Impact of blanching pretreatment on physicochemical properties, and drying characteristics of cabbage (Brassica oleracea)

Abstract

Cabbage (Brassica oleracea) is popular winter vegetables cultivated all over Bangladesh and contains essential nutrients. This study aimed to evaluate the efficacy of pre-blanching on the preservation of cabbage by drying. In this research work, cabbage was blanched at 80°C, 90°C, and 100°C temperature for 12, 8, and 2 mins, respectively. Then the samples were dried at 60°C maintaining 60% relative humidity. The moisture and ash content of untreated and treated dried samples was in the range of 16.07±0.04 to 10.80±0.01% and 5.71±0.06 to 3.81±0.02%, respectively. The total phenolic content in cabbage was 74.47±0.63 mg GAE/100g at 100°C blanching temperature for a short time of 2 mins, which was higher compared to 61.91±0.48 mg GAE/100g at 80°C for 12 mins. It was observed that the antioxidant activity and two water-soluble vitamins-ascorbic acid and beta carotene decreased in pre-blanched dried samples in contrast with fresh ones. Blanching at higher water temperature and a short period was found useful for the retention of total phenolic content and greenness of cabbage. Blanching pre-treatments were also found to have better color retention capacity than untreated dried cabbage. A proper combination of drying time and temperature, along with the incorporation of blanching pretreatment, might be useful to preserve cabbage for a long time.