Improving radio frequency heating uniformity using a novel rotator for microorganism control and its effect on physiochemical properties of raisins

Cui, Baozhong; Fan, Rong; Ran, Chuanyang; Yao, Yishun; Wang, Ke; Wang, Yequn; Fu, Hongfei; Chen, Xiangwei; Wang, Yunyang

doi:10.1016/j.ifset.2020.102564

Cited by 23 publications

(4 citation statements)

References 46 publications

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“…A slow and gentle drying process enabled the evaporation of more acid, which might induce the higher pH (lower titratable acidity) of the dehydrated products [64]. This result was aligned with the finding published by Cui et al [65]. In addition, chips dried using RFHAD + EAR and RFHAD had higher titratable acidity values, which agrees with the observation of a higher Vc retention of those two drying techniques in Table 3.…”

Section: Ph and Titratable Aciditysupporting

confidence: 91%

A High-Efficiency Radio-Frequency-Assisted Hot-Air Drying Method for the Production of Restructured Bitter Melon and Apple Chips

Jin,

Zhang,

Mujumdar

2024

Foods

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Nowadays, consumers are increasingly demanding processed food products with high levels of beneficial components. Bitter melon and apple are both nutritious foods rich in bioactive compounds. In this study, restructured bitter melon and apple chips were processed using four drying techniques: hot-air drying with/without exhaust air recirculation (EAR), and radio-frequency-assisted hot-air drying (RFHAD) with/without EAR. The drying characteristics, effective moisture diffusivity (Deff), specific energy consumption (SEC), total energy consumption (TEC), and some selected quality characteristics of the dehydrated chips were evaluated. The experimental results show that the application of radio frequency (RF) energy significantly facilitates water evaporation in the drying material, resulting in a significant (p < 0.05) reduction of drying duration by 31~39% over the experimental test parameters. The higher Deff values obtained from RFHAD and RFHAD + EAR were 6.062 × 10−9 to 6.889 × 10−9 m2/s, while lower SEC values ranged from 301.57 to 328.79 kW·h/kg. Furthermore, the dried products possessed better or fairly good quality (such as a lower color difference of 5.41~6.52, a lower shrinkage ratio of 18.24~19.13%, better antioxidant capacity, higher chlorophyll, total flavonoid, and total phenolic content, a lower polyphenol oxidase activity of 49.82~52.04 U·min−1g−1, smaller diameter and thickness changes, and a lower hardness of 27.75~30.48 N) compared to those of hot-air-dried chips. The combination of RF-assisted air drying and partial recirculating of dryer exhaust air achieved the highest saving in TEC of about 12.4%, along with a lower moisture absorption capacity and no deterioration of product quality attributes. This drying concept is therefore recommended for the industrial drying of several food materials.

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Section: Ph and Titratable Aciditysupporting

confidence: 91%

A High-Efficiency Radio-Frequency-Assisted Hot-Air Drying Method for the Production of Restructured Bitter Melon and Apple Chips

Jin,

Zhang,

Mujumdar

2024

Foods

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“…This could be due to that the free water in the sample increase with the increasing a w , which makes the loss factor larger and heating rate faster. The relationship between electrodes gap and heating rate had also been reported (Cui et al, 2021; Shen et al, 2020). With the change of electrodes gap, the electric field density and power density in the RF cavity were changed.…”

Section: Resultsmentioning

confidence: 87%

“…There was no significant difference between control and RF treatment groups for AAP and total polyphenols. Cui et al (2021) found that the content of total sugar and reducing sugar in raisins had no significant change after RF heating. Chen et al (2019) also reported that there was also no significant for total polyphenols in cumin seeds between RF treatment and untreated.…”

Section: Quality Analysismentioning

confidence: 91%

“…A 6 kW, 27.12 MHz pilot-scale free running oscillating RF system (GJG-2.1-10A-JY; Hebei Huashijiyuan High Frequency Equipment Co., Ltd, Hebei, China) was used in the study. The electrode gap of RF system could be selected between 100 and 300 mm which affected heating rate and uniformity of samples (Cui et al, 2021). And temperature measurement methods consisted of one optical fiber sensor system (HQFTS-D1F00; Xi'an Heqi Opto-Electronic Technology Co., Ltd, Xi'an, China) which could measure real-time temperature change in samples, and an infrared camera (A300, FLIR Systems, Inc., North Billerica, MA, USA) which could record sample temperature distribution of one layer.…”

Section: Rf Pasteurization Studymentioning

confidence: 99%

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Pasteurization of Salmonella spp. in black fungus (Auricularia auricula) powder by radio frequency heating

Zhang

Zhou

et al. 2022

Food sci. technol. int.

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Radio frequency (RF) heating has been studied to inactivate bacteria in some powder foods. In this study, a 6 kW, 27.12 MHz RF system was used to pasteurize Salmonella in black fungus (Auricularia auricula) powder. The effects of different conditions (initial aw, electrodes gaps, particle sizes) on RF heating rate and uniformity were investigated. The results showed that RF heating rate was significantly ( p < 0.05) improved with decreasing electrodes gap and increasing initial aw, and the heating rate was the slowest when the particle size was 120–160 mesh. However, these factors had no significant ( p > 0.05) influence on heating uniformity. RF pasteurization of Salmonella in black fungus powder was also studied. The results showed that, to inactivate Salmonella for 5 log reductions in the cold spot (the center of surface layer), the time needed and bacteria heat resistance at designated temperature (65, 75, 85 °C) decreased with increasing aw, and the first order kinetics and Weibull model could be used to fit inactivation curves of Salmonella with well goodness. Quality analysis results showed that although RF pasteurization had no significant ( p > 0.05) effect on Auricularia auricula polysaccharide (AAP) and total polyphenols, obvious changes were found on color. Results suggested that RF pasteurization can be considered as an effective pasteurization method for black fungus powder.

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Simulation and measurement of the effects of surrounding material on the uniformity of radio frequency heating of wheat flour

Miran¹,

Palazoğlu

2023

Biosystems Engineering

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Improving radio frequency heating uniformity using a novel rotator for microorganism control and its effect on physiochemical properties of raisins

Cited by 23 publications

References 46 publications

A High-Efficiency Radio-Frequency-Assisted Hot-Air Drying Method for the Production of Restructured Bitter Melon and Apple Chips

A High-Efficiency Radio-Frequency-Assisted Hot-Air Drying Method for the Production of Restructured Bitter Melon and Apple Chips

Pasteurization of Salmonella spp. in black fungus (Auricularia auricula) powder by radio frequency heating

Simulation and measurement of the effects of surrounding material on the uniformity of radio frequency heating of wheat flour

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