SEPARATION OF PROTEIN FRACTION FROM SUGAR BEET LEAVES

Sugar beet leaves are recognized as a potential source for various food applications based on specific nutritional profile and technological properties of leaf components. Furthermore, based on the large availability of sugar beet leaves generated as agricultural waste streams, there is a great economic interest in the valorization of such waste product. In this study, processing approach that aims at separating/generating enriched-protein fraction is applied. The corresponding process includes pressing of sugar beet leaves, chemical treatment of the obtained leaf juice, centrifugation and further sedimentation of the protein fraction by thermal treatment and isoelectric precipitation. The obtained protein fraction was not divided in “green” and “white” protein fraction but rather collected as a total yield which could significantly impact organoleptic properties of the final protein fraction. Total sediment obtained after final centrifugation is air dried and after crushing in mortar used for further analysis. Total amino acids content was measured as well as the content of each 17 amino acids present in the sample by using ion-exchange chromatography equipped with an automatic amino acid analyzer. Protein content was measured and calculated by using standard Kjeldahl nitrogen analyzer. Total amino acid content in the obtained dried sample was 12.48g/100g sample. Amino acids present in the largest amount were aspartic and glutamic acid, leucine, valine and arginine. Protein content measured by standard Kjeldahl method was 20.09%. Total yield of protein fraction obtained in the corresponding experiment was 5 g per 1000 g of sugar beet leaves.