Incorporation of Histidine and β‐Alanine into the Macromolecular Fraction of Beef Soup Stock During Heating

Beef soup stock solution was heated at 95 °C, and the macromolecular fractions were obtained by dialysis. Amino‐acid analysis indicated that histidine and β‐alanine increased. The existence of β‐alanine suggests incorporation of carnosine into the macromolecular fraction during beef extract production. To confirm the incorporation of carnosine, the macromolecular fraction was digested and the β‐alanine‐containing fraction was purified. This resulted in a tripeptide that consisted of glutamic acid, histidine, and β‐alanine which was isolated. It was resistant to an aminopeptidase and a carboxypeptidase and released glutamic acid and carnosine when treated with γ‐glutamyltranspeptidase. These results suggest that a portion of carnisone was incorporated into the macromolecular fraction and formed γ‐glutamyl‐β‐alanyl‐histidine.