Simulation of Bacterial Fermentation of Milk and Possible Acylation of Its Proteins by Acidogen Hydrolysis

Abstract

Gradual, controlled, and homogenous acidification of milk was achieved by addition to milk of acidogens: propionic anhydride, lactide, glucono delta lactone, ethyl butyrate with its esterase, and tributyrin with its lipase. Only glucono delta lactone gave satisfactory delicate creamy and jelly-textured yogurt-like product within a relatively short time. The gellification time was shortened significantly by preacidification of the milk by a mild buffer. Glucono delta lactone released smaller amounts of acid in the presence of proteins than in their absence. It caused the appearance of a new ninhydrin positive spot on the chromatogram of its slightly basic mixture with L-lysine. Therefore, I assumed that glucono delta lactone reacts with milk proteins and also may attack digestive tract tissue in addition to its spontaneous hydrolysis in aqueous medium.