Comparison of Phenolic Content of Easily Removed Pellicle of Japanese Chestnut ‘Porotan’ with Other Japanese and Chinese Chestnut Cultivars

Abstract

The amount of phenolic compound contained in the chestnut pellicle determines the degree of adhesiveness between the pellicle and kernel. The difficulty involved in pellicle removal in Japanese chestnut results from the accumulation of a large amount of phenolic compound in the pellicle. A new Japanese chestnut cultivar, ‘Porotan’, has a pellicle that is easily removed, like Chinese chestnut. In this study, the phenolic content of ‘Porotan’ pellicles was quantified and compared to those of Japanese (‘Kunimi’ and ‘Tsukuba’), Chinese (‘Houji 360’ and ‘Miyazakishinaguri’), and interspecific hybrid (‘Riheiguri’) chestnuts. Even though total phenolic content in ‘Porotan’ was highest among the cultivars measured, the ‘Porotan’ pellicle could be removed quickly. On the other hand, the phenolic content in a water-soluble extract, which shows the amount of phenolic compound accumulated on the inner surface of the pellicle, was low for ‘Porotan’ comparable to Chinese chestnut. Similar to total phenolic content, the phenolic content in an alcohol-soluble extract of ‘Porotan’, which shows the amount of phenolic compound accumulated in pellicle tissue, was highest among the cultivars. These results showed that the accumulation of phenolic compound on the inner surface of the ‘Porotan’ pellicle was low despite a large amount of phenolic compound in the pellicle tissue, and that the low accumulation of phenolics on the inner surface of the pellicle resulted in weak adhesion between the pellicle and kernel in ‘Porotan’.