Hispánico cheese, a semi-hard Spanish variety, was manufactured from a
mixture of pasteurized cows' and ewes' milks (4[ratio ]1) using a commercial mesophilic
LD-type starter comprising Lactococcus lactis subsp. cremoris, Lc. lactis subsp. lactis,
Lc. lactis subsp. lactis var diacetylactis and Leuconostoc mesenteroides subsp. cremoris.
Varying amounts (0–1·0 g/kg) of an Enterococcus faecalis INIA 4 culture in milk were
added as a bacteriocin-producing adjunct. Differences in pH between cheeses
manufactured with and without the bacteriocin producer did not exceed 0·11 pH
units. Starter lactococci lost viability more rapidly in cheeses made with the
bacteriocin producer, which reached counts of up to 6×107 cfu/g during ripening.
Aminopeptidase activity in 1-d-old cheese made from milk inoculated with 1·0 g
bacteriocin-producing culture/kg was twice that in control cheese. Degrees of overall
proteolysis and levels of total free amino acids in 45-d-old cheese made with 1·0 g
bacteriocin-producing culture/kg were 1·80-fold and 2·17-fold those in control cheese
of the same age. Inoculating milk with 1·0 g/kg bacteriocin-producing culture
reduced the level of hydrophobic peptides in the resultant cheese, increased the
concentrations of 3-methyl-1-butanal, diacetyl and acetoin, and resulted in the
highest scores for flavour quality and flavour intensity throughout ripening.
A METHOD FOR THE DETERMINATION OF FREE AMINO ACIDS IN RAT ORGANS AND TISSUES