The Effect of Traditional Cooking and In Vitro digestion on Total Phenolic and Antioxidant Activity of Selected Thai Local Plants

Abstract

The effect of traditional cooking and in vitro digestion were investigated in four Thai local plants—Sum rong (Scaphium scaphigerum Wall.), Kum nam (Crateva magna Lour.), Cha muang (Garcinia cowa Roxb.), and Cha kram (Suaeda maritima L.)—on total phenolic content, total flavonoid content, and antioxidant activity (DPPH, ABTS and FRAP assay). The results showed that before cooking, Cha muang had the highest antioxidant activity in DPPH, Cha kram had the highest antioxidant activity in ABTS, and Kum nam had the highest antioxidant activity in FRAP. Surprisingly, after boiling for 60 minutes, Kum nam had the highest antioxidant activity in DPPH, ABTS, and FRAP. Furthermore, total phenolic and total flavonoid content after cooking of Kum nam, Cha muang, and Cha kram were decreased. However, cooked Sum rong had positive effects on total phenolic and total flavonoid content, and with 60 minutes cooking, Sum rong has the highest content in phenolics and flavonoids. Additionally, four vegetables after cooking also had antioxidant activity, consisting of DPPH, ABTS, and FRAP. After in vitro digestion, the total phenolic and total flavonoid content of Sum rong, Kum nam, and Cha muang were increased in range 4%-15% except for Cha kram. Moreover, the antioxidant activity in DPPH and ABTS after digestion of four plants was increased. However, the FRAP value of four plants after digestion was decreased. These results demonstrated that cooking condition and in vitro digestion effect on the polyphenols, flavonoids, and antioxidant activity

Keywords

• sum rong
• kum nam
• cha muang
• cha kram
• antioxidant activity