Fractioning of the sunflower flour components: Physical, chemical and nutritional evaluation of the fractions

Abstract

Reduced phenolic content products were obtained from defatted sunflower flour using a process designed to make an integral use of the components. In order to eliminate the phenolic compounds, the flour was extracted at pH 5 with extractor solutions: 70 mL/100 mL ethanol, 0.1 g/100 mL sodium bisulfite and a 70:30 mixture of the two. The raw material, protein isolate and fibrous concentrate were chemically characterized. The protein isolates were evaluated for protein extraction yield, protein solubility, heat stability and nutritional properties (chemical score, digestibility, PDCAAS). The fibrous concentrates from the extraction with bisulfite presented 60.84 g/100 g fiber and 35.67 g/100 g protein. The protein isolates result in protein contents above 92.00 g/100 g and phenolic compounds content below 0.45 g/100 g. All showed elevated protein solubility (>84.22%) and in vitro digestibility (>90.00%). The residual phenolic compounds content interfered with the digestibility and coloration of the isolates. The feasibility of the process for the prior extraction of the phenolic compounds to obtain high protein and nutritional value products was demonstrated. The mixture of bisulfite and ethanol was the most promising to obtain the isolate, and bisulfite solution was the best for the co-production of the fibrous concentrate