Evaluation of Freezing Effect on Nutritive Value and Antioxidant Properties of Leafy Vegetables Consumed in Northern Côte d’Ivoire

Postharvest handling is one of the major factors affecting the nutritive value of leafy vegetables and it is important to preserve these nutrients by appropriate processing and storage. Thus, this study was mainly conducted to determine the influence of freezing (-18°C) during 1, 2 and 3 months on the nutrients contents of five leafy vegetables (Hibiscus sabdariffa, Amaranthus hybridus, Andasonia digitata, Vigna unguiculata and Ceiba pentandra) widely consumed in Northern Côte d Ivoire. The results showed that the longer period (more than 1 month) of freezing affected the nutritional value and the registered losses at 3 months of freezing were as follow: ash (4.21 - 16.86%), proteins (3.39 - 13.42%), vitamin C (9.56 - 24.18%), carotenoids (15.38 - 34.19%), total phenolics (2.06 - 19.67%), oxalates (16.41 - 31.28%), phytates (25.12 - 51.26%). The residual contents of minerals were: Ca (360.52 - 824.02 mg/100g), Mg (193.11 - 503.45 mg/100g), K (107.69 - 387.39 mg/100g), Fe (46.84 - 137.18 mg/100g) and Zn (15.05 - 26.45 mg/100g). In view to some essential nutrients losses it would be necessary to preserve traditional leafy vegetables by freezing storage within a period not exceeding 1 month in order to contribute efficiently to the nutritional requirements and to the food security of Ivorian population.