Development of a model system to evaluate ascorbic acid destruction at various time/microwave power levels

A model was developed to evaluate ascorbic acid (RAA) preservation in broccoli at various time/microwave power levels. The implication of this model was tested to predict the RAA retention in other vegetables using green beans and asparagus.; Broccoli was used as model system and was heated using 5 time periods (0, 1, 2, 3 and 4 min) and 4 microwave power levels (100%, 70%, 55% and 30%). Processed broccoli was analyzed for moisture content, reduced ascorbic acid, peroxidase activity and instrumental color. Predictive model was developed using regression analysis. Results indicated significant interaction between time and power levels. RAA content increased and peroxidase activity decreased as the time and power levels increased. The model developed for this study used to evaluate RAA retention in broccoli, which indicated that actual and predicted values for RAA retention using this model were similar. The experiment was repeated using two other vegetables, green bean and asparagus. Results of these experiments indicated similar patterns of time and power level interactions for RAA retention and peroxidase destruction in these vegetables. The model developed using broccoli, was effective for RAA retention prediction in green bean and asparagus.; In conclusion, ascorbic acid retention and peroxidase destruction in all three vegetables was higher at longer times and higher power levels. Model developed to evaluate RAA preservation in broccoli was applicable to predict RAA preservation in green bean and asparagus. These findings are consistent with those of HTST treatments, which are effective to destroy microorganisms and enzymes and preserve nutrient quality of the product.