Academy of the State Administration of Grains

Beijing, China

Academy of the State Administration of Grains

Beijing, China
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Wang Y.,Shandong Jianzhu University | Yang K.,Shandong Jianzhu University | Yu P.,Shandong Jianzhu University | Zhang X.,Shandong Jianzhu University | And 2 more authors.
Journal of the Chinese Cereals and Oils Association | Year: 2016

A diffusive moisture transfer equation for a single grain kernel was presented and solved with Finite Element Method (FEM), moisture content distribution inside the kernel were examined, and the average non-dimensional moisture content and its time-rate of change were obtained. By regression these numerical data, a kernel-average moisture model was derived, which was extended to volumetric mass transfer for a bed of kernels. Based on the kernel-average moisture model, the one-dimensional double-diffusivity heat and moisture transfer model were derived for a stationary bed of kernels, and were solved to simulate the evolution of grain temperature and moisture content of stored wheat in a warehouse during the cooling aeration with a horizontal air flow. Validation was performed by comparing between predicted and measured grain temperature and moisture content of Grain depot. Predicted data were in reasonable good agreement with measured ones, and the effect of the aeration was also evaluated. © 2016, Dept. of JCCOA. All right reserved.


Li X.-J.,Academy of the State Administration of Grains | Wang X.,Jilin University | Li Y.,Academy of the State Administration of Grains | Li Y.,Jilin University | And 2 more authors.
Computers and Electronics in Agriculture | Year: 2016

Moisture effective diffusivity and glass transition temperature (Tg) of paddy during drying were investigated by drying five varieties of paddy with an initial moisture content of 21.1–24.4% wet basis and a temperature range of 45–70 °C in a constant temperature and blast oven. With an increase in drying temperature, the desorption rate and moisture effective diffusivity of paddy kernels increased and drying duration decreased. At a drying temperature of 45 °C, the curve of the desorption rate changed slowly and drying duration was longer. Most of the five paddy varieties had similar desorption rates at drying temperatures of 45–70 °C, and their moisture effective diffusivities were in the range of 2.638 × 10−9–2.514 × 10−8 m2 min−1 with an active energy of 6.547–36.913 kJ mol−1. Tg values of long-grain variety ‘Zhunliang you’ and two medium-grain varieties ‘Zhongjia zao’ and ‘Dianjiang’ determined using the differential scanning colorimeter method increased from 38.7 °C to 51.2 °C when their moisture contents decreased from 20% to 13%. Under similar conditions, differences in Tg values of the three varieties of paddy were observed. When the moisture content of the three varieties of paddy decreases from 20% to 13% at drying temperatures of 50–70 °C, drying time should be 60–80 min for less than 10% damage to kernels. © 2016 Elsevier B.V.


Li Y.,Academy of the State Administration of Grains | Li Y.,Jilin University | Wang X.,Jilin University | Jiang P.,Academy of the State Administration of Grains | Li X.-J.,Academy of the State Administration of Grains
Journal of Stored Products Research | Year: 2016

Equilibrium moisture content (EMC) data for dried wheat noodles of ten Chinese varieties were collected by a gravimetric method at 11-96% equilibrium relative humidity (ERH) and 15 °C, 20 °C, 25 °C, 30 °C, and 35 °C. Five models were fitted to the sorption data, namely the modified Chung Pfost equation (MCPE), modified Henderson equation (MHE), modified Guggenheim Anderson deBoer equation (MGAB), modified Oswin equation (MOE), and a polynomial equation. The best fitting equations were MGAB and the polynomial equation. At a constant ERH, the EMC decreased with increasing temperature, despite the minor effect of temperature on the sorption isotherms of dried noodles. Initially, the isosteric heats of adsorption for dried wheat noodles decrease rapidly with increasing sample moisture content (m.c.); however, after the moisture content is more than 15% of the dry basis (d.b.), they decrease slowly with increasing m.c. The heat of vaporization of Chinese dried wheat noodles approaches the latent heat of pure water at a moisture content of ~20% d.b., which is ~2500 kJ/kg. The isosteric heats of sorption of Chinese dried noodles predicted by MCPE and MHE models at lower temperatures were higher than those at higher temperatures. When the equilibrium relative humidity (ERH) is 60%, the safe-storage moisture content of Chinese dried wheat noodles are 11.74% and 11.57% d.b. at 25 °C and 35 °C, respectively. Among ten varieties of dried wheat noodles, the egg-flavoured noodle had the highest onset temperature (To), peak temperature (Tp), and conclusion temperature (Tc) of gelatinization, but the golden-silk egg noodles had the highest peak enthalpy of gelatinization. The gelatinization To, Tp, and Tc of golden-silk egg noodles were the lowest. Most of the ten varieties of dried wheat noodles demonstrated similar thermal properties and hygroscopic behaviour. © 2016 Elsevier Ltd.


Li X.,Academy of the State Administration of Grains | Sakurai N.,Hiroshima University
Natural Products Journal | Year: 2012

The contents of cell wall polysaccharides in pericarp tissues of immature Hayward kiwifruit were determined during development. Two methods employed to remove starch from the crude cell wall preparations were enzymatic digestion (porcine pancreatic α-amylase and Pseudomonas iso-amylase, Method 1) and dimethyl sulfoxide extraction (DMSO, Method 2). Method 2 was more effective in removing starch than Method 1. After extensive removal of starch, cell wall materials were successively extracted with 50 mM EDTA, followed by 4% and 24% KOH. The hot EDTAsoluble (pectic) and alkaline-soluble (hemicellulosic I and -II) polysaccharides were further treated with enzymatic digestion. In subsequent amylase digestions of fractions derived from cell walls previously subjected to the two methods the glucose content was further depleted by 28-77% (Method 1) and 85-91% (Method 2) in the pectin fraction, and 51- 86% (Method 1) and 45-91% (Method 2) in the hemicellulose fractions, suggesting starch in the crude cell walls was not released by initial enzymatic treatment or DMSO extraction. Moreover, the crude cell walls yielded α-amylase activity upon extraction by 1 M NaCl, further suggesting that starch is present in the cell walls. Methylation analysis of the starch fraction revealed a molar ratio of 0.2~0.6:3.8~11.6:1 for T-Glc, 4-Glc and 4,6-Glc. The red-violet starch-iodine complex had an absorption maximum of 550~565 nm. These results provide evidence for an amylopectin-type starch present in the cell walls of immature kiwifruit. © 2012 Bentham Science Publishers.


Wu Z.,Academy of the State Administration of Grains | Li X.,Academy of the State Administration of Grains
Journal of the Chinese Cereals and Oils Association | Year: 2013

The moisture sorption isotherms of milled rice and soybean respectively from eleven and ten varieties were determined under RH 11%~96% and different temperature (10, 20, 25, 30 and 35°C) conditions and were fitted by CAE equation. For milled rice, the determination coefficient (R) >0.9911, and mean relative percentage error (MRE) < 5.048%. For soybean, R2 > 0.9777, MRE < 10.778%. As well as for soybean, the parameters in CAE model for both milled rice desorption and adsorption isotherms showed appreciable difference, consistent with a hysteresis between desorption and adsorption behavior at lower ERH. The deduced CAE models for both desorption and adsorption of milled rice or soybean were respectively used to make curve graphs for searching equilibrium absolute humidity of the grain with particular moisture at certain temperature. To the purpose of decreasing grain temperature or moisture content, or increasing grain moisture content, one can choose the curve graph for equilibrium absolute humidity of the desorption or adsorption, and quickly make decision on grain aeration operation in a depot after referring to the absolute humidity of atmosphere at that particular RH and temperature.


Li X.,Academy of the State Administration of Grains | Jiang P.,Academy of the State Administration of Grains
Computers and Electronics in Agriculture | Year: 2016

Wheat samples with low (4.97-6.08%), normal (10.11-11.04%), and high (20.7-22.72%) initial moisture content (IMC, wet basis) were used to determine the rate of moisture adsorption by the gravimetric method at 10, 20, 25, 30, and 35 °C under 65%, 86%, and 100% relative humidity (RH), respectively. A moisture diffusion equation was modified to fit the relationship between the moisture ratio of samples and exposure time. From 65% to 100% RH, the IMC of wheat samples was inversely related to the moisture adsorption rate at temperatures from 10 to 35 °C. Moisture adsorption rates of samples increased with increasing temperatures. The moisture adsorption rate of samples with the same IMC increased with increasing RH at a given temperature. A single wheat kernel was considered geometrically to be a finite homogeneous slab shape, and the analytical solution of the partial differential equation for moisture diffusion was given. The effective moisture diffusivity was calculated using the slope method by plotting the experimental data in terms of ln (MR) versus rewetting time. In the range of 10-35 °C, the effective moisture adsorption diffusivity of wheat kernels with normal moisture was 1.681 × 10-8-1.516 × 10-7 m2 h-1, and their activation energy was 23.651-28.434 kJ mol-1. For the same IMC, the effective moisture diffusivity of wheat kernels tended to increase with increasing temperature at a given RH, but decreased with an increase in RH at a given temperature. Activation energy and the pre-exponential factor of Arrhenius equation (D0) tended to decrease with increasing RH. With similar initial moisture content, winter wheat and spring wheat exhibited similar effective moisture diffusivity. © 2016 Elsevier B.V.


Li X.,Academy of the State Administration of Grains | Jiang P.,Academy of the State Administration of Grains | Lu Z.,Academy of the State Administration of Grains
Journal of the Chinese Cereals and Oils Association | Year: 2014

This paper has dealt for researching the changes in some biochemical parameters and mixolab pasting properties of sprouting-treated wheat kernels. Compared to normal kernels, the contents of total amino acids and total protein (dry basis) significantly increased during sprouting-treated kernels. Mixolab torque parameters as protein weakening (C2), starch gelatinization peak (C3), starch gelatinization minimum (C4), starch retrogradation minimum (C5) of wheat dough all decreased during sprouting-treated kernels. In comparison of wheat kernels front and back sprouting, the total free amino acids released by Bacillus amyloliquefaciens protease containing endo-types and exo-types, as well as the content of water-soluble total sugars, showed no significant changes for sprouting wheat kernels of the 6 tested varieties. Except for one variety, the other five varieties had an increase in their total free amino acids released by Aspergillus melleus protease, only containing endo-type and in their contents of water-soluble reducing sugars after sprouting treatment. The content of damaged starch in the flours of 6 wheat varieties changed inconsistently after sprouting treatment. The results showed that total free amino acids and the Mixolab dough pasting parameters as C2, C3 and C4 in wheat flour can be used to detect and evaluate the sprouting of wheat kernels.


Li X.,Academy of the State Administration of Grains | Cao Z.,Academy of the State Administration of Grains | Cao Z.,China University of Mining and Technology | Wei Z.,Academy of the State Administration of Grains | And 3 more authors.
Journal of Stored Products Research | Year: 2011

The moisture sorption isotherm data of five Chinese wheat varieties were investigated via the gravimetric static method at five different temperatures (10, 20, 25, 30, and 35 °C) and relative humidity ranging from 11.3 to 96.0%. The sorption data of wheat decreased with an increase in temperature at a constant relative humidity (r.h.). The hysteresis effect was observed between adsorption and desorption isotherms. The width and span of the hysteresis loop decreased with increased temperature, but was not influenced by the hardness of wheat varieties. Six models, namely the Chen-Clayton (CCE), Modified BET (BET), Modified-Chung-Pfost (MCPE), Modified-Henderson (MHE), Modified-Oswin (MOE) and Strohman-Yoerger (SYE), were employed to describe the experimental data. The BET, MCPE and MOE models were selected to best describe the sorption isotherms of wheat in the ranges of 11.3-49.9, 11.3-96.0 and 11.3-96.0% r.h., respectively. The hygroscopic property difference between hard wheat (cv. 'Longyuan' and 'Nanduan') and soft wheat (cv. 'Zhaozhuang' and 'Lumai') was very small. The sorption isosteric heat of wheat decreased with an increase in moisture content until the dry bulb moisture content (m.c.) of 20% was reached, and then decreased smoothly with increasing moisture content. A big difference was found between adsorption and desorption isosteric heats of wheat below 20% m.c., but the sorption isosteric heat difference between hard and soft wheat isotherms was small. © 2010.


Wu Z.,Academy of the State Administration of Grains | Li X.,Academy of the State Administration of Grains | Guo D.,Institute of Grain Storage | Wang S.,Institute of Grain Storage
6th International CIGR Technical Symposium - Towards a Sustainable Food Chain: Food Process, Bioprocessing and Food Quality Management | Year: 2011

An equilibrium moisture content (EMC) and equilibrium relative humidity (ERH) model called CAE fitted to the moisture sorption data of shelled corn from ten Chinese maize varieties with the determination coefficient (R 2)>0.9914 and mean relative percentage error (MRE)<7.19%. The parameter B1 in the CAE model for shelled corn desorptive and adsorptive isotherms showed appreciable difference, consistent with a hysteresis between their desorptive and adsorptive behaviors in lower ERH. The measured sorption isotherms among shelled corn varieties had no significant difference, in accordance with the similar parameters of CAE model. It is concluded that the shelled corns from different varieties have similar hygroscopic properties, but their adsorptive and desorptive behaviors should be differentiated from. The deduced CAE models for shelled corn adsorption and desorption were respectively used to show the variations of equilibrium absolute humidity and equilibrium RH of shelled corn at particular moisture content (m.c.) with temperature. The variation of equilibrium absolute humidity of shelled corn with temperature could clearly indicate the influence of a change in grain temperature on drying or moisture-adsorbing state of grains during aeration. Referring to the absolute humidity of atmosphere at particular RH and temperature, one can quickly make decision on grain aeration operation in a shelled corn depot.


Li X.,Academy of the State Administration of Grains | Jiang P.,Academy of the State Administration of Grains
Journal of the Chinese Cereals and Oils Association | Year: 2015

The paper has presumed that the Equilibrium Moisture Content (EMC) of grain was both the polynomial function of relative humidity (RH) and the linear function of temperature. Here an EMC/ERH model has been developed with C1~C7 as parameters. The model was used to fit the measured EMC/ERH data of the Chinese varieties including 17 rough rice, 11 milled rice, 14 wheat, 16 shelled corn, and 10 soybean which have a determination coefficients above 0.994, mean relative error (MRE) <3.46%, better than the commonly cited models such as Modified-Chung-Pfost (MCPE), Modified-Halsey (MHAE), Modified-Henderson (MHE), Modified-Guggenheim-Anderson-deBoer (MGAB) and Modified-Oswin (MOE). In comparison of the isotherms derived from the polynomial model, there were apparent hysteresis between desorption and adsorption for cereal grains, while no significant hysteresis for soybean. The relatively safe storage moisture content derived from the developed desorption polynomial equation at 30℃ was below 14% for cereal grain and 11.47% for soybean. © 2015, Editorial Department, Chinese Cereals and Oils Association. All right reserved.

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