INVESTIGATION OF CHANGES IN SOME BIOACTIVE PROPERTIES OF PHENOLIC EXTRACTS FROM PULP AND SEED TISSUES OF ZIZIPHUS JUJUBA DURING IN VITRO DIGESTION

In this study, changes in angiotensin-I converting enzyme (ACE) inhibitory, α-amylase inhibitory and antioxidant activities, total phenolic content (TPC), total monomeric anthocyanin content (TMAC) of ultrasonic phenolic extracts from pulp and seed of Ziziphus jujuba were investigated during in vitro digestion. Bioaccessible fractions of phenolics in seed and pulp extracts were calculated as 23.24±4.46% and 9.43±0.24%, respectively. Moreover, bioaccessibility for TMAC in seed extracts (147.83±9.20%) was higher than pulp (15.76±3.89%) (P<0.05). A decrease in the antioxidant activity of the extracts occurred after in vitro digestion (P<0.05). The ACE inhibitory activity of undigested extracts from seed (86.04±0.00%) was higher than that of the undigested pulp extract (42.74±8.57%) (P<0.05). The α-amylase inhibitory activity of seed and pulp extracts was determined as 49.18±0.35% and 36.07±5.83%, respectively. The results of the study showed that ACE inhibitory activity and α-amylase inhibitory activity of the polyphenolics from pulp increased after in vitro digestion.