Optimization of Nutritional Composition, Bioactive Compounds and Antioxidant Activity in Broccoli (Brassica oleracea) Microgreen Sprinkler using Alternate Drying Techniques

Abstract

Background: Fresh microgreens are nutrient dense crops with high moisture content, thus have a short life span. Application of different drying techniques enhanced its shelf life but leads to nutrient losses. There is permanent need to enhance the nutrient retention in dried microgreen. Methods: The research study of microgreens investigated during 2019-2020 at Punjab Agricultural University. Broccoli (Brassica oleracea var. Palam Samridhi) seeds were soaked overnight and grown in outdoor setting and harvested at 10th day after germination. The harvested broccoli microgreens were dried using shade drying, tray drying and microwave drying. Dried samples were analyzed for nutritional parameters. Result: Microgreens contain significantly higher nutrients (Ca, Fe, Zn, Mg, K, ascorbic acid and b carotene), bioactive compounds (chlorophyll, total flavanoids and total phenols) and antioxidant activity as compared to their sprouts and mature counterparts. These are excellent sources of Fe, Ca, Zn, Mg, Vitamin C and beta carotene (pro-vitamin A), meeting per cent estimated average requirements (EAR) of 536%, 373%, 264%, 228%, 38%, 20% for Indian adult. To address the problem of perishability, there is a need to prolong their shelf life while retaining the nutritional quality. The present research has identified the optimum drying technique, on basis of nutrient retention, from a set of alternate techniques. Significant higher content of ascorbic acid (16.80 mg/100 g), chlorophyll (3.63 g/100 g), antioxidant activity (67.55%), Zn (35.23 mg/100 g), Fe (57.66 mg/100 g), Ca (2857 mg/100 g), K (334.23 mg/100 g) and Mg (706.43 mg/100 g) were observed in microwave dried microgreens. Incorporation of dried microgreen powder in food sprinkler resulted in a significant increase in vitamins, minerals, bioactive compounds and antioxidant activity as compared to the control.