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Sour cherry (Prunus cerasus L.) is a good source of anthocyanins showing antioxidant and anti‐inflammatory activities. Contemporary drying processes of fruits and vegetables should be fast and at relatively low drying temperatures to minimize the energy consumption and the thermal degradation of their nutritional composition. Therefore, sour cherries placed into sample bags were dipped in one of eight different pretreatment combinations consisting of chemical solutions (2% ethyl oleate, 2% K2CO3, 1% citric acid or water) and dipping temperature (23 or 60C) for 1 min to accelerate the skin moisture diffusivity by breaking down the waxy cuticular surface of sour cherry. Pretreated sour cherry samples were dehydrated by three different methods (artificial drying, solar drying and open sun drying). Sour cherries treated with 2% ethyl oleate solution at room temperature (23C) were the fastest to reach the final weight loss percentage (75%). They dried in 24 h in the laboratory tray dryer providing 45.2C drying air. The untreated samples reached the same weight loss percentage of 75% at a drying time of 92 h. A high dipping temperature (60C) eliminated the positive effect of ethyl oleate. Solar drying and open sun drying of sour cherries treated with 2% ethyl oleate at room temperature finished approximately in 149 h and 372 h, respectively. The color of dried sour cherries was used as a quality indicator. The increase of dehydration time decreased redness values as seen in solar drying and open sun drying. The recommended pretreatment and drying processes for sour cherries are dipping them into 2% ethyl oleate solution at room temperature for 1 min and then drying them artificially at 45.2C air temperature to effectively retain their original color.

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ÖZET Bu çalışmada, 'Gerçekcioğlu' kuşburnu çeşidinin meyvesi kurutularak kuruma süresi, renk ve C vitamin kriterleri açısından en uygun kurutma şartının belirlenmesi amaçlanmıştır. Materyal mikrodalga kurutucuda; 360, 540, 720 ve 900 W güç değerlerinde ve etüv kurutucuda ise; 50, 60 ve 70 °C kurutma havası sıcaklıkların da kurutulmuştur. Uygulanan mikrodalga güç değerlerinde belirlenen ortalama kuruma süreleri sırasıyla; 27, 14, 11 ve 9 dakika olarak tespit edilirken, etüv de ise sırasıyla; 16.5 7.5ve 7 saat olarak belirlenmiştir. Tazeye göre renk değeri açısından en uygun kurutma şartı mikrodalga kurutucuda 720 W güç değerinde, etüv kurutucuda ise 60 °C kurutma havası sıcaklığında yapılan kurutma işlemlerinde belirlenmiştir. Taze kuşburnu meyvesine göre, en fazla kaybolan % C vitamini değeri % 91.36 oranla etüv kurutucuda 60 °C sıcaklığında ve mikrodalga kurutucuda ise 540 W güç değerinde hesaplanmıştır. Taze kuşburnu meyvesinin C vitamin değerine göre, en uygun mikrodalga kurutma şartının 900 W, sıcak havalı kurutma şartının ise 70 °C olduğu belirlenmiştir.Quality changes in rosehip (RosamontanaChaixsubsp. woronovii (Lonacz) Ö. Nilsson) fruits dryed by convective and microwave methods Anahtar Sözcükler: Ürün kurutma Renk Kuruma süresi C vitamini ABSTRACT .In this study, it is aimed to determine the most suitable drying condition in terms of drying time, color and vitamin C criteria by drying the fruit of 'Gerçekcioğlu' rosehip variety. The fruits were dried in microwave dryer 360, 540, 720 and 900 W power values. The fruits were dried drying air temperatures of 50, 60 and 70 °C in drying oven. The average drying times determined in the applied microwave power values are as follows 27, 14, 11 and 9 minutes. The average drying times determined in the applied drying air temperatures are as follows 16.5 7.5 and 7 hours. The most suitable drying condition in terms of color value according to freshness was determined at 720 W power in microwave dryer and 60 °C drying air temperature in drying oven. According to fresh rosehip fruits, the most lost vitamin C value was 91.36% at 60 °C in convective dryer and 540 W power in microwave dryer. According to vitamin C value of fresh rosehip fruit, the most appropriate microwave drying condition was 900 W and hot air drying condition was 70 °C.

Kuşburnu, kabin kurutucu, kuruma performansı, efektif difüzyon ve aktivasyon enerji değerleri Determination of drying performance, effective diffusion and activation energy values for rosehip (Rosa canina L.