Rapid separation of carotenes and evaluation of their in vitro antioxidant properties from ripened fruit waste of Areca catechu – A plantation crop of agro-industrial importance

The waste product generated during arecanut processing is the ripened pericarp. The ripened pericarp tissue of Areca catechu accumulates carotene compounds, nevertheless remained unexplored as a source of tapping colourants. A reverse phase-thin layer chromatography (RP-TLC)-based separation was standardised for the first time for pericarp carotenes in A. catechu. UV–vis spectroscopy formed the basis for identification of major pericarp carotenes, and the method was validated subsequently. Solid phase extraction was also performed for rapid separation of β-carotene, using Sep-Pak® cartridge. It was found that β-carotene constitutes ∼30% of the total carotenoid content in the pericarp tissues. The total carotenoid content was found to be 11.67 ± 0.62 mg β-carotene equivalent per 100 g fresh mass of pericarp tissue. The antioxidant capacities of the extractives were evaluate by four different commonly used in vitro assays namely, ferrous reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2′-azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) and DNA nicking assay. Results of all the antioxidant assays point out a significant antioxidant property of the agro-industrial fruit waste of A. catechu.

► A rapid reverse phase-thin layer chromatography (RP-TLC) based technique was validated and used for separation of carotenes from pericarp waste of Areca catechu.
► Solid phase extraction was successfully used for quick isolation of β-carotene from the total carotene mixture of A. catechu.
► Promising antioxidant capacities of the carotenes isolated from fruit (pericarp) waste of A. catechu were demonstrated using DPPH, FRAP, ABTS and DNA nicking assays.