Effect of various drying methods on nutritional quality of okra vegetable

A laboratory investigation was performed to determine the effects of different drying methods on the nutritional qualities of Okra Abelmoschus esculentus. Three drying methods were employed such as: sun drying (natural solar system), hot air oven drying and microwave oven drying for determination of various quality characteristics. The lowest dried weight (0.38936 kg) of Okras was recorded from Okra processed in hot air oven, followed by dried weight of 0.44022 kg (out of 3 kg fresh weight) in case of microwave oven dried samples. The maximum dried weight of Okra samples (0.54162 kg out 3kg fresh weight) was recorded in case of sun drying. Total solids were relatively higher i.e. 93.50 plus minus 0.44 and 93.50 plus minus 0.20 in Okra samples dried by hot air oven and microwave oven, respectively against average soluble solids of 13.0 plus minus 0.37 in the fresh Okra which ranged between 12.0-14.0 percent. The fat percentage was remarkably re duced when Okra samples were dried by microwave oven averaging 1.52 plus minus 0.15% against the 2.84 plus minus 0.41 average fat percent in fresh Okra samples. The fat percentage was relatively higher 2.03 plus minus 0.22 in Okra fruit samples dried through hot air oven method. The nitrogen percentage in Okra remained almost unaffected due to different drying methods with the exception of nitrogen percentage in solar dried Okra. Relatively higher (1.62 plus minus 0.06) nitrogen percentage was recorded when Okra were subjected to solar drying. The nitrogen percentage was 1.52 plus minus 0.06 and 1.52 plus minus 0.27 in case of drying Okra by microwave oven, hot air oven and fresh Okra, respectively. The ash percentage was significantly increased when Okra were dried by different methods. The average ash percentage was maximum i.e. 10.03 plus minus 0.38 recorded in Okra dried by sun drying method, followed by mean ash percentage of 9.92 plus minus 0.40 and 7.79 plus minus 0.78 % recorded from the Okra samples dried by hot air oven and microwave oven drying methods, respectively. The difference were highly significant (P less than 0.01) for ash percentage and non-significant (P greater than 0.05) for fat and nitrogen percentage when comparison was made between fresh Okra and hot air oven. Similarly, difference were significant (P less than 0.05) for fat content in dry Okra when fresh Okras were compared with microwave oven dried fruits, while non-significant for ash and total nitrogen. Under comparison of fresh Okra and solar dried Okras, ash percentage was significantly (P less than 0.01) affected, while non-significant (P greater than 0.05) effects were observed for fat and total nitrogen contents. In case of hot air oven compared with microwave oven and solar dried Okra, the differences for all the quality characters were non-significant (P greater than 0.05). However, differences were significant (P greater than 0.05) for ash and fat contents wh en microwave oven dried Okra were compared with solar dried Okra and non-significant (P greater than 0.05) for total nitrogen. The solar dried Okra acquired 7.8, 8.8 and 7.4 numbers out of 10, averaging 7.7 plus minus 0.12 marks. Similarly, hot air oven dried Okra acquired 6.8, 6.6 and 7.0 marks in sensory analysis, averaging 6.8 plus minus 0.17 numbers, while the microwave oven dried Okra vegetable acquired 7.0, 7.0 and 6.2 numbers out of 10, averaging 6.7 plus minus 0.12 numbers. The sensory analysis indicated that sun dried Okra were more delicious as cooked vegetable as compared to hot air oven dried and microwave oven dried vegetables. It was concluded that sun dried (SD) Okra gave significantly higher nutritional content and achieved higher score for delicious taste in sensory analysis. On the other hand, Okra dried in hot air oven (HAO) significantly resulted in less time as compared to SD. The microwave oven (MWO) dried Okra contained less amount of fat %age as compar ed to SD and HAO. The ash content was relatively higher in solar dried Okra.