Statistical Optimization of Blanching Time and Temperature of Irish York Cabbage Using Desirability Function

The effect of different heat treatments, as a means of preprocessing, on the phytochemicals present in Irish York cabbage was studied. A comparison of blanching (by immersing in water) and microwaving (using water as a medium) indicated that microwaving is detrimental to the phytochemicals present in cabbage. To achieve a blanching time and temperature combination that would result in minimal loss of phytochemicals, central composite design that integrates a desirability approach was used. A second-order polynomial equation was developed, indicating the effect of the blanching time and temperature on the total phenol content (TPC), total flavonoid content (TFC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) values. Contour maps generated using the response surface equation showed that the experimental variables significantly affected the response. The optimized factors (85C and 2 min) were used for blanching York cabbage to obtain a TPC, TFC and half maximal effective concentration for DPPH of 31.01 mg gallic acid equivalents/g, 21.2 mg quercetin equivalents/g and 0.93 mg/mL, respectively