Presenter Information

M Ohshima, Kagawa University

Publication Date

1985

Location

Kyoto Japan

Description

SUMMARY To determine the effect of heat-treatments on the nutritive value of leaf protein concentrate(LPC), several LPCs prepared by different procedures were fed to rats. The nutritive value of ladino clover LPC separated centrifugally from acidified juice and freeze-dried was compared with that of LPC prepared from the same acidified juice by heating to 70°C with an electric heater before the centrifugation and oven-dried at 70°C. The heat-treatments reduced not only the apparent digestibility of crude protein by 5%, but also the nutritionally available lysine content of LPC. Response of rats to lysine supplementation in addition to methionine was observed in the heat-treated LPC, but was not observed in the unheated LPC. To know whether the above thermal damage had derived from the coagulation process or the drying process, oven-dried and feeze-dried Italian ryegrass LPCs were prepared from the same heat-coagulum and were compared their nutritive values using rats. The heat-coagulation process had little effects on the available lysine content of the LPC. While oven-drying reduced not only the digestibility of crude protein by 3%, but also the available lysine content of the LPCs. In the previous study, anaerobically fermented ryegrass LPC was found to be lower by 12% in the digestibility of crude protein but similar in the nutritionally available lysine content compared with non-fermented ryegrass LPC, when both the LPCs were oven-dried. In the present study, it was made clear that both the fermentation and the oven-drying process were responsible to the reduction of the digestibility but the lowering of the lysine availability could be attributed only to the fermentation process.

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Effect of Drying Methods on the Nutritive Value of Leaf Protein Concentrates Coagulated by Acidification, Heat or Anaerobic Fermentation

Kyoto Japan

SUMMARY To determine the effect of heat-treatments on the nutritive value of leaf protein concentrate(LPC), several LPCs prepared by different procedures were fed to rats. The nutritive value of ladino clover LPC separated centrifugally from acidified juice and freeze-dried was compared with that of LPC prepared from the same acidified juice by heating to 70°C with an electric heater before the centrifugation and oven-dried at 70°C. The heat-treatments reduced not only the apparent digestibility of crude protein by 5%, but also the nutritionally available lysine content of LPC. Response of rats to lysine supplementation in addition to methionine was observed in the heat-treated LPC, but was not observed in the unheated LPC. To know whether the above thermal damage had derived from the coagulation process or the drying process, oven-dried and feeze-dried Italian ryegrass LPCs were prepared from the same heat-coagulum and were compared their nutritive values using rats. The heat-coagulation process had little effects on the available lysine content of the LPC. While oven-drying reduced not only the digestibility of crude protein by 3%, but also the available lysine content of the LPCs. In the previous study, anaerobically fermented ryegrass LPC was found to be lower by 12% in the digestibility of crude protein but similar in the nutritionally available lysine content compared with non-fermented ryegrass LPC, when both the LPCs were oven-dried. In the present study, it was made clear that both the fermentation and the oven-drying process were responsible to the reduction of the digestibility but the lowering of the lysine availability could be attributed only to the fermentation process.