Studies on intermittent and stepwise decremental microwave power drying of dill leaves

Abstract

Green leafy vegetables are highly perishable due to high moisture content. An investigation was undertaken to study the dehydration of dill leaves using Intermittent and Stepwise Decreasing Microwave Power Drying to get quality dried food in very short drying time. The variation in chlorophyll, protein, calcium, iron and ascorbic acid between fresh and dried leaves was 7.12 %, 2.58%, 3.33%, 6.68% and 5.88% respectively. The treatment of decreasing power of microwave field with decreasing levels of moisture was given to reduce heat stroke to dill leaves, those otherwise loose useful nutrients. The pulse ratio of 1.5 to 2 shows best results with respect to product quality and reduced final moisture content. The OFF time during drying helps in retention of colour with maximum nutrient. This drying process improves energy efficiency and product quality without increasing capital cost of the drier and enables the drying without chemical pretreatment.