Proteolysis in biceps femoris during Jinhua ham processing英文电子书.pdf

Available online at MEAT SCIENCE Meat Science 79 (2008) 39–45 /locate/meatsci Proteolysis in biceps femoris during Jinhua ham processing G.M. Zhao a, W. Tian c, Y.X. Liu a, G.H. Zhou b,*, X.L. Xu b, M.Y. Li a a College of Food Science and Technology, Henan Agricultural University, Zhengzhou 450002, PR China b College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China c College of Animal Science and Veterinary, Henan Agricultural University, Zhengzhou 450002, PR China Received 15 March 2007; received in revised form 24 July 2007; accepted 27 July 2007 Abstract Sixty experimental Jinhua hams were processed by a traditional method. The nitrogen fractions and free amino acids in biceps femoris were analyzed. Intense proteolysis was found in ham muscle and totally more than 10% of muscle proteins were degraded during the course of Jinhua ham processing. The proteolytic index of Jinhua ham was between 14 and 20. Both insoluble and soluble proteins were degraded to some degree and the later showed more intense degradation. In the soluble fraction, the percentage of non-protein nitrogen (NPN) increased gradually whereas that of protein nitrogen decreased during processing (P 0.05). However, very small amount of pep- tides larger than 1 kDa was accumulated during the whole course of processing, which proved tha