Abstract
For determining the vegetative factors affecting the yields of leaf protein concentrate (LPC), fibrous residue (FR) and brown juice (BJ) in the fractionation of green crops, the relation between the composition of material crops and that of the three process fractions were examined using twice cuts of Italian ryegrass, thrice cuts of lucerne and red clover and single cut of oats. After cutting, the crops were minced with a pulper and then squeezed with an oil-jack press to separate them into green juice (GJ) and FR. The GJ was acidified to pH 4 with HCl, heated to 70℃ and then divided into coagulate (LPC) and BJ through Toyo No.2 filter paper under sucking. The yields of LPC and FR were highly correlated with the moisture, crude protein and crude fiber contents of the crops. The signs of the correlation coefficients were oposite between LPC and FR. The regression equation showed that the moisture, crude protein and crude fiber contents of crops should be over 87% as is, over 20% and less than 24% of dry matter, respectively, to recover more than 12% of the dry matter in LPC. The dry matter distribution in BJ was highly correlated with the moisture content of crops and subsequently with the yields of GJ. When twice or thrice harvests were made, the yields of LPC per acre depended on the yields of crops rather than the kinds of them. LPC contained from 44 to 62% crude protein on dry matter basis regardless of the recovery rates. The composition of FR was highly correlated with that of the crops. As the result, FR from crops ensuring high LPC yield contained enough crude protein for cattle growth. The NFE content of BJ was about 50% of dry matter and significantly correlated with that of the crops.
