OHMIC HEATING INCREASES BIOACTIVE COMPOUNDS AND DECREASES THE THERMAL LOAD MARKERS IN PREBIOTIC CHOCOLATE-FLAVORED WHEY BEVERAGE

Bioactive compounds values (DPPH, ACE, α-amylase, α-glucosidase inhibition, total phenolic compounds [TPC]) and thermal load markers (hydroxymethylfurfural and the whey protein nitrogen index [HMF and WPNI]) of prebiotic chocolate-flavored whey dairy beverages (70:30 % v/v pasteurized milk/sweet whey, 3.0 w/v % galactooligosaccharide) submitted to ohmic heating (30V, 100,200,300 Hz, OH31, OH32, OH33 and 60V, 100,200,300 Hz, OH61, OH62, OH63, 72-75°C/15-20s) or conventional processing (PAST, 72-75°C/15-20s) along a beverage without any processing (CONTROL) were evaluated. Ohmic heating technology generated higher values for all bioactive compounds (p<0.05) compared to the product treated by PAST or CONTROL. Lower frequencies (OH31 and OH61) showed the highest antioxidant activities (67.1 and 78.2% DPPH inhibition, respectively; p < 0.05). Regarding ACE inhibitory activity, α-amylase and α-glucosidase, the opposite was observed, where treatments with higher frequencies (OH65, OH35, and OH63; p < 0.05) showed superior results. PAST presented the highest HMF value (20.04 µmol/L), differing from all the samples treated by OH (p <0.05), in which higher frequencies and voltages presented lower concentrations of HMF. For WPNI, the lowest values were observed for PAST when compared to OH treatments (p<0.05). OH is an interesting technology to increase the bioactive compound levels of prebiotic chocolate-flavored whey dairy beverages.