Fate of Pigments and Phytate During Isolation of Protein from Defatted Glandless Cottonseed Flour

ABSTRACT

In sequentially extracting proteins from defatted glandless cottonseed flour with water, salt (5% NaCl) and alkali (0.2% NaOH) solutions, high concentrations of yellow pigments resulted in watersoluble isolate (WSI), while much of the dark-brown pigments and phosphorus were found in alkali-soluble isolate (ASI) and small amounts of pigments in salt-soluble isolate (SSI). The major protein fractions of WSI and SSI contained small amounts of sugar and pigments and no phosphorus, while that of ASI contained high levels of bound sugar, dark-brown pigments and phosphorus. Yellow pigments were preferentially bound to small molecular weight proteins, but dark-brown pigments were bound to large protein molecules.