Nutrient Composition and Sensory Profile of Differently Cooked Green Leafy Vegetables

Abstract

Four green leafy vegetables commonly consumed in South India were selected for the study. They were subjected to three different methods of cooking namely, conventional, pressure, and microwave cooking. Proximate composition, vitamins (ascorbic acid and b-carotene), mineral content (calcium, phosphorus, and iron), and in vitro available iron of the raw and cooked samples were estimated. The cooked samples were further subjected to sensory analysis. The results showed that the nutrient content of each green leafy vegetable was distinct and spinach was comparatively a poor source of all nutrients. Cooking caused a significant difference only in the ascorbic acid and b-carotene content of the greens. No significant difference was observed in the nutrient content due to the three different methods of cooking adopted. Results of the sensory test revealed that color was the only attribute that varied to a large extent due to cooking. Color of pressure cooked greens was considered inferior to conventionally cooked and microwave cooked samples. The sensory attributes of microwave cooked greens were similar to the conventionally cooked samples.

Retention of mineral constituents in frozen leafy vegetables prepared for consumption

“…As for the remaining elements, no significant differences or decreases were found depending on the vegetable species (see Tables 2-4). In cooking four species of leafy vegetables using three different methods, Kala and Jamuna-Prakash (2004) did not record significant decreases in the content of mineral compounds as opposed to the results obtained by Onyeike et al (2003) in the investigation of six species of leafy vegetables thermally processed in water. The observed lack of significant differences in the relatively high-percentage losses could have resulted from the different level of constituents in the replication samples.…”

Nutritional value of leafy vegetables of sub-Saharan Africa and their potential contribution to human health: A review

“…In comparison to vitamins, minerals have greater stability and their contents do not change significantly due to cooking (Kala and Prakash, 2004). Cooking LVs in iron utensils increases the total iron and bioavailable iron compared to fresh vegetables and those cooked in other metallic utensils such as stainless steel and aluminum (Kumari et al, 2004) and this could also apply to ALVs.…”

“…Consumption of cooked and pureed spinach leads to higher plasma total b-carotene concentrations, compared to when these vegetables are consumed raw (Rock et al, 1998). This could be attributed to the increased extractability on cooking due to destruction of enzymes which otherwise could cause carotene degradation (Kala and Prakash, 2004).…”

“…However, it may be hypothesised that the effects noted above could also occur in ALVs. Kala and Prakash (2004) reported that cooking (not pressure cooking) caused a slight increase in the total dietary fibre (TDF) content of Indian LVs, which was attributed to the hydration or polymerization of TDF fractions. Puupponen-Pimiä et al (2003) reported no significant change in soluble, insoluble and total dietary fibre contents of blanched and freezer stored spinach.…”

Indigenous leafy vegetables (imifino, morogo, muhuro) in South Africa: A rich and unexplored source of nutrients and antioxidants

“…On the other hand, eating cooked and pureed spinach leads to higher plasma total β-carotene concentrations, compared to raw consumption (Rock et al, 1998). This could be attributed to the heat destruction of enzymes that may be responsible for β-carotene degradation (Kala and Prakash, 2004). De Pee et al (1995) reported that reduction in bioavailability of vitamin A from green leafy vegetables could be due to physical inaccessibility of carotenoids in plant tissues which may prevent the release of β-carotene from the matrix and competition for absorption with other carotenoids.…”