DEVELOPMENT OF PROBIOTIC CHEESE MANUFACTURED FROM GOAT MILK - RESPONSE-SURFACE ANALYSIS VIA TECHNOLOGICAL MANIPULATION

Production of caprine milk has been rising steadily, partially because of its good nutritional value; the possibility of improving nutrition al benefits by adding probiotic species such as Bifidobacterium lactis and Lactobacillus acidophilus was assessed. The manufacturing process of a traditional semi-hard goat cheese was technologically modified t o optimize the process. The amount of starter inoculum, the concentrat ion of salt, the addition of a protein hydrolysate, and the ripening t ime were varied to improve the microbiological, biochemical, and senso ry properties of the cheese. Bifidobacterium lactis was able to grow s lightly (up to 3 x 10(8) cfu/g), but growth was dependent on the physi cochemical characteristics of the cheese. Lactobacillus acidophilus di d not grow substantially in any of the experimental cheeses, and maxim um numbers did not exceed 6 x 10(7) cfu/g. Concentrations of lactic ac id and acetic acid increased throughout cheese manufacture, indicating that production of these acids was uncoupled from growth. Viability o f the probiotic strains during ripening was sufficient to yield number s that were above the accepted threshold (10(6) cfu/g) for a probiotic effect. Both strains contributed significantly to ripening, especiall y in the formation of low molecular mass peptides and amino acids, but lipolysis was not greatly affected. Statistical analyses using respon se surface methodology indicated that the manufacture of goat cheese c ould be optimized by the addition of 0.30% (vol/wt) milk hydrolysate, 3 x 10(7) of viable B. Lactis and 7 x 10(6) of viable L. acidophilus c ells/ml of milk, respectively, 3.50% (wt/wt) salt, and ripening for 70 d.