Growth Response of Lactobacillus casei variety casei to Proteolysis Products in Cheese during Ripening

Water extracts of Cheddar cheese at different ages up to 180 days were fractionated on Sephadex G-50 with pyridineacetic acid buffer pH 5.1. Six and nine fractions were obtained from fresh and ripened cheese, respectively, some of which stimulated growth. A fraction containing riboflavin was stimulatory to Lactobacillus casei variety casei. The stimulatory fractions contained N-acetylhexosamine and 23 to 27.8% glutamic acid of the constituent amino acids. Most of the alphas-casein disappeared from the cheese at 35 days while beta-casein remained. Para-kappa-casein was not proteolyzed at 170 days of cheese ripening. The significance of alpha-casein proteolysis in Cheddar cheese is discussed.