Influence of Oxidized Oils on Digestibility of Caseins in O/W Emulsions

Abstract

The impact of lipid oxidation on protein modifications in emulsions and the consequences on protein digestibility remains unclear. In this study, this impact is evaluated in casein (6 mg mL−1) based emulsions containing oxidized soybean or fish oil (3%) in presence (0.3%) or absence of the emulsifier Tween 20. Emulsions are prepared using oils at three oxidation levels and subsequently the impact on protein digestibility is evaluated after 24 h incubation at 4 °C. Remarkably, protein digestibility increass in emulsions containing medium and highly oxidized fish oil: 70 ± 0.4% and 73 ± 0.4% of the proteins are digested, respectively, whereas protein digestibility in emulsions containing low oxidized fish oil amounted to 63 ± 0.4%. Protein digestibility in emulsions containing soybean oil stabilized by Tween 20 is not influenced by the oxidation level of the oil used. A remarkable tendency is observed for the malondialdehyde content of the emulsions depending on the presence of Tween 20. For soybean oil based emulsions, malondialdehyde concentrations are consistently higher in the presence of Tween 20. On the other hand, for the fish oil based emulsions an opposite trend is observed, except at the highest oxidation level evaluated, for which no significant differences can be detected. It is concluded that the composition of the interface in emulsions depends strongly upon the degree of oil oxidation and the presence of other emulsifiers. If the oil is more oxidized, less protein is present in the interface restricting the impact of lipid oxidation products on the proteins and hence their digestibility. Practical Applications: This research was done to highlight the relevance of the interfacial composition in food emulsions and its influence on dairy protein digestibility. The food industry must be aware of the oil quality and the presence of emulsifiers in foods emulsions that allow to preserve the stability and nutritional characteristics of these food emulsions. This article aims to evaluate the impact of the reactions occurring between lipid oxidation products and proteins in emulsions on protein digestibility. This impact is evaluated in casein based emulsions containing oxidized soybean or fish oil (3%) in presence or absence of an emulsifier (0.3%). Emulsions are prepared using three oxidation levels and subsequently the impact on protein digestibility is evaluated after 24 h incubation at 4 °C. It is concluded that the composition of the interface in emulsions depends strongly upon the degree of oil oxidation and the presence of other emulsifiers.

How to Efficiently Remove tert‐butylhydroquinone from Commercial Soybean Oils to Obtain Stripped Oils: Eliminating tert‐butylhydroquinone's Influence on Oxidative Stabilities of Model Oil‐in‐Water Emulsions

“…Moreover, the palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1), linoleic acid (C18:2n6), and α‐linolenic acid (C18:3n3) were the main fatty acids existing in the soybean oil, which was consistent with the previous study of Obando et al. [ 33 ] Furthermore, no obvious differences were observed in the fatty acid compositions of the E‐SSO4, AC‐SSO4, and AL‐SSO4 when compared with the control sample ( P < 0.05), either from the kinds of fatty acids or from the levels of fatty acid compositions. For example, the contents of ΣSFAs, ΣMUFAs, and ΣPUFAs for control sample and E‐SSO4 were 15.53 and 15.61, 21.83 and 21.88, 62.72 and 62.64, respectively.…”

Influence of malondialdehyde‐induced modifications on physicochemical and digestibility characteristics of whey protein isolate

“…Especially with the trend of the fortification of dairy products with functional lipids [such as α‐linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] (Ganesan, Brothersen, & McMahon, ), the continuous exposure of WPI to oxidized lipids and their decomposition products may have potential deleterious effects (Cucu et al, ; Hidalgo & Kinsella, ). Impaired physicochemical, structural, and digestibility characteristics were recently observed in casein and whey proteins during the co‐incubation with oxidized fish oil, soybean oil, and sunflower oil (Cucu et al, ; Obando, Papastergiadis, Li, & De Meulenaer, ; Obando, Soto, & De Meulenaer, ). Such modification on proteins was introduced by the oxidized lipids and their secondary products including di‐aldehyde malondialdehyde (MDA) and α, β‐unsaturated aldehydes (4‐hydroxy‐2‐nonenal and acrolein) (Esterbauer, Schaur, & Zollner, ).…”

Epicatechin Inhibited Lipid Oxidation and Protein Lipoxidation in a Fish Oil-Fortified Dairy Mimicking System

“…As shown in Table 1 , at the end of digestion, a sharp decrease to 8.22% of DH was observed after total gastrointestinal digestion while the DH of unoxidized WPI was 13.92%, suggesting the oxidized WPI was less accessible for proteases. The impact of oxidation on protein hydrolysis has been investigated in several previous studies and protein modification, and cross-linking and aggregation are thought to be responsible for changed digestive behavior, especially in the presence of PUFAs, which are more prone to oxidation [ 12 , 34 ]. In this study, a gradual increase in DH of WPI was found in EC-incorporated emulsions.…”