Hurdle technology for minimally processed radishes: a response surface methodology approach

Abstract

Response surface methodology was used to determine the optimum processing conditions that yielded maximum vitamin C content, minimum discoloration and minimum polyphenoloxidase activity after 4 days of refrigerated storage of minimally processed radishes. Ascorbic acid (0–2 %), sodium chloride (0–1 %) and immersion time (0–2 min) at 50 °C were the factors investigated related to polyphenoloxidase activity (PPO), vitamin C (VITC) and total color difference (ΔE). Experiments were conducted according to a Box-Behnken Design with three factors at three different levels. For each response, second order polynomial models were developed using multiple linear regression analysis. Analysis of variance (ANOVA) was performed to check the adequacy and accuracy of the fitted models. The response surfaces showing the interaction of process variables were constructed and analyzed. Based on desirability function, optimum operating conditions were found to be 2 % of ascorbic acid, 0 % of NaCl and 1.5 min of immersion time at 50 °C. At this optimum point, relative PPO activity, relative VITC content and ΔE values were 0.218, 3.227 and 4.929, respectively.