Optimization of copper chlorophyllin production from grass and evaluating its stability in the mint drink during storage

Copper chlorophyllin is a water soluble pigment and has a wide application in the drink industry. The aims of the research were, first to compare single and double step extraction of chlorophyll to achieve the highest yield, second to optimize the producing of copper chlorophyll complex and finally, to study the stability of copper chlorophyllin in mint drink at room and accelerated temperatures during time. First, the chlorophyll was extracted from grass by single and double step extraction and the optimum condition was determined. The effect of Cu concentration (0-200 % w/w), pH (3-9), temperature (40-100 C) and time (15-180 min) on the greenness value (a*) was optimized. After saponification of the produced copper chlorophyll, water soluble copper chlorophyllin was produced. Finally, mint drink containing copper chlorophyllin was produced and its color stability was investigated at light/dark and room and accelerated temperatures (25 and 42 C) during time. The results indicated that the highest yield of chlorophyll (590 mg/100 g d.m.) was obtained by double step extraction with the solvent/solid ratio of 10:1 (ml/g). The highest a* was obtained at cu concentration of 100 % at 80 C during 60 min. Mint drink containing copper chlorophyllin was  stable at different conditions of light/darkness and room and accelerated temperatures but in the drink containing commercial copper chlorophyllin, this pigment was precipitated.