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Composition of Saccharomyces fragilis biomass grown on lactose permeate
Author(s) -
Delaney Rory A. M.,
Kennedy Robert,
Walley Bernard D.
Publication year - 1975
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740260816
Subject(s) - food science , lactose , methionine , fractionation , chemistry , essential amino acid , casein , ultrafiltration (renal) , amino acid , composition (language) , biomass (ecology) , biology , biochemistry , chromatography , linguistics , philosophy , agronomy
Saccharomyces fragilis (NRRL y 1109) was grown on a medium composed of Cheddar cheese whey ultrafiltration permeate, supplemented with inorganic nitrogen. The biomass had a crude protein content of 49.5% and an ash content of 7.6%. The “true protein” content, based on a N fractionation procedure was 37.2% and the total nucleic acid content was 5.7%. Qualitatively, the amino acid composition of S. fragilis was similar to that reported for other whey‐yeasts. The quantity of individual essential amino acids was greater in the permeate grown S. fragilis. The sulphur containing amino acids, methionine and cyst(e)ine were present at a combined level of 3.2 g/16g N, compared with 2.2g/16 g N in a commercial whey‐yeast product. The chemical score (CS) and essential amino acid index (EAAI) were 58.2 and 76.0 respectively. Rats fed on a diet containing S. fragilis biomass as the sole source of dietary protein showed a net weight increase. NPU carcass for S. fragilis protein was 67.0±3.9 compared with a value of 75.3±3.0 for a casein control. Supplementation of S. fragilis biomass with DL‐methionine(2 g/16 g N) raised the NPU carcass value to 84.4 ± 2.8.