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Effect of Excitement, Fasting, and Sucrose Feeding on Porcine Muscle Phosphorylase and Post‐Mortem Glycolysis a, b
Author(s) -
SAYRE R. N.,
BRISKEY E. J.,
HOEKSTRA W. G.
Publication year - 1963
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1963.tb00229.x
Subject(s) - glycogen phosphorylase , glycolysis , glycogen , medicine , endocrinology , biology , chemistry , zoology , biochemistry , metabolism
SUMMARY Phosphorylase activities were studied in relation to pre‐slaughter treatment, post‐mortem glycolysis, and ultimate characteristics of porcine longissimus dorsi. Total phosphorylase activity was not affected by pre‐slaughter treatment and did not appear to be associated with post‐mortem muscle glycolytic rate or ultimate muscle characteristics. The Hampshire muscles which had high muscle glycogen levels immediately post‐mortem also possessed especially high levels of total phosphorylase; however, when all breeds were considered, the within breed correlations for these two factors were not significant (p 0.05). Insufficient knowledge exists on the relation of the time course of phosphorylase activation and glycolytic rate in post‐mortem muscle. Nevertheless, extracts of porcine muscle at 10 min post‐mortem generally showed the phosphorylase to be in the b form. Short‐term excitement and exercise immediately prior to slaughter caused a rapid post‐mortem glycolysis, indicated by a rapid pH decline and decrease of color intensity in the muscle. This rapid glycolysis resulted in muscle with inferior water‐binding properties and low color and texture scores. Long‐ and short‐term sucrose feeding elevated the glycogen level of the muscle at slaughter, which ultimately resulted in muscle that was slightly soft and pale. Fasting 70 hr prior to slaughter lowered the initial glycogen content of the muscle and also slowed pH decline and color change during post‐mortem glycolysis. Correlation between pH values and the ultimate color and water‐binding properties of the muscle were significant soon after death, declining thereafter.