The physicochemical stability and in vivo gastrointestinal fates of flaxseed oil bodies with the introduction of soluble flaxseed gum polysaccharides

The natural oil bodies (OBs) were considered minimally processed entities for delivering bioactive lipids and minor lipid concomitants, such as α-linolenic acid (ALA), tocopherols, etc. when incorporated into food systems. The current study investigated the physicochemical stability and in vivo gastrointestinal digestion of flaxseed OBs with the introduction of soluble flaxseed gum polysaccharides (SFG), which always consistently coexisted in flaxseed milk. The results showed that the particle sizes of flaxseed OB emulsions consistently decreased by 37.46% (p < 0.05), while the zeta potential values gradually increased by 60.91% (p < 0.05) as the SFG concentrations raised from 0.1% to 0.5% (wt %). SFG improved the physical stability of flaxseed OB emulsions by preventing bridging flocculation among adjacent OBs, and achieving the movement restriction of single OBs via the direct interface anchoring and network structure formation in bulk aqueous phase. SFG apparently suppressed the gastrointestinal lipolysis rate of flaxseed OBs due to the complex coacervation with intrinsic interfacial proteins, subsequent deep encapsulation and gastric emptying delaying of OB remnants. Then, the slower micellar absorption and chylomicron transport within rat enterocytes were occurred, contributing to the suppressed ALA accumulation and subsequent conversion into n-3 long chain fatty acids in rat upper jejunum. Collectively, the introduction of SFG in flaxseed OBs at high concentration allows lower intestinal ALA bioaccessibility.