optimization of drying process of parsley using the combination of hot air and microwave methods

Document Type : Complete scientific research article

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Abstract

In this study, parsley was dried using three drying methods: hot air (50, 60 ‎and 70 ºc), microwave (90, 180, 360, 600 and 900 W) and a combination of ‎hot air – microwave (60ºc and 360w). Selection of the optimum levels for ‎drying in combination method took place with quality tests of dried ‎samples. The drying data of parsley with hot air and microwave methods ‎was fitted with eight models: page, Newton, Henderson and Pabis, ‎logarithmic, Midilli et al., two-term exponential, Verma et al and Wang and ‎Singh. Results showed that page model have the best description for drying ‎belongs of parsley. The checking the combination process and the ‎qualitative testing of the final product showed that using of the microwave ‎energy as the final drying process leads to many different and favorable ‎aspects. This method can significantly improve the quality parameters such ‎as color, rehydration, and the amount of vitamin C and also it reduces the ‎drying time of parsley. Longest drying time of parsley was in drying with ‎hot air at 50 ºc that which lasted 420 minutes. This time, in combination ‎drying process in order was reduce the 43‎‏.‏‎66% in drying time of parsley ‎than drying with hot air in 50 ºc.‎

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