Enzyme-assisted extraction of stabilized chlorophyll from spinach

Abstract

Zinc complex formation with chlorophyll derivatives in spinach pulp was studied by adding 300ppm Zn2+ for production of stable food colorant, followed by the heating at 110°C for 15min. Zinc complex formation increased at pH values of 7.0 or greater. Pectinex Ultra SP-L was selected for enzyme-assisted release of zinc–chlorophyll derivatives from spinach pulp. Effect of enzyme concentration (1–9%), treatment temperature (30–60°C), and time (30–210min) on total chlorophyll content (TCC) were optimized using response surface methodology. A quadratic regression model (R2=0.9486) was obtained from the experimental design. Optimum treatment conditions were 8% enzyme concentration, 45°C, and 30min, which yielded a 50.747mgTCC/100g spinach pulp. Enzymatic treatment was followed by solvent extraction with ethanol at a solvent-to-sample ratio of 2.5:1 at 60°C for 45min for the highest TCC recovery. Pretreatment with enzyme and extraction in ethanol resulted in 39% increase in Zn–chlorophyll derivative yield.