Occurrence and evolution of amino acids during grape must cooking

A study of the involvement of amino acids and other amino compounds in sugar degradation during mustcooking was pursued. Two white musts (Trebbiano toscano and Spergola) and a red one (Lambrusco)were cooked by means of a lab-scale equipment emulating the real process.Must composition and amino compound concentration were studied in order to understand the modificationsinduced by the heating process.Results showed that amino acids and related compounds tend to decrease at different rates during the30 h of the cooking process. The behaviour of nitrogen compounds was studied by the ratio between initialand final concentrations, and by plotting amino compound concentrations vs. time. In both cases theeffect of concentration was considered to eliminate its influence on discussion.Principal Component Analysis (PCA) clearly showed how time and heating produced similar trendsduring the cooking process of the different musts. The initial differences in composition characterisedthe whole process, and samples of each must were clearly apart from the other ones.