Proximate composition and selected phytochemical component of Dawrach (Raphanus raphanistrum L.) as affected by blanching temperature

Abstract

Dawrach (Raphanus raphanistrum L.) is an underutilized wild edible plant belonging to the Brassicaceae family. Dawrach is widely regarded as a weed, and there is a lack of information about its nutritional profile such as, proximate, antioxidant properties, health-promoting vitamins, minerals and significant phytochemicals. The plant also contains anti-nutrients which need a pretreatment to be minimized and deteriorating enzymes that should be inactivated to make shelf stable products. Blanching temperature is the most critical factor that needs great attention during the blanching process to minimize the anti-nutrients and minimize the loss of desirable components of Dawrach such as, proximate and phytochemical contents and antioxidant activity. Thus, this study aimed to investigate the influence of blanching temperatures on the proximate, phytochemicals and antioxidant activity of Dawrach leaves. The parameters were evaluated following standard analytical methods and procedures. Dawrach leaves were blanched at 50, 60, 70, 80, and 90 °C temperature for 3 min, and raw or unblanched Dawrach was used as a control. Blanching temperature significantly affected the proximate, phytochemicals, antioxidant activity and anti-nutrients of the Dawrach. As a result, the moisture content of raw and blanched at 90 °C was 10.77 and 7.69 g/100g, respectively. Thus, blanching decreases the moisture content of Dawrach to the recommended safe moisture level for the products. Moreover, there was a significant decrease in the values of antioxidants activities, beta carotene, and l-ascorbic acid as the blanching temperature increased from 50 to 90 °C. Besides, as blanching temperature increased, there was a reduction in oxalate and tannin of the Dawrach leaf.