Fatty acid and amino acid profiling, antioxidant activity and other quality characteristics of vacuum packed cheddar style-yak milk cheese during ripening

This study aimed to formulate Cheddar-style cheese from standardised yak milk (casein-fat ratio: 0.7) and examined different quality parameters during 5 months ripening at 7 +/- 1 degrees C. The chemical components viz., fat, protein, ash, and salt contents, increased significantly (p<0.05), whereas the moisture content decreased considerably (p<0.05) during ripening. Similarly, pH, titratable acidity [lactic acid (% by weight)], soluble protein (%), ripening index, tyrosine value (mu g/g), total free fatty acids (mu m/g), and peroxide value (mEq of O2/ kg) increased considerably (p<0.05) during ripening. Yeast and mould count (logCFU/g) showed a significant (p<0.05) increase, while the coliform count (logCFU/g) were undetectable at the end of ripening. Further, cheese textural attributes and colour value (L*, a* and b*) also decreased significantly (p<0.05). The protein hydrolysis pattern in cheese was detected using electrophoresis. The water-soluble extracts of cheese exhibited significant antioxidant activity. Palmitic (27.2%) and oleic acid (24.4%) were the prominent fatty acids detected in higher concentrations at the end of ripening. The majority of amino acids such as glutamic acid and histidine, were also retained in the cheese. The sensory ratings of cheese significantly increased as ripening proceeded, and the formulated product was acceptable for up to 120 days.