Abstract
For adding a further value to carcasses of spent laying hens, which are produced annually 150,000 tons in Japan, we attempted to develop a large scale purification and concentration process of functional dipeptides in the chicken extract obtained from these carcasses by using a combination of ion-exchange chromatography and nanofiltration (NF). The functional dipeptides, Anserine and Carnosine, constituting with β-alanine and L-histidine (ACmix), show a basic property and can be adsorbed directly onto a cation exchange resin. The ACmix were completely separated from other elements when the chicken extract was passed through the column packed with a cation exchanger and the dipeptides were eluted from the column by using diluted alkaline solution. The major contaminated substances in the ACmix were Na+, K+ and creatinine. A NF can remove these contaminants and concentrate ACmix as a desirable purity without a heating process. Of thirteen NF membranes examined, three polyamide membranes were appropriate to this purpose. By using a mathematics model, we designed a NF process that can purify ACmix to 90% purity and concentrate to more than ten times. The ACmix had an antioxidant activity specifically to hypochlorite radicals and markedly reduced an oxidative stress in normal human volunteers in combination with vitamin C and ferulic acid.
