Separation and character analysis of anthocyanins from mulberry (Morus alba L.) pomace

Abstract

Mulberry pomace, as a by-product of juice and wine making, was investigated as a potential source of natural anthocyanins. The results showed that anthocyanin contents in mulberry pomace from two varieties were above 250 mg/100 g, that is 74%–79% of that in mulberry whole fruit. Thus, mulberry pomace could be a potential anthocyanins source. The anthocyanins in mulberry pomace had an attractive red colour with the chroma at 5.0 and hue angle at 6.8. Five anthocyanins were identified in mulberry pomace, cyanidin-3-glucoside and cyanidin-3-rutinoside being the major anthocyanins. The method of the separation of the two anthocyanins was studied showing that both anthocyanins with purities above 98% could be well separated on Sephadex LH-20 by eluting with 10% ethanol containing 1% of acetic acid after purification with AB-8 macroporous resin. The recovery of the complete process of both anthocyanins was 57.4%. Cyanidin-3-glucoside and cyanidin-3-rutinoside had more attractive colours and strong antioxidant activities and could be used as potential food colourants and antioxidants.