Date juice decolorized by ultra-filtration and its use with stevioside sweetener in beverage formulation

Abstract

Date juice was treated by cross- flow ultra-filtration with molecular weight cut-off (MWCO) of 5 kDa. Optimized levels of feed brix, TMP and operation time were determined as 47.13, 82.11 psi and 30 min, respectively. Under such conditions, 80.94% decolourisation and 97.78% turbidity reduction were obtained while loss of glucose and fructose were estimated to be only 3.49% and 9.62%, respectively. Regarding sweetness, the results of beverage sensory indicated that samples prepared by 100% decolorized date juice, 50% sugar, + 50% stevioside, 50% decolorized date juice and + 50% stevioside did not show significant differences compared with the sample prepared by 100% sugar. From the view point of the bitter aftertaste, samples prepared by 100% sugar and 100% stevioside had the highest and lowest desirability, respectively, while there was no significant difference between colour and clarity of the samples.