Emulsifiers modulate the extent of gastric lipolysis during the dynamic in vitro digestion of submicron chia oil/water emulsions with limited impact on the final extent of intestinal lipolysis

Abstract

Consumer demands for healthier foods are constantly on the rise and results in the diversification of sources suchas vegetable oils. Chia oil is a relevant source of α-linolenic acid. One of the targeted applications is the inclusionof chia oil in emulsified form in beverages where it is necessary to obtain stable submicron emulsions, acting ascarrier of nutrients such as lipids. In the present work, high-pressure homogenization was employed to produceemulsions (10% chia oil) with small oil droplets (300 nm), formulated with different emulsifiers (beta-lactoglobulin (BLG), lecithin and Tween 80). These emulsions were submitted to a dynamic in vitro digestion (DIDGI)to better understand the main mechanisms involved in the process of lipolysis, in order to design systems thatmay allow the modulation of the digestive action of lipases, thus ensuring the maximum bioaccessibility of thelipids. This device mimics part of the transient biochemical conditions as well as the flow of foods through thedifferent compartments occurring in the real digestion. Significant differences were observed in the lipolysisduring the gastric phase. BLGemulsions reached a lipolysis degree of 30%. Lecithin-stabilized emulsions behavesimilarly to BLG ones during the first 90 min but lipolysis levelled off further ~20%. Finally, Tween-80-stabilizedemulsions remained almost undigested (around 2%). No significant differences were noticed in duodenum anddistal small intestine, irrespective of the emulsifier employed. After digestion, the fatty acid bioaccessibility washigher with BLG as emulsifier.