Variable polyphenol oxidase (PPO) activity indicates grain quality in bread wheat (Triticum aestivum L.)

Wheat (Triticum spp.) is one of the important cereals in the world. Discoloration of wheat grains and accumulation of by product due to polyphenol oxidase (PPO) activities is an important problem faced by food industries. In this study, seeds of 115 Indian bread wheat cultivars representing different six agroclimatic zones were screened for their PPO activities using different PPO substrates, like caffeic acid, catechol, tyrosine and L-DOPA. Among these substrates, L-DOPA was found as best substrate to detect PPO activity. Highest PPO activity with L-DOPA was found in wheat cultivar HS 207, while lowest was detected in HP 1633. Among different agroclimatic zones, seeds of 40% of the cultivars representing NWPZ showed low PPO activity (< 10 unit min−1 g−1) with an average value of 14.22 unit min−1 g−1 and 38% cultivars of NEPZ had low PPO activity with the mean of 13.56 unit min−1 g−1. Therefore, wheat cultivars form NWPZ and NEPZ can be used for producing wheat byproducts. © 2018, Indian Society for Plant Physiology.