Pyruvate and flavor development in macerated onions ( Allium cepa L.) by γ-glutamyl transpeptidase and exogenous C-S lyase

• Published in: Food chemistry Vol. 54; no. 2; pp. 183 - 188
• Main Authors: Hanum, Tirza, Sinha, Nirmal K., Guyer, Daniel E., Cash, Jerry N.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 1995
• Subjects: Allium cepa
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/0308-8146(95)00027-G

Effect of γ-glutamyl transpeptidase in conjunction with exogenous C-S lyase on pyruvate content in macerated onion and flavor profile was studied. Pyruvate production of 2.5-fold greater than that of the control was obtained in γ-glutamyl transpeptidase and exogenous C-S lyase treated onions held for 20 h at 37 °C. Relative abundance of flavor compounds in Spartan Banner, a pungent onion, varied from a yellow sweet salad-type onion. The effect of γ-glutamyl transpeptidase and exogenous C-S lyase on onion flavor profile was shown by a shift of major components from methyl propyl disulfide, methyl propenyl trisulfide, dimethyl tetrasulfide and propyl 1-propenyl trisulfide, into new major components, methyl 1-propenyl disulfide, dipropyl disulfide, propyl 1-propenyl disulfide, methyl 1-propenyl trisulfide, and propyl 1-propenyl trisulfide. This increase in 1-propenyl containing flavor compounds may effect overall flavor of γ-glutamyl transpeptidase and exogenous C-S lyase treated onion extracts.