Changes in nutritional value of potato proteins during the preparation of potato protein concentrate from tuber sap

Abstract Nutritional value of potato proteins and its changes during the preparation of potato protein concentrates was studied. Proteins were coagulated by a heat treatment (80‐85°C) at pH 4.5, the coagulate was washed with water and spray‐ or drum‐dried. Both the chemical analyses (amino acid content, available lysine and trypsin inhibitor activity) and the biological evaluation (true N digestibility, biological value, net protein utilization) showed that no changes (with the exception of slight fluctuations during the drum drying) occurred during the technological procedure which could adversely affect the nutritional value of proteins. Protein of the products obtained had a high nutritional value, comparable with that of the soy protein concentrate.