Study of relations between chemical, colour and fluorescence properties of raw and dried meat powders of cow and yak (Bos grunniens).

Gluteus medius, Longissimus thoracis, and Semitendinosus muscles from the cow and yak (Bos grunniens) reared in the Kyrgyz Republic were dried by convective (hot air) drying and freeze drying. The dried muscles were grinded into fine powders and along with raw muscles were evaluated for water activity (aW ), chemical composition (moisture, fat, protein), colour characteristics (L, a, and b values), fluorescence of intrinsic fluorophores (tryptophan, vitamin A, and riboflavin). Processing of measured data tables using common components and specific weights analysis (CCSWA) showed close relations among the chemical, colour, and fluorescence data. CCSWA discriminated muscles depending on chemical composition, animal type, and drying technique applied based on the chemical properties, colour characteristics, and fluorescence spectra. The freeze drying was approved as a preferable dehydration technique comparing with convective drying as the one causing less discoloration to meat. Partial Least Squares Regression (PLSR) models developed using fluorescence spectra allowed accurate quantitative predicting of water activity (aW ), moisture, fat, and protein contents, and colour characteristics (L, a, and b values).