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Tropentag, September 14 - 16, 2022, Prague

"Can agroecological farming feed the world? Farmers' and academia's views."


The effect of sun-drying on nutritional and sensory properties of wilted African leafy vegetables

Amina Ahmed1, Saliath Almas2, Suleiman Rashid3

1University of Goettingen, Dept. of Crop Science, Division of Quality of Plant Products, Germany
2Sokoine University of Agriculture, Department of Food Sciences and Agroprocessing
3Sokoine University of Agriculture, Department of Food Sciences and Agroprocessing, Tanzania


Abstract


African leafy vegetables are rich in micronutrients that can help solve hidden hunger problems in Sub-Saharan Africa. However, their availability is limited due to seasonality and high postharvest losses, which account for about 50%. For example, wilted vegetables are usually discarded from the markets or households. Therefore, a study was conducted in the Morogoro region, Tanzania, to investigate whether wilted African leafy vegetables could be sun-dried as fresh leafy vegetables. The common practice of handling fresh vegetables by vendors was adopted by putting the freshly harvested vegetables in an open basin at 24 ± 2˚C for three days. The stored vegetables were either sprayed or dipped in water to reduce the wilting rate. The portion of fresh and the wilted vegetables were then blanched in water at 100°C for 7 minutes. After that, the vegetables were sundried (22.5 ± 5.5˚C) for three consecutive days. The fresh and dried vegetables were used to prepare sauces using traditional recipes. To study the effect of wilting, blanching, and sun drying, both the fresh and dried vegetables were analysed for ascorbic acid, β-carotene, antioxidant activity, nitrate, and ash content. The vegetable sauces were tested for their sensory attributes using 30 semi-trained panellists. After drying, the contents of ascorbic acid, nitrate, and antioxidant activity were reduced from 34.5 mg/100g to 3.9 mg/100g, 23.0 mg/g to 1.1 mg/g and 37.2% to 14.9%, respectively. However, the β-carotene and ash contents increased significantly after drying the vegetables. The sensory results showed no significant difference among the sauces prepared from the fresh, fresh-dried, and wilted-dried vegetables. In conclusion, the wilted vegetables are suitable for sun-drying to minimise postharvest losses.


Keywords: African leafy vegetables, blanching, postharvest loss, sauces, sun drying, wilting


Contact Address: Amina Ahmed, University of Goettingen, Dept. of Crop Science, Division of Quality of Plant Products, Carl-Sprengel Weg 1, 37075 Goettingen, Germany, e-mail: aahmed1@gwdg.de


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