Co‐oxidation of Antarctic krill oil with whey protein and myofibrillar protein in oil‐in‐water emulsions

Abstract

Antarctic krill oil (AKO) is usually encapsulated by the protein materials, enhancing its oxidative stability. Proteins exhibit immense effect on lipid oxidation and induce protein–lipid co‐oxidation. This study aimed at elucidating the co‐oxidation mechanism of AKO and whey protein (WP) or myofibrillar protein (MP) in oil‐in‐water emulsions. The estimations of malondialdehyde (MDA) content, phospholipid molecular species, and pyrrole content resulted in increased and decreased oxidation rate of AKO (especially phosphatidylethanolamine) by WP and MP, respectively. Meanwhile, protein concentration, sulfhydryl content, the loss of tryptophan fluorescence intensity, and sodium dodecyl sulfate‐polyacrylamide gel electrophoresis results demonstrated that AKO promoted WP oxidation but inhibited MP oxidation. Further, the antioxidative abilities of seven common antioxidants were evaluated. Ascorbyl palmitate showed the most substantial antioxidative effect for both AKO and proteins (about 70% decrease of MDA content and 30% decrease of the decrease ratio of tryptophan fluorescence intensity). This finding supported that different proteins could exhibit different pro/anti‐oxidative effects on lipid oxidation, especially for marine lipids abundant in phospholipids and polyunsaturated fatty acids. Besides, MP could also act as antioxidant in MP AKO emulsions, further extending its application from traditional surfactants. Practical Application AKO is usually encapsulated by the protein materials, enhancing its oxidative stability. The results demonstrated MP could inhibit AKO oxidation, and vice versa, especially when ascorbyl palmitate was added at the same time. As a result, this finding explored a new potential wall material with antioxidative ability for the encapsulated products of AKO.

Advances in encapsulation systems of Antarctic krill oil: From extraction to encapsulation, and future direction

“…The malondialdehyde content of AKO emulsion prepared by whey protein was higher than that of myofibrillar protein after 6 days of storage at 37°C. This is because the zeta‐potential of whey protein emulsion (−38.4 mV) is lower than that of myofibrillar protein (−6.5 mV), and the latter is more likely to attract metal ions to the oil‐water interface, catalyzing the production of more free radicals from the unsaturated fatty acids and phospholipids (Wang, Liu, Ma, Yang, et al., 2020).…”

“…In the preparation of AKO emulsion, amphiphilic proteins are unfolded at the oil‐water interface, where hydrophilic groups are bound to water and hydrophobic groups are bound to and encapsulated in AKO to form water‐in‐oil emulsions. Commonly used proteins include casein (Wang, Zhao, Zhang, et al., 2022), whey protein isolate (Wang, Zhao, Liu, et al., 2022), Antarctic krill protein (Shi et al., 2018), chickpea protein isolate (Xu et al., 2021), and myofibrillar protein (Wang, Liu, Ma, Yang, et al., 2020) etc.…”

Comparative Analysis of Lipid Oxidation Stability and Bioaccessibility in Krill Oil Emulsions: Microfluidization vs. High-Pressure Homogenization

“…Traditionally, researchers have addressed KO's limited solubility and vulnerability to oxidation by introducing antioxidants or surfactants into the emulsion system. Antioxidants play a crucial role in mitigating lipid oxidation, while surfactants enhance emulsification and stabilize the resulting emulsion (Wang et al, 2020). While these additives have proven effective in extending the shelf life of KO-infused products, they have also attracted significant attention and scrutiny from consumers.…”

Multi-scale imaging of protein oxidation in mayonnaise

“…33 Therefore, ethylenediaminetetraacetic acid (EDTA) is often 34 added to mayonnaise to bind free metal ions via chelation 35 and thus reduces the formation of lipid peroxidation (LPO) 36 products (Lee and Decker, 2011;Nielsen et al, 2004). In 37 food emulsions, protein emulsifiers are known to react with 38 free radicals formed via lipid oxidation thus acting as antioxi-39 dants via scavenging free radicals (Berton-Carabin et al, 2014;40 Schaich, 2008;Schaich and Karel, 1976;Wang et al, 2020;41 Berton et al, 2012). Emulsions stabilized by whey proteins, 42 for example, showed better oxidation stability than emulsions onnaise.…”