An investigation into some causes of the differences of protein expressibility from leaf pulps

On a laboratory scale, changes in expressibility of protein with age from leaf pulp of lucerne, amaranth, garden orache, sunflower, fat hen, dock and field beans were not closely correlated with changes of fibrous dry matter, cell robustness, pH or tannin content. However, for amaranth, garden orache and fat hen, a strong correlation was found between protein expressibility and the proportion of the total leaf water that was expressed. This suggests that expressibility from those species was determined more by the proportion of leaf water that was expressed as juice than by the concentration of protein in the juice. Interspecific differences of protein expressibility between fat hen, amaranth, sunflower, beans and pea, all at the same age, were strongly correlated with differences in leaf tannin content. However, garden orache was also examined and it did not fit the pattern established by the other crops. Therefore, the correlation exhibited by the other crops may not be general.