Solar drying - An effective means of food preservation

According to investigations around 15 % of the today's world population is undernourished. The increase of world's population, which is predicted to be around 3 billion people within the next 30 years, will strengthen the yet existing population-food imbalance. Besides increase of food supply and limitation of the population growth, drastically reducing the food losses which occur throughout food production, harvest-, post-harvest and marketing seems to be a viable option. The reduction of food losses is particularly a problem for small farmers in developing countries who produce more than 80 % of the food. Since the traditional sun drying is a relatively slow process considerable losses can occur. In addition, a reduction in the product quality takes place due to insect infestation, enzymatic reactions, microorganism growth and myctoxin development. The technology used in industrialized countries or even at large scale plantation in developing countries for food preservation is neither technically nor economically feasible for smallholders. In contrast, numerous investigations have shown that solar drying can be an effective means of food preservation since the product is completely protected during drying against rain, dust, insects and animals. But still some obstacles have to be overcome that solar drying will become a technology with a broad dissemination. Although a lot of research work has been conducted during the last decades, only a small number of appropriate solar dryers which can be used by farmers or small scale industries in developing countries are commercially available. Furthermore there is still a lack of knowledge how to process fruits, vegetable, fish, etc, in a proper way to ensure a high quality product and to minimize post-harvest losses. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.