Phenolic constituents in major fractions of tropical rapeseed

Phenolic constituents in major fractions such as seed, cotylendons and hulls of commercial rapeseed varieties Ganyou‐5, Westar, Raya‐brown and Raya yellow grown under tropical conditions in Pakistan, were determined. Quantitative determination in percentage of sinapine, catechin, tannic acid and total phenolics as well as in absorption units at 550 nm of procyanidine, proanthocyanidine and flavan‐4‐ols in relation to different extractants such as methanol, methanol‐HCl and their totals, were made. These varieties and their fractions widely varied in different phenolic constituents in respect of extractants used. Hulls of all cultivars contained higher levels of catechin, procyanidine, pronanthocyanidine and flavan‐4‐ols while lower amounts of sinapine, tannic acid and total phenols than the cotylendons. Cotylendons and hulls in seeds of raya‐brown were exceptionally high in procyanidine.