AUTHOR=Ramesh S. V. , Pandiselvam R. , Shameena Beegum P. P. , Shil Sandip , Sugatha P. , Sharanya K. , Manikantan M. R. , Gopal Murali , Hebbar K. B. , Uchoi Anok , Das Alpana , Bhat Ravi , Gowda B. Hanumanthe , Kumar Prabhat 

TITLE=Valorization of coconut (Cocos nucifera L.) testa as a biocolourant

JOURNAL=Frontiers in Sustainable Food Systems

VOLUME=Volume 8 - 2024

YEAR=2024

URL=https://www.frontiersin.org/journals/sustainable-food-systems/articles/10.3389/fsufs.2024.1382214

DOI=10.3389/fsufs.2024.1382214

ISSN=2571-581X

ABSTRACT=Coconut testa, a by-product of the coconut processing industry, is currently underutilized. This study aimed to extract a coconut testa-based food colourant using various organic solvents and physical methods, and to utilize this colourant in food product preparation. Different organic solvents, along with various time and temperature combinations, were employed for colourant extraction using both a laboratory-scale water bath and ultrasonication. The colour coordinate values (CIELab) of the testaderived colourants were measured, and the colourants were screened for various phytochemicals. The in vitro antioxidant potential of the testa colourant was assessed by quantifying total phenolics, and the phytochemical composition, including monomeric anthocyanins, was evaluated. The study determined the optimal combinations of organic solvents, temperature and time to obtain extracts with maximum antioxidant activity and total phenolic content (TPC). Acidified ethanol-based extracts of testa colourants yielded highest polyphenol content (154.39±2.63 mg GAE/g) and flavonoids content (53.65±0.62 mg QE/g). Similarly, ethanol-based extractants of coconut testa produced high anthocyanin content (823.02 ±1.81 mg Cy-3-glc equivalents (C3GE) / 100g). Acidified (0.3M HCl) solvents at relatively high temperature and time combinations exhibited high antioxidant potential of testa colourant, as measured by CUPRAC, FRAP and DPPH assays. Following the foam mat drying process of the colourant, a mature coconut water-based jelly was prepared by incorporating the testa colorant extracted with acidified ethanol. Therefore, this study highlights the biochemical and antioxidant potential of the food colorant derived from coconut testa and explores its suitability for functional food applications