Protein effects on volatiles and sensory characteristics of a process flavor.

摘要

Wheat gluten was hydrolyzed enzymatically with an endopeptidase (SP737 Novo Nordisk Biochem, Inc., Franklinton, NC) to serve as a precursor in a patented process flavor. A large proportion of LMW, hydrophilic peptides was desired. The most satisfactory enzyme hydrolysate was produced after 4 hours at 50{dollar}spcirc{dollar}C with an E/S = 1% and initial pH = 5.5. Insoluble material losses were approximately 70%, yielding 30% soluble hydrolyzed protein. Greater than 40% of the soluble protein obtained from this hydrolysate consisted of peptides of 2-9 amino acids in length. These peptides possessed hydrophilic character. Liberation of nearly 40% free amino acids was also noted.; In addition, an acid hydrolyzed wheat gluten product was prepared for comparison. HCl hydrolysis was followed by neutralization with sodium bicarbonate and debittering and filtering with charcoal.; A patented, process chicken flavor was used to investigate protein effects on volatiles and sensory characteristics. Seventeen permutations of the hydrolysates and amino acids (alanine, glycine, histidine, proline, and valine) were used as protein precursors in the process flavor. A total of 70 different compounds were qualitatively and quantitatively identified by GC/MS. Five unknowns were also quantified. Several of the identified compounds have been previously reported in roasted chicken fat or, cooked chicken meat, and hydrolyzed vegetable protein. GC/MS results were analyzed to determine correlations between types of compounds present and various subgroupings of the 17 reactions. Correlations did not reveal any unique trends most likely because the reaction mechanisms are too complex for simple interpretation.; Correlation coefficients were calculated between specific volatiles and sensory characteristics of the 17 process flavor reactions. Meaty, sulfurous, and vegetable broth aromas and sour and bitter flavors were analyzed for correlations to twenty-five volatiles common to the seventeen reactions. Benzenoid derivatives from lipid or sugar degradation were negatively correlated to meaty and sulfurous aroma, but were positively correlated with vegetable broth aroma. Correlations between sour or bitter and the volatiles were difficult to explain as the correlated compounds are not typically associated with these flavor sensations.