Pear (Pyrus spp.) with more than 6000 varieties is one of the most widely consumed fruit in the whole world. The annual production of pear was more than 23.7 million tons in 2018. Pear can be consumed as fresh, dried, juice, canned food, etc. Dried pear can also be used as raw material and additive in the production of various food products such as fruit ice cream, yogurt, cereals, and bakery products (FAOSTAT, 2019;Özaydin & Özçelik, 2016).The high nutritional content of dried products is the main reason for their increasing popularity. Therefore, new techniques such as ultrasound, radio frequency, infrared, etc., are used for the production of nutritious and high-quality dried products (Guo et al., 2020;Zhou et al., 2019). These novel technologies provide high-quality product, short process times, and energy savings compared to traditional drying methods. On the other hand, if the appropriate novel technology and parameters are not selected, burning problem in foods and high HMF formation in sugary products may occur (Türker & İşleroğlu, 2017;Zhou et al., 2019). Infrared is defined as a form of electromagnetic radiation, that travels at the speed of light like all electromagnetic waves such as UV light, radio waves, visible light, X-rays, and gamma rays. Infrared energy is transmitted directly from the heat source to the product surface, so the product is heated more quickly and homogenously without heating the surrounding air (Jafari et al., 2020). Infrared technology has important advantages including high thermal efficiency, fast heating rate, short response time, uniform drying temperature, and easy process control (Doymaz et al., 2016;Liu et al., 2020). However, there is a possibility of partial burning or browning in the product because of the fast-heating rate during infrared drying. Therefore, the infrared power and distance between the product

In this research, fresh green peppers were dried in a kitchen microwave oven at 600W, 700W and 800W. The drying curves of the study were compared with 5 different thin layer drying models in the literature. The changes in the moisture values of the samples against time were expressed graphically. R2, χ2 and RMSE values were used to determine the most suitable model for dried green peppers. Color values of fresh and dried peppers were determined. It was found that the L* and b* values of the dried peppers were lower, and the a* value was higher than the fresh green peppers. In addition, the rehydration rate of dried peppers was calculated. It was determined that the rehydration ability of the peppers decreased as the applied microwave power increased. For this reason, it was found that the peppers with the highest rehydration rate were those dried with 600W. Also, it was found that the most suitable model for all microwave powers among the five drying models was the Logarithmic drying model. It was calculated that the R2 values of the drying models ranged between 0.830-0.999, χ2 values between 0.0001- 0.4684 and RMSE values between 0.0014-0.6121. It was determined that the highest R2 (0.997-0.999), the lowest χ2 (0.0001-0.0002) values, and the lowest RMSE (0.0014-0.0035) values for all microwave powers belong to the Logarithmic drying model.

Gıdalar üretimden tüketime kadar pek çok farklı şekilde kalite kaybına uğramaktadır. Bu nedenle; depolama, nakliye ve pazarlama süresince gıdaların duyusal özellikleri ve besin değeri korunurken söz konusu kalite kayıplarının önlenmesi esastır. Son zamanlarda, yenilebilir film ve kaplamalar alternatif bir ambalaj yöntemi olarak önem kazanmıştır. Yenilebilir film ve kaplamalar; özellikle tüketime hazır, pişmeye hazır ya da ön pişirme uygulanmış parça, derisiz veya kabuksuz gıdalarda, gıda ile asıl ambalaj materyali arasında ikincil bir kaplama olarak kullanılabilir. Yenilebilir film ve kaplamalar; antioksidanlar, antimikrobiyeller, renk ve tat bileşenleri gibi fonksiyonel bileşenlerin taşınmasında önemli bir rol oynayabilir. Yenilebilir film ve kaplamaların üretiminde pek çok doğal biyopolimer kullanılabilmektedir. Bu biyopolimerlerden biri olan jelatin; kolay bulunması, nispeten ucuz olması, çok fonksiyonlu olması, gıdalarla uyumlu olması, kolay kullanımı ve genel olarak güvenli kabul edilmesi nedeniyle bazı avantajlar sunmaktadır. Bu derlemede, son yıllarda yapılan çalışmalar ışığında jelatin bazlı yenilebilir film ve kaplamaların üretimi, uygulamaları, formülasyonları, kullanılan bileşenler, mekanik kuvvet, geçirgenlik ve fonksiyonel özellikleri değerlendirilmiştir.

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In this study, the quality characteristics of pear slices dried in vacuum-combined infrared dryer equipped with a two-way infrared heating (100-300 W infrared power) and convectional dryer (40-70 °C) were comparatively investigated. Increasing infrared power in vacuum-combined infrared dryer decreased the drying time.  However, the differences between vacuum pressures (100 mmHg and 250 mmHg) were generally negligible. Drying process at 200 and 300 W IP under vacuum was approximately 2- and 2.5-times shorter than conventionally drying at 55 and 70 °C, respectively. Although a very low amount of HMF in dried pear slices by the conventional dryer was detected only at 70 °C after 300 min, high amounts of HMF was detected at 300 W after 120 minutes. The rehydration rate of pear slice dried with vacuum-combined infrared dryer was higher than those of pear slice dried with conventional dryer. Syringic, chlorogenic and ellagic acids were identified in dried pear samples. Chlorogenic acid was found to be the most among phenolic compounds in dried pears. While the ellagic acid was not detected in fresh pear, dried pears had ellagic acid content (8.14-16.93 mg/kg d.m.). It was found that total phenolic content, ABTS and DPPH values of dried pears by vacuum-combined infrared dryer was lower than those of dried sample by conventional dryer. The pear slices dried at 300W and 250 mmHg had the highest sensory scores. The results show that the vacuum-combined infrared drying provided a shorter drying time and better sensory quality for dried pear compared to conventional drying.