Comparisons of different single-strain starter cultures for their effects on ripening and grading of Beyaz cheese

The performance and relative contribution of four single strains of lactococci (UC317, NCD0763, HP or SK11) as starters for cheese-making and ripening properties of Beyaz cheeses were compared. Gross composition, secondary proteolysis (water-soluble, 12% trichloroacetic acid-soluble, 5% phosphotungstic acid-soluble nitrogen fractions and total free amino acid contents), lipolysis (acid degree values, ADV) and cheese grading were monitored during 90 days of ripening. Chemical composition of whey samples obtained during cheese-making were found to be quite similar; however, whey samples obtained from NCD0763 or HP cheeses had the highest and the lowest pH values, respectively (P < 0.05). Acidity and pH developments were low levels in the cheeses made with NCD0763 than those of other cheeses during ripening (P < 0.05), however gross composition of all experimental cheeses were similar during ripening. Water-soluble, 12% trichloroacetic, acid-soluble, 5% phosphotungstic acid-soluble nitrogen fractions and total free amino acid contents were significantly influenced by use of different strains of lactococci and cheese age (P < 0.05). However, ADV of the cheeses were not significantly influenced (P > 0.05). The highest concentrations of soluble nitrogen and total free amino acid contents were observed in the cheeses made with NCD0763. The cheeses made with different strains of lactococci showed marked differences in cheese proteolysis during ripening.