Abstract:
Citrus fruit juices have taken great attention for their health benefits with high variety of antioxidants such as phenolic compounds and flavonoids, which have protective effects against heart disease and cancers. Nevertheless, very little informations are known about the antioxidant activity of citrus fruit juices during the digestion process. The aim of this study was to examine the influence of digestive condition in gastrointestinal system on the antioxidant capacities and antioxidant compounds of citrus fruit juices including mandarin, tangerine, pomelo, orange juice concentrate, leech lime and juices. The antioxidant activity and antioxidant compounds of some citrus fruit juices both before and after in vitro digestion were evaluated by DPPH scavenging activity, FRAP assay, total phenolic contents (TPC) and total flavonoid contents (TFC). Additionally, superoxide radical scavenging activity was also determined. The results revealed that before in vitro digestion the bioaccessible total phenolic content (0.32-0.09 mg GAE/mL), total flavonoid content (2.38-9.8 mg of hesperidin/mL) and antioxidant activity DPPH scavenging activity (12.96-96.28% inhibition), FRAP value (0.08-5.52 mM/mL). Although, antioxidant compounds and antioxidant activity before in vitro digestion have highest value but the results observed that after in vitro digestion decreased the antioxidant compounds total phenolic content (0.02-0.04 mg GAE/mL), total flavonoid content (1.01-1.18 mg of hesperidin/mL) and antioxidant activity DPPH scavenging activity (24.68-72.85% inhibition), FRAP value (0.01-2.11 mM/mL) (p<0.05). Moreover, we found that orange juice concentrate had the highest inhibitory effect against superoxide radical with = 0.25±6.41%. Thus, the present study can be concluded that digestive system effect to the bioaccessibility of citrus fruit juice.