Valorisation of carrot peel waste by water-induced hydrocolloidal complexation for extraction of carotene and pectin

Abstract

Food processing waste is a potential resource of a variety of bioactive compounds. Carrot peel is a good example of phytonutrient-rich agroindustrial byproducts generated from the processing of carrots. The conventional methods for the extraction of phytonutrients typically involve large volume of organic solvents, complex procedures and expensive equipment. Hence, the development of green and simpler extraction method is advantageous to the valorisation of agroindustrial waste in terms of economic and sustainability. In this study, the applicability of carotene-pectin hydrocolloidal complexation to the co-extraction of carotenoids and pectin from carrot peel waste was evaluated. Carrot peel waste is a potential feedstock for this extraction method because it is rich in carotenoids and pectin, which could form the colloidal complex induced by water. The operating conditions of complexation process were optimized using response surface methodology. The maximum yield and purity of β-carotenes extracted from carrot peel are 1.17 mg/100 g wet sample and 96%, respectively. In comparison to the conventional solvent extraction method, the number of operating steps in carotene-pectin hydrocolloidal complexation is significantly lower and the antioxidant activity of β-carotenes was higher. The carotene-pectin hydrocolloidal complexation method is therefore a green extraction method that enables the valorisation of agricultural waste to recover carotenoids.

Keywords: Carotene; Carotene-pectin complexation; Carrot peel; Colloidal complex; Pectin.