Infl uence of Thermal Sterilization on Antioxidant Capacity and Total Phenolics of Spicy Thai Foods

Abstract

Two different styles of spicy Thai food were developed. The fi rst group were sauces for readyto-cook products—‘Mee Kathi’ sauce (MeKa), ‘Phat Mee Paktai’ sauce (PMeP), ‘Phat Khimao’ sauce (PKhi). ‘Kaeng Khua’ sauce (KK), ‘Om Isan’ sauce (OmIs), ‘Chu Chi’ sauce (CC) and ‘Homok’ sauce (HoM). The second group was ready-to-eat foods—‘Khao Soi Nuea’ (KSoi), ‘Mu Phat Phrik Khing’ (PPK) and ‘Khua Kling Mu’ (KKM). These foods and sauces were each packed in a stand-up type aluminum pouch and were heated at 120 °C for an appropriate time of 15, 25 or 30 min. The antioxidant capacity of the methanol extracts obtained from the sterilized food samples ranged from 5.77 to 42.11 mg vitamin C equivalent per 100 g and the total phenolic content of these foods ranged from 27.73 to 145.93 mg gallic acid equivalent per 100 g. Five selected foods, MeKa, KSoi, PKhi, PPK and KKM, were studied for the infl uence of heat on natural antioxidants to scavenge the 1, 1-diphenyl-2-picrylhydrazyl radical and for changes of the phenolic content. The results showed that the antioxidant capacity in KSoi, KKM, MeKa and PPK was enhanced by amounts of 3–113% and the phenolic content was increased in all products, by amounts of 4–52%.