Lipid oxidation in emulsions: New insights from the past two decades.

Lipid oxidation constitutes the main source of degradation of lipid-rich foods, including food emulsions. The complexity of the reactions at play combined with the increased demand from consumers for less processed and more natural foods result in additional challenges in controlling this phenomenon. This review provides an overview of the insights acquired over the past two decades on the understanding of lipid oxidation in oil-in-water (O/W) emulsions. After introducing the general structure of O/W emulsions and the classical mechanisms of lipid oxidation, the contribution of less studied oxidation products and the spatiotemporal resolution of these reactions will be discussed. We then highlight the impact of emulsion formulation on the mechanisms, taking into consideration the new trends in terms of emulsifiers as well as their own sensitivity to oxidation. Finally, novel antioxidant strategies that have emerged to meet the recent consumer's demand will be detailed. In an era defined by the pursuit of healthier, more natural, and sustainable food choices, a comprehensive understanding of lipid oxidation in emulsions is not only an academic quest, but also a crucial step towards meeting the evolving expectations of consumers and ensuring the quality and stability of lipid-rich food products.

Dataset of the nutritional composition of follow-on infant formulas commercialized worldwide in 2021.

The main objective of infant follow-on formulas, consumed from the age of 6 to 12 months, is to mimic the composition of breast milk in order to meet the nutritional needs of infant. In this context, their composition is governed in Europe by a strict regulation that has evolved in 2020 to force manufacturers to improve the nutritional profile of the formulas. The objective of this dataset was to collect the ingredient lists and nutritional values of infant follow-on formulas present on the world market with a focus on the lipid fraction. The data collection was carried out from December 2020 to April 2021 directly on the product packaging or on the websites of the different brands. Only "classic" infant follow-on formulas that are widely consumed were listed. Thus, the ingredient lists and nutritional values of 91 infant formulas were collected. The nutritional values are systematically presented for 100 g of powder, for 100 Kcal and for 100 mL of formula. The sources of fats, emulsifiers and vitamins A and E were also extracted from the ingredient lists. This dataset can be used as a tool for the formulation of infant follow-on formulas or to situate the positioning of products in relation to the market.

Comparison of the effect of various sources of saturated fatty acids on infant follow-on formulas oxidative stability and nutritional profile.

Fortification of infant follow-on formulas (IFF) with docosahexaenoic acid (DHA), which is prone to lipid oxidation, is required by European regulation. This study aimed to identify lipid formulation parameters that improve the nutritional profile and oxidative stability of IFF. Model IFF were formulated using different lipid and emulsifier sources, including refined (POM) or unrefined red palm oil (RPOM), coconut oil (COM), dairy fat (DFOM), soy lecithin, and dairy phospholipids (DPL). After an accelerated storage, RPOM and DFOM with DPL had improved oxidative stability compared to other IFF. Specifically, they had a peroxide value twice lower than POM and 20% less loss of tocopherols for DFOM-DPL. This higher stability was mainly explained by the presence of compounds such as carotenoids in RPOM and sphingomyelin in DFOM-DPL very likely acting synergistically with tocopherols. Incorporation of dairy lipids and carotenoids into DHA-enriched IFF compositions seems promising to enhance their stability and nutritional quality.

Furan fatty acid extracted from Hevea brasiliensis latex increases muscle mass in mice.

Skeletal muscle is essential for locomotion and plays a crucial role in energy homeostasis. It is regulated by nutrition, genetic factors, physical activity and hormones. Furan fatty acids (FuFAs) are minor fatty acids present in small quantities in food from plants and animals origin. Recently, we showed that a preventive nutritional supplementation with furan fatty acid in a DIO mouse model reduces metabolic disorders. The present study was designed to determine the influence of FuFA-F2 extracted from Hevea brasiliensis latex on skeletal muscle phenotype. In C2C12 myotubes we found that FuFA-F2 whatever the concentration used increased protein content. We revealed that in C2C12 myotubes FuFA-F2 (10 µM) increases protein synthesis as shown by the stimulation of mTOR phosphorylation. Next, to confirm in vivo our results C57Bl6 mice were supplemented by oral gavage with vehicle or FuFA-F2 (20 mg/kg) for 3 and a half weeks. We found that mice supplemented with FuFA-F2 had a greater lean mass than the control mice. In line with this observation, we revealed that FuFA-F2 increased muscle mass and promoted more oxidative muscle metabolism in mice as attested by cytochrome c oxidase activity. In conclusion, we demonstrated that FuFA-F2 stimulates muscle anabolism in mice in vitro and in vivo, mimicking in part physical activity. This study highlights that in vivo FuFA-F2 may have health benefits by increasing muscle mass and oxidative metabolism.

Preventive nutritional supplementation with furan fatty acid in a DIO mouse model increases muscle mass and reduces metabolic disorders.

The increase in obesity has become a major global health problem and is associated with numerous metabolic dysfunctions. Furan fatty acids (FuFAs) are minor lipids present in our diet. Recently we showed that FuFA-F2 extracted from Hevea brasiliensis latex stimulates muscle anabolism in mice in vitro and in vivo, mimicking in part physical activity. While skeletal muscle is essential for energy metabolism and is the predominant site of insulin-mediated glucose uptake in the post prandial state, our results suggested that FuFA-F2 could have favorable effects against obesity. The aim of this work was therefore to study whether a preventive nutritional supplementation with FuFA-F2 (40 mg or 110 mg/day/kg of body weight) in a diet-induced obesity (DIO) mouse model may have beneficial effects against obesity and liver and skeletal muscle metabolic dysfunction. We showed that 12 weeks of FuFA-F2 supplementation in DIO mice decreased fat mass, increased lean mass and restored normal energy expenditure. In addition, we found that FuFA-F2 improved insulin sensitivity. We revealed that FuFA-F2 increased muscle mass but had no effect on mitochondrial function and oxidative stress in skeletal muscle. Furthermore, we observed that FuFA-F2 supplementation reduced liver steatosis without impact on mitochondrial function and oxidative stress in liver. Our findings demonstrated for the first time that a preventive nutritional supplementation with a furan fatty acid in DIO mice reduced metabolic disorders and was able to mimic partly the positive effects of physical activity. This study highlights that nutritional FuFA-F2 supplementation could be an effective approach to treat obesity and metabolic syndrome.

Chelating peptides from rapeseed meal protein hydrolysates: identification and evaluation of their capacity to inhibit lipid oxidation.

An optimized proteolysis process was applied to rapeseed meal proteins (RP) and the hydrolysate was separated by membrane filtration allowing the production of highly metal-chelating peptides in the permeate. In order to identify the chemical structure of the most active obtained metal-chelating peptides, immobilized metal affinity chromatography (IMAC) was applied. The RP-IMAC peptide fraction was mainly composed of small peptides from 2 to 20 amino acids. Using the Ferrozine assay, RP-IMAC peptides showed a significant chelating efficiency higher than sodium citrate and close to that of EDTA. The peptide sequences were identified by UHPLC-MS and several possible iron binding sites were found. ß-carotene oxidation assay and lipid oxidation in bulk oils or emulsion were carried out to evaluate the potential of such peptides as efficient antioxidants to protect lipids from oxidation. While chelating peptides showed a limited efficiency in bulk oil, they performed more efficiently in emulsion.

Identification of novel bioactive proteins and their produced oligopeptides from Torreya grandis nuts using proteomic based prediction.

Torreya grandis nut is a chief functional food in China consumed for centuries. Besides its rich protein composition, increasing studies are now focusing on T. grandis functional proteins that have not yet identified. In this study, liquid chromatography coupled with mass spectrometry detection of smaller and major proteins, revealed that the major peptide was 36935.00 Da. Proteome sequencing annotated 142 proteins in total. Bioactive proteins such as defensin 4 was annotated and its anti-microbial function was verified. Finally, functional oligopeptides were predicted by searching sequences of digested peptides in databases. Ten group of oligopeptides were suggested to exhibit antioxidant, Angiotensin-converting enzyme inhibition, anti-inflammatory. The predicted antioxidant activity was experimentally validated. It is interesting that a peptide GYCVSDNN digested from defensin 4 showed antioxidant activity. This study reports novel functional peptides from T. grandis nuts that have not been isolated and/or included as functional ingredients in nutraceuticals and in food industry.

Lipid oxidation in emulsions and bulk oils: a review of the importance of micelles.

Lipid oxidation is a major cause of quality deterioration in food products. In these foods, lipids are often present in a bulk or in emulsified forms. In both systems, the rate, extent and pathway of oxidation are highly dependent on the presence of colloidal structures and interfaces because these are the locations where oxidation normally occurs. In bulk oils, reverse micelles (association colloids) are present and are believed to play a crucial role on lipid oxidation. Conversely, in emulsions, surfactant micelles are present that also play a major role in lipid oxidation pathways. After a brief description of lipid oxidation and antioxidants mechanisms, this review discusses the current understanding of the influence of micellar structures on lipid oxidation. In particular, is discussed the major impact of the presence of micelles in emulsions, or reverse micelles (association colloids) in bulk oil on the oxidative stability of both systems. Indeed, both micelles in emulsions and associate colloids in bulk oils are discussed in this review as nanoscale structures that can serve as reservoirs of antioxidants and pro-oxidants and are involved in their transport within the concerned system. Their role as nanoreactors where lipid oxidation reactions occur is also commented.

Optimization of Selective Hydrolysis of Cruciferins for Production of Potent Mineral Chelating Peptides and Napins Purification to Valorize Total Rapeseed Meal Proteins.

Preventing oxidation and microbial spoilage are both major concerns in food industries. In this context, this study aimed to valorize the total rapeseed meal proteins with controlled enzymatic proteolysis to generate potent mineral-chelating peptides from cruciferins while keeping intact the antimicrobial napins. Implementation of proteolysis of total rapeseed protein isolate with the Prolyve® enzyme highlighted an interesting selective hydrolysis of the cruciferins. Hence, the mechanism of this particular hydrolysis was investigated through a Design of Experiments method to obtain a model for the prediction of kinetics (cruciferin degradation and napin purity) according to the operating conditions applied. Then, multicriteria optimization was implemented to maximize the napin purity and yield while minimizing both enzymatic cost and reaction time. Antioxidant assays of the peptide fraction obtained under the optimal conditions proved the high metal-chelating activity preservation (EC50 = 247 ± 27 µg) for more than three times faster production. This fraction might counteract lipid oxidation or serve as preventing agents for micronutrient deficiencies, and the resulting purified napins may have applications in food safety against microbial contamination. These results can greatly help the development of rapeseed meal applications in food industries.

Application of deep eutectic solvents in protein extraction and purification.

Deep eutectic solvents (DESs) are a mixture of hydrogen bond donor (HBD) and hydrogen bond acceptor (HBA) molecules that can consist, respectively, of natural plant metabolites such as sugars, carboxylic acids, amino acids, and ionic molecules, which are for the vast majority ammonium salts. Media such as DESs are modular tools of sustainability that can be pointed toward the extraction of bioactive molecules due to their excellent physicochemical properties, their relatively low price, and accessibility. The present review focuses on the application of DESs for protein extraction and purification. The in-depth effects and principles that apply to DES-mediated extraction using various renewable biomasses will be discussed as well. One of the most important observations being made is that DESs have a clear ability to maintain the biological and/or functional activity of the extracted proteins, as well as increase their stability compared to traditional solvents. They demonstrate true potential for a reproducible but more importantly, scalable protein extraction and purification compared to traditional methods while enabling waste valorization in some particular cases.

Alkyl chain length modulates antioxidant activity of gallic acid esters in spray-dried emulsions.

Lipid oxidation is a well-recognized issue in dried food emulsions, such as infant milk formula. Antioxidants can be used to mitigate this issue; however, their efficiency in such complex systems is far from understood. In this study, antioxidant polarity is varied through the alkyl chain length of gallic acid esters (0-16 carbon atoms) incorporated to O/W emulsions that are subsequently spray-dried. During processing and subsequent storage of the samples, antioxidants with more than eight carbon atoms are effective. Both for encapsulated fat and surface free fat, we observe a slight cut-off effect, meaning that beyond eight alkyl groups, a more nonpolar antioxidant is slightly less effective. Depending on the antioxidant polarity, lipid oxidation is faster either in the encapsulated or in the surface free fat. The insights obtained contribute to understanding lipid oxidation in low moisture food emulsions, and thus lead to effective antioxidant strategies.

Tocopherols as antioxidants in lipid-based systems: The combination of chemical and physicochemical interactions determines their efficiency.

Lipid oxidation is a major concern in the food, cosmetic, and pharmaceutical sectors. The degradation of unsaturated lipids affects the nutritional, physicochemical, and organoleptic properties of products and can lead to off-flavors and to the formation of potentially harmful oxidation compounds. To prevent or slow down lipid oxidation, different antioxidant additives are used alone or in combination to achieve the best possible efficiency with the minimum possible quantities. In manufactured products, that is, heterogeneous systems containing lipids as emulsions or bulk phase, the efficiency of an antioxidant is determined not only by its chemical reactivity, but also by its physical properties and its interaction with other compounds present in the products. The antioxidants most widely used on the industrial scale are probably tocopherols, either as natural extracts or pure synthetic molecules. Considerable research has been conducted on their antioxidant activity, but results regarding their efficiency are contradictory. Here, we review the known mechanisms behind the antioxidant activity of tocopherols and discuss the chemical and physical features that determine their efficacy. We first describe their chemical reactivity linked with the main factors that modulate it between efficient antioxidant capacity and potential prooxidant effects. We then describe their chemical interactions with other molecules (phenolic compounds, metals, vitamin C, carotenes, proteins, and phospholipids) that have potential additive, synergistic, or antagonist effects. Finally, we discuss other physical parameters that influence their activity in complex systems including their specific interactions with surfactants in emulsions and their behavior in the presence of association colloids in bulk oils.

Production and antioxidant capacity of bioactive peptides from plant biomass to counteract lipid oxidation.

Preventing lipid oxidation, especially with the polyunsaturated fat-based products, is a major concern in sectors as agri-food and cosmetic. Even though the efficiency of synthetic antioxidants has been recognized, both consumers and manufacturers are looking for more innovative, healthy and quality products while rejecting synthetic additives due to their concern about safety, along with their environmental impact issues. In this context, plant biomass, which have shown to be rich in compounds, have raised interest for the isolation of novel naturally occurring antioxidants. Among their myriad of molecules, bioactive peptides, which are biologically active sequence of amino acid residues of proteins, seem to be of a great interest. Therefore, the number of identified amino acids sequences of bioactive peptides from plant biomass with potential antioxidant action is progressively increasing. Thus, this review provides a description of 129 works that have been made to produce bioactive peptides (hydrolysate, fraction and/or isolate peptide) from 55 plant biomass, along with the procedure to examine their antioxidant capacity (until 2019 included). The protein name, the process, and the method to concentrate or isolate antioxidant bioactive peptides, along with their identification and/or specificity were described. Considering the complex, dynamic and multifactorial physico-chemical mechanisms of the lipid oxidation, an appropriate in-vitro methodology should be better performed to efficiently probe the antioxidant potential of bioactive peptides. Therefore, the results were discussed, and perspective for antioxidant applications of bioactive peptides from plant biomass was argued.

Metabolomics of Pigmented Rice Coproducts Applying Conventional or Deep Eutectic Extraction Solvents Reveal a Potential Antioxidant Source for Human Nutrition.

Rice bran (RB) corresponds to the outer layers of whole grain rice and contains several phenolic compounds (PCs) that make it an interesting functional food ingredient. PC richness is enhanced in pigmented RB varieties and requires effective ways of extraction of these compounds. Therefore, we investigated conventional and deep eutectic solvents (DES) extraction methods to recover a wide array of PCs from red and black RB. The RB were extracted with ethanol/water (60:40, v/v) and two DES (choline chloride/1.2-propanediol/water, 1:1:1 and choline chloride/lactic acid, 1:10, mole ratios), based on Generally Recognized as Safe (GRAS) components. Besides the quantification of the most typical phenolic acids of cereals, nontargeted metabolomic approaches were applied to PCs profiling in the extracts. Globally, metabolomics revealed 89 PCs belonging to flavonoids (52%), phenolic acids (33%), other polyphenols (8%), lignans (6%) and stilbenes (1%) classes. All extracts, whatever the solvents, were highly concentrated in the main phenolic acids found in cereals (37-66 mg/100 g in black RB extracts vs. 6-20 mg/100 g in red RB extracts). However, the PC profile was highly dependent on the extraction solvent and specific PCs were extracted using the acidic DES. The PC-enriched DES extracts demonstrated interesting DPPH scavenging activity, which makes them candidates for novel antioxidant formulations.

Microwave-Assisted One-Pot Lipid Extraction and Glycolipid Production from Oleaginous Yeast Saitozyma podzolica in Sugar Alcohol-Based Media.

Glycolipids are non-ionic surfactants occurring in numerous products of daily life. Due to their surface-activity, emulsifying properties, and foaming abilities, they can be applied in food, cosmetics, and pharmaceuticals. Enzymatic synthesis of glycolipids based on carbohydrates and free fatty acids or esters is often catalyzed using certain acyltransferases in reaction media of low water activity, e.g., organic solvents or notably Deep Eutectic Systems (DESs). Existing reports describing integrated processes for glycolipid production from renewables use many reaction steps, therefore this study aims at simplifying the procedure. By using microwave dielectric heating, DESs preparation was first accelerated considerably. A comparative study revealed a preparation time on average 16-fold faster than the conventional heating method in an incubator. Furthermore, lipids from robust oleaginous yeast biomass were successfully extracted up to 70% without using the pre-treatment method for cell disruption, limiting logically the energy input necessary for such process. Acidified DESs consisting of either xylitol or sorbitol and choline chloride mediated the one-pot process, allowing subsequent conversion of the lipids into mono-acylated palmitate, oleate, linoleate, and stearate sugar alcohol esters. Thus, we show strong evidence that addition of immobilized Candida antarctica Lipase B (Novozym 435®), in acidified DES mixture, enables a simplified and fast glycolipid synthesis using directly oleaginous yeast biomass.

Synthesis and Evaluation of Antioxidant Activities of Novel Hydroxyalkyl Esters and Bis-Aryl Esters Based on Sinapic and Caffeic Acids.

Novel hydroxyalkyl esters and bis-aryl esters were synthesized from sinapic and caffeic acids and aliphatic α,ω-diols of increasing chain lengths from 2 to 12 carbon atoms. Then, their antiradical reactivity (DPPH assay) and their antioxidant activity in a model oil-in-water emulsion (CAT assay) were evaluated. All the esters showed lower antiradical activities compared to their corresponding phenolic acid. This decrease was associated with the steric hindrance in hydroxyalkyl esters, and intramolecular interactions in bis-aryl esters. Regarding the two bis-aryl esters series in emulsion, the antioxidant capacity was improved with alkyl chain lengthening up to four carbons, after which it decreased for longer chains. This "cutoff" effect was not observed for both hydroxyalkyl esters series for which the alkyl chain lengthening results in a decrease of the antioxidant activity.

Investigation on the Double CutOff Phenomenon Observed in Protocatechuic Acid and Its Alkyl Esters under Various CAT-Based Assays.

A strange cutoff phenomenon of a series of protocatechuic acid alkyl esters had been noticed using the conjugated autoxidizable triene (CAT) assay. Two parabolic shapes of antioxidant activities of protocatechuic acid alkyl esters described as ″the double cutoff effect″ have been speculated as a result of an oxidative driving force generated in the aqueous phase. The aim of this research was to investigate the double cutoff effect using various types of oxidation driving forces in different CAT-based assays. To further explain the phenomenon, the natural oxidation of conjugated autoxidizable triene (NatCAT) assay has been developed for the first time by relying solely on only the lipid autoxidation of tung oil-in-water (O/W) emulsions. In conclusion, NatCAT exhibited different antioxidant and oxidation patterns from both CAT and apolar radical-initiated CAT assays, and only one cutoff point was obtained. This discovery would lead to a greater understanding of the complexity of antioxidant/lipid oxidation dynamics in O/W emulsion systems.

Encapsulation of ß-Carotene by Emulsion Electrospraying Using Deep Eutectic Solvents.

The encapsulation ß-carotene in whey protein concentrate (WPC) capsules through the emulsion electrospraying technique was studied, using deep eutectic solvents (DES) as solvents. These novel solvents are characterized by negligible volatility, a liquid state far below 0 °C, a broad range of polarity, high solubilization power strength for a wide range of compounds, especially poorly water-soluble compounds, high extraction ability, and high stabilization ability for some natural products. Four DES formulations were used, based on mixtures of choline chloride with water, propanediol, glucose, glycerol, or butanediol. ß-Carotene was successfully encapsulated in a solubilized form within WPC capsules; as a DES formulation with choline chloride and butanediol, the formulation produced capsules with the highest carotenoid loading capacity. SEM micrographs demonstrated that round and smooth capsules with sizes around 2 µm were obtained. ATR-FTIR results showed the presence of DES in the WPC capsules, which indirectly anticipated the presence of ß-carotene in the WPC capsules. Stability against photo-oxidation studies confirmed the expected presence of the bioactive and revealed that solubilized ß-carotene loaded WPC capsules presented excellent photo-oxidation stability compared with free ß-carotene. The capsules developed here clearly show the significant potential of the combination of DES and electrospraying for the encapsulation and stabilization of highly insoluble bioactive compounds.

Biomolecules extraction from coffee and cocoa by- and co-products using deep eutectic solvents.

BACKGROUND: Coffee pulp (CP), cocoa husk (CH), and pod husk (CPH) are the main agro-residues from coffee and cocoa industries. They are sources of useful biomolecules, such as phenolic compounds, fibers, and alkaloids, among others. In this study, different compositions of deep eutectic solvents (DES) were investigated as a green and sustainable extraction media, with respect to their extraction capacity. The extraction yields were evaluated using heat stirring-assisted extraction (HSE) or ultrasound-probe assisted extraction (UPAE). RESULTS: The results showed an important effect of the DES composition. Choline chloride (ChCl) based-DES were the most effective, specifically lactic acid:ChCl (2:1 mol ratio), and the extraction capacity of DES was higher with UPAE (3 min/constant duty cycle (200 W)), in comparison with HSE (1 h/30 min). Chlorogenic acid, caffeine, and theobromine were identified as the main bioactive compounds. Interestingly, under specific conditions, DES allowed the formation of a molecule, identified as furfural by ultrahigh-performance liquid chromatography mass spectrometry (UPLC-MS), which could not be obtained using conventional extraction solvent (ethanol 70% v/v). CONCLUSION: DES showed a sustainability and high extraction capacity of biomolecules. In addition, their use as extraction solvents could lead to the formation and production of valuable building block molecules from plant biomass. © 2019 Society of Chemical Industry.

Identification and quantification of phytoprostanes and phytofurans of coffee and cocoa by- and co-products.

Phytoprostanes (PhytoPs) and phytofurans (PhytoFs) are isoprostanoids that result from the peroxidation of α-linolenic acid and are biomarkers of oxidative stress in plants and humans. These compounds exhibit several interesting biological activities (e.g. neuroprotection and anti-inflammatory activities). The aim of this research was to add value to coffee pulp (CP), cocoa husk (CH) and cocoa pod husk (CPH) by identifying and quantifying PhytoPs and PhytoFs by liquid chromatography-tandem mass spectrometry. The contents of PhytoPs and PhytoFs in CP, CH, and CPH were, respectively, 654.6, 474.3 and 179.9, and 543.2, 278.0 and 393.8 ng per g dry weight (dw). The main PhytoP found in CP (171.37 ng per g dw) and CPH (37.12 ng per g dw) was 9-epi-9-F1t-PhytoP, while ent-9-L1t-PhytoP was the most abundant in CH (109.78 ng per g dw). The main PhytoF found in all sources was ent-16(RS)-13-epi-ST-Δ14-9-PhytoF, at 196.56, 126.22, and 207.57 ng per g dw in CP, CH, and CPH, respectively. We provide the first complete profile of PhytoPs and PhytoFs for these agro-residues, which could be used in the functional food industry for enriching food or as nutritional supplements.