Effect of thermal processing on antioxidant activity and in-vitro starch digestibility of pumpkin flesh
Laboratory of Agricultural Science and Biochemistry, School of Agro-Industry,
Mae Fah Luang University, Thailand
This study aims to assess phenolics, carotenoids, antioxidant activity and in-vitro starch digestibility in pumpkin after different thermal process. Pumpkin flesh was subjected to the controlled time and temperature of drying, boiling and steaming. Untreated pumpkin served as control. Results showed that all thermal process promoted losses in total phenolics and total carotenoids content and consequently, the reduction in antioxidant capacity based on FRAP and DPPH. Results showed that among thermal process, boiling best retained TPC and TCC in pumpkin. However, the antioxidant activity was the highest in hot air dried sample and steamed sample as assessed by DPPH and FRAP, respectively. It was clearly seen that thermal process decreased resistant starch content of pumpkin, resulting in the increased starch hydrolysis based on In-vitro digestion. The highest rate of starch hydrolysis was observed in boiled and steamed samples. That of hot air dry sample was the lesser. Differences were found in thermal process among samples regarding the remaining nutrients, suggesting that care should be taken in applying thermal process onto pumpkin.