Development of a reliable pH-STAT in-vitro model for gastrointestinal digestion of lipids and application for infant formula

Abstract

Present study aims to establish a reliable infant digestion model using pH-STAT method and the model is also applied to static in-vitro digestion of different infant formulas. Model-3 which consisted of NaCl, KCl and CaCl2 as gastrointestinal digestive fluids demonstrated better repeatability than model-1 was selected for the evaluation of static in-vitro digestion of different infant formulas (different fatty acids, protein composition and with/without milk fat globule membrane) using pH-STAT method. Three infant formulas (IF) with different fatty acids composition were evaluated and IF2 which contained the highest amounts of medium-chain saturated fatty acids (8.02 ± 0.47%) demonstrated the highest in-vitro gastrointestinal lipolysis rate (65.88 ± 0.24%). Infant formulas containing peptides and amino acids were more easily hydrolyzed by protease, which probably enhanced the release of FFA (IF1, 50.60 ± 0.87%; IF4, 60.17 ± 2.97%; IF5, 62.21 ± 2.27%; IF6, 66.51 ± 2.38%). In addition, the presence of milk fat globule membrane (MFGM, IF7) was found to accelerate in-vitro gastrointestinal lipolysis (IF1, 50.60 ± 0.87%; IF7, 58.05 ± 1.77%). In summary, the new developed model is suitable for investigating in-vitro digestion of different infant formulas.