Microwave assisted extraction of bio-colorant from walnut hull

Abstract

This study aimed at exploring the feasibility of using the walnut hull as a natural colorant source using microwave-assisted extraction. Extraction was carried out with different combinations of Microwave Power (160, 320,480 W), treatment time (2, 3, 4 mins), solvent volume (20, 30, 40 ml/g) and particle size (150, 300, 450 µm). As a result, the highest yield of 44.99% was attained at the microwave power (160, 320, 480 W), microwave time (2, 3, 4 mins), Solvent (Water) volume (20, 30, 40 ml) and particle size (150,300,450µm). In fact, application of microwave irradiation method proved to be a rapid and improved technique for natural colorant extraction and extensively reduced the extraction time.