Study of the Inhibitors of Cooked Off-Flavor Components in Heat-Treated XiZhou Melon Juice

This research applied inhibitors to reduce the content of cooked off-flavor components (dimethyl sulfide, dimethyl disulfide, dimethyl trisulfide, and 3-(methylthio)propanaldehyde) in heat-treated melon juice. The effects of glucose oxidase (GOD) on the formation and release of these four volatile sulfur compounds were also investigated. Results showed that GOD strongly inhibited the formation of the four compounds. In GOD-treated melon juice, S-methylmethionine was strongly protonated and not easily degraded into dimethyl sulfide. Moreover, the release of the dimethyl sulfide that did form was restrained by the hydrophobic interactions of gluconic acid and oxidation by hydrogen peroxide. In addition, gluconic acid (or glucose) and hydrogen peroxide could form a stable complex with methionine in an acidic matrix and thus prevented the methionine from producing 3-(methylthio)propanaldehyde, dimethyl disulfide, and dimethyl trisulfide by the Maillard reaction during heat processing.