Anthocyanin pigments are widely distributed in fruits, vegetables and colored grains. A body of evidence has shown their positive functions in human health as being antioxidant, anti-diabetic, anti-carcinogenic and ocular enhancing substances. In addition they also hold a potential as natural colorants, nutraceuticals and pharmaceuticals. Previous research in our lab has identified purple wheat bran as a promising material for the development of anthocyanin-rich products based on its high content of anthocyanin pigments, i.e. about 500-820 mg/kg subject to wheat type and bran fraction. A mechanical-chemical process using abrasive milling, solvent extraction, column chromatography and air drying was developed to isolate anthocyanin pigments from purple wheat in a powder form. Different size batches and purification packing materials (e.g. amberlite and C18) were found to produce anthocyanin powders having different appearance, yield and composition. About 24 anthocyanin pigments were detected and quantified based on HPLC analysis with cyanidin 3-glucoside being the dominant compound. Further characterization by Triple Quad mass spectrometer showed additional anthocyanin isomers and compounds. The identity of anthocyanin compounds was confirmed based on UV absorption and mass spectra. The anthocyanin powder was also characterized for gum and sugar composition by HPLC analysis without and with acid hydrolysis. Glucose and xylose were the predominant sugars in the powder which could indicate the presence of glucans and arabinoxylans. More research is underway for thorough characterization and potential applications of anthocyanin powder.

Characterization and isolation of anthocyanin pigments from purple wheat

247th National Meeting (2014)

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