LAUSR

Indian blackberry (Syzygium cumini) is an excellent source of antioxidants and anthocyanins. The fruit juice can be concentrated by membrane filtration for use as nutritional supplements. The juice was extracted and clarified by ultrafiltration (50 kDa) and concentrated by nano-filtration (300 Da). Physicochemical properties of permeate and retentate were analysed. Protein, polyphenol and antioxidant contents were determined by spectrophotometric method. Anthocyanidins were quantified by RP-HPLC-photodiode array detector method. The nano-filtered concentrate had various anthocyanidins such as cyanidin chloride (5.9 mg/10 g), malvidin chloride (20.8 mg/10 g) and delphinidin chloride (3.6 mg/10 g). Rejection rates of protein, polyphenol and antioxidants for ultra- and nano-filtered permeates were 48%, 22.3%, 51% and 63%, 74%, 40%, respectively. The particle size distribution of the concentrated juice followed a parabolic curve justifying proper filtration. The results suggest possible use of the fruit juice concentrate in beverage and pharmaceutical industry.