Stability to Heat, Hydrogen Peroxide at Different pH Values and Antioxidant Activity of Terminalia nigrovenulosa Extract

The aim of this study is to investigate the stability of Terminalia nigrovenulosa (T. nigrovenulosa) extract to heating, hydrogen peroxide at pH 4 and pH 7. The changes of total polyphenol content, DPPH radical scavenging and reducing power were examined. The results indicated that the investigated extract is relatively stable to heating and sterilization conditions at pH 4 but unstable at pH 7. In addition, hydrogen peroxide also adverse effects to total polyphenol content, DPPH radical scavenging activity and reducing power are total different at pH 4 and pH 7. It was more stable at pH 4 than that at pH 7. Moreover, extract solution contained higher total polyphenol contents possessed stronger DPPH radical scavenging activity and reducing power. Thus, polyphenol compounds were responsible for the antioxidant activity of extracts. It indicated that the extract has potent use as an antioxidant additives in the food system, particularly at acid pH.