Kluyveromyces fragilis fermented whey was spray dried and the protein quality of dried product was assayed by aminoacid analysis and three biological methods: Protein Efficiency Ratio (PER), Net Protein Ratio (NPR) and Net Protein Utilization (NPU). Aminoacid analysis using casein and FAO protein as standards had a high level of lysine (65.6mg/g protein) and low levels of methionine (14.9mg/g protein) and valine (45.8mg/g protein). Biological evaluation of dried fermented whey protein, using 24 weaned rats, 23 days of age, during four weeks, using casein as standard protein, resulted in PER, NPR and NPU, 19.75%, 46.33% and 26.54%. Nutritional quality of the dried fermented whey protein was lower than the casein protein.
protein quality; Kluyveromyces fragilis; yeast protein; food yeast; whey
