EFFECT OF DRYING PROCESS ON NUTRITIONAL VALUE, CHEMICAL, PHYSICAL AND SENSORY PROPERTIES FOR ONION

Drying onions from the food industry economically important, because it reduces transportation costs, and the microbial spoilage, as well as storage space, also lead to the distribution of the crop throughout the year, in addition to price stability.       The aim of this study is to examine the effect of the drying process on the chemical, physical  and sensory properties for onion slices. The results obtained showed that the increase in temperature led to a reduction in moisture content and increasing the dry material components. Also decreased the level of amino acids with increasing temperature due to its interaction with the free sugars composed brown color (Miller reaction). As shown by the study of the sensory properties that sun dried onion and dried in the oven at 40 °C was more acceptable than onion powder 50 °C. Also found that the color of the onion growing darker with increasing temperature, while the total phenolic compounds increased with drying due to reduced moisture content, especially among fresh onions and sun dried onion and dried in the oven at 40 and 50 °C, where it was 27, 520, 581 and 596 mg/100, respectively. Based on these results, we recommend drying onions slices by the sun or dryers at a temperature not exceeding 50 degrees Celsius so as not to be affected  its chemical, physical, sensory properties and nutritional value.