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Studies on nutritive value of leaf proteins and some factors affecting their quality
Author(s) -
Subba Rau B. H.,
Ramana K. V. R.,
Singh N.
Publication year - 1972
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.2740230211
Subject(s) - biological value , protein quality , protein efficiency ratio , biology , weight gain , skimmed milk , nitrogen , net protein utilization , zoology , food science , body weight , agronomy , horticulture , botany , chemistry , organic chemistry , endocrinology
Nutritional responses in albino rats on diets containing different leaf proteins at 1.6% nitrogen (N) were studied. From the data on 4‐week growth and protein efficiency ratio ( PER ), leaf proteins from 19 different plant species were placed in 4 different categories: (1) 5 of no food value, causing loss or negligible gain in weight of rats; (2) 6 of poor quality, inducing a weight gain of less than 15 g with a PER below 1.0; (3) 3 of medium quality, inducing a weight gain of 20–35 g with PER of 1.3–1.75; and (4) 5 of good quality, inducing a weight gain of more than 40 g with a PER greater than 1.75. The last 5, all of them cruciferous leaf proteins, were nutritionally 66% as efficient as skim milk powder (SMP). The apparent digestibility ( D ) and true digestibility ( TD ) values, from experiments with either young and growing or adult rats, were close to each other for the medium and good quality categories of leaf proteins. The values differed considerably for the poor quality leaf proteins and were lower than those for good quality leaf proteins. The TD values for carrot, beetroot, lucerne and cauliflower leaf proteins in adult rats were around 40, 74, 87 and 89%, respectively, with that for SMP about 90%. The biological values ( BV ) were in a narrower range than the TD , falling between 70 and 77 in growing rats and between 55 and 59 in adults. A pre‐extraction wash of carrot vegetation decreased the ash content in extracted leaf protein, greatly enhanced its digestibility without changing its BV , while a hot acid wash of the heat coagulated leaf protein caused some improvement in BV but none in digestibility. Among different leaf proteins, the nutritional inferiority was also associated with reduced diet intake, suggesting adverse acceptability factors. Various analyses suggested that the likely factors, singly or in combination affecting the quality of leaf proteins adversely, were associated with the occurrence of low N, high ash, high soluble solids, high phenolic: N ratios, and/or low organic sulphur: N ratios.