Effects of in vitro Human Digestion on the Antioxidant Activity and Stability of Lycopene and Phenolic Compounds in Pork Patties Containing Dried Tomato Prepared at Different Temperatures.

The antioxidant activity can be changed during digestion. The effects of in vitro human digestion on the antioxidant activity and stability of tomato powders (TPs), dried at three different temperatures (60, 80, and 100 °C) and added to pork patties (1% TP by weight), were investigated. The pork patties with three TPs underwent in vitro human digestion with enterobacteria. Lycopene and individual phenolic compounds were analyzed by using HPLC. The highest total phenolic compounds (6.96 g/100 g) and lycopene concentrations (2.68 mg/100 g) were observed in pork patties with TP dried at 100 °C. In addition, antioxidant activity of pork patties containing TPs were measured during in vitro human digestion. Gallic acid (23.8 to 41.6 g/100 g), chlorogenic acid (11.2 to 25.7 g/100 g), and caffeic acid (11.1 to 21.7 g/100 g) were detected as the main phenolic compounds in the TPs. Lycopene, and total and individual phenolic compound contents increased with increasing drying temperatures. Moreover, in vitro human digestion increased the antioxidant activity of TP-containing pork patties. The lycopene and total phenolics contents were increased during in vitro human digestion with enterobacteria by 146% to 220% and 1549% to 2095%, respectively as compared to the samples of before digestion. Hence, we hypothesized that the antioxidant activity of each TP increased during in vitro human digestion and depended on the amount of lycopene and phenolic compounds released. The TP dried at the highest temperature (100 °C) had the highest antioxidant activity in pork patties during in vitro human digestion.

PRACTICAL APPLICATION: In this study, we revealed that in vitro human digestion increases the antioxidant activities of tomato powder. In addition, tomato powder dried at the highest temperature (100 °C) showed the highest antioxidant activity. Therefore, tomato powder at 100 °C could be used as strong antioxidants in meat products.