ABSTRACT Vitamin A is an essential fat‐soluble micronutrient widely used in food and feed sectors to combat deficiency symptoms worldwide and meet nutritional needs, yet its intrinsic oxidative instability continues to challenge product design and shelf‐life. Although various delivery strategies, ranging from bulk oils to advanced encapsulation systems, have been employed, its degradation remains difficult to predict. Vitamin A is susceptible to oxygen mediated oxidation, forming epoxides, cleavage products, hydrolysis derivatives, and dimers through mechanisms influenced by environmental factors (light, heat, etc.), matrix composition, and molecular structure. While antioxidants can provide protection, their performance is highly system‐dependent, and some compounds may even become pro‐oxidant under certain conditions. The design of stable vitamin A formulations is hindered by an incomplete understanding of the fundamental oxidative processes. Most existing studies emphasize radical‐driven propagation steps, but emerging evidence suggests that earlier, perhaps non‐radical activation events, such as triplet‐state excitation and electron‐transfer processes leading to reactive species, may play a critical role in initiating degradation. Furthermore, the microstructural organization of formulations, molecular interactions within encapsulating systems, and the potential involvement of concerted pathways have been largely overlooked. These factors may significantly modulate vitamin A reactivity by altering molecular environments and influencing activation energy. A deeper mechanistic understanding of these oxidative initiation processes is therefore essential. Such knowledge would enable the design of next‐generation formulations that stabilize vitamin A at its ground state, improving efficacy, safety, and long‐term nutritional value. Practical Applications : A better understanding of how vitamin A degrades has direct practical value for the food and feed industries. By identifying not only its links to well‐known radical oxidation pathways but also its early‐stage activation mechanisms, manufacturers can design more effective stabilization strategies, either by improving encapsulation systems or by selecting antioxidants that remain protective rather than becoming pro‐oxidant under certain conditions. Additionally, insights into how formulation structure and ingredient interactions influence vitamin A degradation can guide the development of optimized delivery matrices, such as emulsions or microcapsules, tailored to specific products. Applying this knowledge helps extend shelf life, maintain nutritional value, and reduce economic losses due to degradation. It also supports the creation of safer, more reliable fortified foods, ensuring that populations at risk of deficiency receive consistent and effective vitamin A intake over time.

Lipid oxidation remains a major challenge in the food industry due to its detrimental effects on nutritional value, shelf life, and safety of edible oils. While the radical-based chemical mechanisms of lipid oxidation have been extensively studied, recent research highlights the importance of physical and supramolecular factors in bulk oils. This review provides an updated synthesis of current knowledge on lipid oxidation pathways, antioxidant mechanisms, and insights into the role of association colloids, particularly reverse micelles in bulk oils. Evidence indicates that association colloids act as reaction centers by concentrating water, hydroperoxides, and pro-oxidant metals at the oil–water interface, thereby accelerating radical initiation and propagation. Conversely, these interfacial structures may also enhance oxidative stability by promoting the targeted localization and synergistic action of antioxidants at critical reaction sites. The review discusses how intrinsic factors such as oil composition, amphiphilic constituents, water content, and oxygen solubility, together with extrinsic conditions, shape colloidal organization and oxidation kinetics. Special attention is given to the molecular structure of antioxidants, including polarity, spatial orientation of functional groups, and their impact on antioxidant efficiency, induction period extension, cutoff effects, and synergism. Recent advances in monitoring oxidation, including approaches targeting antioxidant depletion, are also addressed. Finally, key knowledge gaps and future research directions are identified, emphasizing the need for advanced structural characterization techniques and kinetic modeling to elucidate colloidal dynamics during oxidation. A deeper understanding of these interfacial and supramolecular phenomena is essential for developing more effective and sustainable strategies to control oxidation in bulk oils.

Vitamin A is an essential micronutrient involved in vision, immunity, and growth. Despite its widespread use in food, cosmetic, and pharmaceutical products, vitamin A is highly prone to oxidation due to its conjugated double bonds, leading to reduced biological activity and efficacy. While various formulation strategies have been explored to enhance its stability, there is a notable lack of stability data and understanding of vitamin A oxidation, particularly in dispersed systems. This study aimed to evaluate the oxidative stability of vitamin A in model emulsions and identify how emulsion composition affects its degradation. Studying the influence of emulsion composition provides a better understanding of the possible oxidation pathways, including a nonradical pathway. An innovative method combining gentle emulsification via solvent displacement with real-time degradation monitoring was used. Retinyl palmitate (RP) demonstrated the highest stability compared to retinol (RO) and retinyl acetate (RA), due to structural and electronic factors. Among emulsifiers, the cationic type slightly improved stability by repelling positively charged pro-oxidant molecules. Three phenolic antioxidants, alpha-tocopherol (TOH), butylated hydroxytoluene (BHT), and carnosic acid (CA), improved stability, with TOH being the most effective. However, early-stage degradation could not be completely prevented, suggesting the existence of a predominant nonradical degradation pathway. The impact of iron (Fe2+) was minimal and attributed to the low hydroperoxide production, reinforcing the hypothesis of a nonradical initiation. Additionally, electrostatic repulsion in positively charged emulsions further limited iron's pro-oxidant effect. These findings enhance our understanding of vitamin A oxidation mechanisms and highlight potential stabilization strategies for its formulation in emulsified systems.

Mono- and digalactosyldiacylglycerols (MGDG, DGDG), the main lipids of plant photosynthetic membranes, represent a large but unexploited reservoir of fatty acids on earth. They are dispersed in plant biomass (milligrams per gram of dry mass) and not as accessible as vegetable oils by simple physical means. The identification and characterization of galactolipid acyl hydrolases, or galactolipases, raise the possibility to use these biocatalysts for the bioconversion of galactolipids. Here, we show that two enzymes of mammalian and microbial origins, pancreatic lipase-related protein 2 from guinea pig (GPLRP2) and cutinase from Fusarium solani, have the capacity to directly and fully release the fatty acids of MGDG and DGDG present in various plant leaves and green wastes. This high substrate accessibility to enzymes was further explored by performing alcoholysis reactions in situ and showing the conversion of galactolipid fatty acids into fatty acid alkyl esters (FAAE) when the enzyme and leaves were incubated in the presence of 6 or 2.5 M ethanol. These findings pave the way to the recovery of fatty acids dispersed in green biomass and the exploitation of an additional and renewable source of fatty acids for oleochemistry and nutrition in a context of competition for vegetable oils.

Lipid oxidative degradation contributes to the deterioration of food quality and poses potential health risks. A promising approach to counteract this is the use of plant-based antioxidants. However, accurately evaluating the antioxidant capacity and effectiveness of these compounds remains a challenge. While many rapid in vitro tests are available, they must be categorized according to their specific responses to avoid overinterpreting results. This review opens with an overview of current knowledge on lipid autoxidation and recent findings that highlight the challenges in measuring antioxidant capacity. We then examine various methods, addressing their limitations in accurately anticipating outcomes in complex compartmentalized lipid systems. The aim is to clarify the gap between predictions and real-world efficacy in final products. Additionally, the review compares the strengths and weaknesses of methods used to evaluate antioxidant capacity and assess oxidation degrees in complex environments, such as those found in food and cosmetics. Finally, new analytical techniques for multiproduct detection are introduced, paving the way for a more ‘omic’ and spatiotemporally defined approach.

Lipases, crucial enzymatic tools for potential replacement therapy, must possess specific characteristics for ideal functionality. An effective lipase replacement therapy necessitates the maintenance of robust lipolytic activity at both acidic and neutral pH levels, as well as in the presence of normal and low physiological concentrations of intra-intestinal bile salts. Additionally, it should resist proteolytic digestion by pepsin and trypsin, actively hydrolyzing a wide range of dietary triacylglycerols. This study focuses on the production, purification and biochemical characterization of Burkholderia lata LBBIO-BL02 lipase, emphasizing its potential in digestive environments. The enzyme demonstrated activity against fatty acids with carbon chains from 8 to 20, displaying a preference for palmitic (16:0) and oleic (18:1) acids. It displayed regioselectivity for the external positions sn-1 and sn-3 of triacylglycerol. Kinetic revealed Michaelis-Menten behavior, with a Km of 22 mmol and Vmax of 12.7 mmol/min, with kcat 225s(-1) and catalytic efficiency 10(4) mol(-1) s(-1). Operating optimally at 55 degrees C, the enzyme showed stability at 60 degrees C. The optimal pH range was 4-9, retaining >100% of initial activity in the pH range 2.2-10.0. In simulated gastric environments, the lipase exhibited high activity and stability under low pH conditions, demonstrating remarkable activation in the presence of high bile salt concentrations. BLL emerged as an enzyme comparable in potency to gastric and pancreatic lipases, encompassing a substrate variety while resisting proteases and bile salts. The biochemical insights from this study lay a robust foundation for further exploration of BLL in enzyme replacement therapy.

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.

Extracellular vesicles (EVs) are nanoscopic structures that are involved in intercellular communication. Recent works have highlighted the existence of these assemblies in several plants and shown that they are able to vectorize hydrophilic and lipophilic molecules. In this study, we have isolated EVs from the two main olive oil by-products (wastewaters [WWs] and pomace) by differential centrifugation/ultracentrifugation and have characterized their main physicochemical properties (size, charge, multimolecular structure, lipid and phenolic contents) and radical scavenging activity. Lipid content in EV fractions was 3.4 (0.2) % (% dry material) for WWEVs and 7.7 (0.3) % and 5.9 (0.9) % for EVs, respectively, from plurivarietal or monovarietal pomaces. Polar lipids represented around 49% of total lipids, and their profiles were globally similar in all EVs. Phosphatidylcholine and phosphatidic acid were the more abundant molecules. Their phenolic contents ranged from 2.1 to 4.6 mg hydroxytyrosol (HT) eq g(-1) of raw material, with HT, oleuropein, and verbascoside being among the most abundant. Transmission electron cryomicroscopy showed the presence of spherical vesicles delimited by a single bilayer of amphiphilic lipids. Finally, the 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity of EVs was high and depended on their original by-product type. Practical Application: Recent works have highlighted the existence of extracellular vesicles in several plants and shown that they are able to vectorize hydrophilic and lipophilic molecules. Herein, we have isolated and provided a chemical characterization of such vesicles from olive wastewater and pomace. Results showed that these vesicles are rich in the phenolic compounds that are generally found in olives and that the potential radical scavenging activity of extracellular vesicles from olive could be valorized as new antioxidants for the food or cosmetic sectors.

Olive extracellular vesicles and synthetic liposomes were evaluated as carriers of antioxidants to stabilize oil-in-water emulsions against oxidative degradation. For this, hydroxytyrosol, rosmarinic acid and their lipophilic counterparts, (hydroxytyrosyl dodecanoate esters or eicosyl rosmarinate esters) were loaded into these carrier vesicles and the antioxidant efficiencies of these formulations were compared with those of the corresponding antioxidants alone. Using the conjugated autoxidizable triene assay (CAT assay), our results shows that loaded synthetic liposome mimicking the lipid membrane composition of olive extracellular vesicle allowed to enhance the antioxidant effect of the loaded antioxidant especially with the two lipophilic hydroxytyrosol and rosmarinic acid esters. On the contrary, the loading of the studied antioxidant into the olive extracellular vesicles did not result in an improvement of the antioxidant activity. The antioxidant effects of loaded vesicles were also evaluated in rapeseed oil (1% w/w)-in-water emulsions that were stored at 40 degrees C for 21 days and for which oxidative status was monitored by the quantification of primary and secondary oxidation compounds. In that case, the boosting effect of liposomal carriers was not confirmed. This could be due to a different type of emulsions compared to the one used with the CAT assay as different surfactants and oxidation inducers were employed. Additionally, the limited physical stability of the carrier could be involved as liposomes loaded with the most lipophilic antioxidants, namely hydroxytyrosyl dodecanoate and eicosyl rosmarinate were shown to be instable for period exceeding 10 days of storage.

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.

p-Hydroxycinnamic acids, such as sinapic, ferulic, p-coumaric and caffeic acids, are among the most abundant phenolic compounds found in plant biomass and agro-industrial by-products (e.g. cereal brans, sugar-beet and coffee pulps, oilseed meals). These p-hydroxycinnamic acids, and their resulting decarboxylation products named vinylphenols (canolol, 4-vinylguaiacol, 4-vinylphenol, 4-vinylcatechol), are bioactive molecules with many properties including antioxidant, anti-inflammatory and antimicrobial activities, and potential applications in food, cosmetic or pharmaceutical industries. They were also shown to be suitable precursors of new sustainable polymers and biobased substitutes for fine chemicals such as bisphenol A diglycidyl ethers. Non-oxidative microbial decarboxylation of p-hydroxycinnamic acids into vinylphenols involves cofactor-free and metal-independent phenolic acid decarboxylases (EC 4.1.1 carboxyl lyase family). Historically purified from bacteria (Bacillus, Lactobacillus, Pseudomonas, Enterobacter genera) and some yeasts (e.g. Brettanomyces or Candida), these enzymes were described for the decarboxylation of ferulic and p-coumaric acids into 4-vinylguaiacol and 4-vinylphenol, respectively. The catalytic mechanism comprised a first step involving p-hydroxycinnamic acid conversion into a semi-quinone that then decarboxylated spontaneously into the corresponding vinyl compound, in a second step. Bioconversion processes for synthesizing 4-vinylguaiacol and 4-vinylphenol by microbial decarboxylation of ferulic and p-coumaric acids historically attracted the most research using bacterial recombinant phenolic acid decarboxylases (especially Bacillus enzymes) and the processes developed to date included mono- or biphasic systems, and the use of free- or immobilized cells. More recently, filamentous fungi of the Neolentinus lepideus species were shown to natively produce a more versatile phenolic acid decarboxylase with high activity on sinapic acid in addition to the others p-hydroxycinnamic acids, opening the way to the production of canolol by biotechnological processes applied to rapeseed meal. Few studies have described the further microbial/enzymatic bioconversion of these vinylphenols into valuable compounds: (i) synthesis of flavours such as vanillin, 4-ethylguaiacol and 4-ethylphenol from 4-vinylguaiacol and 4-vinylphenol, (ii) laccase-mediated polymer synthesis from canolol, 4-vinylguaiacol and 4-vinylphenol.

The residual biomass of cold-pressed green coffee oil (GCO), rich in chlorogenic acids (CGA), was reused by incorporating the press cake (CE) and sediment (SE) extracts into carboxymethyl cellulose (CMC) films. The effect of these extracts combined with GCO was investigated on the physicochemical, barrier, and antioxidant properties, and on the ability of the active films to delay fish oil oxidation. The films with added CE and GCO (CCE) or SE and GCO (C-SE) showed high antioxidant activity, 3.61 +/- 0.01 and 2.03 +/- 0.01 mmol Trolox eq/g dry film, respectively. These findings are in line with the CGA content in CE and SE (9.8 and 9.0% w/w, respectively), as determined by HPLC. The addition of SE and GCO slightly affects the oxygen barrier of CMC films, while providing them with high Ultraviolet-Visible (UV-Vis) absorption. The evolution of peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) in fish oil samples covered by C-CE and C-SE films and inert headspace was significantly lower than those of controls (storage at 40 degrees C for 16 days). The antioxidant release from films with added CE and SE showed an antagonistic behaviour into the food simulants. Although both active films are promising for active packaging, the C-SE film appeared as more advantageous for oil-rich food protection.

Galactolipids are the most abundant lipids on earth where they are mainly found in photosynthetic membranes of plant, algae, and cyanobacteria. Pancreatic lipase-related protein 2 (PLRP2) is an enzyme with galactolipase activity allowing mammals, especially herbivores, to digest this important source of fatty acids. We present a method for the quantitative analysis of galactolipids and galactosylated products resulting from their digestion by guinea pig PLRP2 (GPLRP2), using thin-layer-chromatography (TLC), thymol-sulfuric acid as derivatization reagent and scanning densitometry for detection. Thymol-sulfuric acid reagent has been used for the colorimetric detection of carbohydrates. It is shown here that the derivatization of galactosyl group from galactolipids by this reagent is not affected by the bound acyl glycerol, acyl chains length and number of galactose residues in the polar head. This allowed quantifying simultaneously the initial substrate and all galactosylated products generated upon the hydrolysis of monogalactosyl di-octanoylglycerol (C8-MGDG) by GPLRP2 using a single calibration with C8-MGDG as reference standard. The reaction products, monogalactosyl monooctanoyl glycerol (C8-MGMG) and monogalactosyl glycerol (MGG), were identified and quantified, MGG being recovered from the aqueous phase and analyzed by a separate TLC analysis. This method is therefore suitable to quantify the products resulting from the release of both fatty acids present in MGDG and thereby shows that PLRP2 can contribute to the complete digestion of galactolipids and further intestinal absorption of their fatty acids.

The effect of the presence of surfactant micelles and of the mode of incorporation (pre-homogenization or post-homogenization) on the antioxidant efficiency of a homologous series of n-alkyl gallates phenolipids (G0, G3, G8, G12 or G16) was investigated in oil-in-water nanoemulsions. In both absence and presence of surfactant micelles, G12 and G16 were the best antioxidants. The effect of the mode of incorporation was modulated by the presence of surfactant micelles. In absence of surfactant micelles, G8 and G16 had higher efficiency when incorporated pre-homogenization, suggesting that the mode of incorporation promoted a distinct initial distribution of these compounds. In contrast, in presence of surfactant micelles, the antioxidants could be incorporated in any phases without efficiency loss. These results demonstrate the important role of surfactant micelles in modulating the antioxidant efficiency and could be used by the food industry to optimize emulsion formulations.

Rapeseed and sunflower meal are mainly used as animal feed but they can also be considered as a potential source of bioactive phenolic compounds. However, the desolventization/toasting processes that are needed to produce these meals might influence concentration and chemical structure of phenolic compounds, and change their bioactive properties. Moreover, the recovery processes of these molecules from meals are based on the use of solvent that generates effluents and might affect the integrity of the other constituents of the meals. Knowing this, the PHENOLEO project, funded by the SAS PIVERT, was a research program based on the biorefinery of rapeseed and sunflower meals that aimed to develop new routes of valorization of these materials mostly by the separation and valorization of their simple phenolic compounds. Thus, we decided to focus this study on the impact of the desolventization process on the biochemical composition of meals, the separation process of their simple phenolic compounds, the production of phenolic acids from meals and the potential valorization routes of the phenolic fraction.

Galactolipids, mainly monogalactosyl diglycerides and digalactosyl diglycerides are the main lipids found in the membranes of plants, algae and photosynthetic microorganisms like microalgae and cyanobacteria. As such, they are the main lipids present at the surface of earth. They may represent up to 80% of the fatty acid stocks, including a large proportion of polyunsaturated fatty acids mainly α-linolenic acid (ALA). Nevertheless, the interest in these lipids for nutrition and other applications remains overlooked, probably because they are dispersed in the biomass and are not as easy to extract as vegetable oils from oleaginous fruit and oil seeds. Another reason is that galactolipids only represent a small fraction of the acylglycerolipids present in modern human diet. In herbivores such as horses, fish and folivorous insects, galactolipids may however represent the main source of dietary fatty acids due to their dietary habits and digestion physiology. The development of galactolipase assays has led to the identification and characterization of the enzymes involved in the digestion of galactolipids in the gastrointestinal tract, as well as by microorganisms. Pancreatic lipase-related protein 2 (PLRP2) has been identified as an important factor of galactolipid digestion in humans, together with pancreatic carboxyl ester hydrolase (CEH). The levels of PLRP2 are particularly high in monogastric herbivores thus highlighting the peculiar role of PLRP2 in the digestion of plant lipids. Similarly, pancreatic lipase homologs are found to be expressed in the midgut of folivorous insects, in which a high galactolipase activity can be measured. In fish, however, CEH is the main galactolipase involved. This review discusses the origins and fatty acid composition of galactolipids and the physiological contribution of galactolipid digestion in various species. This overlooked aspect of lipid digestion ensures not only the intake of ALA from its main natural source, but also the main lipid source of energy for growth of some herbivorous species.

Two protein tanning methods were evaluated to contribute to the withdrawal of formaldehyde as a tanning agent of meals for feeding ruminants. The experimental materials were two fractions of rapeseed and sunflower meals collected at the positive electrode of an electrostatic separator, presenting high contents in proteins and phenolic compounds. The objective was to make phenolics and proteins interact without addition of exogenous tannins. Treatment CH incubated a meal fraction:water mixture (1:2, w:w) for 48 h at 50 °C. Treatment FR incubated a meal fraction:water mixture (1:10, w:w) at pH 9.0 for 48 h at 4 °C. Microbial proteolysis on meal fractions were quantified during 24 h rumen batch fermentations with cellulose and starch as nitrogen-free energy sources. The net production of ammonia tended to be reduced by treatment FR mostly on rapeseed, corresponding to an 8% saving of rapeseed meal proteins degradable in the rumen. When untreated, the sunflower fraction decreased methane production by 50%, while treatments restored the fermentation pattern. Cold alkaline treatment could be considered to protect meal proteins from degradation by rumen micro-organisms.

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.