Comparative study between microwave and conventional dehydration of okra.

Abstract

This study was conducted to evaluate different pre-treatments and dehydration methods on the quality of okra. No significant differences were found among pretreatments and dehydration methods for the chemical composition of dehydrated okra samples. Dipping in 0.1 % sodium metabisulphite solution at room temperature and immersion in 0.1 % sodium metabisulphite solution at 92-95 °C improved the retention of ascorbic acid of okra samples after dehydration by either conventional or microwave oven. Also, the reduced dehydration time required for microwave dehydration produced far less destruction of ascorbic acid. The highest rehydration ratio was found in unwashed okra sample and dehydrated by microwave after immersion in 0.1 % sodium metabisulphite solution at 92-95 °C. Dehydrated okra samples by sun drying and conventional oven had lower retention percentages of total chlorophyll and carotenoids than those of dehydrated okra samples by microwave oven. The general appearance and colour scores of dehydrated okra samples by microwave were significantly different from those of conventionally dehydrated or sun dried okra samples.