The effects of processing methods and cholesterol addition on the nutritive value of leaf protein concentrates in chicks.

Abstract

The effects of processing methods and cholesterol addition on the nutritive value of LPCs prepared from alfalfa, Italian ryegrass and ladino clover were studied in chicks. Each LPC fortified with methionine was used as a sole protein source, providing 10% protein in the diet.The washing by ethanol of thermally-treated coagulum obtained from alfalfa was effective in reducing the medicagenic acid content and improving the nutritive value, whereas this treatment had little effect on the nutritive value of Italian ryegrass and ladino clover LPCs.The adjustment of the alfalfa extract to pH 8 by NaOH had little effect on the medicagenic acid content but significantly improved the nutritive value although it was still inferior to the nutritive value of the ethanol-treated LPC.The heated and NaOH-treated alfalfa LPCs high in the medicagenic acid content had a hypocholesterolemic effect. The addition of 1.0% cholesterol was as effective as the ethanol treatment in improving the nutritive value of the heated and NaOH-treated alfalfa LPCs.The nutritive value of alfalfa and Italian ryegrass LPCs coagulated by anaerobic fermen-tation of the extract for 7 days was much lower than that of the thermally-treated LPCs. In the case of the fermented alfalfa LPC, the accumulation of medicagenic acid was observed and the cholesterol addition was not so effective.This work was supported by a grant-in-aid for Co-operative Research No. 59360036 from the Ministry of Education, Science and Culture in Japan.