Tarımsal ürünler bünyesinde bulunan yoğun nem sebebiyle hasattan kısa bir süre sonra çürüme ve bozulma eğilimine girmektedir. Çürüme rejimine giren bu ürünlerin aroma, renk, görünüş ve besinsel özelliklerinde kayıplar meydana gelmektedir. Bu kalite kayıplarını önlemek ve ürünlerin raf ömrünü artırmak amacıyla geçmişten günümüze kadar uygulanan çeşitli muhafaza yöntemleri uygulanmıştır. Bu yöntemlerden en ekonomik ve yaygın olarak kullanılanı kurutarak muhafaza yöntemidir. Kurutulmuş ürünün; taşıma ve depolamada kolaylık sağlaması, besin içeriği açısından daha konsantre bir özellik göstermesi, çok uzun süre boyunca muhafaza edilebilmesi, paketleme masrafının daha az olması gibi diğer muhafaza yöntemlerine göre üstünlükleri vardır. Ayrıca kurutma işlemi ile kuru incir, kuru kayısı, kuru üzüm gibi ticari değeri olan ürünler elde edilmektedir. Bu çalışmanın amacı literatür bilgileri doğrultusunda tarımsal ürünlerin kurutulmasında yararlanılan güneşte, gölgede, konvektif, vakumlu, mikrodalga, dondurarak, sprey, köpük, puf, kızılötesi, ozmotik, elektrohidrodinamik ve hibrit kurutma yöntemlerinin incelenmesidir.

No abstract

Deveci pear (Pyrus communis L. cv. Deveci) slices, whose initial moisture content is 5.24 ± 0.003 kgsu kgKM-1 (%83.95 ± 0.01 w.b), were dried by shade drying and hot-air drying at 60, 80 and 100°C until the final moisture reached 0.13 ± 0.001 kgsu kgKM-1 (%11.40 ± 0.06 w.b), and the drying processes of these methods were completed in 11150, 437, 252, and 148 minutes, respectively. In the study, experimentally obtained time-dependent moisture ratios were modeled using twenty different thin-layer drying equations. Accordingly, the model that gives the closest results to experimental data for 60°C and 100°C was the Modified Henderson & Pabis's equation. On the other hand, Alibas equation and Jena & Das equation were found to be the best models in shade drying and hot-air drying at 80°C, respectively. Despite no energy consumption in the shade drying method, some reasons such as this method being quite long and causing negative effects on the quality parameters of the product revealed that the shade drying method was not suitable for drying of Deveci pear. It was observed that total energy consumption increased with the increase of the drying temperature. Also, it was determined that the increase in temperature negatively affected the quality parameters. It was found to be a suitable method for drying the Deveci pear of the hot-air drying at 60°C due to the operating parameters such as drying time and specific energy consumption, as well as quality parameters such as brightness, redness, yellowness, chroma, hue angle, total color change and browning index were very close to the fresh product.

Drying is one of the most effective preservation methods applied to increase the shelf life of agricultural products. In this study, the effect of different pre-treatments on drying dragon fruit with a microwave was investigated. It is also aimed to determine the drying method with the minimum energy consumption. Dragon fruit slices were dried by microwave at 300 W output power in four different pretreatments as ultrasound, gum arabic, sucrose, and without pretreatment. Pretreatment applications were carried out by performing ultrasound for 10 minutes on dragon fruit slices and soaking them in 10% gum arabic and sucrose solutions before drying. Results showed that the shortest and longest drying times were measured in gum arabic and without pretreatment, respectively. Time-dependent estimation data were calculated by six different thin-layer drying models, considering the drying times and moisture rates. Jena&Das model showed the best fitting performance. As a result, it has been determined that pretreatment applications reduce drying time and energy consumption. In addition, gum arabic pre-treatment is advantageous in terms of energy consumption in microwave drying of dragon fruit.