Buffering Capacity and Taste of Carnosine and Its Methylated Compounds

Abstract

The effects of carnosine, anserine, and balenine on the buffering capacities and the taste of meat extracts were studied. The titration curves indicated that these dipeptides possessed strong and almost identical buffering capacities above pH 6 and required about 0.6mol NaOH/1mol to raise the pH from 6.5 to 7.5. The buffering capacities were determined on the composite simulated estracts (CSE). These were prepared by mixing authentic reagents to reproduce the natural meat extracts (ME) from the shark Lamna cornubica and the sei whale Balaenoptera borealis, which contained a considerable amount of anserine and balenine, respectively. About 90% of the buffering capacities of ME were accounted for by the amino acids, organic bases, nucleotides, organic acids, sugars, sodium chloride, and the dipeptides; among these, the dipeptides made the important contribution in the physiological pH range. Carnosine and anserine show sweetness and a slight bitterness, whereas balenine shows bitterness and a slight sweetness. However, CSE containing anserine or balenine was more meaty than that without the dipeptides. The taste profiles of consommé with or without carnosine or balenine, at three different pH's, were compared by the triangle difference test. The dipeptides enhanced only sourness at pH 5.7, but enhanced sweetness, heaviness, and thickness at pH 6.8 and 7.6. These changes in the taste profiles seemed to be due not only to the dissociation of the imidazole residue but also to the buffering capacity of the dipeptides.