Fractionation of forage legumes using a screw press

Summary

Technical advances in fractionation and biorefining of grassland crops may allow farmers to produce feed for monogastrics and ruminants. The objective of the present work was to quantify yields of juice and pulp from different forage legumes. We established field trials with plots of monocultures of lucerne, red clover and alsike clover in Röbäcksdalen, Sweden and Tingvoll, Norway in 2018. We harvested the crops three times in Röbäcksdalen and four times in Tingvoll in 2019 and used a twin-gear screw press to separate juice and pulp. Red clover had the highest total yields, with higher yields in Sweden than Norway. In Norway, the average dry matter (DM) content in juice was 10.7% and in pulp 33.0%. Juice accounted for 43.8% of DM on average. Lucerne had lower juice DM proportion than the clover species. No effects of harvest number on juice DM proportion were found. These preliminary results indicate that clover species yield more juice and less pulp, compared with lucerne. Quality analyses will be carried out to estimate feed value of both fractions.