Allelic variation of polyphenol oxidase genes impacts on Chinese raw noodle color

Polyphenol oxidase (PPO) activity is a factor in time-dependent discoloration of Asian noodles. At least two major genes Ppo-A1 and Ppo-D1 control kernel PPO activity in wheat. The goal was to determine the relative importance of allelic variation for Ppo-A1 and Ppo-D1 on Chinese raw noodle color profile and kernel and flour characteristics using a winter wheat recombinant inbred population segregating for Ppo-A1 and Ppo-D1. Ppo-A1 allelic variation explained 80% and Ppo-D1 allelic variation explained 2% of the variation in kernel PPO activity. The low PPO allele at each locus gave noodles that were brighter (greater L*), more yellow (greater b*) and more red (greater a*) at 24 h, and noodles with less change in L* but more change in a* and b* with time (0-24 h). The two loci combined explained 27, 35, and 17% of variation in L*, a*, and b* at 24 h, and 51, 55, and 58% of the variation in change in L*, a*, and b* with time, respectively. Allelic variation at Ppo-D1 explained a larger percentage of variation than did Ppo-A1 in each case except b* at 24 h where the two loci explained equal amounts.