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EFFECT OF SQUID LIVER EXTRACT ON PROTEINS AND ON THE TEXTURE OF COOKED SQUID MANTLE
Author(s) -
KOŁODZIEJSKA ILONA,
PACANA JOANNA,
SIKORSKI ZDZISLAW E.
Publication year - 1992
Publication title -
journal of food biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 47
eISSN - 1745-4514
pISSN - 0145-8884
DOI - 10.1111/j.1745-4514.1992.tb00442.x
Subject(s) - casein , squid , chemistry , mantle (geology) , food science , hydrolysis , myofibril , sarcoplasm , biochemistry , chromatography , biology , endoplasmic reticulum , paleontology , ecology
ABSTRACT The liver extract of squid Illex argentinus has a proteolytic activity at pH 2–8, with optimum at pH 2.6–3.1. At pH 6 the enzymes retain about 30 and 55% of the maximum proteolytic activity towards hemoglobin and casein, respectively. In squid mantle meat treated with the extract 24 h at 4C and 20C, the sarcoplasmic and myofibrillar proteins were hydrolyzed to low molecular fractions, as was shown by SDS‐PAGE. Soaking isolated collagen fibers in the liver extract resulted after 24 h in almost complete solubilization of the fibers in buffered SDS/urea solutions. The solubilized product contained only low molecular weight components. A significant hydrolysis of the proteins in the squid mantle, treated with the liver extract at 20 or 4C, was accompanied by a decrease in toughness of the cooked product by about 65 and 40%, respectively, as compared to the toughness of untreated cooked samples. Cooking of the mantle directly in the liver extract had practically no tenderizing effect.