Pacheco M T, Caballero-Córdoba G M, Sgarbieri V C
Faculdade de Farmácia, Universidade Federal de Goiás, Goiânia, S.P., Brasil.
J Nutr Sci Vitaminol (Tokyo). 1997 Dec;43(6):601-12. doi: 10.3177/jnsv.43.601.
Yeast biomass (Saccharomyces sp.) produced in local breweries as a by-product was utilized in this study. Percent proximate composition, amino acid composition, and protein nutritive value were determined for the yeast cell biomass (YC), a sodium perchlorate extracted and isoelectrically precipitated protein concentrate (P-PC), and a sodium trimetaphosphate treated extract followed by isoelectrical precipitation (TMP-PC). Protein concentrates averaged 75% protein as compared to 48.5% in the yeast biomass. Precipitation of the protein in the presence of either sodium perchlorate or sodium trimetaphosphate was reduced to 71% and 51% of the cell RNA content, respectively. Protein nutritive value was 70% of casein when measured by the protein efficiency ratio (PER), and over 90% of casein when net protein utilization (NPUa) was the criteria of evaluation.
本研究利用当地啤酒厂作为副产品生产的酵母生物质（酿酒酵母属）。测定了酵母细胞生物质（YC）、经高氯酸钠提取和等电沉淀的蛋白质浓缩物（P-PC）以及经三聚偏磷酸钠处理后再进行等电沉淀的提取物（TMP-PC）的近似成分百分比、氨基酸组成和蛋白质营养价值。蛋白质浓缩物平均含蛋白质75%，而酵母生物质中蛋白质含量为48.5%。在高氯酸钠或三聚偏磷酸钠存在下蛋白质的沉淀分别降至细胞RNA含量的71%和51%。以蛋白质效率比（PER）衡量时，蛋白质营养价值为酪蛋白的70%，而以净蛋白质利用率（NPUa）为评价标准时，超过酪蛋白的90%。
