Effect of milk proteins and food-grade surfactants on oxidation of linseed oil-in-water emulsions during in vitro digestion

Citation

Lamothe, S., Desroches, V., Britten, M. (2019). Effect of milk proteins and food-grade surfactants on oxidation of linseed oil-in-water emulsions during in vitro digestion. Food Chemistry, [online] 294 130-137. http://dx.doi.org/10.1016/j.foodchem.2019.04.107

Plain language summary

Consumption of omega-3 fatty acids is associated with many health benefits. However, these substances are sensitive to oxidation, which can generate potentially toxic derivatives. These derivatives can be formed during the production and storage of food, but also during digestion. The objective of this study was to produce linseed oil emulsions (rich in omega-3) using milk proteins or food surfactants as emulsifiers and to compare the digestibility of the oil and the production of toxic derivatives in a digestion simulator. The results show that the nature of the emulsifier influences the behaviour of the emulsion during gastric transit. The emulsion stabilized by an anionic surfactant showed strong coalescence, which reduced lipolysis and oxidation in the intestinal phase. In contrast, the emulsion produced with a non-ionic surfactant resisted coalescence in the gastric phase and increased the release of fatty acids and the production of toxic derivatives in the intestinal phase. Emulsions stabilized by milk proteins underwent strong aggregation during the gastric phase, and the casein showed better protection against oxidation. This study suggests that the destabilization mechanism of the emulsions in the gastric environment can modulate lipolysis and oxidation during in vitro digestion.

Abstract

Health benefits are associated with polyunsaturated fatty acids, but their sensitivity to oxidation may generate toxic oxidation species. The objective of this study was to compare the effect of milk proteins (casein, whey protein) and surfactants (Citrem, Tween 20) on the in vitro digestion and oxidation of linseed oil emulsions. The emulsion produced with Tween 20 resisted coalescence in the gastric phase and showed the highest concentrations of free fatty acids and reactive carbonyl compounds in the intestinal digestion phase. The Citrem-stabilized emulsion showed extensive coalescence in the gastric environment, which reduced lipolysis and the formation of advanced oxidation species. The protein-stabilized emulsions showed aggregation with some coalescence in the gastric phase, and casein provided better protection than whey protein against oxidation. This study suggests that the mechanism of emulsion destabilization in the gastric environment and the type of protein can modulate lipolysis and oxidation during in vitro digestion.

Publication date

2019-10-01