Determination of the proportion of κ-casein hydrolysed by rennet on coagulation of skim-milk

Autor:	Brian Chaplin, Margaret L. Green
Rok vydání:	1980
Předmět:	animal structures food.ingredient Chromatography Chemistry food and beverages General Medicine Micelle Hydrolysis fluids and secretions food Clotting time Casein Skimmed milk Coagulation (water treatment) Animal Science and Zoology Rennet Polyacrylamide gel electrophoresis Food Science
Zdroj:	Journal of Dairy Research. 47:351-358
ISSN:	1469-7629 0022-0299
DOI:	10.1017/s0022029900021245
Popis:	SummaryA method has been developed for quantitative determination of para-κ-casein, involving spectrophotometric scanning of stained protein bands following polyacrylamide gel electrophoresis. The rate of hydrolysis of κ-casein in skim-milk at pH 6·6 and 30 °C was compared with that in EDTA-treated skim-milk under the same conditions. This showed that at the visually observed clotting time, at least 90% of the total κ-casein in milk had been hydrolysed. The time course of the reaction was consistent with all the κ-casein molecules being hydrolysed with the same efficiency. The results strongly suggest that essentially all of the κ-casein in milk is equally accessible to rennet action. This is consistent with the casein micelle being porous, or having all the κ-casein on the surface.
Databáze:	OpenAIRE
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