Enzymatic Modification of Wheat Proteins for Flavor Generation
Wheat gluten was modified by enzymatic hydrolysis only or in combination with enzymatic deamidation. When subjected to Maillard reaction, the hydrolysates generated important flavor compounds such as pyrazines and furans. Umamizyme or Flavourzyme was used for hydrolysis whereas Glutaminase Daiwa was used for deamidation. Isolation of volatile compounds was conducted by solid–phase microextraction (SPME) followed by identification by gas chromatography–mass spectrometry (GC–MS). Single or double enzymatic treatment produced same volatiles but in general, deamidation increased the quantities. The major pyrazines identified were methylpyrazine, 2,5-dimethylpyrazine, 2-ethylpyrazine, and 2-methyl-6-propylpyrazine whereas the major furans include 2-furfural, 2-acetylfuran, 2-furfurylalcohol, and 5-methyl-2-furfural. Although similar volatile profiles were obtained in Umamizyme and Flavourzyme systems, much greater amounts of flavor compounds were observed in the former.