Vitamin retention in vegetables submitted to heat treatment

Abstract

PurposeThe purpose of this paper is to evaluate the retention rate of vitamin C and carotenoids in vegetables submitted to heat treatment.Design/methodology/approachSamples of carrot and broccoli were submitted to conventional cooking, steaming, microwaving and autoclave. Ascorbic acid concentrations were determined according to the methodology of Zhang and Hamauzu. The extraction of carotenoids was done using the methodology of Niizu and Rodriguez‐Amaya. The formula of Murphy et al. was used to calculate the retention rate of vitamins.FindingsThe highest retention percentage of ascorbic acid, α‐carotene, β‐carotene and lutein in carrots was obtained using microwave cooking. In the case of broccoli, the best retention for α‐ and β‐carotene was by steam cooking, whereas ascorbic acid was best preserved in the autoclave and lutein by conventional cooking.Practical implicationsAscorbic acid and carotenoids are compounds present in vegetables relevant mostly from a therapeutical point of view, as they appear to be associated with the prevention of many diseases. However, these vitamins are lost during the cooking process, which is of great importance in developing countries where deficits of these nutrientes are quite common in the population.Originality/valueThe results obtained in this study indicate that the cooking technique of choice is of fundamental importance not only at home but also for the food industry, considering the increasing consumption of processed foods.