Divergent selection for polyphenol oxidase and its influence on agronomic, milling, bread, and Chinese raw noodle quality traits
Martin, J.; Berg, J.; Fisher, A.; Jukanti, A.; Kephart, K.; Kushnak, G.; Nash, D.B.uckner, P.
Crop science 45(1): 85-91
ISSN/ISBN: 0011-183X Accession: 004110938
Polyphenol oxidase (PPO) (EC.220.127.116.11) activity has been shown to be related to time-dependent discoloration of Asian noodles. Our objective was to determine the impact of divergent selection for PPO activity on agronomic, milling, bread baking, and Chinese raw noodle quality traits in winter wheat (Triticum aestivum L.) populations. Progeny from seven winter wheat populations were selected for high or low PPO activity by the L-3,4-dihydroxyphenylalanine (L-DOPA) assay on whole kernel meal on the basis of a single replication with equal number of high and low lines in each population. The selected lines were evaluated in replicated trials in multiple environments. Agronomic, milling, bread baking, and Chinese raw noodle traits were measured for all entries. The high versus low PPO classification was confirmed from replicated trials with no overlap between low and high PPO lines for any of the populations. Divergent selection had no impact on agronomic traits except for heading date where low PPO lines averaged 1 d later to head than high PPO lines. Flour ash averaged 0.11 g kg(-1) higher for low compared with high PPO lines, but flour protein and flour yield did not differ between groups. The low PPO selection group had weaker dough, as reflected by lower mixograph tolerance, and lower crumb grain scores. Chinese raw noodle texture was altered by divergent selection so that the low PPO group produced noodles that were less elastic, sticky, and chewy than the high PPO group. Chinese raw noodles became darker (lower L*), more yellow (greater b*), and more red (greater a*) with time. Low PPO lines averaged less change in L* (8.9 vs. 9.6) but more change in b* (-7.70 vs. -7.02) and a* (-0.74 vs. -0.62) than high PPO lines over 24 h. Whether these changes in noodle color and texture are desirable may depend on the type of noodle and regional and personal preferences.