In vitro digestion of sodium caseinate emulsions loaded with epigallocatechin gallate

Abstract

The digestion behaviour of a structured emulsion interface loaded with epigallocatechin-gallate (EGCG) was investigated. Oil in water emulsions were prepared with 0.35% sodium caseinate, 0, 2, and 6 mg/ml epigallocatechin-gallate (EGCG), and 0.45% of high methoxyl pectin (HMP). Emulsions were subjected to a static in vitro digestion, simulating the three stages of human upper gastrointestinal digestion, to investigate EGCG-salivary protein associations, and the effect of incorporated EGCG on gastric proteolysis and duodenal lipolysis. Confocal microscopy observations demonstrated that the addition of HMP reduced saliva's mucin-induced aggregation of the emulsions. Gel electrophoresis results indicated that sodium caseinate was fully hydrolysed, regardless of the presence of EGCG or HMP. The presence of EGCG reduced the extent of free fatty acid release during the duodenal phase. The findings from this study suggest that sodium caseinate-stabilized emulsions can be employed as a platform for delivery of EGCG.