STREPTOCOCCUS-THERMOPHILUS AS ADJUNCT CULTURE FOR A SEMIHARD COWS MILK CHEESE

The influence of the addition of Streptococcus thermophilus as adjunct to the mesophilic starter on chemical, textural and sensory character istics of a semi-hard cows' milk cheese was studied. Addition of the t hermophilic adjunct increased alpha(s1)-casein hydrolysis and the leve l of N soluble at pH 4.6 after 30 d of ripening, reduced the level of N soluble in TCA and did not affect the level of N soluble in PTA. Low er apparent elastic modulus, breaking force and hardness were recorded for cheeses with thermophilic adjunct, as a consequence of the lower dry matter and the slightly enhanced casein hydrolysis. Flavour qualit y, flavour intensity and cheese bitterness were not affected by S. the rmophilus addition. In cheese made from milk with Bacillus subtilis ne utral proteinase added to accelerate ripening and induce bitter flavou r formation, the use of S. thermophilus as adjunct enhanced proteolysi s and produced a considerably higher concentration of N soluble in PTA . Textural characteristics were not affected. Flavour quality was impr oved and cheese bitterness significantly reduced by the addition of th e thermophilic adjunct. (C) Inra/Elsevier, Paris.