ENZYMATIC HYDROLYSIS OF PUMPKIN SEEDS AND ITS EFFECTS ON RECOVERY OF COMPOUNDS WITH ANTIOXIDANT POTENTIAL

It is very common to discard seeds during food consumption, although for some plant species, the use of seeds is part of eating habits, as is the case with pumpkin seeds. Due to the nutritional content and bioactive compounds, the seeds are also used for nutritional enrichment of other foods. Seeds of the pumpkin species Cucurbita maxima (Cmax) and Cucurbita moschata D. (Cmos) were used as substrate to hydrolysis using three enzymes with different catalytic actions (Flavourzyme® 500L – protease; Cellucast® 1.5L – cellulase; Viscozyme® L – mixture of carbohydrases) that were evaluated singly or in binary/ternary combinations according to an experimental design. Suspensions of 50 mL containing seed flour at a concentration of 5% (w/v) were dispersed in 100 mmol/L acetate buffer pH 5 in which 0.5% (v/v) of the enzymes was added. The reaction mixture was incubated at 45ºC under agitation of 100 rpm for 120 min. The control assay was performed under similar conditions for hydrolysis but without enzymes. After the treatments, the total phenolic content (TPC) and antioxidant activity (ABTS, DPPH and FRAP) were evaluated. The results for TPC showed that the enzymatic treatments applied were efficient, allowing increase in the recovery of phenolic compounds ranging from 81 to 272% for Cmos and from 104 to 225% for Cmax compared to the control. For antioxidant activity, the hydrolyzed material obtained using Flavourzyme® in isolation for Cmos species showed the highest increases compared to the control, as follows: i) 86% for ABTS; ii) 142% for DPPH and 266% for FRAP. Regarding to the Cmax species, it was observed that the combination of Flavourzyme® and Viscozyme® in equal proportions resulted in hydrolyzed seeds with the highest increases in antioxidant activity, asfollows: i) 28% for ABTS; ii) 186% for DPPH and iii) 190% for FRAP, compared to the control.