Modelling and experimental study on vitamin C content of foods dried by microwave technique

Drying of foods has been a process being applied for centuries. The process, being achieved simply in early times, has a place in the food industry and a lot of new ones, high efficient, low cost and high quality in final products, have been developed in time. The method widely used for drying in Turkey, an agricultural country, is solar drying. However, solar drying is not a preferred method due to some disadvantages such as dusting, long period of drying, low efficiency and insufficient exposure to solar beam every time. In this stage, microwave drying gained a great importance and became an alternative way for applying in food technologies.In this study, the effect of microwave drying technique on Vitamin C loss of purslane, basil and celery leaves have been examined. It has been observed that Vitamin C content has decreased by increasing the microwave output power or decreasing the sample amount. As a result of the microwave drying at 180 W microwave power for purslane sample; the vitamin C content decreased to 8.76 mg/100 g from 21.61 mg/100 g; for basil samples; the vitamin C content decreased to 5.56 mg/100 g from 21.19 mg/100 g and for celery leaves sample; the vitamin C content decreased to 13.33 mg/100 g from 30.00 mg/100 g. In addition, the activation energies were calculated by using an exponential expression based on Arrhenius equation. The Activation energies for Vitamin C content with drying of purslane, basil and celery leaves were found as 10.70 W.g-1, 14.98 W.g-1 and 9.61 W.g-1, respectively.Keywords: Purslane, Basil, Celery leaves, Microwave Drying, Vitamin C, Mathematical Modelling, Activation energy