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Fruit and Vegetable Quality Assessment via Dielectric Sensing.

El Khaled D, Novas N, Gazquez JA, Garcia RM, Manzano-Agugliaro F - Sensors (Basel) (2015)

Bottom Line: The demand for improved food quality has been accompanied by a technological boost.A better electrical characterization of the dielectric properties of fruits and vegetables is required for this purpose.It comprehensively and chronologically covers the dielectric experiments explored for fruits and vegetables, along with their appropriate sensing instrumentation, analytical modelling methods and conclusions.

View Article: PubMed Central - PubMed

Affiliation: Departmentof Engineering, University of Almería, 04120 Almería, Spain. dalia.elkhaled@gmail.com.

ABSTRACT
The demand for improved food quality has been accompanied by a technological boost. This fact enhances the possibility of improving the quality of horticultural products, leading towards healthier consumption of fruits and vegetables. A better electrical characterization of the dielectric properties of fruits and vegetables is required for this purpose. Moreover, a focused study of dielectric spectroscopy and advanced dielectric sensing is a highly interesting topic. This review explains the dielectric property basics and classifies the dielectric spectroscopy measurement techniques. It comprehensively and chronologically covers the dielectric experiments explored for fruits and vegetables, along with their appropriate sensing instrumentation, analytical modelling methods and conclusions. An in-depth definition of dielectric spectroscopy and its usefulness in the electric characterization of food materials is presented, along with the various sensor techniques used for dielectric measurements. The collective data are tabulated in a summary of the dielectric findings in horticultural field investigations, which will facilitate more advanced and focused explorations in the future.

No MeSH data available.


Example of ε′ and ε″ variations with frequency on a logarithmic scale.
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sensors-15-15363-f001: Example of ε′ and ε″ variations with frequency on a logarithmic scale.

Mentions: The electrical linear properties of tissues and cell suspensions, because of their variation with frequency, are mostly considered to be unusual. These properties include the dielectric constant ε′ and the conductivity, which has been proven to be inversely proportional. To illustrate with an example, a graph is plotted in Figure 1 to show the variations of these parameters with frequency. An interpretation of the parameters behaviour versus frequency is to be analyzed in the discussion section to explain the curve patterns. Three distinct major steps accompany the variation of the frequency at low RF and GHz frequencies that are termed as α, β and γ dispersions. Moreover, the dielectric constants reach very high values relative to free space at low frequencies [20]. While the α dispersion remains incomplete for several reasons, the β dispersion is due to the cellular structure of tissues and occurs in the range of 0.1 to 10 MHz. The γ dispersion was noted above 1 GHz for a variety of tissues and protein solutions. In addition to the main dispersion that is due to plasma membranes, the β dispersion possesses additional dispersions on the high frequency side [21].


Fruit and Vegetable Quality Assessment via Dielectric Sensing.

El Khaled D, Novas N, Gazquez JA, Garcia RM, Manzano-Agugliaro F - Sensors (Basel) (2015)

Example of ε′ and ε″ variations with frequency on a logarithmic scale.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541835&req=5

sensors-15-15363-f001: Example of ε′ and ε″ variations with frequency on a logarithmic scale.
Mentions: The electrical linear properties of tissues and cell suspensions, because of their variation with frequency, are mostly considered to be unusual. These properties include the dielectric constant ε′ and the conductivity, which has been proven to be inversely proportional. To illustrate with an example, a graph is plotted in Figure 1 to show the variations of these parameters with frequency. An interpretation of the parameters behaviour versus frequency is to be analyzed in the discussion section to explain the curve patterns. Three distinct major steps accompany the variation of the frequency at low RF and GHz frequencies that are termed as α, β and γ dispersions. Moreover, the dielectric constants reach very high values relative to free space at low frequencies [20]. While the α dispersion remains incomplete for several reasons, the β dispersion is due to the cellular structure of tissues and occurs in the range of 0.1 to 10 MHz. The γ dispersion was noted above 1 GHz for a variety of tissues and protein solutions. In addition to the main dispersion that is due to plasma membranes, the β dispersion possesses additional dispersions on the high frequency side [21].

Bottom Line: The demand for improved food quality has been accompanied by a technological boost.A better electrical characterization of the dielectric properties of fruits and vegetables is required for this purpose.It comprehensively and chronologically covers the dielectric experiments explored for fruits and vegetables, along with their appropriate sensing instrumentation, analytical modelling methods and conclusions.

View Article: PubMed Central - PubMed

Affiliation: Departmentof Engineering, University of Almería, 04120 Almería, Spain. dalia.elkhaled@gmail.com.

ABSTRACT
The demand for improved food quality has been accompanied by a technological boost. This fact enhances the possibility of improving the quality of horticultural products, leading towards healthier consumption of fruits and vegetables. A better electrical characterization of the dielectric properties of fruits and vegetables is required for this purpose. Moreover, a focused study of dielectric spectroscopy and advanced dielectric sensing is a highly interesting topic. This review explains the dielectric property basics and classifies the dielectric spectroscopy measurement techniques. It comprehensively and chronologically covers the dielectric experiments explored for fruits and vegetables, along with their appropriate sensing instrumentation, analytical modelling methods and conclusions. An in-depth definition of dielectric spectroscopy and its usefulness in the electric characterization of food materials is presented, along with the various sensor techniques used for dielectric measurements. The collective data are tabulated in a summary of the dielectric findings in horticultural field investigations, which will facilitate more advanced and focused explorations in the future.

No MeSH data available.