Comparing the antioxidant activity of gallic acid and its alkyl esters in emulsion gel and non-gelled emulsion

Lipophilized rosmarinic acid: Impact of alkyl type and food matrix on antioxidant activity, and optimized enzymatic production

In this study, the initial focus was on exploring the simultaneous impact of the oil-based food matrix and the polarity of rosmarinic acid derivatives on the antioxidant properties. Rosmarinic acid (RA) showed remarkable DPPH, FRAP, and ABTS radical scavenging activities, followed by methyl rosmarinate (MR) and ethyl rosmarinate (ER). In bulk oil, both conjugated dienes and p-AnV values reached a peak in the following order after 30 days: ER > MR > RA = BHT > control (no antioxidant). In the oil structured using monoacylglycerol, MR was more effective than ER and RA. For ethyl cellulose oleogel, emulsion, and gelled emulsion systems, RA was more effective. Additionally, after confirming the importance of the food matrix on the antioxidant activity of RA derivatives, the lipophilization of RA with ethanol was optimized as a model with Lipozyme 435 in hexane. A conversion yield of as high as 85.59% for ER was achieved, as quantified by HPLC-UV and confirmed by HPLC-DAD-ESI-qTOFMS.

Simulating the behavior of antioxidant to explore the mechanisms of oxidative stability in Pickering emulsion

This study explores effective strategies for bolstering emulsion oxidative stability via optimized interfacial distribution of varying hydrophobicity antioxidants (gallic acid, propyl gallate, octyl gallate) in zein nanoparticle (ZP) stabilized Pickering emulsions. Experimental and simulation methods revealed that antioxidant (AO) with higher hydrophobicity or loaded into ZP demonstrated stronger hydrogen bonding and van der Waals interactions with ZP. This increased interfacial loading of antioxidants resulted in improved oxidative stability in Pickering emulsions. The flow, distribution and orientation of AO, as revealed by dissipative dynamics simulations, highlighted the role of hydrophobic interactions during initial AO migration, influenced by varied alkyl chain lengths. Subsequent interface rearrangements arose from conservative force interactions between the AO's phenol hydroxyl ends and ZP. These findings inform effective interfacial engineering to optimize antioxidant efficiency, guiding practical applications in emulsion systems for improved oxidative stability.

Antioxidant potency and inhibitory mechanism of curcumin and its derivatives in oleogel and emulgel produced by linseed oil

The antioxidant activity of curcumin and curcumin esters was investigated in oleogel and emulgel produced by linseed oil. In the initiation phase, curcumin acetate at 1.086 mM concentration showed the highest antioxidant activity in linseed oil, while curcumin at 2.172 mM concentration showed the highest antioxidant activity in oleogel. In the propagation phase, curcumin and curcumin esters exhibited higher efficiency in linseed oil samples than those of oleogel samples. In the initiation phase, curcumin hexanoate showed higher antioxidant activity than curcumin acetate and curcumin butyrate, while curcumin hexanoate showed lower efficiency than curcumin acetate and curcumin butyrate in the propagation phase. Investigating the mechanism of action of curcumin and curcumin esters in oleogel and emulgel showed that in addition to inhibiting peroxyl radicals, curcumin and curcumin esters were likely to pro-oxidatively attack hydroperoxides. Also, curcumin and curcumin esters radicals were likely to attack lipid substrates in these systems.

New anti-α-Glucosidase and Antioxidant Ingredients from Winery Byproducts: Contribution of Alkyl Gallates

Wine-making activity entails the production of solid and semisolid byproducts (grape stems and pomace and wine lees) that negatively impact the environment and industrial sustainability. Their features as sources of bioactive compounds support valorization procedures for functional and healthy ingredients. This work uncovers the quantitative alkyl gallates (gallic acid esters, C1-C12) profile of fresh (freeze-dried) materials and the effect of oven-drying on their stability by UHPLC-ESI-QqQ-MS/MS. The functionality was established concerning DPPH• scavenging and antihyperglycemic power. Wine lees exerted the highest high-free concentration of galloyl derivatives, ethyl gallate being the most abundant ester (3472.62 ng/g dw, on average). About the impact of the stabilization process, although as a general trend, the thermal treatment reduced the concentration, the reduction dimensions depended on the compound/matrix, remaining in valuable concentrations. Concerning radical scavenging, ze-dried stems and pomace displayed the highest capacity (24.11 and 18.46 mg TE/g dw, respectively), being correlated with propyl gallate (r2 = 0.690), butyl gallate (r2 = 0.686), and octyl gallate (r2 = 0.514). These two matrices exerted α-glucosidase inhibitory activity (1.58 and 1.46 units/L) equivalent to that of acarbose (a recognized α-glucosidase inhibitor). The newly described bioactive phytochemicals in winery residues (galloyl esters) and their correlation with functional traits allow for envisioning valorization alternatives.

The Biochemistry and Effectiveness of Antioxidants in Food, Fruits, and Marine Algae

It is more effective to maintain good health than to regain it after losing it. This work focuses on the biochemical defense mechanisms against free radicals and their role in building and maintaining antioxidant shields, aiming to show how to balance, as much as possible, the situations in which we are exposed to free radicals. To achieve this aim, foods, fruits, and marine algae with a high antioxidant content should constitute the basis of nutritional elements, since natural products are known to have significantly greater assimilation efficiency. This review also gives the perspective in which the use of antioxidants can extend the life of food products, by protecting them from damage caused by oxidation as well as their use as food additives.

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.