Deliverable D1.2 New process for the extraction of protein from green biomass

Objectives

The objective of task 1.2 was to optimize the extraction conditions for protein from green biomass in a pilot plant. The experiments involved extraction of protein from ryegrass, clover, and legume without and with the addition of cell wall degrading enzymes during processing. We also studied technologies for the elimination of anti-nutritional compounds. The deliverable is based on activities in WP1 task 1.2 and has strong links to tasks 1.4, 1.5, and 1.6.

Rationale

Task 1.2 focused on optimizing the extractions conditions for protein from green biomass (i.e., ryegrass, clover, legumes) in a pilot plant. The green biomass was separated into two main streams – a liquid stream composed of soluble proteins, carbohydrates and minerals, and a fibre-rich solid stream that contains the majority of cell walls and insoluble proteins. The protein in the liquid stream was precipitated by acid following spontaneous fermentation or by heat (i.e., heat exchange, steam precipitation), and finally freeze-drying. Cell wall degrading enzymes (i.e, cellulases, xylanases, and pectinases) were selected in vitro and used to study the potential to increase the yield of protein in the pilot plant. Furthermore, the removal of antinutritional compounds in protein concentrates precipitated by acid and steam was studied. The protein concentrates and the pulp were analysed for ash, fat, protein, amino acids, and carbohydrates and the digestibility of protein in the concentrates was evaluated in vitro using the pH-stat method. The protein concentrates produced in task 1.2 were evaluated nutritionally in pigs in task 1.4 and the pulp in task 1.5.