​Standardization of Cold Solvent Extraction Parameters for Natural Red Pigments

Abstract

Background: Selecting an appropriate extraction technique and optimization of extraction conditions must be done to improve the efficiency and productivity of natural colorant. Methods: Flesh and peels of four different raw materials viz., beetroot, carrot, pomegranate and grape were extracted independently using 100% ethyl alcohol using cold solvent extraction method adopting 1: 1 and 1: 2 w/v solid to solvent ratio for 24 and 48 hrs, forming 8 treatments replicated thrice in three factorial CRD. The collected extracts were evaporated at 60oC; per cent yield and pigment content were calculated. Result: Extract yield and pigment content were significantly influenced by raw material, solid to solvent ratio and duration of extraction. Extract yield was higher in flesh of carrot and beetroot as well as in peels of grape and pomegranate. Anthocyanin content in grape and pomegranate and betalain content in beetroot were high in peel where as β-carotene content was higher in carrot flesh extract. Per cent yield and pigment content increased with increased duration of extraction and solid to solvent ratio. Requirement of more solvent and longer extraction time are the drawback of conventional extraction methods and there is a growing demand for non-conventional techniques to enhance yield and maintain pigment stability.