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THE MORPHOLOGY AND PHYSIOLOGY OF TWO LACTOSE‐FERMENTING YEASTS AND CHEMICAL CHANGES DURING THE RIPENING OF CHEESE FROM MILK CONTAINING THEM
Author(s) -
ALLEN L. A.,
THOENLEY B. D.
Publication year - 1929
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1929.tb07635.x
Subject(s) - lactose , biology , yeast , fermentation , casein , food science , ripening , proteolysis , biochemistry , enzyme
Summary. Two lactose‐fermenting yeasts isolated from cheese have been described and though markedly similar in many respects they have been referred to separate species, the one being a Torula whose close relationship could not be definitely established, and the other being a true yeast believed to be correctly identified with Zygosaceharomyces lactis (Dombrowski). The two yeasts have been found to have an appreciable proteolytic effect on the casein of milk after several weeks. The effect of one of the yeasts alone and of the yeast plus Streptococcus lacticus on the lactose of milk has also been studied. Cheddar cheese inoculated with the yeasts has been found to differ considerably in quality and texture from the control cheese. A comparative study of the extent of protein degradation in two ripe cheeses, one inoculated with the Torula and one control, has shown the proteolytic effect of the yeast in the course of ripening. The authors wish to express their thanks to Dr S. G. Paine for his constant interest and help in this work, and to Mr A. T. R. Mattick for many valuable suggestions.