Effect of oil phase properties on peptide release from water-in-oil-in-water emulsions in gastrointestinal conditions

Abstract β-Lactoglobulin hydrolysate was encapsulated in water-in-oil-in-water (W 1 /O/W 2 ) emulsions. The effects of digestible (linseed) and non-digestible (jojoba and mineral) oil phases on emulsion characteristics and peptide release in gastrointestinal conditions were compared. Peptide release was studied at gastric pH (3) and intestinal pH (7) in the absence of lipase and at intestinal pH (7) in the presence of lipase. Released peptides were analyzed by RP-HPLC and identified by LC-MS. The encapsulation efficiency of the three emulsions was over 90%. The W 1 /O/W 2 emulsion produced from mineral oil had the highest droplet diameter. In the absence of lipase, the proportions of peptides released after 4 h of agitation (37 °C) were significantly lower at gastric pH (4.1%–18.8%) than at intestinal pH (10.6%–35.3%) and varied in the order mineral oil