling the power of bene (Pistacia atlantica) hull scum: Boosting oxidative stability with methanolic extract and ferrous ions

This study investigated the antioxidant potential of Bene hull methanolic extract (BHME) in mitigating lipid oxidation in vegetable oils across four systems (oil-in-water emulsions and bulk oils, both with and without Fe+2). The BHME's free radical-scavenging assay and ferric reducing abilities were compared with natural (α-tocopherol, CEX) and synthetic (BHT) antioxidants. The research analyzed different BHME concentrations (0, 400, 800, and 1600 ppm) and evaluated the effects of storage time on lipid oxidation, monitored through Peroxide Value (PV) and Carbonyl Value (CV) measurements. An array of statistical analyses, including ANOVA and a robust Support Vector Machine (SVM) model were employed to predict oxidation dynamics. The findings revealed that BHME demonstrated significant antioxidant activity, comparable to BHT, with both showing similar IC50 values (7.59 μg/ml and 7.45 μg/ml, respectively. In emulsions, PV increased 2.5 times at 800 ppm and 13 times at 1600 ppm compared to bulk oils. The presence of Fe+2 led to a 40 % higher PV in emulsions. CV values rose by 35 and 56 units at 800 and 1600 ppm, respectively, and increased six fold over the storage period. The SVM model showed high predictive accuracy, with R2 values exceeding 0.97. Response surface graphs indicated that storage time had a more pronounced effect on PV and CV than antioxidant concentration. This study highlights BHME's potential as an effective natural antioxidant, particularly in bulk oils, and demonstrates the utility of SVM for analyzing lipid oxidation. These findings provide valuable insights for improving the oxidative stability and shelf life of lipid-based food products.

Synthesis, characterization and application of sugar beet pectin-ferulic acid conjugates in the study of lipid, DNA and protein oxidation

In this study, ferulic acid (FA) was enzymatically grafted onto sugar beet pectin (SBP) via laccase catalysis. Structural characterization of sugar beet pectin-ferulic acid conjugates (SFC) with varying substitution degrees was performed using UV-vis, FT-IR, and NMR analyses. Mechanistic analyses revealed that phenolic hydroxyl groups (-OH) on FA reacted with carboxyl groups (-COOH) of SBP via enzymatic catalysis, forming covalent linkages. Additionally, amide bond formation between FA's carboxyl groups and amino groups (-NH₂) of pectin-associated proteins was observed. Compared to unmodified pectin, SFC exhibited reduced crystallinity, lower apparent viscosity, and smoother surfaces, whereas thermal stability and in vitro antioxidant capacity were markedly improved. Notably, SFC with high substitution (>159.60 ± 0.60 mg/g) effectively inhibited malondialdehyde (92.18 %) and peroxide (61.29 %) formation in linoleic acid oxidation systems, while demonstrating DNA (66.07 %) and protein (17.79 %) oxidation inhibition through reduced carbonyl generation. These findings highlight SFC's potential as a multifunctional antioxidant in food and pharmaceutical applications.

Effect of lecithin on the antioxidant mechanism of action of fucoidan in stripped bulk sunflower oil and respective oil in water emulsion

The objective of this study was to investigate the antioxidant mechanism of action of fucoidan in sunflower oil and its oil-in-water emulsion. In addition, the effect of lecithin on the antioxidant mechanism of action of fucoidan in sunflower oil was investigated. In sunflower oil, fucoidan at 0.02 % (w/w) concentration showed the highest induction period (591.02 h), while in sunflower oil-in-water emulsion, fucoidan at 0.04 % (w/w) concentration showed the highest induction period (141.57 h). In addition, the induction period of sunflower oil samples containing fucoidan with lecithin was higher than those without lecithin. Evaluating the mechanism of action of fucoidan in sunflower oil and its oil-in-water emulsion indicated that fucoidan took part in the initiation chain's side reactions and the major termination reaction. The interfacial tensions of samples containing lecithin were significantly lower than those without lecithin. In addition, the reverse micelle size of samples containing lecithin was considerably lower than those without lecithin. Therefore, lecithin enhanced fucoidan's effectiveness by decreasing interfacial activity and increasing the capacity to incorporate lipid hydroperoxides within the structure of reverse micelles. The water produced during oxidation played an essential role in the antioxidant potency of fucoidan. Taken together, lecithin significantly enhanced the antioxidant activity of fucoidan by improving its interfacial activity in sunflower oil.

Antioxidant activity and mechanism of action of phycocyanin in bulk sunflower oil and respective oil-in-water emulsion

This study compared the inhibitory mechanism of phycocyanin in sunflower oil with its activity in a sunflower oil-in-water emulsion. Additionally, the impact of lecithin on the inhibitory mechanism of phycocyanin in sunflower oil was evaluated. A sigmoidal model effectively described the oxidation kinetics. In both sunflower oil and sunflower oil-in-water emulsion, phycocyanin pro-oxidatively attacked lipid hydroperoxides besides inhibiting lipid hydroperoxides. The antioxidant activity of sunflower oil containing phycocyanin and lecithin was 2.2-fold greater than that of sunflower oil containing lecithin alone. The addition of lecithin enhanced the interfacial activity of phycocyanin and altered its hydrogen donating and electron transfer mechanisms. Also, by comparing the reverse micelles size samples of sunflower oil samples containing lecithin, we discovered that lecithin can enhance the potency of phycocyanin by boosting the ability of reverse micelles to incorporate lipid hydroperoxides within their structure.

Non-covalent interactions between rice protein and three polyphenols and potential application in emulsions

Rice protein (RP) and polyphenols are often used in functional foods. This study investigated the non-covalent interactions between RP and three polyphenols (curcumin, CUR; quercetin, QUE; resveratrol, RES) and used the complexes as emulsifiers to create emulsions. Three polyphenols interacted with RP to varying extents, with QUE showing the greatest binding affinity and inducing the greatest alterations in its secondary structure. Molecular docking analysis elucidated the driving forces between them including hydrophobic interactions, hydrogen bonding, and van der Waals forces. Combination with QUE or RES induced structural changes of RP, increasing particle size of complexes. The synergistic effect of polyphenols and protein also enhanced radical scavenging capacity of complexes. Compared to pure protein, all complexes successfully created emulsions with smaller particle size (378-395 nm vs. 470 nm), higher absolute potential (37.43-38.26 mV vs. 35.62 mV), and greater lipid oxidation stability by altering protein conformation.

Dietary gallic acid as an antioxidant: A review of its food industry applications, health benefits, bioavailability, nano-delivery systems, and drug interactions

Gallic acid (GA), a dietary phenolic acid with potent antioxidant activity, is widely distributed in edible plants. GA has been applied in the food industry as an antimicrobial agent, food fresh-keeping agent, oil stabilizer, active food wrap material, and food processing stabilizer. GA is a potential dietary supplement due to its health benefits on various functional disorders associated with oxidative stress, including renal, neurological, hepatic, pulmonary, reproductive, and cardiovascular diseases. GA is rapidly absorbed and metabolized after oral administration, resulting in low bioavailability, which is susceptible to various factors, such as intestinal microbiota, transporters, and metabolism of galloyl derivatives. GA exhibits a tendency to distribute primarily to the kidney, liver, heart, and brain. A total of 37 metabolites of GA has been identified, and decarboxylation and dihydroxylation in phase I metabolism and sulfation, glucuronidation, and methylation in phase Ⅱ metabolism are considered the main in vivo biotransformation pathways of GA. Different types of nanocarriers, such as polymeric nanoparticles, dendrimers, and nanodots, have been successfully developed to enhance the health-promoting function of GA by increasing bioavailability. GA may induce drug interactions with conventional drugs, such as hydroxyurea, linagliptin, and diltiazem, due to its inhibitory effects on metabolic enzymes, including cytochrome P450 3A4 and 2D6, and transporters, including P-glycoprotein, breast cancer resistance protein, and organic anion-transporting polypeptide 1B3. In conclusion, in-depth studies of GA on food industry applications, health benefits, bioavailability, nano-delivery systems, and drug interactions have laid the foundation for its comprehensive application as a food additive and dietary supplement.

Recent advances in understanding the interfacial activity of antioxidants in association colloids in bulk oil

The chemical stability of edible oils rich in polyunsaturated fatty acids (PUFAs) is a major challenge within the food and supplement industries, as lipid oxidation reduces oil quality and safety. Despite appearing homogeneous to the human eye, bulk oils are actually multiphase heterogeneous systems at the nanoscale level. Association colloids, such as reverse micelles, are spontaneously formed within bulk oils due to the self-assembly of amphiphilic molecules that are present, like phospholipids, free fatty acids, and/or surfactants. In bulk oil, lipid oxidation often occurs at the oil-water interface of these association colloids because this is where different reactants accumulate, such as PUFAs, hydroperoxides, transition metals, and antioxidants. Consequently, the efficiency of antioxidants in bulk oils is governed by their chemical reactivity, but also by their ability to be located close to the site of oxidation. This review describes the impact of minor constituents in bulk oils on the nature of the association colloids formed. And then the formation of mixed reverse micelles (LOOH, (co)surfactants, or antioxidations) during the peroxidation of bulk oils, as well as changes in their composition and structure over time are also discussed. The critical importance of selecting appropriate antioxidants and surfactants for the changes of interface and colloid, as well as the inhibition of lipid oxidation is emphasized. The knowledge presented in this review article may facilitate the design of bulk oil products with improved resistance to oxidation, thereby reducing food waste and improving food quality and safety.

Metabolomics and in-vitro bioactivities studies of fermented Musa paradisiaca pulp: A potential alpha-amylase inhibitor

The in-vitro synthesis of bio-compounds via fermentation is a promising route for bioactive molecules intended for disease control and management. Therefore, this study evaluated the effect of fermentation on the antioxidants, antihyperglycemic and anti-inflammatory properties and the resultant chemometric phytochemical profiles of unripe plantain fruits. The results revealed that Escherichia coli and Propionibacterium spp. are suspected as the key fermenters. The E coli showed negative results to the pathogenicity test; Propionibacterium appeared to be opportunistic. A significant increase in the total polyphenols and protein and decreased flavonoids was recorded in the phytochemical profile of the methanolic extract of the fermented unripe plantain pulp; however, the ascorbic acid content was not significantly altered. The 1H NMR fingerprint showed that there is a closely related chemical shift among the shorter fermentation time (days 2-6) and the unfermented, while the more extended fermentation periods (days 7-12) with enhanced bioactivities were closely related based on the chemometrics analyses. Furthermore, the UPLC-QTOF-MS analysis annotated the presence of bioactive compounds in the day-9 fermented sample: polyhydroxy glucose conjugates (3-Methoxy-4-hydroxyphenyl 6-O-(3,4,5-trihydroxybenzoyl)-beta-D-glucopyranoside), short chain peptide (leucyl-glycyl-glycine), amino acid derivatives (4-Aminophenylalanine, and N-Acetylhistidine), linear and cyclic fatty acid derivatives (palmitoyl putrescine, ricinoleic acid, phytosphingosine, gabalid, rubrenoic acid, 2-aminocyclopentanecarboxylic and cystodienioc acid). The synergistic effect of these newly formed compounds and the increase in the phenolic content of the day-9 fermented unripe plantain may account for its more potent antioxidant, anti-inflammatory and antihyperglycemic activity. Therefore, the products obtained from the day 9 fermentation of unripe plantain pulp may serve as potential nutraceutical agents against gastro-enteric sugar digestion and absorption and sugar-induced oxidative stress, inflammation and metabolic disease.

Frying Performance of Gallic Acid and/or Methyl Gallate Accompanied by Phosphatidylcholine

This study shows the possibility of using gallic acid (GA) and/or methyl gallate (MG) accompanied by phosphatidylcholine (PC) instead of tert-butylhydoquinone (TBHQ) for frying purposes. The antioxidants and PC were added in the concentrations of 1.2 mM and 500-2000 mg/kg, respectively. Oxidative stability index (OSI) and the kinetics of change in conjugated dienes (LCD), carbonyls (LCO), and acid value (AV) were used to assess the antioxidative treatments. GA alone and GA/MG (50:50) plus PC at 2000 mg/kg yielded the same OSI as that of TBHQ (18.4 h). The latter was of the highest frying performance in preventing the formation of LCD (rn = 0.0517/h and tT = 10.6 h vs. rn = 0.0976/h and tT = 4.5 h for TBHQ), LCO (rn = 0.0411/h and tT = 12.7 h vs. rn = 0.15/h and tT = 4.3 h for TBHQ), and hydrolytic products (AVm = 37.8 vs. 24.0 for TBHQ); rn: normalized the maximum rate of LCD/LCO accumulation; tT: the time at which the rate of LCD/LCO accumulation is maximized; AVm: quantitative measure of hydrolytic stability.

Kinetics of chemical deteriorations over the frying protected by gallic acid and methyl gallate

The present work shows the possibility of use of gallic acid (GA) and methyl gallate (MG) as natural antioxidants replacing the powerful synthetic antioxidant TBHQ in frying process. Oxidative stability index (OSI) and the kinetics of change in lipid-peroxidation conjugated dienes (LCD), carbonyls (LCO), and acid value were adopted for the evaluation purposes. GA alone (1.2 mM) and in combination with MG (75:25) provided OSI values comparable to that of TBHQ (18.5-19.0 h). The GA/MG 75:25 exerted a frying performance quite better than TBHQ (r_n = 0.1351 vs. 0.1784 h^-1) in preventing the LCD formation. From the LCO formation standpoint, the GA/MG 75:25 (r_n = 0.0758 h^-1) and then MG (r_n = 0.1004 h^-1) provided better performances than TBHQ (r_n = 0.1216 h^-1). Lipid hydrolysis was also inhibited well by GA (AV_m = 8.6) and GA/MG 75:25 (AV_m = 7.9), respectively (AV_m = 9.2 for TBHQ).

Interfacial behavior of gallic acid and its alkyl esters in stripped soybean oil in combination with monoacylglycerol and phospholipid

The effect of gallic acid alkyl esters and their combination with monoacylglycerol (MAG) and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) on the formation of hydroperoxides and hexanal were determined during the oxidation of stripped soybean oil. Interfacial tension, water content, and droplet size were evaluated to monitor the physical properties of the oil system. Adding MAG and DOPC, especially MAG/DOPC, to the oil promoted the partitioning of antioxidants into the water-oil interfaces by further reducing the interfacial tension. The stripped oil containing methyl gallate (MG) accompanied by MAG/DOPC had lower values of the critical micelle concentration of hydroperoxides and larger micellar size at the induction period. This confirms that MG was able to more effectively reduce the free hydroperoxides concentration and inhibit them in an interfacial way. The conjunction of surfactants has been shown as a promising strategy to improve the interfacial and antioxidant activity of gallates in the oxidative stability of soybean oil.

Recent Trends in Improving the Oxidative Stability of Oil-Based Food Products by Inhibiting Oxidation at the Interfacial Region

In recent years, new approaches have been developed to limit the oxidation of oil-based food products by inhibiting peroxidation at the interfacial region. This review article describes and discusses these particular approaches. In bulk oils, modifying the polarity of antioxidants by chemical methods (e.g., esterifying antioxidants with fatty alcohol or fatty acids) and combining antioxidants with surfactants with low hydrophilic–lipophilic balance value (e.g., lecithin and polyglycerol polyricinoleate) can be effective strategies for inhibiting peroxidation. Compared to monolayer emulsions, a thick interfacial layer in multilayer emulsions and Pickering emulsions can act as a physical barrier. Meanwhile, high viscosity of the water phase in emulsion gels tends to hinder the diffusion of pro-oxidants into the interfacial region. Furthermore, applying surface-active substances with antioxidant properties (such as proteins, peptides, polysaccharides, and complexes of protein-polysaccharide, protein-polyphenol, protein-saponin, and protein-polysaccharide-polyphenol) that adsorb at the interfacial area is another novel method for enhancing oil-in-water emulsion oxidative stability. Furthermore, localizing antioxidants at the interfacial region through lipophilization of hydrophilic antioxidants, conjugating antioxidants with surfactants, or entrapping antioxidants into Pickering particles can be considered new strategies for reducing the emulsion peroxidation.

Effect of polyglycerol polyricinoleate on the inhibitory mechanism of sesamol during bulk oil oxidation

In this study, effects of sesamol on improving the oxidative stability of sunflower oil and its oil-in-water emulsion was investigated. To investigate the kinetic parameters related to the initiation and propagation stages of oxidation, a sigmoidal-model was used. Sesamol exhibited higher antioxidant activity in sunflower oil-in-water emulsion than that of sunflower oil. In both sunflower oil and sunflower oil-in-water emulsion, the inhibitory effect of sesamol against lipid oxidation continued even after the induction period. To improve the efficiency of sesamol in sunflower oil, polyglycerol polyricinoleate (PGPR) was incorporated into the functional environment of the sesamol. Sesamol exhibited a synergistic effect with PGPR during both initiation (synergistic effect of 68.87%) and propagation (synergistic effect of 36.84%) stages. Comparison of the size of reverse micelles in samples containing PGPR with those without PGPR revealed that PGPR can enhance the efficiency of sesamol by increasing the acceptance capacity of lipid hydroperoxides in reveres micelles structures. This can result in enhancing the effective collisions between sesamol and lipid hydroperoxides in the presence of PGPR. The water produced as a major byproduct of oxidation played a key role on the antioxidant activity of sesamol alone or in combination with PGPR during oxidation process.

Effect of triacylglycerol structure on the antioxidant activity of γ-oryzanol

In this study, the triacylglycerol structure of vegetable oils was removed and the effects of this removal were observed on the antioxidant efficiency of γ-oryzanol. A sigmoidal-model was used for calculating kinetic parameters relevant to the initiation and propagation phases during the peroxidation of soybean, corn, sesame, and olive oils as well as their fatty acid methyl esters. Removing the triacylglycerol structure caused an increase in the antioxidant activity of γ-oryzanol (26.49%) by affecting both inhibitory mechanisms, i.e. hydrogen-donating (7.80%) and electron-transfer (14.72%). Unexpectedly, the antioxidant performance of γ-oryzanol continued even when the induction period had ended. During the propagation phase, the highest antioxidant activity was observed in the fatty acid methyl esters of soybean oil (3.86) based on hydroperoxides decomposition. An evaluation of how the endergonic activated complexes formed could indicate that the removal of the triacylglycerol structure increased the effective collisions between the γ-oryzanol molecules and free radicals.

New insights into the kinetic and thermodynamic evaluations of lipid peroxidation

Simultaneous evaluations over the whole practical range of peroxidation, including the initiation and propagation phases, provide more informative and reliable data than single-parameter analyses being mostly employed only over the course of the initiation phase. Besides an overview on the dominant mechanisms governing the initiation and propagation phases, this article highlights a number of unifying parameters that represent inclusively the two phases. Then, the reliable method to calculate induction period and critical reverse micelle concentration of lipid hydroperoxides as the two interstitial parameters when transitioning from the initiation to the propagation phase is reviewed. Next, a reconsidered form of the conventional methodology on the kinetics of chain-breaking antioxidants is presented. After that, the Arrhenius kinetic and thermodynamic Eyring-Polanyi parameters calculated from the initiation, composite, and decomposition rate constants are compared in order to assess oxidative stabilities. Finally, shelf-life predictions based on a number of proposed end-points of peroxidation are addressed.

Investigating relationship between water production and interfacial activity of γ-oryzanol, ethyl ferulate, and ferulic acid during peroxidation of bulk oil

In this study, lecithin (as a surfactant) was added to promote the inhibitory-mechanism of γ-oryzanol, ethyl-ferulate and ferulic acid (based on the interfacial phenomena) so as to inhibit the oxidation of stripped sunflower oil. Monitoring the amount of water production as a byproduct of oxidation showed that the water content of the lipid system increased remarkably through the oxidation progress. Lecithin enhanced the critical concentration of hydroperoxides in reverse micelles, compared to the basic state (14.8 vs. 9.2 mM), thereby improving the hydrogen-donating mechanism of antioxidants. The size of reverse micelles increased progressively during the oxidation, while two breakpoints were pointed out in the micelles growth, i.e. at the end of the initiation and the propagation phases. Based on the kinetic data, ferulic acid showed the highest antioxidant activity (23.4), compared to ethyl-ferulate (15.5) and γ-oryzanol (13.7). Generally, lecithin enhanced antioxidant activity (~ 65%) by improving the interfacial performance of antioxidants.

A comprehensive review on polarity, partitioning, and interactions of phenolic antioxidants at oil-water interface of food emulsions

There has been a growing interest in developing effective strategies to inhibit lipid oxidation in emulsified food products by utilization of natural phenolic antioxidants owing to their growing popularity over the past decades. However, due to the complexity of emulsified systems, the inhibition mechanism of phenolic antioxidants against lipid oxidation is rather complicated and not yet fully understood. In order to highlight the importance of polarity of phenolic antioxidants in emulsified systems according to the polar paradox, this review covers the recent progress on chemical, enzymatic, and chemoenzymatic lipophilization techniques used to modify the polarity of antioxidants. The partitioning behavior of phenolic antioxidants at the oil-water interface, which can be influenced by the presence of synthetic surfactants and/or antioxidant emulsifiers (e.g., polysaccharides, proteins, and phospholipids), is discussed. In addition, the emerging phenolic antioxidants among phenolic acids, flavonoids, tocopherols, and stilbenes applied in food emulsions are elaborated. As well, the interactions of polar-nonpolar antioxidants are stressed as a promising strategy to induce synergistic interactions at oil-water interface for improved oxidative stability of emulsions.