Effects of layer arrangement on heating uniformity and product quality after hot air assisted radio frequency drying of carrot

Wang, Chenchen; Kou, Xiaoxi; Zhou, Xu; Li, Rui; Wang, Shaojin

doi:10.1016/j.ifset.2021.102667

Cited by 47 publications

(20 citation statements)

References 38 publications

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“…Wang et al. (2021) presented the effects of layer arrangement on improving the heating uniformity and product quality during hot air‐assisted RF drying.…”

Section: Resultsmentioning

confidence: 99%

Hot air‐assisted radio frequency drying of apricots: Mathematical modeling study for process design

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Göğüş

Özbek

et al. 2022

Journal of Food Science

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Conventional hot air and solar energy processes have been used for apricot. These processes had adverse effects on the quality due to the longer process times, and this indicates the need for an innovative approach. Radio frequency (RF) processing has innovation potential for drying with its volumetric heating feature, but an optimal process should be designed for process efficiency in industrial‐scale applications. Therefore, the objective of this study was to confirm the RF process for industrial‐scale apricot drying. For this purpose, a mathematical model was developed to predict temperature and moisture content change of apricots during drying, and experimental validation study was carried out. For the RF drying process, pre‐dried apricots (0.58–0.75 kg water/kg dry matter, db) by solar energy were used. The purpose was to start the RF process at a suitable moisture content level as this process was not feasible to apply directly due to the high initial moisture content of apricots (up to 4 kg water/kg dry matter, db). RF drying experiments were carried out in a 10 kW hot air‐assisted (50–60°C) staggered through electrode system. Optimum electrode gap was 81 mm with 2500 V potential of the charged electrode. Final moisture content of the dried apricots was 0.25–0.33 kg water/kg dry matter (db). Following the model validation for temperature and moisture content change, industrial‐scale apricot drying scenarios were demonstrated to confirm the RF process for feasibility and process design. Practical Application A comprehensive mathematical model was developed for radio frequency (RF) drying of apricots. This model was experimentally validated with respect to the temperature and moisture content change. Various process design studies were carried out for an industrial‐scale apricot drying process to confirm the process feasibility. With this background, the results of this study can be directly used in an industrial drying for an optimal process design and energy efficiency.

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“…Wang et al. (2021) presented the effects of layer arrangement on improving the heating uniformity and product quality during hot air‐assisted RF drying.…”

Section: Resultsmentioning

confidence: 99%

Hot air‐assisted radio frequency drying of apricots: Mathematical modeling study for process design

Topcam

Göğüş

Özbek

et al. 2022

Journal of Food Science

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“…Each dehydration time was 10 min. Final samples were immersed in 100% tert-butanol for 15 min and then placed in a vacuum freeze drying machine for processing [ 22 , 23 , 24 , 25 , 28 , 29 , 30 ]. The sample observation surface was placed upward and fixed on the scanning electron microscopy sample table with conductive tape after treatment, and the surface was coated with an ion sputter-coating instrument for 90 s, then placed under a scanning electron microscope.…”

Section: Methodsmentioning

confidence: 99%

“…In addition, the drying time was significantly reduced. When hot air-assisted RF technology was used in the final stage of pre-dried carrot slices [ 30 ], the heating uniformity and drying rate were good, and the drying time was shortened by more than 50% compared with conventional hot air drying; furthermore, the color, hardness, chewiness, and ascorbic acid content (V C ) retention rate were improved over conventional drying. In summary, RF-hot air combined drying can be widely used as a high-quality dehydration process in the drying of some agricultural products after harvest.…”

Section: Introductionmentioning

confidence: 99%

Characteristics and Quality Analysis of Radio Frequency-Hot Air Combined Segmented Drying of Wolfberry (Lycium barbarum)

Zang

Zhang

et al. 2022

Foods

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To overcome the problems of a long conventional drying time, low energy efficiency, and poor product quality, a segmented drying approach was developed for fresh wolfberry (Lycium barbarum) using a radio frequency (RF)-hot air drying process, which was investigated under different parameters of plate spacing (80, 90, 100 mm), vacuum degree (0.015, 0.025, 0.035 Mpa), and hot air temperature (50, 55, 60 °C). Analysis of the wolfberry’s drying characteristics, comprehensive quality, and microstructure indicated that: combined drying was faster and less time-consuming than natural drying or hot air drying, and components such as polysaccharides, ascorbic acid, and betaine in wolfberries were effectively retained. Based on the acceptable drying rate, stable temperature application, and avoidance of arcing effects, the optimal combined segmented drying parameters were determined to be as follows: a plate spacing of 90 mm, vacuum degree of 0.025 MPa, and air temperature of 55 °C. For the dried wolfberries under these conditions, the total drying time was 17 h and the berries had an improved comprehensive quality, the content of total soluble sugars was 0.62 g/g, total phenol was 10.01 mg/g, total flavonoids was 2.60 mg/g, VC was 3.18 mg/100 g, betaine was 3.48%, oxidation resistance represented by an inhibition rate was 66.14%, color was better, and rehydration rate was 48.56%. The microstructure was more regular because of the special dielectric heating characteristics of RF vacuuming. Despite the differing drying characteristics of individual materials, the overall RF-hot air combined drying process was found to achieve high-quality dehydration of wolfberries.

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“…Wenjun et al, (2021) conducted the hot-air assisted RF drying of in-shell hazel nuts for the higher heating rate and drying rate and the better quality of dried product comparing to hot air drying. Chenchen et al, (2021) conducted the drying of carrot with hot air drying and RF assisted hot air drying. The combined drying method could shorten the drying time by 30% and maintain heat sensitive ingredient in carrot well.…”

Section: Frontiers In Heat and Mass Transfermentioning

confidence: 99%

Mathematical Model of Thin Layer Drying of Ganoderma Lucidum by Radio Frequency Assisted Heat Pump Drying

Pham¹,

Duc²,

Hay³

2022

Frontiers in Heat and Mass Transfer

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This study determined the most appropriate thin layer drying model, the effective moisture diffusivity and the activation energy of moisture within Ganoderma lucidum in radio frequency (RF) assisted heat pump drying method. The thin layer drying experiments were conducted with input drying parameters such as: drying temperature of 40, 45 and 50°C and RF power of 0.65, 1.3 and 1.95 kW. In order to select a suitable form of drying curve, seven different thin layer drying models (Lewis, Page, Modified Page, Henderson and Pabis, Verma, Midilli, and Wang and Singh) were fitted to the experimental data. The Verma model was the most adequate model for describing the thin layer drying of Ganoderma lucidum. The average effective moisture diffusivity values varied from 2.34×10 -9 to 3.54×10 -9 m 2 /s. The activation energy values varied from 18.27 to 19.61 kJ/mol over the proposed range of drying temperature and RF power.

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Effects of layer arrangement on heating uniformity and product quality after hot air assisted radio frequency drying of carrot

Cited by 47 publications

References 38 publications

Hot air‐assisted radio frequency drying of apricots: Mathematical modeling study for process design

Hot air‐assisted radio frequency drying of apricots: Mathematical modeling study for process design

Characteristics and Quality Analysis of Radio Frequency-Hot Air Combined Segmented Drying of Wolfberry (Lycium barbarum)

Mathematical Model of Thin Layer Drying of Ganoderma Lucidum by Radio Frequency Assisted Heat Pump Drying

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