The production of food-grade protein matrix enriched with polyphenolic compounds from cranberry

Abstract

The technology of innovative functional foodstuffs (FFSs) for the prophylaxis of type 2 diabetes involves supplementation with polyphenols (PPs) featuring hypoglycemic and/or hypolipidemic properties. The aim of the study presented was to develop an approach for the enrichment of food-grade protein matrix (PM)–coagulated egg albumen (CEA)–with PPs absorbed from cranberry juice (CJ). Concentration of total polyphenols (TPP) in gallic acid equivalents was determined using the Folin-Ciocalteu method. Concentration of total anthocyans (A) in cyanidin-3-glucoside equivalents was determined using pH-differential spectrophotometry; profile of individual anthocyans was determined according to State Standard GOST 32709-2014. Concentrations of simple saccharides (SS) were determined by the reverse-phase HPLC. The PPs from 100 ml portions of CJ with different juice concentration were sorbed by 10 g portions of CEA. After preliminary incubation and centrifugation the precipitates were lyophilized. The sorption rates of TPP and A were determined as a difference between the initial concentration in cranberry juice and in corresponding supernatants after centrifugation. The quantification of TPP and A in the lyophilized precipitates involved triple elution by 1% solution of HCl in 80% ethanol at 55° C and subsequent ultrasound treatment. Maximal specific sorption for TPP and A from 100% CJ was 14.0 mg-eq. of gallic acid/g and 1.48 mg/g, respectively. Sorption rate for SS on the CEA was 30.3±3.1% of their initial concentration in CJ. The TPP/SS ratio in the enriched PM was 2.0 times higher as compared to CJ. The results of the study can be used in the development of new FFSs with antidiabetic properties.