The fate of beta-carotene in processed leaves of fluted pumpkin (Telfairia occidentalis Hook. f.): A popular vegetable in Nigerian diet

The effects of blanching, sun-oven-drying and storage conditions on beta-carotene content of the fresh leaves of fluted pumpkin were investigated. The beta-carotene (mg/100 g) of fresh leaves (unblanched) was 98.9 whereas on blanching the value was reduced to 86.3 for steam blanch and 83.8 for water blanch. After dehydration the losses in the beta-carotene were in the ranges of 37.6 to 48.8%, 40.5 to 51.3% and 68.8–72.0% for the steam-, water-blanched and unblanched leaves, respectively. The lower limit loss values were for the oven-dried leaves whereas the upper limit values were obtained from sundried ones. The ambient (30±2 °C) and refrigeration (7±1 °C) storage conditions showed some slight changes in beta-carotene contents of the leaves. The losses were in the ranges of 2.0 to 25.7% (refrigeration) and 9.2 to 36.3% (ambient) conditions. Blanching and storage conditions affected the organoleptic characteristics of the leaves.     

Effect of home processing on total and extractable calcium and zinc content of spinach (Spinach oleracia) and amaranth (Amaranthus tricolor) leaves

Spinach (Spinacia oleracia) and amaranth (Amaranthus tricolor) leaves were stored in polyethylene bags and without packing for 24 and 48 hours in a refrigerator at 5 and 30 °C in polyethylene bags. The fresh leaves were also dried (oven and sun); blanched (5, 10 and 15 min) and cooked in an open pan and a pressure cooker. The processed leaves were analysed for total and extractable calcium and zinc content. The Ca and Zn content of these leaves varied from 1320 to 2120 and 11.70 to 12.60 mg/100 g DM and the percentage HCl-extractability was 77.82 to 81.92 and 85.16 to 86.15, respectively. No significant effects of drying and storage were observed on total Ca and Zn content and HCl-extractability while blanching and cooking resulted in significant improvement of HCl-extractibility of these two minerals. Thus, cooking and blanching are good ways to improve the HCl-extractibility of Ca and Zn.