Biochemical Properties of Natural Actomyosin Extracted from Normal and Pale, Soft, and Exudative Pork Loin After Frozen Storage |
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| Authors: | Haihong Wang Mary D. Pato Phyllis J. Shand |
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| Affiliation: | Authors Wang and Shand are with Dept. of Applied Microbiology and Food Science, Univ. of Saskatchewan, 51 Campus Drive, Saskatoon, SK, S7N 5A8, Canada.;Author Pato is with Dept. of Biochemistry, Univ. of Saskatchewan, Saskatoon, Canada. Direct inquiries to author Shand (E-mail: ). |
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| Abstract: | ABSTRACT: The studies of natural actomyosin (NAM) extracted from normal and pale, soft, and exudative (PSE) pork longissimus muscle stored at -20°C for up to 6 mo, revealed that the surface hydrophobicity (S0-ANS) of NAM from PSE pork was significantly ( P < 0.05) higher than that from normal pork indicating greater conformational changes in proteins from PSE meat that resulted in the exposure of hydrophobic aromatic amino acid residues on the surface. Also, the S0-ANS of NAM was a function of storage time. The equations were as follows: S0-ANS = 16.9 × storage mo + 123 for normal and S0-ANS = 17.5 × storage mo + 164 for PSE. NAM from frozen normal pork had lower α-helical content than comparable fresh pork. With extended frozen storage, viscosity of NAM from PSE meat was lower than that from normal pork. The sulfhydryl and disulfide contents were unchanged. Electrophoresis revealed an extra 95 to 100 kDa band from PSE meat NAM, possibly from α-actinin or myosin degradation. Water-binding capacity (WBC) of normal and PSE meat decreased with increasing storage time; however, there were only minor changes in thaw loss. The decrease of WBC of pork meat partially can be explained by the increase of S0-ANS observed for the NAM. These results suggest that proteins from PSE pork are more susceptible to denaturation and degradation in fresh meat and following frozen storage. |
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| Keywords: | biochemical properties hydrophobicity actomyosin frozen storage PSE |
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