Volume 37, Issue 4 (2021)
Frontier View
Research progress on formation mechanism and influencing factors of egg yolk gel
ZHANG Gen-sheng, XU Yi-meng, YU Shi-you, and PAN Lei
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.001
In this review, gelation process, physicochemical properties and formation mechanism of egg yolk gel induced by heat, alkali and freezing were introduced. On this basis, the effects of different factors on heat-induced gel, alkali-induced gel and freezing-induced gel were elaborated, and the research direction of egg yolk gel was prospected.
Fundamental Research
Effects of ultrasound-assisted glycation on the allergenicity of β-lactoglobulin during digestion
MA Qiu-ping, WANG Hui, TU Zong-cai, WEN Ping-wei, and HU Yue-ming
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.002
The method of indirect competitive ELISA, scanning electron microscopy (SEM) and dynamic light scattering (DLS) were used to study the ultrasound-assisted glycation with lactose (UAG) on changes in allergenicity and structure of β-lactoglobulin (β-Lg) during digestion in vitro. The results showed that the allergenicity and the degree of hydrolysis of UAG modified β-Lg had a reduced during gastrointestinal digestion. Glycation limited β-Lg to form a smaller particle structure during gastric digestion, then aggregated during intestinal digestion. The fluorescence intensity first increased and then decreased, and the maximum emission wavelength appeared red shift. These results indicated that UAG modification could effectively reduce the allergenicity of protein during digestion. The decrease of allergenici-ty was closely related to structural changes of UAG modification.
Study on quality kinetics of fermented sour meat during cooking
WU Hui-lin, LI Miao-yun, ZHAO Li-jun, ZHAO Gai-ming, and ZHU Yao-di
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.003
Kinetic analysis was carried out on the dynamic changes of ripening factors (color, shear force) and superheating factors (water activity, water content) during the heating process of fermented sour meat in 70~80 ℃water bath. The results showed that the changes of ripening factor (color, shear force) and superheating factor (water activity, water content) of fermented sour meat were all in accordance with the first-order kinetic equation, the Z value of brightness value was 63.751 ℃ and the Ea value was 4.016 kJ/mol; The Z value of redness change was 35.500 ℃, Ea value was 4.029 kJ/mol, and the Z value of yellowness change was 32.459 ℃, Ea value was 4.031 kJ/mol. Z value of shear force was 102.070 ℃, Ea value was 4.047 kJ/mol. The Z value of water activity was 55.118 ℃, the Ea value was 3.643 kJ/mol. The Z value of water content was -2.366 ℃, and the Ea value was 4.034 kJ/mol. The Z values of the color redness and yellowness of the ripening factors were less than the Z values of the water activity. The Z values of the brightness value and shear force of the ripening quality factor were greater than those of the water activity and water content during cooking of the overheated quality factor. The changes of the brightness value and shear force value were contrary to those of the optimized cooking conditions, indicating that the ripening and overheating factors of the fermented sour meat were optimized during the heating process The quality of fermented sour meat needs to be further optimized.
Analysis of fatty acid profile in metabolites and cells of five Bifidobacterium strains by GC-MS
CHEN Shi-yang, LIU Feng-ying, CHEN Hui-min, CHEN Li-jun, and CHEN Shu-xing
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.004
Gas chromatography-mass spectrometry (GC-MS) was used to analyze fatty acid profile in metabolites and cells of five strains of Bifidobacterium. The results showed that the fatty acid content of different Bifidobacterium was significantly different among the metabolites, and there were some differences among the cells. Differences of fatty acid were also found among the same Bifidobacteriium strains derived from different sources. Methyl palmitate (C16:0), methyl lignocerate (C24:0), and methyl stearate (C18:0) were the main fatty acids in metabolites and cells of the five strains. Among them, the C16:0 was significantly different (P＜0.05), and the content ratio of C16:0 to C18:0 was between 2.607 and 3.120; the content ratio of acetic acid to lactic acid was between 2.085 and 2.295. Compared with the metabolites, methyl erucate (C22:1n-9), methyl nervonate (C24:1n-14), methyl 5, 8, 11, 14, 17-eicosapentaenoate (C20:5n-3) were not detected in the cells of the five strains.
The relationship between selenium-containing rice milling rate and selenium loss in Jiangjin district, Chongqing
SUN Rui, ZHONG Geng, ZHANG Yang, ZENG Zuo-hua, and FANG Li-kui
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.005
19 kinds of selenium-containing rice were collected from 7 towns in Jiangjin District, and the influence of milling on the selenium content of rice was investigated. Significant differences were found in the selenium content in different varieties of brown rice (P<0.05). Yuxiang 203, Jing 1 You Huazhen, Q Xiang You 100 and Jing Liang You 510 had stronger selenium accumulation ability. Under the influence of rice varieties and planting environment, rice bran with different milling rate, selenium content and selenium loss in the milling process were different. The selenium content in rice bran of Yuxiang 203 and Jing1 Youhuazhen was higher, up to 0.82 mg/kg, which could be widely used as selenium-rich by-products produced in the processing process. All the samples showed that higher milling rate could cause higher processing precision and higher loss rate of selenium, and the highest loss rate of selenium was up to 44.39%. During the milling process, the selenium loss of Jing1 Youhuazhen and Jing Liang You 510, planted in Jiasui Town, Q Xiang You 100, and Yuxiang 203 planted in Baisha town and Zhongshan town, was relatively small. After grinding the 80 s, the selenium content in first-grade polished rice could still reach the level of selenium enrichment.
The effect of pH and buffer systems on the inhibition of lipoxygenase activity by plant polyphenols
YE Feng-ling, JIA Li-rong, HE Qiang, and DONG Yi
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.006
In order to optimize the Ultraviolet (UV) spectrophotometric method for determination of polyphenols inhibiting LOX activity, and to explore the influences of the buffer systems and pH on LOX enzyme activity and polyphenol auto-oxidation, this paper studied the changes of LOX enzyme activity and the auto-oxidation of gallic acid, quercetin, catechin and 3,4-dihydroxyphenylacetic acid under different buffer systems and pH conditions. The results showed that the activity of LOX was stronger under alkaline conditions, and the 4 polyphenols had the weakest self-oxidation in the borate system and the strongest self-oxidation in the Tris-HCl system. The higher the pH in each system, the stronger the self-oxidation of the 4 polyphenols, and the more intermediate and final products of auto-oxidation reflected in the UV spectrum. Finally, the pH 7.5 borate buffer was determined as the detection buffer system. It was found that LOX enzyme activity decreased first and then rised with the increase of 4 kinds of polyphenol concentration. The inhibitory effect of 4 kinds of polyphenols on LOX enzyme activity was in order: quercetin＞catechin＞gallic acid＞3,4-Dihydroxyphenylacetic acid.
Rheological properties of fenugreek gum on improving the safety of drinking water in nursing dysphagia
HAO Lu-lu, WANG Ling, SHANG Long-chen, and LI Bin
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.007
In this paper, according to the American Dysphagia Diet standard, based on the viscosity at 50 s-1, fenugreek gum was prepared into thickening fluids with viscosity of 180 cP(nectar),1 000 cP(honey) and 2 500 cP(pudding), that the rheological properties had been systematically studied to evaluate the potential of fenugreek gum in improving the safe drinking water of patients with dysphagia. And then the rheological properties of fenugreek gum prepared at different temperatures were further explored. The results showed that the dissolution temperature was the key to whether the rheological properties of fenugreek gum meet the requirements of drinking water safety for people with dysphagia. Similar to xanthan gum and gellan gum, fenugreek gum dissolved at 80 ℃ had the following properties: it had a significant shear thinning behavior and less dependence on the thickening level; it had the weak gel elastic properties with G′>G″ and tanδ<1. What’s more, at high thickening level, fenugreek gum dissolved at 80 ℃ had better fluidity than xanthan gum and gellan gum. Therefore, it will have a good application prospect in improving the safety of drinking water for people with swallowing disorders.
Study on absorption and desorption properties of macroporous resin for pericarps of Trapa bispinosa Roxb.
YUAN Huan, PENG Li-sha, SUN Meng-yao, CAO Qing-ming, and LONG Qi-zhi
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.008
This study describes a method for separation and purification of polyphenolics of ethyl acetate extract (EAE) of Trapa bispinosa Roxb. pericarps (TBP) by macroporous resins. The abilities of static absorption and desorption of seven kinds of macroporous resins were studied. The best macroporous resin D101 was selected. The dynamic absorption and desorption conditions were optimized as follows: 5 mg/mL of the sample concentration, 1 mL/min of the flow rate of sample loading, 70% of ethanol as the eluent, 4 mL/min of the elution flow rate and 5 BV of the elution volume. After enrichment by D101 macroporous resin, the content of total polyphenols increased from 478 mg GAE/g in freeze dried extracts to 825 mg GAE/g in purified samples by 1.73 times, and the recovery was 59.43%. In the scale-up test, the recovery and purification rate did not change with the increase of macroporous resin, indicating that the optimized conditions were suitable for large-scale production.
Safety & Inspection
Fluorescence aptasensor detection of chloramphenicol based on MnO2 nanosheet and Exo-I
MA Peng-fei, QI Shuo, LU Yan, ZHOU You, and WANG Zhou-ping
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.009
In order to develop rapid detection method for chloramphenicol in food, in this study, a novel chloramphenicol aptasensor was constructed based on fluorescence quenching ability of MnO2 nanosheet and fluorescence amplification ability of Exo-I digestion. Results showed that under optimal fluorescence detection conditions of 50 nmol/L concentration of aptamer, 0.05 mg/mL concentration of MnO2 nanosheet, 0.4 U/μL concentration of Exo-I and Exo-I digestion time of 50 minutes, and the fluorescence intensity had a good linear relationship with the concentration of chloramphenicol (R2=0.995). The linear range of detection was 0.1~80.0 nmol/L with the detection limit of 0.08 nmol/L. The constructed detection approach had the advantages of simple operation and high sensitivity, and could realize accurate detection of chloramphenicol in food samples.
Determination of total fluorine in tea by nuclear magnetic resonance spectroscopy combined with oxygen bomb combustion
ZHOU Mi, HAN Zhi, ZHU Zheng-wei, ZHU Song-song, WANG Hui-xia, JIANG Feng, and ZHU Qian
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.010
Quantitative analysis of total fluorine in tea was established by using 19F quantitative nuclear magnetic resonance combined with the pretreatment method of oxygen bomb combustion. The 19F qNMR method used the signal characteristic of fluoride ion at δ=-119 as the qualitative peak and the signal characteristic of trifluoroacetic acid at δ=-75 as the internal standard peak. The fluorine-containing substances in tea sample was burned by oxygen bomb and converted into inorganic fluorine. Mixed metal chelating agent which included sodium citrate and disodium EDTA was added to eliminate interference and then the absolute content of fluoride ion in tea was determined. The minimum detection concentration of the method is 2.0 μg/mL. The results of the quality control samples were satisfactory. The recovery rate of the actual samples were 96.3%~107.0% and the method repeatability and precision were good. The sample test can be completed within 30 minutes which effectively reduces the analysis time and the measurement result is accurate and reliable by using the method to determine the total fluorine content in tea.
Detection of foodborne pathogenic bacteria based on hyperspectral imaging
DUAN Peng-sheng, XU Jin-chai, CHEN Yi-lei, YE Da-peng, and WENG Hai-yong
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.011
Aiming at the problem of foodborne pathogenic bacteria detection process is time-consuming, composed a application highlights like technology obtained 12,18,24 h 3 phase 5 kinds of pathogenic bacteria [Staphylococcus aureus (S. aureus), Listeria monocytogenes (LM), Diarrheagenic e.coli (DEC), Salmonella enteritidis (SE) and Shigella spp flexneri (S. flexneri)] of hyperspectral image, using successive projections algorithm (SPA) in combination with relevant analysis (CA) to extract various growing pathogenic bacteria sensitive wave bands and established the least squares support vector machines (LS-SVM) discriminant model. The results showed that the reflectivity of the five types of pathogens to different wavelengths of light was different. The reflectance of the five sensitive bands (462,498,649,853,979 nm) screened by SPA-CA could well reflect the spectral characteristics of the five types of pathogens at different growth stages. The LS-SVM model based on the reflectance of this sensitive band can effectively identify S. aureus, LM and DEC, while SE and S. flexneri are easily misjudged by each other. The probability of SE being misjudged as S. flexneri is 11.2%, and the probability of S. flexneri being misjudged as SE is 19.9%. The overall recognition accuracy of LS-SVM model was 90.9% for the five types of pathogenic bacteria. In conclusion, hyperspectral imaging combined with stoichiometry has the ability of rapid diagnosis of foodborne pathogens.
Research on the application methods of classifying and recognizing Baijiu wine based on deep learning
LIU Xin, HAN Qiang, ZHOU Yong-shuai, and TUO Xian-guo
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.012
A deep learning-based model for the classification and prediction of Baijiu wine brands is developed, combining with the Tensorflow and Keras frameworks. The test sample data set is established by collecting the feature information of Baijiu wine to be tested through an electronic tongue (an array sensor), combining the known Baijiu wine categories with that of the unknow one (to be test). Then the deep learning-based Baijiu wine brand classification prediction model was trained and tested for, preparing for the performance by using the trainedand tested sets. The results showed that the prediction model achieves 99.987% of Baijiu wine brand recognition rate, showing a high accuracy.
Administrative supervision system of internet food trade in Germany and the enlightenment to China
SHAO Ru-hua
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.013
The administrative supervision system for online food trade in Germany was built by German Federal Consumer Protection and Food Safety Office mainly based on 《German Food, Commodity and Feed Law》and other relevant laws and regulations, the German official monitoring center of e-commerce in food and D21 Quality Criterion. From the perspective of German mature administrative supervision system for online food trade, China has not yet set up an administrative agency which unifies and coordinates organization for online food safety, a unified operation platform for the administrative supervision of online food trade and a widely acknowledged quality certification criterion. Therefore, establishing a coordinative department, a unique monitoring center, and taking the HACCP as the core standard certification for online food are good ways for Chinese administrative supervision system to develop online food trade.
Uncertainty evaluation for determination of free gossypol in vegetable oil by high performance liquid chromatography
LONG Jin-lin, WANG Chun-lin, TAO Yin-feng, SUN Xiao-han, and LI Shuo
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.014
According to the detection method of free gossypol in vegetable oil，this paper establishes a mathematical model of uncertainty evaluation for determination of free gossypol in vegetable oil . The main sources of uncertaintyin measurement arising from procedure of testing were analyzed and evaluated. The evaluation results showed that the fitting of standard curve, the performance of liquid chromatograph and the repeatability of sample pretreatment made great contribution to the uncertainty of free gossypol detection results. When the content of free gossypol in edible oil was 48 mg/kg, the expanded uncertainty was 5 mg/kg (k=2).
Comprehensive evaluation model of heavy metal pollution in meat products based on best-worst method and entropy method
WANG Xian-fa, CHEN Yi, and SUN Yue-hong
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.015
In order to evaluate the degree of heavy metal (Cd, Cr, Pb, As) pollution in different meat products and different regions comprehensively and quantitatively, a comprehensive evaluation method of heavy metal pollution in meat products based on the best-worst method (BWM)-entropy(E) model was proposed. Firstly, Building a comprehensive evaluation index system based on heavy metal toxicity and content. Then, the best-worst method was applied to evaluate the degree of heavy metal pollution in various meat products. Finally, the entropy method was used to comprehensively evaluate the degree of heavy metal pollution in different regions. The case study used in this study was from the results of heavy metal detection results on four meat products in five cities of a province. For the degree of heavy metal pollution in the different meats products, the ranking of results from higher to lower by two methods, the Nemero index method and over-standard rate, were dried cooked meat pro-ducts＞cured meat products＞sauced meat products＞smoked and boiled sausage and ham products, and cured meat products＞sauced meat products＞dried cooked meat products＞dried cooked meat products, respectively. However, the ranking of results from higher to lower by the comprehensive evaluation value proposed by this study was sauced meat products＞cured meat products＞dried cooked meat products＞dried cooked meat products. For the degree of heavy metal pollution over different regions, the ranking of results from higher to lower by two methods, the Nemero index method and over-standard rate, were city A＞city C＞city B＞city E＞city D, and the ranking of result is consistent with that of the method of this study. Comparing above ranking results by the two methods, and the comprehensive evaluation method of this paper, the same and different aspects were found. The reason for the discrepancy was that the comparison methods had limitations in terms of the completeness of evaluation. Our evaluation model in this study can evaluate the degree of heavy metal pollution more comprehensively and effectively, and can highlight the difference in degree of heavy metal pollution among different regions.
International experiences and inspirations of dairy product safety and quality supervision
ZHANG Li-ping
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.016
At present, the quality and safety supervision of dairy products in China are facing many challenges. Some successful experiences and advanced technologies in dairy product quality and safety supervision, safety risk assessment, quality standards and safety standards, management mode, and the examination system of in developed countries, such as Europe and the United States, were reviewed. It was concluded that, to improve the Chinese dairy products quality and safety supervision system, the integrated use of economic, administrative and legal means should be used to strengthen the macro-control. Moreover, strategies including constructing a safety-oriented inspection and testing system, speeding up technical research, standardizing the process control of production, processing and sales, strengthening the source management, promoting the union of producers and industry self-discipline, and giving full play to the market mechanism are also necessary.
Machine & Control
Simulation in counter-rotating twin screw extruder by adaptive grid technology
AN Qi, HUANG Zhi-gang, HU Shu-zhen, MI Guo-qiang, and LI He
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.017
Applied the existing adaptive grid technology to the counter-rotating twin-screw extruder, useed Autocad software to draw the end profile of the counter-rotating thread element, and establisheed the corresponding 3D model on the Solidworks software. Then imported the geometric model Gambit software for mesh generation. Selecting the adaptable mesh technology of Polyflow software, the mesh of the fluid channel is locally densified according to the Maxdiv value. The finite element solution task of isothermal transient flow problem of counter-rotating twin-screw was designed, and the Maxdiv value was also studied. The effects of the value were studied, on the shear rate field, viscosity field, and pressure field of the flow channel. And compared the effects of the number of mesh refinements in the adaptive grid technology on the computing resources. It is showed that Application potential of the method in the twin-screw extrusion process during the simulation.
Motion reliability analysis of pre-formed cam-link assembly mechanism of aseptic filling machine
HE Xian-rong, PAN Liao, LU Li-xin, LIN Zi-dong, and LI Fu-man
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.018
In order to ensure that the designed cam meets the requirements of high precision and stable motion of the end position of the actuator under the high speed state of the aseptic filling machine. Based on the harmonic analysis method, the dynamic response of the design of the pre-formed cam mechanism end in different working sections is checked. Under the ADAMS environment, the dynamic simulation of the cam mechanism obtains the trajectory of the end gripper of the actuator and the kinematics and dynamic characteristic curve of the mechanism at the working speed. The results show that the clamping jaws at the end of the actuator meet the requirements of no obvious vibration response; the pre-formed cam-link combination mechanism requires that the cam and the roller keep good contact at the speed, and the angular acceleration curve of the swing arm is gentle, which provides a basis for the actual use of the cam mechanism.
Conjugate tooth profile solution and meshing analysis of harmonic drive based on envelope theory
LI Peng-chao, HE Xue-ming, LU Li-xin, and LIN Zi-dong
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.019
In order to solve the problem of complex derivation of conjugate tooth profile in harmonic drive, a method based on the trajectory envelope of flexspline is used to solve the conjugate tooth profile, and the different tooth height along the axial direction of the flexspline profile is adjusted to avoid interference between the flexible gear and the conjugate steel gear. In order to analyze the influence of tooth root circle radius and torque on the stress of flexspline, a multi-body contact model was established by ANSYS Workbench to explore the influence of root circle radius and torque on the stress of flexspline. The results show that the sensitivity of flexspline stress to tooth profile parameters is higher than that of torque, because harmonic drive is multi tooth meshing transmission, the stress of single tooth is smaller, and the influence of load on flexspline stress is less than that of tooth profile parameters.
Development of a continuous laser scanning electromechanical system for brown rice profile cross section
YANG Si-ping, TANG Xiao-hua, LI Tian-jiao, ZHENG Long-an, and AN Jia-qiang
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.020
A laser scanning contour measuring device for brown rice was developed. The mechanism principle of the device was adapted to the point cloud data collection representing the geometric characteristics of brown rice. It has the functions of mutually vertical triaxial movement and two-axis rotation to realize the circular sweep of the ellipsoid of brown rice, the deflection of the embryo and the linear sweep of its main section. The ellipsoid of brown rice was measured by circular discrete and continuous laser scanning. The results showed that the continuous and discrete scanning data were consistent in describing the surface of brown rice, and the errors met the test requirements. The experimental device could realize the effective data acquisition of the main section of germ by linear discrete scanning.
Dynamic performance analysis of the herringbone transmission system of konjac fine flour
HU Qing-ming, HOU Jun-peng, XU Chang-shun, SUN Dan-dan, YANG Ming, BAI Song, and GUO Jian-hua
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.021
Taking the fourth-stage transmission system of the konjac flour machine as the research object, a multi-body dynamic model was established based on the straight tooth synchronous belt and double helical synchronous belt with new profile, and the influence of the tooth line shape on the belt tooth stress and system vibration was analyzed. Then the influence of the structural parameters of the helix angle and the dislocation coefficient between the teeth on the dynamic performance of the transmission system were investigated. The results showed that when the toothed helix angle β was 30° with the inter-tooth dislocation coefficient k of 0.00, the tooth root stress of the belt tooth was smaller. Under this condition, the stress distribution was more uniform, and the lateral vibration was smaller, with lower transmission error and smaller interference fluctuation.
Anomaly vibration detection method of the refrigeration compressor based on autoencoder
WANG Yuan-tao, FENG Tao, SUN Qia, WANG Jing, and WANG Yi-han
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.022
The compressor is the core component of refrigeration equipment. This paper proposeed a method of anomaly vibration detection of refrigeration compressor based on autoencoder technology in order to solve the quality control problems in the production process of refrigeration compressor. The principle and process of anomaly vibration detection were given, based on autoencoder and the acquisition method of compressor vibration signal sample. The relationship was studied between the mean square error of the input and output of the autoencoder and the distribution of the signal samples. By means of the autoencoder model, the decision fundament of the abnormal vibration of the compressor was given. From two aspects of the autoencoder parameters and the number of training samples, this paper discussed the influence of three kind of autoencoder parameters including calculation iteration number, hidden layer number and training sample number on the detection accuracy. The study finds that the number of iterations and hidden layers has an impact on the detection accuracy, but no obvious law; the number of the training samples has a significant impact on the detection accuracy. It is an effective method to improve the accuracy of autoencoder to increase the number of training samples. The autoencoder can be used to detect anomaly vibration of refrigeration compressor.
Improvement on cigarette guide plate device of YJ19 cigarette maker
WU Shu-qing, SUN Yong, YANG Fang, and HUANG Xue-yan
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.023
In order to solve the problem of water pollution and cigarette wrinkle at the cigarette guide plate device of YJ19 Cigarette Maker, the structure of the cigarette guide plate device was improved by combining the arc groove with the air suction hole. The cigarette transferring mode was changed from closed type to open type, and then the results were validated. The experiment results showed that the unclean defect rate of cigarette lap was reduced from 1.45% to 0, and the wrinkle defect rate of cigarette decreased from 1.16% to 0.30%. The quality of cigarettes has been improved.
Storage Transportation & Preservation
Effect of storage conditions on protein quality of walnut kernel
PENG Wu, WANG Wei-qing, WANG Ping, YU Xiong-wei, FU Qing-li, and LI Shu-gang
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.027
Walnut kernel was used to research the influence of temperature and vacuum degree on its protein structure and function properties. The results showed that the quality of walnut kernel protein was significantly affected by factors of temperature and vacuum, and the influence degree of these factors was valued as: temperature > vacuum, constant temperature (35 ℃) > room temperature (25 ℃)> refrigeration (4 ℃). Moreover, with the extension of storage time, the content of sulfhydryl groups in walnut kernel protein decreased, and the content of disulfide bonds and carbonyl compounds increased. The results obtained from electrophoresis and infrared analyses indicated that the protein aggregation phenomenon occurred, and the ratio of β-sheet and random coils in the secondary structure increased, with the decrease of the ratio of α-helix to β-turn. In terms of functional properties, the surface hydrophobicity of walnut kernel protein increased, and solubility decreased, as well as its digestive properties significantly changed.
Study on drying characteristics and drying kinetic model of kiwi fruit slices in fluidized bed
ZOU San-quan, LIU Xian-xi, ZHAO Zhen-chao, and ZHANG Xue-bo
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.028
In order to improve the drying quality and shorten the drying time of kiwifruit slices, the effects were studied in different temperatures (55, 65, 75, 85 ℃), wind speed (1.5, 2.5, 3.5, 4.5 m/s) and thickness (5, 10, 15 mm) on the hot air drying curve, water effective diffusion coefficient and drying activation energy of kiwifruit slices. The results showed that the whole drying process of kiwifruit slices belonged to reduced-speed drying, and the effective water diffusion coefficient was 1.296 39×10-9 ~4.589 94×10-9 m2/s, which increased with the increase of temperature and wind speed, and decreased with the decrease of slice thickness. The activation energy of kiwifruit slices was 23.03 kJ/mol. After fitting 10 common drying kinetic models, it is found that the Logarithmic model is the best model.
Preparation of catalyst Cu/Ce0.75Zr0.25O2 and its catalytic performance in dry reforming of ethanol
HUANG Jia-miao, LI Liang-yi, CAO Dong, and HUANG Zhong-pei
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.029
Cu/Ce0.75Zr0.25O2 catalysts was prepared by urea co-precipitation with assistant of microwave. The activity and stability of the catalyst for ethanol dry gas reforming was studied. The result showed that the Cu/Ce0.75Zr0.25O2 catalyst possessing high catalytic activity. The activity increased with the rising of the reaction temperature. The catalyst stayed stable under 750 ℃ during the 90-hour reaction process and the conversion factor of ethanol remained 100%.
Extraction & Activity
Bioactivities of different solvents extracts from the ethanol extract of Rhodiola rosea
LIU Cun-fang, WEI Ling-ling, WANG Yi-ying, WU Rui, and TIAN Guang-hui
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.030
The ethanol extract was obtained from the powder of Rhodiola rosea with ethanol recycling in Soxhlet extractor, and was dissolved in water to disperse system after recovering the ethanol, then respectively extracted with cyclohexane, chloroform, ethyl acetate and butanol to get different solvent extracts. These different solvent extracts were determined total phenols and flavonoids content by a spectrophotometer, in the same time, their anti-oxidation activities were tested by DPPH· method, Fenton reaction method and prussian blue method with using Vc as a reference substance, and their antibacterial activities were evaluated by using minimum inhibitory concentration and minimum bactericidal concentration. The results showed that the highest content of total phenols and flavonoids were in ethyl acetate extract, its content was (469.32±1.15), (338.57±0.92) mg/g extract, these different solvent extracts and the aqueous extract had obvious action to scavenge effect for DPPH· and ·OH, showed a strong total reduction capacity, its ethyl acetate extract and butanol extract exhibited relatively good anti-oxidation activities, the content of total phenols and flavonoids related to the antioxidant activity (P＜0.05), the MBC values of these extracts between 0.28~16.94 mg/mL showed inhibitory activities against the nine bacteria strains, inhibited the growth of testing bacteria and sterilized them especially against Staphylococcus aureus, its chloroform extract and ethyl acetate extract were very obvious to antibacterial effect. These different solvent extracts and the aqueous extract of the ethanol extracts from Rhodiola rosea showed certain antioxidant activities and antibacterial activities, they had potential applications.
Optimization on subcritical extraction of oil from Cucumariafrondosa visceral by response surface method
XU Meng-hao, LIANG Yang, YAO Yan-yan, ZHU Ji-hai, and ZHAO Xiang-zhong
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.031
A new process for subcritical extraction of Cucumariafrondosa oil was established using freeze-dried Cucumariafrondosa visceral which is rich in lipid active substances. The subcritical extraction conditions were optimized by single factor and response surface methodology, and the best extraction process was obtained: material-liquid ratio 1∶3 （g/mL）, extraction pressure 0.4 MPa, extraction times 5 times, extraction time 56.18 min, extraction temperature 48.55 ℃, extraction rate 23.38%. By comparing the physical and chemical indexes of oil extracted by different methods and gas chromatography-mass spectrometry (GC-MS) graphs, the physicochemical indexes of oil extracted by subcritical method are better than other methods, the content of EPA in the oil reaches 40.7%, indicating that the subcritical method for extracting Cucumariafrondosa oil has high process efficiency and more stable oil quality.
Development & Application
Suitability evaluation for processing chips from different mushroom varieties
WANG Chun, DAI Yan-jun, SUN Yue, LI Xue-ling, and LIANG Jin
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.032
Using Pleurotus eryngii, Lentinus edodes, Coprinus comatus, Agaricus bisporus and Volvariella volvacea as the main raw materials and adding wheat flour, five kinds of mushroom chips were processed by air frying pan. The sensory quality, texture, color difference, flavor free amino acids and reducing sugar of the chips were comprehensively evaluated. The results showed that significant differences were found in the quality of different kinds of mushroom chips. The contents of reducing sugar and total free amino acids in five kinds of mushroom chips were 0.197~0.214 g/100 g and 88.79~334.84 mg/100 g, respectively, and the contents of delicious amino acids and sweet amino acids were higher. The sensory scores of Pleurotus eryngii and Lentinus edodes chips were higher, and the taste was crisp. The color difference values before and after processing had relatively small changes, The L* values were 67.25±0.51 and 70.02±0.87, respectively. They were attractive yellow and suitable for baking products. Coprinus comatus, Agaricus bisporus and Volvariella volvacea had strong non enzymatic browning and low L* value during processing.
Effect of germination on grain quality of tartary buckwheat and optimization of technology
TONG Xiao-meng, CHAI Chun-xiang, and WANG Yong-qiang
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.033
Using tartary buckwheat seeds as raw materials, the effects of different temperature and time during seed soaking and germination were analyzed, on the content of total flavonoids and γ-aminobutyric acid (GABA), DPPH free radical clearance rate, germination rate and bud length of tartary buckwheat seeds, and the germination conditions of tartary buckwheat tea were optimized. The results showed that the optimal germination conditions of tartary buckwheat seeds were as followd: soaking temperature 20 ℃, soaking time 8 h, germination temperature 26 ℃, and germination time 98 h. Under these conditions, the total flavonoids content of germinating tartary buckwheat was 10.34 mg/g, which was 2.27 times of the control group, and the GABA content was 2.86 mg/g, which was 1.17 times of the control group. After tea preparation, the concentration of total flavonoids in germinated tartary buckwheat tea was 7.678 mg/100 mL, which was 3.71 times that of the control group. The mass concentration of GABA was 13.142 mg/100 mL, 1.63 times that of the control group. The results of sensory evaluation were better than those of the control group. Germination treatment can improve the content of total flavonoids, GABA and sensory quality of tartary buckwheat tea.
Optimization of acetic acid fermentation process and antioxidant activity of Qiuxiang pear vinegar
YAN Fei-xiang, ZHU Dan, NIU Guang-cai, WEI Wen-yi, and WANG Si-pu
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.034
Taking the Qiuxiang pear wine as the raw materials, Huniang 1.01 acetic acid bacteria as the strain, and the total acid content as the index, the response surface methodology was used to optimize the fermentation process of fruit vinegar, and its antioxidant capacity was evaluated. The results showed that the optimum conditions for acetic acid fermentation of Qiuxiang pear vinegar were as follows: the inoculation amount of acetic acid bacteria was 9.4%, the fermentation time was 6 d, the fermentation temperature was 31 ℃, and the initial pH was 4.5. The fruit vinegar obtained under these conditions, which the total acid concentration was 54.45 g/L, was golden in color and fruity in aroma. The DPPH free radical scavenging rate, ABTS free radical scavenging rate and Fe3+ reducing capacity of Qiuxiang pear vinegar fermented by acetic acid bacteria were increased by 21.17%, 23.65% and 30.23%, respectively. It indicated that the pear vinegar had a good antioxidant activity.
Prediction and control method of moisture content after cutting based on machine learning
GAO Li-xiu, CHEN De-li, WAN Xing-miao, WANG Xing-hao, ZHU Zhi-yuan, LI Yong-hua, SHE Di, and KONG WEI-xi
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.035
In order to improve the stability of the moisture content after cutting in the production process of silk making, the matching degree of the indexes between the moisture content at the outlet of loose moisture return, the moisture content at the outlet of moistening leaf feeding and the moisture content after cutting was guaranteed. The steady state data samples of “Yunyan (A)” brand silk production process was selected and the influence variables of the model were analyzed by Recursive Feature Elimination Method (RFE). Based on the temperature and humidity prediction model of the workshop, Monte Carlo simulation, Neural Network algorithm and XGBoost algorithm were used to establish the moisture content control model after cutting. The model was tested by comparing the predicted value with the actual value. Within the error range of ±0.15% of the process standard value, the accuracy of moisture content after cutting increased from 62.57% to 86.49%. CPK compliance rate increased from 91.44% to 97.30%. The prediction and control method of the moisture content after cutting based on machine learning can realize the coordination and accurate control of the process parameters before and after cutting, and effectively ensure the stability of the moisture content after cutting in the process of silk making.
Study on toasting characteristics of different parts of tobacco
LI Jin-lan, WANG Dao-quan, LUO Deng-yan, XIAO Hong-li, and CHANG Ming-bin
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.036
Toasting characteristics of different parts of tobacco were studied based on different parts of tobacco leaves planted in Liaoning and Jiangxi Province, and the changes in physical indexes, sensory quality, and Maillard reaction products under different treatment intensity of tobacco toasting were investigated in a rotary toaster. The results showed that: ① the upper and middle cut strips should be toasted under medium or high intensity, the lower cut strips should be toasted under medium or low intensity; ② cut strips toasting treatment had a positive effect on the taste, the local mixed gas decreased, the baking aroma and burnt sweet aroma increased significantly; ③ principal component analysis showed that there was no significant correlation between sensory quality and comprehensive scores of Maillard reaction products. This study provides a new drying method for tobacco, and also provides a reference for improving the baking aroma and burnt sweet aroma of tobacco.
Advances
The progress of detection methods for norovirus in foods
LIAO Xiao-yan, CHEN Li-li, and BAI Ya-long
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.037
This paper mainly introduces the enrichment technology of norovirus, and reviews the research advances of norovirus in the nucleic acid detection, immunological detection and biosensor detection at domestic and abroad and also analyzes and compares the advantages and disadvantages of various method. Finally, the future research direction of norovirus was prospected.
Research progress on the main active components and physiological functions of sugarcane molasses and beet molasses
LI Qing-lan, CUI Chun, and WANG Wei
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.038
In this review, the application scope of molasses was summarized, and the main active substances and their physiological activities of sugarcane molasses and beet molasses were introduced. In addition, the development prospect of molasses active substances was prospected.
Effects of nanofiber from plant on stability of food emulsion
SUN Zhe-hao and LI Qiao-ling
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.039
This paper elucidates the preparation and characteristics of nanofiber from plant, analyzes influence on food emulsion stability and the research direction of its preparation and modification technology is also prospected.
Recent advances in simultaneous detection of food hazards based on aptasensor
GAO Lin-chen-meng, YE Hua, HUANG Sheng-bo, LI Zhan-ming, GUO Yuan-xin, LI Chao, and WANG Zhou-ping
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.040
The aptamers used for screening various food hazards, such as pathogens, biotoxins, antibiotics, veterinary drugs, pesticides, heavy metal ions and so on, was firstly introduced in this review, and then the advances in simultaneous detection of these food hazards based on aptasensor were summarized. Finally, the future prospects were discussed in the perspectives section.
Packaging & Design
Flat design process of cocktail packaging based on the whole life cycle concept
LIU Zong-ming, LI Chun-ping, and CHEN Wei
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.024
Combined with the concept of flat and the concept of full life cycle, the whole life cycle of cocktail packaging was proposed. Through the analysis of typical design cases, the whole life cycle of flat cocktail packaging was explained, and a complete design process of flat cocktail packaging was constructed. Taking the design of self-created cocktail brand as an example, the flat design process was verified experimentally. The results show that the flat design process is helpful for designers to judge and design flat packaging in the whole life cycle.
Analysis of tea brand packaging the visual expression from the perspective of cultural gene
XIE Qi and XU Xin-yi
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.025
From the perspective of design, the cultural gene method was introduced to collect and sort out The Tea Road cultural gene. The tea brand packaging of The Tea Road in Hunan and Hubei was used as an example, the application types and the visual expression in its design were analyzed. Our study would provide new ideas for the packaging design of different tea brands.
International experience and enlightenment of the guiding stars front of package labeling
HUANG Ze-ying and HUANG Bei-xun
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.026
This study elaborated nutritional evaluation algorithm and its characteristics, the promotion, the product search database, publicity and education activities, implementation effect of Guiding Stars labeling, summarized three enlightenments for Chinese enterprises to enter the field of FOP labeling certification, and put forward policy suggestions to promote enterprises to carry out FOP labeling certification.
Market Analysis
Research progress of intelligent equipment and technology for livestock and poultry slaughter and processing
LI Jun, XIE Bin, ZHAI Zhi-qiang, ZHANG Peng, and HOU Song-tao
Date posted: 4-28-2021
DOI: https://doi.org/10.13652/j.issn.1003-5788.2021.04.041
This review introduced the main slaughtering and processing enterprises, advanced equipment and intelligent technology at home and abroad. The research status and existing problems of existing technologies, were analyzed and expounded, and the development trend of slaughtering and processing intelligent technology and equipment were prospected.
