Proteolysis in Cheddar Cheese Made with Sodium Chloride, Potassium Chloride or Mixtures of Sodium and Potassium Chloride

Abstract

Cheddar cheese from a split lot of cheese curd was prepared with or without added NaCl, KCl or mixtures of NaCl/KCl (2:1, 1:1, 1:2 and 3:4, all on wt/wt basis) to achieve final salt concentrations of approximately 15.0 or 17.5 g/kg. Cheeses were ripened at 3 ± 1°C and proteolysis was determined over a 36 wk period. Peptide material soluble in trichloroacetic acid (120 ml/L) (TCA sol-N) and free amino acids measured as phosphotungstic acid-soluble amino N (PTA sol-amino N) increased in all cheeses during ripening through 36 wk. There were no significant (P > 0.05) differences attributable to various salt treatments in levels of TCA sol-N and PTA sol-amino N of cheeses tested after 12, 24 and 36 wk of ripening. Unsalted cheese generally had more proteolysis than salted cheeses. Peptide extracts of selected cheeses from trials 1 (made with Lactococcus lactis subsp. lactis and L. lactis subsp. cremoris) and 2 (made with L. lactis subsp. lactis) were chromatographed using a Sephadex G-25 column. Sensory evaluation indicated that only eluent fractions of cheeses from trial 1 were slightly to markedly bitter. In trial 2, fractions from unsalted cheese were slightly bitter and those from cheeses made with NaCl or NaCl/KCl mixtures were not bitter. Thus it is unlikely that KCl was responsible for bitterness in cheeses of trial 1.