Nutritional, safety and sensory quality evaluation of unleavened flatbread supplemented with thermal and non-thermal processed spinach powder

Abstract

Spinach (Spinacia oleracea L.) is a leafy green vegetable that belongs to the family Amaranthus, sub-family Chenopodiaceae. It is famous for its low-calorie content and rich nutritional profile of zinc, folic acid, iron, calcium, magnesium, retinol, and ascorbic acid. In contrast, pesticide residues like imidacloprid, cypermethrin, bifenthrin, chlorpyrifos, and deltamethrin and antinutrients like alkaloids, phytates, tannins, and oxalates are also found in spinach, which inhibit nutrient absorption and also exert deleterious effects in humans. The present study was aimed at determining the technofunctional and nutritional characteristics and improving the consumer safety aspects of dehydrated spinach powder (SP). Spinach was processed to improve its safety characteristics using thermal and non-thermal processing techniques, including microwave heat processing, blanching, acid, and alkali soaking. Findings on the nutrient composition of raw and treated forms suggest SP developed from raw spinach as a promising source of ash (2.9%), fibers (8.19%), proteins (19.1%), Na (97.9 mg/100g), Ca (1304 mg/100g), K (234.2 mg/100g), Fe (41.1 mg/100g), and Zn (14.3 mg/100g). Microwave heating anticipated the highest decline of the content of alkaloids, oxalates, tannins, and phytates by 85, 87, 88 and 89%, respectively. Similarly, microwave heating of SP was found to be more promising in reducing the burden of pesticides such as imidacloprid, cypermethrin, bifenthrin, chlorpyrifos, and deltamethrin by 86, 74, 84, 80 and 78%, respectively. Value-added unleavened flatbreads (chapatis) with 5% SP were observed to have the better color, taste, and textural attributes. The study proposes thermal processing i.e., microwave heat processing in particular as a safer approach to reduce the natural antinutrients and extrinsic toxicants of spinach to a level considerably safer for consumption.