A review on non-destructive methods for the measurement of moisture contents in food items
19 Mar 2015-pp 1-6
TL;DR: In this article, a non-destructive method is proposed to measure moisture content in which grains or food items can be directly used without any process like cleaning or crushing, and the time taken to measure the moisture content using this method is less.
Abstract: Moisture content [MC] in food items should be tracked at right time with high precision as it is important for processing and storage of food items. Moisture content in some of the food grains has to be reduced to avoid its damage. In this paper we go through different techniques used to measure MC in different food grains. There are destructive and non-destructive methods to measure MC. In destructive method peanuts or samples have to be cleaned and shells are removed, so that this method is time consuming and samples are wasted. In this paper we study different non-destructive technique, to measure moisture content in which grains or food items can be directly used without any process like cleaning or crushing. Time taken to measure moisture content using this method is less.
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TL;DR: In this paper, a review of the existing moisture content measurement methods followed by an evaluation of their applicability for this proposed application in developing countries is presented, and two potential methods, equilibrium relative humidity and infrared imaging, are identified as promising techniques, but further research and development would be needed to make them suitable for use in small-scale operations in developing country.
Abstract: Background Moisture-related microbial growth is a key factor contributing to food spoilage in developing countries. Dehydration or drying of food reduces the moisture content supporting this microbial growth, thereby addressing this problem. Hence the moisture content of food materials is a key factor influencing the quality of storage thereby reducing post-harvest loss and is thus very important for the farmers. Scope and approach Current moisture measurement techniques (both destructive and non-destructive) available do not take into account the inherent difficulties in the context of developing countries including the relatively high instrumentation cost, unreliable power supply, specificity of the measurement method to food type, and training and maintenance requirements, among others. This paper includes a review of the existing moisture content measurement methods followed by an evaluation of their applicability for this proposed application in developing countries. Key Findings and Conclusions: A few recently developed instruments show promise but there is little research on how small-scale farms and co-operatives in developing countries can achieve a safe standard for their dried foods. Of these, two potential methods, equilibrium relative humidity and infrared imaging, were identified as promising techniques, but further research and development would be needed to make them suitable for use in small-scale operations in developing countries.
89 citations
05 Feb 1983
19 citations
TL;DR: An integrated circuit was interfaced with personal computer to measure the capacitance which in turn help to calculate the moisture content of rice and this technique is fast, reliable, accurate and gives hundred set of readings in few seconds.
2 citations
01 Jan 2012
TL;DR: In this article, a low-cost impedance analyzer designed by Kandala, and assembled in the National Peanut Laboratory was used to measure the impedance and phase angles of wheat and compared with the standard air-oven values.
Abstract: A simple, low cost instrument called the CI meter, that measures impedance and phase angle was used along with a parallel-plate capacitance system to estimate the moisture content (MC) of six types of wheat. MC measurement of grain is important at various stages of their purchase, processing and storage. Samples of about 150 g of wheat at different MC levels were placed separately between a set of parallel plate electrodes, and the impedance and phase angle of the system were measured at 1 and 5 MHz. The MC values of all these samples were obtained by the standard air-oven method A semi- empirical equation was developed using the measured impedance and phase angle values and the computed capacitance, and the oven MC values obtained. Multi Linear Regression (MLR) method was used for the development of the empirical equation. In the present work, a low-cost impedance analyzer designed by Kandala, and assembled in the National Peanut Laboratory was used to measure the impedance and phase angles. MC values of wheat samples in the moisture range of 9% to 25%, not used in the calibration, were predicted by the equation develop, and compared with the standard air-oven values. For over 97% of the samples tested from the six varieties of wheat, the predicted MC values were within 1% of the air-oven values. This method, being nondestructive and rapid, will have considerable application in the buying, processing, drying and storage processes of wheat and similar field crops.
2 citations
TL;DR: In this paper, a high precision impedance converter was used to measure the capacitance of paddy grains, designed integrated circuit was interfaced with the PC and frequency sweep can be done using the circuit.
Abstract: The moisture content in agricultural products is very critical. The presence of moisture also affects the quality of agricultural products like rice, wheat, nuts etc. Moisture content in food grains should be reduced and made optimum value otherwise it would encourage fungi development. The development of fungus makes the grain useless. For measuring the capacitance of paddy grains, designed integrated circuit was interfaced with the PC. The arrangement used is a high precision impedance converter. It is a 12 bit frequency generator and 1 Mega samples / sec analog to digital converter. Frequency sweep can be done using the circuit. This converter is interfaced with PC to measure the capacitance of paddy. Initially ceramic capacitors of different values were used to check the designed circuit. Then using the designed circuit, capacitance of representative amount of samples was measured and calculated the moisture content from the obtained readings. The technique is fast, simple, accurate and non-destructive method. Though the method is accurate, there is a slight variation in decimal points and the error was also corrected using Matlab.
References
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TL;DR: In this paper, the nature of the variation of dielectric properties with frequency, temperature, and product density is discussed, and graphical data on the dielectrics properties of grain and soybeans as functions of moisture content, frequency and temperature and bulk of density are presented.
Abstract: The nature of the variation of dielectric properties with frequency, temperature, and product density is discussed. Techniques for measurement of dielectric properties are briefly reviewed, and graphical data on the dielectric properties of grain and soybeans as functions of moisture content, frequency, temperature, and bulk of density are presented. Applications in the electrical measurement of the moisture content and in the dielectric heating of these materials are discussed. >
266 citations
"A review on non-destructive methods..." refers methods in this paper
...Electrical grain moisture meters have been also used previously [5,6,7]....
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TL;DR: An overview of the peanut composition in terms of the constituent biomolecules, and their biological functions is presented to highlight the usefulness of considering peanuts as an essential component in human diet considering its nutritional values.
Abstract: Peanut is a legume crop that belongs to the family of Fabaceae, genus Arachis, and botanically named as Arachis hypogaea Peanuts are consumed in many forms such as boiled peanuts, peanut oil, peanut butter, roasted peanuts, and added peanut meal in snack food, energy bars and candies Peanuts are considered as a vital source of nutrients Nutrition plays an important role in growth and energy gain of living organisms Peanuts are rich in calories and contain many nutrients, minerals, antioxidants, and vitamins that are essential for optimum health All these biomolecules are essential for pumping vital nutrients into the human body for sustaining normal health This paper presents an overview of the peanut composition in terms of the constituent biomolecules, and their biological functions This paper also discusses about the relationship between consumption of peanuts and their effect on human metabolism and physiology It highlights the usefulness of considering peanuts as an essential component in human diet considering its nutritional values
117 citations
"A review on non-destructive methods..." refers methods in this paper
...The same techniques were used to measure the MC of single peanut pods, nuts, grains inshell peanut, bio-fuel materials[wood chips and related powder], dry cherries, different types of wheat [30,31,32,33,34,38,41,45,46,47]....
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TL;DR: The importance of grain-moisture measurement and the use of electrical moisture meters are discussed briefly in this article, and suggestions are given concerning information needed to determine the best frequency ranges to use for more reliable moisture measurement of grain using electrical properties.
Abstract: The importance of grain-moisture measurement and the use of electrical moisture meters are discussed briefly. References to earlier work with such moisture meters are cited, and a brief description of the electrical or dielectric properties which such instruments depend upon is included. The information available in the literature on the dielectric properties of grain is reviewed from the viewpoint of its usefulness in grain-moisture measurement. Factors other than moisture that influence the dielectric properties of grain are discussed, and suggestions are given concerning information needed to determine the best frequency ranges to use for more reliable moisture measurement of grain using electrical properties
87 citations
"A review on non-destructive methods..." refers methods in this paper
...Due to these relations many equipments presently available in market have been developed, parallel plate capacitance or coaxial sample holders with grains between electrodes, conductance meters were used [6, 15]....
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...Electrical grain moisture meters have been also used previously [5,6,7]....
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TL;DR: Results indicate that reliable density-independent moisture content determinations can be realized by measurements on grain at RF and microwave frequencies, and development of these techniques will provide useful instruments for on-line monitoring of moisture content in flowing grain.
Abstract: A brief history of cereal grain moisture measurement by sensing the electrical properties of grain is presented. The basic principles are also described for using radio-frequency (RF) and microwave dielectric properties, or permittivity, of grain for sensing moisture through their correlation with moisture content. The development of density-independent functions of the permittivity is explained. The findings of recent research are summarized, which indicate that reliable density-independent moisture content determinations can be realized by measurements on grain at RF and microwave frequencies. Development of these techniques will provide useful instruments for on-line monitoring of moisture content in flowing grain to manage moisture in grain, prevent spoilage in storage and transport, improve processing, and provide information important for yield determinations in precision agriculture applications.
86 citations
"A review on non-destructive methods..." refers methods in this paper
...Electrical grain moisture meters have been also used previously [5,6,7]....
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TL;DR: A brief historical perspective on dielectric properties of agricultural products is presented in this article, including their use for rapid measurement of moisture content in grain and in considering potential heat-sensitive applications.
Abstract: A brief historical perspective on dielectric properties of agricultural products is presented, including their use for rapid measurement of moisture content in grain and in considering potential dielectric heating applications. General principles are discussed as they relate to dielectric properties of materials and energy absorption from radio-frequency and microwave electric fields. Measurement principles and techniques for determining the dielectric properties of agricultural materials are described, and appropriate references are cited for detailed information. Dielectric properties data for some grain, insects, fruits, and vegetables are presented that relate to applications for selective heating of insects in grain and potential maturity and quality sensing in fresh fruits and vegetables. Principles are discussed for the use of microwave dielectric properties for sensing moisture content in grain, and relationships between dielectric properties of granular and powdered materials and their bulk densities are described
82 citations
"A review on non-destructive methods..." refers methods in this paper
...So in 1908 Briggs used the same technique for the measurement of MC of wheat [8,9,10]....
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