Effect of processing and in vitro digestion on antioxidant contents and activities in cherry tomatoes

Abstract

Cherry tomatoes are a major source of antioxidant, vitamins and minerals. However various processing methods and digestion system may lead to phytochemical change. Aims of study are to 1) compare antioxidant contents and activities of fresh and processed tomatoes. 2) compare antioxidant contents and activities before and after the in vitro digestion of fresh and processed tomatoes. Fresh cherry tomatoes were processed by hot air drying and freeze drying and then the samples were analyzed total phenolic, flavonoids, lycopene, antioxidant activities (ABTS and O₂^-) before and after the in vitro digestion. The results showed that total phenolic and lycopene contents were decreased while total flavonoids contents were significantly (p<0.05) increased by processing methods when compared with fresh tomatoes. ABTS radical scavenging activity was significantly increased in processed tomatoes (hot air drying) when compared with fresh tomatoes; however, it was not different to freeze drying tomatoes. Antioxidant activity of O₂^- in tomatoes was only significantly (p<0.05) decreased after using hot air drying method when compared with fresh tomatoes. After the in vitro digestion, it was found that total phenolic contents were decreased in fresh and processed tomatoes while total flavonoids (only in fresh and freeze drying tomatoes) and lycopene contents were significantly (p<0.05) increased. Radical scavenging activities of ABTS and O₂^- (except hot air drying tomatoes) were significantly (p<0.05) decreased after the in vitro digestion. Processing of tomatoes result in a lower tendency of antioxidant content and activities when compared with fresh tomatoes. After the in vitro digestion, most of antioxidant contents tend to increase while antioxidant activities tend to decrease compared with those before the in vitro digestion. Therefore, it should be taken into account that the processing methods and in vitro digestion highly effected on the change of antioxidant contents and activities by increasing and decreasing its level.