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蜜瓜和西瓜果汁的射频介电特性及其与糖度的关系 被引量:39
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作者 郭文川 Smart O. Nelson +1 位作者 Samir Trabelsi Stanley J. Kays 《农业工程学报》 EI CAS CSCD 北大核心 2008年第5期289-292,共4页
为了解果汁的介电特性与其主要内部品质——糖度之间的关系,该文利用末端开路的同轴探头和阻抗分析仪测量了10 MHz~1.8 GHz的频率范围内不同成熟度的3个品种密瓜汁和4个品种西瓜汁的介电特性,同时测量了反映果汁糖度的可溶性固形物含... 为了解果汁的介电特性与其主要内部品质——糖度之间的关系,该文利用末端开路的同轴探头和阻抗分析仪测量了10 MHz~1.8 GHz的频率范围内不同成熟度的3个品种密瓜汁和4个品种西瓜汁的介电特性,同时测量了反映果汁糖度的可溶性固形物含量和果肉的含水率,分析了介电特性和糖度间的关系。结果显示:密瓜和西瓜果汁的相对介电常数和介质损耗因数皆随频率的增大单调减小,品种间的差异对介电特性有影响;1.8 GHz下密瓜汁的损耗角正切与糖度有较好的线性关系,其决定系数为0.784,但西瓜汁的介电特性与糖度的相关性较差;密瓜和西瓜果汁的糖度与果肉的含水率有很好的线性相关性,其决定系数分别为0.973和0.906。该研究将为基于介电特性的果汁糖度检测仪的开发提供了研究基础。 展开更多
关键词 蜜瓜 西瓜 果汁 介电特性 可溶性固形物含量 含水率
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Near-Infrared Analysis of Peanut Seed Skins for Catechins 被引量:2
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作者 Ronald A. Holser 《American Journal of Analytical Chemistry》 2014年第6期378-383,共6页
Peanuts (Arachis hypogea) produce several phenolic compounds such as catechins that may be isolated as co-products from peanut seed testae or skins during peanut processing. Peanut skins are currently underutilized al... Peanuts (Arachis hypogea) produce several phenolic compounds such as catechins that may be isolated as co-products from peanut seed testae or skins during peanut processing. Peanut skins are currently underutilized although they are a potential source of bioactive compounds for use in functional foods and animal feeds. The phenolic compounds in the skins can degrade during processing and lose bioactivity. Extracted peanut skins were analyzed by near-infrared (NIR) spectroscopy to detect phenolic compounds. Spectra were collected from 10000 - 4000 cm﹣1 and evaluated by principal component analysis (PCA) to compare differences in peanut skins before and after alcohol extraction. PCA of derivative spectra showed clear separation into two groups. These results support the development of predictive models to measure catechins in blanched peanut skins. 展开更多
关键词 ANTHOCYANIDINS ARACHIS hypogea NEAR-INFRARED Phenolics SPECTROSCOPY
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Application of NIR Reflectance Spectroscopy on Rapid Determination of Moisture Content of Wood Pellets 被引量:1
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作者 Jaya Sundaram Sudhagar Mani +1 位作者 Chari V. K. Kandala Ronald A. Holser 《American Journal of Analytical Chemistry》 2015年第12期923-932,共10页
NIR spectroscopy was used to measure the moisture concentration of wood pellets. Pellets were conditioned to various moisture levels between 0.63% and 14.16% (wet basis) and the moisture concentration was verified usi... NIR spectroscopy was used to measure the moisture concentration of wood pellets. Pellets were conditioned to various moisture levels between 0.63% and 14.16% (wet basis) and the moisture concentration was verified using a standard oven method. Samples from various moisture levels were separated into two groups, as calibration and validation sets. NIR absorption spectral data from 400 nm to 2500 nm with 0.5 nm intervals were collected using pellets within the calibration and validation sample sets. Spectral wavelength ranges were taken as independent variables and the MC of the pellets as the dependent variable for the analysis. Measurements were obtained on 30 replicates within each moisture level. Partial Least Square (PLS) analysis was performed on both raw and preprocessed spectral data of calibration set to determine the best calibration model based on Standard Error of Calibration (SEC) and coefficient of multiple determinations (R2). The PLS model that yielded the best fit was used to predict the moisture concentration of validation group pellets. Relative Percent Deviation (RPD) and Standard Error of Prediction (SEP) were calculated to validate goodness of fit of the prediction model. Baseline and Multiple Scatter Corrected (MSC) reflectance spectra with 1st derivative model gave the highest RPD value of 4.46 and R2 of 0.95. Also it’s SEP (0.670) and RMSEP (0.782) were less than the other models those had RPD value more than 3.0 with less number of factors. Therefore, this model was selected as the best model for moisture content prediction of wood pellets. 展开更多
关键词 Wood PELLETS NIR Reflectance Spectroscopy MOISTURE Content Partial Least SQUARE RELATIVE PERCENT Deviation
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Analysis of Peanut Seed Oil by NIR
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作者 Babankumar Bansod Ritula Thakur Ronald Holser 《American Journal of Analytical Chemistry》 2015年第12期917-922,共6页
Near infrared reflectance spectra (NIRS) was collected from Arachis hypogaea seed samples and used in predictive models to rapidly identify varieties with high oleic acid. The method was developed for shelled peanut s... Near infrared reflectance spectra (NIRS) was collected from Arachis hypogaea seed samples and used in predictive models to rapidly identify varieties with high oleic acid. The method was developed for shelled peanut seeds with intact testa. Spectra was evaluated initially by principal component analysis (PCA) followed by partial least squares (PLS). PCA performed with full spectra and reduced spectra with one principal component accounted for 97% to 99% variability, respectively. The PLS model generated from first derivative spectra provided a standard error of prediction (SEP) of 7.7204808. This technique provides a non-destructive method to rapidly identify high oleic peanut seeds to support the selection and cultivation of high oleic acid peanut varieties. The method can also be useful at peanut processing facilities for screening and quality assessments. 展开更多
关键词 CHEMOMETRICS INFRARED Spectroscopy OILSEED Oleic ACID Quality Control
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Docosahexaenoic Acid Ester Degradation Measured by FTIR-ATR with Correlation Spectroscopy
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作者 Ronald A. Holser 《American Journal of Analytical Chemistry》 2014年第6期373-377,共5页
Highly unsaturated fatty acids such as docosahexaenoic acid and linolenic acid are prone to oxidation with a resulting loss of bioactivity and generation of malodorous degradation compounds. Degradation proceeds by fo... Highly unsaturated fatty acids such as docosahexaenoic acid and linolenic acid are prone to oxidation with a resulting loss of bioactivity and generation of malodorous degradation compounds. Degradation proceeds by formation of the corresponding hydroperoxyl free radical with subsequent oxidative cleavage at the double bond site. FTIR-ATR was used to detect degradation through spectral changes that were correlated to oxidative degradation. The spectrometer was equipped with a heated stage so that a series of spectra could be collected while the sample was exposed to elevated temperatures. The appearance of new bands at 972.8 cm﹣1, 2934 cm﹣1, and 3498 cm﹣1 with the disappearance of bands at 703.6 cm﹣1 and 3013 cm﹣1 were observed after heating and these spectral changes were evaluated by correlation spectroscopy analysis. These results provide a method to quickly detect the oxidative degradation of polyunsaturated fats. This approach is expected to be applied for the quality assessment of feed formulations fortified with omega-3 fatty acids. 展开更多
关键词 Correlation SPECTROSCOPY INFRARED SPECTROSCOPY Polyunsaturated ACID Linolenic ACID
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Nondestructive Determination of Moisture Content in Dry Fruits by Impedance and Phase Angle Measurements
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作者 Chari V. Kandala Ron Holser +1 位作者 Jaya Sundaram Naveen Puppala 《Journal of Sensor Technology》 2015年第4期73-80,共8页
An electronic method to estimate the moisture content (MC) of dry fruits by measuring the impedance (Z) and phase angle (θ) of a cylindrical parallel-plate capacitor with dry fruit sample between the plates, using a ... An electronic method to estimate the moisture content (MC) of dry fruits by measuring the impedance (Z) and phase angle (θ) of a cylindrical parallel-plate capacitor with dry fruit sample between the plates, using a CI meter (Chari’s Impedance meter) at 1 and 9 MHz is described. Capacitance C was derived from Z and θ, and using the C, θ, and Z values of a set of dried cherries, whose MC values were later determined by the vacuum hot air-oven method, a calibration equation was developed. Using this equation, and their measured C, θ, and Z values, the MC of a group of cherries, not used in the calibration, was predicted. The predicted values were compared with their air-oven values. Similar predictions were done using the same method on dried blueberries. The method worked well with a good R2 value, and showed a low standard error of prediction (SEP) in the measured MC range between 5% and 30% for cherries, and 9% and 22% for blueberries. 展开更多
关键词 CHERRIES BLUEBERRIES CI Meter Moisture Content CAPACITANCE IMPEDANCE Dry FRUITS
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Lipid Encapsulated Phenolic Compounds by Fluidization
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作者 Ronald A. Holser 《Journal of Encapsulation and Adsorption Sciences》 2013年第1期13-15,共3页
Phenolic compounds exhibit antioxidant and antimicrobial activities with applications as functional food and feed additives. Ferulic acid, a phenolic compound present in grain crops and lignocellulose biomass, was enc... Phenolic compounds exhibit antioxidant and antimicrobial activities with applications as functional food and feed additives. Ferulic acid, a phenolic compound present in grain crops and lignocellulose biomass, was encapsulated with saturated triglycerides using a laboratory fluidizer. Stability of the encapsulated ferulic acid particles was evaluated over a 3 month storage period. Laser light scattering and fluorescence spectroscopy were used to characterize particles. Loss of ferulic acid from particles was measured by emission spectra. Results showed no significant changes in particle diameter, 717.6 nm ± 28.4 nm, or loss of ferulic acid from lipid particles during storage. This combination of renewable materials, physical processing techniques, and nondestructive analytical methods promotes sustainable agriculture. 展开更多
关键词 CAPSULE Ferulic ACID Fluidizer NANOPARTICLE Stability
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Sensing grain and seed moisture and density from dielectric properties 被引量:2
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作者 Stuart O.Nelson D.Sc.Samir Trabelsi 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2011年第1期75-81,共7页
The importance of moisture measurement in grain and seed is discussed,and a brief history of the development of moisture sensing instruments,based on sensing of dielectric properties of these materials,is presented.Da... The importance of moisture measurement in grain and seed is discussed,and a brief history of the development of moisture sensing instruments,based on sensing of dielectric properties of these materials,is presented.Data are presented graphically on the permittivities or dielectric properties of grain and seed showing their variation with frequency,moisture content,temperature,and bulk density,and references are cited for further information.More recent developments on microwave measurements for moisture content and bulk density sensing are briefly described,and numerous studies are cited providing sources of information on these newer techniques. 展开更多
关键词 SENSING dielectric properties moisture content DENSITY PERMITTIVITY cereal grain OILSEED
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Disruption of Cortical Microtubules by Overexpression of Green Fluorescent Protein-Tagged a-Tubulin 6 Causes a Marked Reduction in Cell Wall Synthesis 被引量:2
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作者 David H. Burk Ruiqin Zhong +1 位作者 W. Herbert Morrison III Zheng-Hua Ye 《Journal of Integrative Plant Biology》 SCIE CAS CSCD 2006年第1期85-98,共14页
It has been known that the transverse orientation of cortical microtubules (MTs) along the elongation axis is essential for normal cell morphogenesis, but whether cortical MTs are essential for normal cell wall synt... It has been known that the transverse orientation of cortical microtubules (MTs) along the elongation axis is essential for normal cell morphogenesis, but whether cortical MTs are essential for normal cell wall synthesis is still not clear. In the present study, we have investigated whether cortical MTs affect cell wall synthesis by direct alteration of the cortical MT organization in Arabidopsis thaliana. Disruption of the cortical MT organization by expression of an excess amount of green fluorescent protein-tagged a-tubulin 6 (GFP-TUA6) in transgenic Arabidopsis plants was found to cause a marked reduction in cell wall thickness and a de- crease in the cell wall sugars glucose and xylose. Concomitantly, the stem strength of the GFP-TUA6 overexpressors was markedly reduced compared with the wild type. In addition, expression of excess GFP- TUA6 results in an alteration in cell morphogenesis and a severe effect on plant growth and development. Together, these results suggest that the proper organization of cortical MTs is essential for the normal synthesis of plant cell walls. 展开更多
关键词 Arabidopsis thaliana cell elongation cell wall synthesis cortical microtubules microtubule organization.
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