Clover-grass protein by bio-refining: nutrient composition and shelf life (OK-Net EcoFeed practice abstract)

Abstract

Green protein can substantially increase the proportion of locally produced protein used in animal feed, reducing imports of soy-based protein sources. Green protein concentrate contains a high protein and amino acid content. Storage of the green protein preserves protein quality and extends its value as a feed source. Anaerobic storage on farm would be much cheaper than drying. • Protein content of the green protein concentrate was 48.5% DM on the day of harvest and the methionine (10.8g/kg DM) and lysine content (31.4g/kg DM) was optimal for both poultry and pigs. • Dry matter, ash, protein (Figure 1) and amino acid (Figures 2 and 3) content increased during storage. • Samples stored at 24°C had high concentrations of butyric acid. Butyric acid-forming bacteria, e.g. clostridia, use lactic acid as a substrate to produce butyric acid (Figure 4). It is crucial that the product maintains a good quality during storage. Concentration of lactic acid bacteria was highest in samples stored at 4 °C (Figure 5). • Shelf life of fresh green protein concentrate is limited. Under anaerobic conditions, the product is stable at: 24°C for a maximum of 2 months, at 4°C for a maximum of 3 months. • Temperature was the most significant determinant of shelf life – adding lactic acid bacteria had minimal effect. • Dried green protein has a dry matter content > 90-95%. The dry matter content of the green protein the day of harvest was 44%. To avoid microbial spoilage during anaerobic storage, reducing the water content during the bio-refining process would be desirable. • Cooperation with a bio-refinery plant is recommended to produce the clover-grass protein concentrate, for either wet or dry storage