Carassius auratus oil as a human milk fat substitute: study on the in vitro digestion model of infants

A human milk fat substitute (HMFS) based on Carassius auratus oil (CAO) and plant oils was developed. The resulting HMFS mimicked the lipid composition and structural characteristics of human milk fat, potentially promoting infant digestion and absorption. The optimal conditions to enrich C52 (52 carbon atoms) triacylglycerols (TAGs) through solvent fractionation were a mixing ratio of CAO to acetone of 1:8 ( w / v ) and extraction at −40 °C for 24 h. The C52 TAGs content increased to 61.30 %, a 20.38 % improvement compared to unfractionated CAO. The total palmitic acid increased to 24.83 %, with 47.27 % located at sn -2. The in vitro digestion revealed a maximum free fatty acid release rate of 60.94 % from the CAO HMFS emulsion, with oleic acid (44.23 %) and linoleic acid (22.71 %) as the main components. Palmitic acid monoacylglycerol accounted for 72.16 % of the digestion products, suggesting a favorable TAG structure and potential benefits for infant lipid absorption.