Chapter 13 - Conventional and rapid methods for measurement of total bioactive components and antioxidant activity in Hibiscus sabdariffa

Abstract

Roselle (Hibiscus sabdariffa) is used as folk medicine and food as well. Being high in anthocyanin, Roselle calyces are both a good colorant and potentially a good source of antioxidants. Bioactive components and antioxidant activity are considered as an important quality index of Roselle. Many attempts have been carried out to establish a highly sensitive and selective analytical tool for quantitative determination of polyphenols. The aim of this chapter is to provide information on the most techniques modern and conventional methods used in the investigation of total polyphenols and antioxidant activities. The concentrations of total phenol content, total flavonoid content, total antioxidant content, ferric reducing antioxidant power, anthocyanins, and 1,1-diphenyl-2-picrylhydrazyl of Roselle can be predicted accurately using near-infrared spectroscopy (NIRS). The overall review suggests that there is a great potential for the field application of NIRS to be used for in situ and nondestructive determination of bioactive components and antioxidant activity in Roselle.