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Drying processes reduce the amount of available essential nutrients in dried plant-based foods to a large extent compared to fresh produce. This reduction is much larger than the differences in the final quality of products dried using various processing parameters and, in most cases, different drying methods. This aspect is, however, rarely highlighted. Here, the extent to which different convective drying methods reduce the nutritional content, namely vitamin C, carotenoids and phenolic content of dried fruits and vegetables, compared to fresh produce was quantified using literature data. The impact of different drying process parameters, such as air temperature, airspeed and relative humidity on the nutritional content of fruits and vegetables were compared. Results revealed that convective drying reduced the amount of vitamin C, carotenoids and the phenolic content of dried fruits and vegetables by up to 70%. The reduction in the residual vitamin C and carotenoid content of dried fruits and vegetables due to differences in air temperature (∼40%), airspeed (∼20%), and relative humidity (∼20%) is much less than the nutritional quality losses due to the drying process. The residual vitamin C, carotenoids and phenolic contents in convective-dried fruits and vegetables are ∼30% less than those in freeze-dried products. This study confirms that little absolute gains in nutritional quality can be achieved by opting for either an alternative drying method or optimizing processing parameters since the drying process already results in a low nutritional quality of dried products. As such, the remaining micronutrient concentration of dried products should not necessarily be a decisive criterion in selecting the most appropriate drying method or processing parameters for fruits and vegetables. Instead, other key performance indicators such as the drying time, energy consumption, or sensory properties such as color, texture, and rehydration capacity could eventually have a greater influence on the decision-making process., Food and Bioproducts Processing, 131, ISSN:0960-3085, ISSN:1744-3571

The aim of this study was to investigate the effect of vacuum drying conditions on the quality characteristics of oyster mushroom slices. The moisture desorption isotherms and changes in the lovastatin content of samples during drying were also determined. Drying generally took place in both constant and falling rate periods. Page and GAB models with the highest R-2 and lowest chi(2) and RMSE values were found to satisfactorily describe the drying and desorption behavior of the oyster mushroom slices. An increase in vacuum temperature resulted in a decrease in L and Hue angle, however, the opposite effect was observed for a, b, Delta E, and chroma (p < .05). Lovastatin degradation followed the first-order reaction kinetic and average lovastatin losses were calculated as 69.47%, 73.88%, and 83.98% for 45, 55, and 65 degrees C temperatures and 74.72% and 76.82% for 0.04 and 0.08 MPa absolute pressures, respectively. Practical applications The perishable structure of mushrooms shortens its shelf life and makes postharvest processing methods such as drying, freezing, canning, etc. mandatory. Drying is a common method that is used to extend the shelf life and increase the consumption of oyster mushrooms in the off-seasons. Although the mushrooms are generally dried as a whole or slice, dried mushrooms can be used as ingredients in sauces and instant soups. That is why the drying of mushrooms by an appropriate drying method is essential. The vacuum drying technique generally prefers for oxidizable and temperature-sensitive products. The vacuum drying method has many advantages like low drying temperature, oxygen-free environment, etc. that provides a higher quality product. This study focused on the effect of vacuum drying conditions (temperature and pressure) on the drying kinetics, quality characteristics, moisture desorption isotherms, and changes in the lovastatin content during drying of the oyster mushroom slices., Pamukkale University Research fundPamukkale University [2016BSP002], Pamukkale University Research fund, Grant/Award Number: 2016BSP002

The effect pre-drying method in terms of freeze (FD), hot air (HD), and microwave drying (MD), moisture content of turkey breast meat (50%, 40%, 30%, w.b.) prior to puff drying and pre-drying conditions following pressure (15, 20, 25 Pa) for FD, air temperature (65, 70, 75 °C) for HD and power (180, 360, 540 W) for MD was evaluated on puff dried turkey breast meat. Samples that dried with different pre-drying and puff drying were examined physically (moisture content, water activity, bulk density and color properties), chemically (salt, fat, protein and TBARS), texturally (crispness, expansion and rehydration ratio, macro and micro structure, mean pore diameter) sensorially (color, puffing degree, hardness, elasticity, crispness, taste, overall impression). The freeze pre-drying method exhibited smaller porous structure and resulted in low moisture content, water activity, bulk density, high expansion and rehydration ratio after puff drying. The hot air pre-dried samples had larger pore diameters and high elasticity because of higher moisture content and water activity values. The mean pore diameter of the microwave pre-dried products did not affect the rehydration and expansion ratio. Generally, the results showed that freeze pre-drying till 50% moisture content at 20 Pa pressure was the most suitable method. © 2021 Elsevier Ltd, 117 O 954 Türkiye Bilimsel ve Teknolojik Araştirma Kurumu, TÜBITAK, This research was supported by the Scientific and Technological Research Council of Turkey (TUBITAK 117 O 954). The authors are also grateful to P?nar Integrated Meat and Flour Industry Inc. Company for providing turkey breast meat., This research was supported by the Scientific and Technological Research Council of Turkey ( TUBITAK 117 O 954 ). The authors are also grateful to Pınar Integrated Meat and Flour Industry Inc., Company for providing turkey breast meat.

Apricot is one of the fruits dried by using different methods, such as sun, convective or microwave drying. The effects of drying methods on the components of this fruit differ depending upon the temperature or time parameters. In this research, the impacts of convective, microwave and microwave-convective drying techniques on color, beta-carotene, minerals and antioxidant activity of apricots were investigated. The color values (L-star, b(star), Delta E-ab, h degrees and C-ab(star)) of dried fruit were decreased, while the a(star) values increased. Compared with a fresh sample, the dried apricots showed a 1.4-3.9-fold proportional increase in beta-carotene based on the increment of dry matter. The samples dried at high temperature and microwave levels, at 75 degrees C+90 watt and 75 degrees C+160 watt, showed lower antioxidant activity. Of the different drying treatments, the microwave-convective method (50 degrees C+160 watt) obtained a higher beta-carotene content while maintaining antioxidant activity with a short drying time.

Summary In this study, the effects of convective, microwave and microwave–convective drying methods on the drying characteristics, colour, total phenolic content and antioxidant capacity of goldenberry fruits were investigated. To select the most appropriate thin-layer drying model for drying treatments, nine mathematical drying models were fitted to the experimental data. Based on the statistical tests used for evaluation, the Midilli et al. and Wang and Singh models were considered the best models to describe the drying behaviours of goldenberry fruits in all drying methods. The colour values (L*, a* and b*) of fresh fruit were decreased by drying. Compared with the fresh sample, the dried samples exhibited a 64–75% and 65–75% decrease in total phenolic content and antioxidant capacity, respectively. Among the different drying treatments, the values closest to those of fresh samples with respect to colour values, total phenolic content and antioxidant capacity were achieved with the 160 W microwave drying method.