Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: November 7, 2009
Publication Date: November 20, 2010
Citation: Fuerst, E., Anderson, J.V., Morris, C.F. 2010. Effects of polyphenol oxidase on noodle color: mechanisms, measurement, and improvement. In: Hou, G.G., ed. Asian Noodles: Science, Technology, and Processing. Hoboken, NJ: John Wiley & Sons, Inc. Chapter 12. pp. 285-312. Interpretive Summary: Many wheat breeding programs now routinely screen germplasm and breeding lines for noodle color quality potential since this is a key trait in consumer acceptability of Asian noodles. Substantial progress has been made in understanding darkening mechanisms, especially the role of PPO, and improving the color of foods made from wheat. Research overwhelmingly indicates that high PPO levels can substantially contribute to the darkening of raw Asian noodles. Reducing or eliminating PPO-based darkening via genetic improvement is a plausible goal and a proven approach for reducing darkening. The development of whole-kernel assays for PPO activity has enabled many wheat breeding programs to identify and eliminate problematic wheat lines early in the breeding process. Advances in our understanding of PPO genetics and the development of genetic markers will facilitate the development of elite breeding germplasm with near-zero PPO activity and the capability to monitor PPO genes and alleles at any stage in the breeding process. However, the elimination of PPO activity alone will not eliminate darkening due to other darkening mechanisms. Therefore, once PPO-based darkening has been minimized the question becomes “What is the next step in improving noodle color?” In part, the answer lies in determining all of the factors that contribute to the darkening process, including the potential role of endogenous inhibitors of PPO and/or inhibitors of other darkening reactions, the extent to which proteins and specific phenolic substrates contribute to darkening, and the specific reactions involved in non-enzymatic and other darkening mechanisms. All of this research would benefit from the development of small-scale high-throughput assays for color change and darkening; such assays would also enable early-generation screening of germplasm for these key traits.
Technical Abstract: Not applicable to a Book Chapter.