Prevention of browning in potato with a heat-treated onion extract.

The inhibitory effect of an onion extract on browning of potato was investigated. The addition of the heated onion extract to potato exhibited a marked inhibitory effect on potato polyphenol oxidase and the formation of a brown color. The inhibitory effect of the onion extract was dependent upon its heating temperature. The addition of both glycine and glucose increased the inhibitory effect of the onion extract toward potato polyphenol oxidase.