Combined use of hydrocolloids in pomegranate juice and their effects on clarification and copigmentation

Pomegranate juices (PJs) were clarified using hydrocolloids [albumin (A), casein (C), chitosan (CH) and xanthan gum (XG)] and in combination with each other. The lowest turbidity was observed in PJs clarified with 'CH+XG' and 'A+C+CH'. Unlike 'CH+XG', effects of albumin and its combinations on clarity were mainly related with the contents of ellagic acid (r = -0.861), alpha-punicalagin (r = -0.761), rutin (r = -0.734), beta-punicalagin (r = -0.730) and total punicalagin (r = -0.713). 'CH+XG' caused the highest phenolic (602 mg L-1) and anthocyanin (449 mg L-1) contents, and the second highest A(max) (0.811 ABS), resulting from copigmentation of delphinidin-3-glucoside and delphinidin-3,5-diglucoside with CH. Since A showed moderate copigmentation effect, A had lower hyperchromic effect than CH. Moreover, C reduced A(max), anthocyanin content and colour density when combined with other hydrocolloids. As a result, 'CH+XG' would be the best combination to obtain high clarity, maintain phenolics and anthocyanins and provide high copigmentation effect in PJ.