Quality Preservation and Shelf Life Extension of Broccoli Florets Using Tragacanth Gum Coating

Broccoli (Brassica oleracea L. var. italica) as an important vegetable has a high postharvest respiration rate, so, it loses its quality rapidly. The use of edible films and coatings as protective layers to create a covering on the surface of fruits and vegetables plays a key role in maintaining the quality of this product. The present research investigated the qualitative and biochemical traits of broccoli coated with tragacanth gum (0, 0.1, 0.2, and 0.4%) and cellophane and uncoated ones (as control) weekly during three-weeks cold storage. Based on the results, coating influenced all measured traits (except flavonoid content, vitamin C and antioxidant activity) and storage time influenced all recorded traits significantly (P< 0.01). The results revealed that over the storage period, the physicochemical and biochemical parameters and visual quality of the broccoli decreased. Tragacanth gum 0.2% led to less weight loss, however, appropriate soluble solids content, and higher titratable acidity and organoleptic properties were recorded for 0.4% coated florets. Cellophane was effective in retaining some physicochemical characteristics, weight, and marketability, but it reduced phenolics. Tragacanth gum coating can be used as a biomaterial, as a substitute for synthetic cellophane film to preserve broccoli.