OPTIMIZATION OF PROTEIN EXTRACTION FROM PASTURE HERBAGE QUANTITATIVE AND QUALITATIVE CONSIDERATIONS

Abstract

An attempt has been made to develop a mathematical model in which by using herbage dry matter (DM) and crude protein (CP) analysis it would be possible to predict the yields of protein which may be recovered from pasture herbage during large-scale protein extraction operations. The nutritional characteristics of the leaf protein concentrates (LPC) recovered from pasture have also been studied in relation to the optimum regrowth stage as determined by the use of the designed mathematical model. The relationship between both herbage DM and CP content and protein yields, obtained during protein extraction procedures, was found to be statistically highly significant. Therefore, a simple mathematical model was designed for predicting protein yields from pastures based on these two routine analysis of herbage. It appears that a fair prediction of the protein extraction efficiency from pasture can be made before the start of a large-scale extraction operation. A three-dimensional model of protein extraction from pasture also has been built. The nutritional quality of LPC extracted from pasture in its “optimal” regrowth stage (as indicated by the mathematical model) was significantly higher than the LPC recovered from herbage cut in its earlier regrowth stages. Delay in the protein extraction, beyond the herbage regrowth considered as optimum, decreased the yields of recoverable protein but did not affect the nutritional quality of the recovered protein. The relationships presented in this paper were found to be significant only in the case of herbage processing after its previous treatment with water, i.e. when herbage was processed in the state of its physiological moisture saturation.