Analysis of the Heat Transfer of Ginkgo Biloba Seeds during Radio-Frequency Heating
-
Chunfang Song
,
Yao Chen
Abstract
Fresh ginkgo biloba (GB) seeds are seasonal and susceptible to microbial spoilage, especially the growth of mold owing to GB seeds’ high-water content, which greatly limits their shelf life. As an efficient and special heating method, radio-frequency (RF) heating can be used to dehydrate ginkgo to preserve its nutritional value and reduce postharvest losses. However, the non-uniformity of RF heating restricts the development in industrialized application. In this study, the RF drying of GB seeds was performed to investigate the effect of RF heating on temperature. The distribution law of the entire temperature field was also observed. Using numerical simulation method, the coupling model of electromagnetic and heat transfer was established. The model was validated by the 6-min heating profile of GB seeds in a 12 kw and 27.12 MHz RF system. The model was also qualitatively validated by comparing the simulated temperature profiles on the three planes in the GB seeds with the corresponding thermal images. Quantitative validation was performed by comparing the simulated temperature of GB seeds on the three planes with experimental temperature acquired at places using thermocouples. Furthermore, the model can be effectively used to identify the distribution of electric fields in different positions and to achieve satisfactory heating uniformity.
Funding statement: This work was supported by the Open Fund of Beijing Advanced Innovation Center for Food Nutrition and Human Health [grant number 20181039] and Jiangsu Province Union Innovation Funds-Prospective Joint Research Project [grant number BY2016022-10].
Nomenclature
- E
internal electric field (V/m)
relative permeability (H/m S/m)
Relative dielectric constant permeability
electrical conductivity (S/m)
- ε0
vacuum dielectric constant (F/m)
excitation frequency of electromagnetic wave (rad/S)
- k0
free-space vector (rad/m)
dissipated power per unit volume (W/m–3)
- ε0
vacuum dielectric constant (8.854 × 10–12F/M)
dielectric loss factor
- f
frequency of the magnetron (Hz)
conductivity of the food material (S/m)
dielectric constant of the food material
- V
electrode gap potential (V)
- D
electric displacement vector
- B
magnetic induction intensity
- J
current density
- H
magnetic field intensity
- n
steering
- h
surface convective heat transfer coefficient (W/m°C)
- Ta
initial temperature (°C)
- k
thermal diffusivity (m/S)
density (kg/m3)
specific heat capacity (S/m)
current density (S/m)
height between the top electrode and the food sample surface (m)
thickness of the food sample (m)
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Articles in the same Issue
- Articles
- Discrimination of Volatiles of Shiitakes (Lentinula edodes) Produced during Drying Process by Electronic Nose
- Influence of Potato Flour on Dough and Steamed Bread Quality and Correlation Analysis
- Microwave-Assisted Extraction and Ultrasound-Assisted Extraction of Bioactive Compounds from Grape Pomace
- Analysis of the Heat Transfer of Ginkgo Biloba Seeds during Radio-Frequency Heating
- The Impact of an Inert Gas Atmosphere on the Kinetics of Changes in the Physical and Chemical Properties of Carrot Lyophilisate
- Special section for selected papers from VI Food Enginering Symposium (Warsaw, Poland)
- The Use of a Hybrid Drying Method with Pre-Osmotic Treatment in Strawberry Bio-Snack Technology
- The Influence of the Agglomeration Process on Stability of Microencapsulated β-Carotene
- The Impact of the Pre-Treatment in Ethanol Solution on the Drying Kinetics and Selected Properties of Convective Dried Apples
- Influence of the Freeze-drying Conditions on the Physicochemical Properties and Grinding Characteristics of Kiwi
- The Influence of Osmotic Dehydration Conditions on Drying Kinetics and Total Carotenoid Content of Kiwiberry (Actinidia Arguta)
