Fractionation of Alfalfa for Food, Feed, Biomass, and Enzymes

Freshly expressed alfalfa juice was fractionated a total of 146 times on 43 different days from 18 June to 13 October 1993 and 76 times on 20 different days from 22 July to 31 August 1994. Seasonal means, maxima, and minima for the yields of various fractions were determined as a fraction of herbage dry matter and/or juice dry matter. In addition to plant maturity, processing variables in the juice conditioning step (treatment to enhance aggregation of particulates) which were evaluated included method of heat addition, treatment temperature, and hold time. For 1993, seasonal mean dry matter yields as a fraction of herbage dry matter were: juice, 18.3%; particulate protein concentrate, 7.5%; and soluble protein concentrate, 2.7%. Yields for immature herbage (bud to early bloom stage) were about 33% higher than the seasonal means. Increase in treatment temperature, up to 45°C and increase in hold time facilitated removal of particulates by centrifugation. The method of heat addition (waterbath, microwave, AC electricity, or pulsed high-voltage DC electricity) did not generally change the yield of soluble protein.