Antioxidant activity and stability of natural colour recovered from Roselle juice production
Biologically active phenolic compounds recovered from Roselle discarded from juice production were studied. An optimized process used to minimize the amount of waste from Roselle juice production was proposed. An attractive red colour was obtained after EtOH extraction, which was found to be the most stable at pH 3 and 23 °C throughout 10 days of storage. The Roselle EtOH extract is a potential source of gallic acid, chlorogenic acid, quercetin, caffeic acid and ferulic acid. This ecologically obtained colour is applicable for decorative aspects of pharmaceutical products including cosmetics. Roselle vale and profitability in agribusinesses will be increased by the transformation of the waste into active extracts that function as antioxidants or decorative colourants.
Natural products, including essential oils and extracts, are the main source of biologically active compounds, which can potentially promote good health conditions. In particular, residues from agricultural products are an interesting ecological resource for biologically active compounds. The application of the recovered antioxidants beyond health promotion aspects includes a decorative function as natural colourants (1, 2).
Hibiscus sabdariffa L. is an annual shrub of the Malvaceae family. It is commonly called Roselle, sorrel or karkade. The herb is widely grown in tropical and sub-tropical countries. The swollen calyces are of major commercial interest. The brilliantly red-coloured edible calyces with a sweet, slightly sour taste are harvested and sold to the herbal food and beverage industries for manufacturing such goods as tea, jelly, jam and fruit juices in Thailand and international commercial markets (3). Furthermore, the purple-red Roselle is receiving great attention as a potential colourant for food, pharmaceuticals and cosmetics (4). Roselle has been used in Thai traditional medicine due to claims of antimicrobial, hypoc ...