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

Gradual, controlled, and homogenous acidification of milk was achieved by addition to milk of acidogens: propionic anhydride, lactide, glucono delta iactone, 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.