EFFECT OF COMMERCIAL FUNGAL PROTEASES AND FREEZE-SHOCKED LACTOBACILLUS-HELVETICUS CDR-101 ON ACCELERATING CHEESE FERMENTATION .2. PROTEOLYSIS

Rapid proteolysis of beta-casein and an additional band in the gamma-c asein region was observed in fungal protease-treated cheese on PAGE pa tterns. beta-casein was comptetely hydrolyzed in fungal protease-treat ed cheese whereas after 12 wk approximately 60 and 80 % were still int act in conventional and UF cheeses, respectively. The rate of alpha(s) -casein hydrolysis in fungal protease-treated cheese was slightly fast er than in control cheese during ripening. More than 90 % of alpha(s)- casein was hydrolyzed in control cheeses after 18 wk, which were made from either regular or UF milk. Cheese made from milk 5-fold concentra ted by UF retained more beta-lactoglobulin than control cheese as dete rmined by SDS-PAG E. The rate of increase in trichloracetic acid (TCA ) and phosphatungstic acid (PTA) soluble nitrogen (N) was proportional to the amounts of enzymes added during ripening. Addition of freeze-s hocked L. helveticus cells to Gouda cheese increased TCA and PTA solub le N concentrations during ripening. Cheese containing Corolase PN sho wed a great increase in TCA soluble N above levels in the control. Fun gal proteases released more TCA soluble N than 2 % freeze-shocked L. h elveticus. Combining L. helveticus and Corolase PN had an additive eff ect on the generation of TCA soluble N. The bitter fraction was extrac ted from the fungal proteases-treated cheeses after 12 wk. The molecul ar weight approximated 3800 daltons.