Effect of solvent extraction on the nitrogen compounds in alfalfa protein concentrates
1995
Hernández, M. Teresa | Centeno, Carmen | Martínez, Carmen | Hernández, Amelia
Freezing curd prepared from alfalfa juice, untreated or washed in water, was extracted with 2-propanol. Protein and non-protein nitrogen, crude protein, and amino acids were determined in unextracted concentrate and in the two extracted concentrates to examine the effect of extraction on its content. Direct extraction of unwashed freezing curd with 2-propanol increased the protein content by 15% but did not affect the percentage of non-protein nitrogen, which accounted for 10% of the total nitrogen; washing in water before extraction with 2-propanol yielded a 19% increase in the protein content and lowered the percentage of non-protein nitrogen by half. The amino acid profiles were similar for all three concentrates. However, the effect of extraction and washing on the individual amino acids differed, the most notable effect being the substantial increase in methionine in the extracted concentrates. The amino acid scores calculated on the basis of the amino acid composition were indicative of high protein quality of the extracted concentrates.
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