Measurement and maintenance of Hibiscus sabdariffa quality

The consumption of nutraceutical foods, like Roselle extracts (Hibiscus sabdariffa) from calyces and other parts, positively influences human health and prevents several diseases. This is partly due to the activities of anthocyanins, which contain appealing colorants. Also, Roselle calyces contain substantial amounts of phytochemicals, including phenolics and flavonoids. These bioactive compounds have functional applications such as antihypertensive, antioxidants, and hyperlipidemia and against low-density lipoprotein oxidation. However, they exhibit sensitivity in ultraviolet rays, high temperatures, and oxygen, which affect the quality and consequently the longevity. Furthermore, these substances deteriorate fast when subjected to varying internal and external conditions, particularly during the preparation of certain products. Therefore, to avoid quality loss and extend the shelf life of Roselle products available, various processing techniques have been proposed. This chapter reports several processing options, including heating, encapsulation, acidification, and carrier agents, for the purposes of maintaining the quality of Roselle products and quality measurement indices. Most measurement methods are explored; emphasis is given to spectrophotometric methods, particularly 1,1-diphenyl-2-picrylhydrazyl since it is simple to use.