Pilot Scale Ultrafiltration of Clarified Alfalfa Juice

Pilot scale ultrafilter units were tested for use in concentrating and Purifying soluble alfalfa leaf protein solutions. Tubular and hollow fiber type units with noncellulosic membranes were employed. Operating temperature was generally maintained at 10° C because of microbial growth and precipitation of the heat labile protein at higher temperatures. Higher permeation rates and lower protein losses were obtained with the tubular unit. Concentrating the clarified alfalfa juice to 1/10 of the original volume produced protein concentrates containing about 50% crude protein and 10% ash. Diafiltration of the clarified alfalfa juice until the permeate volume was 10 times the original sample volume resulted in products containing 70–76% protein. Although diafiltration removed more than 86% of the orthodihydroxy phenolic compounds, the dried protein products were tan colored.