Volume 31,Issue 4,2023 Table of Contents

1 Positioning, Practice and Influence of Chinese Food Security from the Perspective of Integrated National Security(Online First, Recommended Article)

MAO Lu-xuan , LI Xin

2023, 31(4):1-9.

[Abstract](73) [HTML](119) [PDF 569.24 K](286)

Abstract:
Since the 18th CPC National Congress, China has put forward the overall food security goal of "keeping the Chinese people's bowl firmly in their own hands" in the new era. The central leadership has introduced a food security policy of "ensuring basic self-sufficiency of grain and absolute security of staple food". The Chinese government has established a national strategy on food security featuring self-sufficiency based on domestic grain production, guaranteed food production capacity, moderate imports, and technological support. This paper summarized the consistency of food security thought in the new era and the integrated national security concept in entirety, representing the people and epochal nature. It is also summarized the successful practice of realizing food security in China under the guidance of the integrated national security concept and the new era food security thought in five aspects: systematic construction, legal guarantee, professional coordination, science technology-based surport and normalization of food saving. In the domestic, the above achievements have a positive impact on the maintenance of core interests, balancing development and security, as well as the upgrading of food industry, triggering the vigor of agricultural modernization. In the globe, Chinese food security is of great significance to the realization of the UN 2030 Sustainable Development Goals. In the new era, China has also made important contributions to stabilizing world food security and global food governance, which could be an important force in global food governance. With the Communist Party of China's 20th National Congress putting forward higher requirements for food security in a broad sense, the connotation of food security in China will be further deepened in the future.

2 The Risks and Policy Suggestions in Chinese Food Supply Security under the New Situation(Online First, Recommended Article)

LIU Yu , ZHANG Shuo , LIANG Dong

2023, 31(4):10-17.

[Abstract](93) [HTML](111) [PDF 472.76 K](256)

Abstract:
In recent years, as the unseen changes in a century and the pandemic are intertwined, the increasingly complex and uncertain external environment aggravated the risk faced by Chinese food supply security. This paper is based on the perspectives of international geopolitical conflicts, frequent extreme events, concentration of domestic food imports, emergency guarantee mechanism of agricultural products, and food supply and demand structure under the new situation. It pointed out that the security of Chinese food supply is faced with such risks as worsening international food supply and demand imbalance, increasing food supply uncertainty and cost, increasing domestic food supply vulnerability, insufficient ability to resist risks, and escalating contradiction between food supply structure and consumers’ diversified demands. Based on the research and judgment of the current risks of food supply security, this paper proposed that first of all, we should strengthen the research and development of seeds and other key technologies to optimize the grain planting structure, and use new technologies to improve the comprehensive grain production efficiency and capacity for consolidating the foundation of food security. Secondly, the emergency guarantee system of important agricultural products should be established for ensuring the effective supply of important agricultural products under the new situation. Finally, we should strengthen Chinese food trade partnership, which could promote the high-quality development of China’s food trade and enhance the competitiveness of international food trade by promoting the distribution of food industry chain in the “Belt and Road” countries. In addition, we could make use of the Regional Comprehensive Economic Partnership (RCEP) to create a good grain trade pattern, and deepering agricultural cooperation with African countries. This paper provides a reference basis for ensuring the security of food supply.

3 Promoting Reform of the Global Food Security Governance System to Strengthen the Foundation of Chinese Food Security(Online First, Recommended Article)

LIN Hai , LUO Xuan

2023, 31(4):18-27.

[Abstract](89) [HTML](123) [PDF 660.97 K](280)

Abstract:
With the liberalization of food trade and the development of the specialized division in global agriculture, global food production and consumption space are separated, and the food system of each country is increasingly dependent on the global food system. However, global food security faces unprecedented challenges due to multiple factors, such as anti-globalization, COVID-19, and climate change. This paper briefly summarized the changing trend of global food supply and demand and its impact on Chinese food security under the existing food security governance system, and elaborated the characteristics and difficulties of the current global food governance system from five aspects: food security connotation, global food supply and demand structure, international trade, governance pattern, and governance institutions. The study found that the existing food security governance system, led by developed countries, had problems such as unbalanced global food distribution, fragile supply chains, deficient governance, inadequate multilateral harmonized system, and lagging reform. To build a fairer, open and inclusive global food security governance system and strengthen the foundation of Chinese food security, it breaks the current governance deadlock and lead the reform of the global food security governance system by strengthening international agricultural cooperation, reforming the food trade system, increasing the participation of developing countries, giving full play to the driving role of digital technology, and stressing the coordination advantages of regional food security governance systems.

4 The Impact of Public Opinion on Food Security under the Internet Ecology(Online First, Recommended Article)

WANG Xiao-hui

2023, 31(4):28-35.

[Abstract](68) [HTML](122) [PDF 559.00 K](280)

Abstract:
After the global outbreak of the COVID-19 (hereinafter referred to as the "epidemic"), some major food producing countries have restricted exports, and some countries have added barriers to international trade and blocked logistics, leading to the distortion of healthy global food supply and demand relations, and the global food price has soared, causing governments and people of all countries to pay close attention to food security. The traditional factors that affect food security include changes in actual production, stock, consumption, and trade volume, which trigger changes in supply and demand relationships and affect prices. In the context of highly developed internet, the above factors, after being disseminated and fermented through the internet, will form a certain scale of social public opinion, and its dissemination effect may even distort short-term supply and demand relationships and prices, which is also an important factor affecting food security. This article takes several international and domestic food related public opinion events during the epidemic as examples to analyze the impact of public opinion on food security under the Internet ecosystem. It proposes that the foundation of food security still needs to be continuously strengthened, and that the relationship between normal and extreme thinking security, micro security and macro security, the relationship between current security and future security, and the continuous improvement of information dissemination and public opinion management under the Internet should be addressed, To provide reference for grasping the positive guidance expectations and managing the initiative of public opinion.

5 Research on Digitization in Chinese Food Security Management in the New Era(Online First, Recommended Article)

SONG Jie , ZHANG Fan , WANG Rong-jin-zi

2023, 31(4):36-41.

[Abstract](89) [HTML](122) [PDF 455.21 K](322)

Abstract:
Nowadays the digital technology led by technological enhancement has revolutionized the traditional industries, and pushed the world into an intelligent era of data-driven decision-making. Scientific innovation and digital transformation have given the grain industry new kinetic energy to accelerate the high-quality development, which is an important foundation for ensuring grain security. In the paper, we discussed the connotation and values of digitalization of food security from two aspects: daily food supply chain security and emergency food security. On the one hand, the digital technology plays a critical role in strengthening information sharing and interaction between multiple agents in the production, transportation, storage, processing and consumption of daily food supply chain, which made contribution to refining grain production and promoted the dynamic balance of food supply and demand. On the other hand, the digital technology is able to capture the detailed logic and randomness of the system, which is of great theoretical and application value for establishing the grain security management model in emergencies. It can effectively improve grain reserve capacity, optimize grain reserve layout, strengthen grain warning capabilities, achieve a dynamic balance between supply and demand of grain, improve grain emergency supply guarantee capacity, and achieve coordinated regional grain scheduling. The paper helps build a digital platform for grain emergencies, promotes intelligent decision-making in grain emergencies, which could support the digital construction of food security in China in the information age.

6 An Analysis on the Control Mode of International Grain Merchants(Online First, Recommended Article)

LI Sheng-jun

2023, 31(4):42-47.

[Abstract](18) [HTML](122) [PDF 424.28 K](307)

Abstract:
Analysing the development trend and control mode of international grain merchants in the new period has the important guiding significance for cultivating local transnational grain merchants and ensuring our country's grain security. With the change of macro environment, the international big grain merchants show three development trends: diversification of business scope, diversification of main body types, and emergence of new grain merchants. The control mode is constantly adjusted and improved, which could control both front-end grain sources and back-end food. Not the key nodes, but also the industrial chain were also controlled. Control is based on the present, but also leads the future. The internationalization road of domestic grain merchants is still in the initial stage, so we should fully learn from the successful development experience of international grain merchants, which could improve our own control, and serve the domestic work of grain supply and market stability.

7 Effect of Kneading Time on the Properties of Zein in Acidified Model Dough

LIU Hao , LI Yue , ZHENG Yan-cheng , XIE Sheng-hai , WU Dong-liang , QIAO Han , ZHAO Jin-hui

2023, 31(4):48-54.

[Abstract](50) [HTML](162) [PDF 2.34 M](234)

Abstract:
In this study, zein-based gluten-free model dough (Z dough) was prepared with zein, corn starch, and wormwood gum. Based on the flour quality test, the kneading torque, water composition and protein distribution of the zein simulated dough with different lactic acid content were compared when finish dough (torque up to 1.1 Nm; set as ZS dough) and kneading for 12 minutes (set as ZL dough) conditions. The optimal amount of lactic acid added to kneadable dough was explored, and the physical and chemical properties of zein in dough with different lactic acid content were discussed under the action of kneading for a certain period of time, which could and provide reference for the preparation of related cereal products. Studies have shown that adding a small amount of lactic acid could promote zein to build a protein network in the dough, but long-term kneading would lead to decreasing the strength of the acidified dough, destroying the continuity of the zein network in the dough, reducing the level of zein wrapping on starch granules and weak bonding in the dough. The proportion of water decreased and the proportion of free water increased. The surface hydrophobicity increased and the relative molecular weight decreased, when the deamidation reaction of zein occurred. The analysis showed that the dough gradually weakened after a long time of kneading, because the kneading effect would expand the effect of lactic acid on zein in the dough, which would increase the hydrophobicity of the protein surface and fragment the protein, and lead to a decrease in the coherence of the zein network.

8 Effect of Different Sugar Alcohols on Quality of Orange Sweet Potato Puree

XIONG Jing , WEI Jia-yi , DU Ya-xin , LI Shang-wei , XIAO Jian-hui

2023, 31(4):55-62.

[Abstract](54) [HTML](118) [PDF 984.33 K](243)

Abstract:
In this study, different sugar alcohols (maltitol, erythritol, xylitol, sorbitol) were added to make low sugar orange sweet potato puree. The effects of different sugar alcohols on rheological properties, storage color, β-carotene content and digestive properties of orange sweet potato puree were investigated. The results showed that all samples were pseudoplastic fluid. After Power-law model fitting, maltitol and erythritol significantly reduced the viscosity of sweet potato puree (P<0.05), and the system was more uniform than that of the blank group. During sterilization and storage, sugar alcohols can effectively reduce the loss of β-carotene and thus stabilize the color (color difference ΔE<4). After 21 days of storage, β-carotene content of maltitol group was 504.66 mg/kg, which was 35.5% higher than that of blank group, and corresponding antioxidant activity (clearance rate of DPPH· and ABTS+·) was also increased. After digestion in vitro, the release of β-carotene in sweet potato puree with maltitol and sorbitol were higher than 85%. In conclusion, maltitol is the optimal choice for developing low-sugar sweet potato puree.

9 FAN Jun-ying, YIN Yong-zhi, LU Cai-yun, CHUI Xing, HAN Xi-yan, WANG Bin(D.Co International Food Co., Ltd, Jiaozuo, Henan 454850, China)(Online First, Recommended Article)

FAN Jun-ying , YIN Yong-zhi , LU Cai-yun , CHUI Xing , HAN Xi-yan , WANG Bin

2023, 31(4):63-68.

[Abstract](50) [HTML](123) [PDF 1.11 M](364)

Abstract:
As a complex multiphase food, ice cream is composed of fat globules, bubbles and ice crystals dispersed in a semi-frozen solution. The fat content is usually 8%~16%, which plays an important role in the ice cream system. However, excessive fat intake can have a negative impact on health, so the use of fat substitutes to replace part or all of ice cream fat has become a research focus. This paper reviewed the research progress of fat substitutes in ice cream by domestic and foreign scholars in recent years, and focused on the introduction of different types of fat substitutes, as well as the effects on the physicochemical and sensory characteristics of low-fat ice cream. The applications were summarized and the future research direction and focus were also prospected.

10 Process Optimization and Functional Determination of Peanut Protein by Complex Enzymatic Extraction

GAO Feng , MA He , ZHANG Wen-yu , LIU Chang-jin

2023, 31(4):69-77.

[Abstract](46) [HTML](128) [PDF 2.04 M](325)

Abstract:
Peanuts were hydrolyzed step by step with various enzymes to prepare protein powder. Using peanuts as raw materials, protein extraction rate response value, enzyme addition amount, temperature, and pH as experimental factors, were used to establish a data model to optimize the extraction process with response surface. The protein powder prepared under this condition was compared with the protein powder prepared by water extraction method, single enzyme extraction method and commercially available protein. The particle size distribution, solubility, emulsification and surface hydrophobicity of protein powder extracted by compound enzyme were studied. The results showed that the optimal enzymatic hydrolysis conditions of the complex enzyme were 1.8% enzyme addition, 55 ℃ reaction temperature, and pH 9.2. Under these conditions, the protein extraction rate reached 89.21%. The particle size distribution of the protein powder prepared by the complex enzymes was uniform, and the particles were smaller, indicating that the protein solubility and emulsification were significantly improved.

11 Ultrasonic-assisted Extraction Process Optimization and Antioxidant Activity of Pectin from Hawthorn Peel Dregs

WANG Bo , YAO Lun-guang , LU Yun-feng

2023, 31(4):78-86.

[Abstract](50) [HTML](111) [PDF 2.51 M](242)

Abstract:
The purpose of this study was to determine the optimum technological parameters of ultrasonic assisted extraction of pectin from Hawthorn peel residue and study the antioxidant activity of the extracted pectin. Taking the solid-liquid ratio, extraction temperature, ultrasonic power and ultrasonic time as the research factors, on the premise of single factor experiment, the response surface experimental design method was used to establish the corresponding mathematical model and carry out data analysis. The effects of four factors on the yield of pectin in Hawthorn peel residue were as follows: solid-liquid ratio > ultrasonic power > ultrasonic time > extraction temperature. The optimum technological parameters of ultrasonic assisted extraction of pectin from Hawthorn peel residue were as follows: the ratio of solid to liquid 1∶15, the extraction temperature 74 ℃, the ultrasonic power 425 W, and the ultrasonic time 55 min. Under this condition, the optimal extraction rate of pectin from hawthorn peel residue was 6.154±0.041%. In the antioxidant test of pectin ultrasonic-assisted extraction process in hawthorn peel residue, it was found that the extracted pectin had better scavenging ability on hydroxyl radicals and superoxide anion radicals. The ultrasonic assisted extraction process of pectin from hawthorn peel residue optimized by response surface methodology was feasible, and the extracted pectin from hawthorn peel residue had certain antioxidant activity.

12 Study on the Antioxidant Activity Hetao Wheat Germ Polypeptides

NIU Pei-rong , LI Wei , XIA Mei-ru , A Mu-ri-han , WANG Ji-li-te , LIU Cong

2023, 31(4):87-94.

[Abstract](31) [HTML](118) [PDF 1.29 M](228)

Abstract:
In this experiment, the peptides were obtained by enzymatic digestion of wheat germ proteins from river sets using neutral protease, trypsin and pepsin. In vitro antioxidant capacity of samples was determined and their polypeptides distribution was determined using polyacrylamide gel electrophoresis (SDS-PAGE). The results showed that germ protein and polypeptides concentrations were positively correlated with antioxidant capacity.The antioxidant capacity of the peptides obtained by enzymatic digestion of neutral protease at different concentrations was significantly higher than that obtained by enzymatic digestion of pepsin and trypsin (P<0.05), and their reducing capacity, 2,2-biazo-bis(3-ethyl-benzothiazole- 6-sulfonic acid) diammonium salt (ABTS+), 1,1-diphenyl-2-picrylhydrazyl (DPPH) clearance was up to (1.17±0.004) 1.0 mg/mL, (84.82%±0.87%) 1.5 mg/mL and (55.01%±0.01%) 1.0 mg/mL, respectivety, and their ABTS+ and DPPH radical scavenging rates were significantly higher than those of germ proteins (p<0.05). In addition, for the hydrolysis capacity of different proteases differs, pepsin had the greatest hydrolysis capacity while neutral protease had the least. The antioxidant capacity of germ protein polypeptides correlated with their molecular weight, but it is not necessarily the case that the smaller the molecular weight of a protein peptide had the better antioxidant effect. The results of these experiments provide a theoretical basis for further research on the antioxidant polypeptides of wheat germ in the Hetao.

13 Effects of Common Food Additives on the Detection of Plant Components in Vegetable Protein Beverages

ZHANG Shuang , ZHANG Zi-lun , CHEN Bo-xu , WANG Hui , XU Miao-miao , YAN Tao-tao , SHI Guo-hua , ZHOU Wei

2023, 31(4):95-101.

[Abstract](36) [HTML](113) [PDF 1.26 M](204)

Abstract:
The influence of common additives on the detection of plant derived components in vegetable protein drinks was studied. Different concentrations of additives were added into the fluorescent PCR reaction system to determine the interference concentration of soybean DNA fluorescence PCR reaction, and the DNA UV absorption peak was measured. And three methods: reagent kit, reagent kit+chloraform, and “Method for Identification of Plant-derived Components in Vegetable Protein Drinks” were compared. When the concentration of acesulfame was greater than 105.00 μg/μL, and the concentration of sodium cyclamate was greater than 100.00 μg/μL, and the concentration of ascorbic acid was greater than 108.30 μg/μL. In addition, the concentration of D-sodium erythorbate was greater than 132.00 μg/μL, and the concentration of disodium inosinate was greater than 335.00 μg/μL. Under this condition, the concentration of monosodium glutamate was greater than 150.00 μg/μL and potassium chloride was greater than 37.85 μg/μL, indicating that the RT-PCR reaction of soybean DNA was inhibited and the results were false negative. When acesulfame concentration was greater than 75.00 μg/μL, sodium cyclamate concentration was greater than 133.38 μg/μL, and ascorbic acid concentration was greater than 65.00 μg/μL. D-sodium erythorbate concentration was greater than 79.13 μg/μL, and disodium inosinate concentration was greater than 335.00 μg/μL, while DNA uv absorption peak could not be detected. The DNA UV absorption peaks of disodium inosinate, 100.00 μg/μL and 200.00 μg/μL monosodium glutamate at 298.75 μg/μL were significantly different from those of the control group, but no significant differences were found between the other additive groups and the control group. Among the three methods, had the best DNA extraction effect and the lowest Ct value, which was significantly different from the other two methods. The additive had an effect on RT PCR detection of plant components. This study laid a foundation for further study on the influence of additives on the detection of plant derived ingredients.

14 Influence of Baking Degree on the Content of Chlorogenic Acid in Coffee by High Performance Liquid Chromatography(Online First, Recommended Article)

LUO Fa-mei , TAN Wen-han , JIN Hong-fang , HU Yuan-yuan , ZHANG Xiao-hua

2023, 31(4):102-110.

[Abstract](53) [HTML](114) [PDF 1.44 M](296)

Abstract:
The effect of baking degree on the change of seven chlorogenic acid compounds in 10 different origins (origin 1: Yunnan, origin 2: Africa and America) of Cardim coffee. The content of chlorogenic acid, neochlorogenic acid, cryptochlorogenic acid, isochlorogenic acid A, isochlorogenic acid B, isochlorogenic acid C and 5-ferulicquinic acid in green coffee and baked coffee were determined by high performance liquid chromategraphy (HPLC). The optimum extraction conditions of seven chlorogenic acid compounds were optimized by response surface methodology. 100 mL 0.1% phosphoric acid solution was extracted in water bath for 30 min, and the calibration curves of the seven chlorogenic acid compounds showed good linearity with correlation coefficients of above 0.999 4 in the range of 2~150 mg/L. Limit of the detection (LOD) and the limit of the quantitative (LOQ) were 0.005~0.5 mg/g and 0.02~2 mg/g respectively. The content of chlorogenic acid in green coffee beans was the highest, followed by 5-ferulicquinic acid. With the increase of baking degree, the content of chlorogenic acid and 5-ferulicquinic acid decreased significantly (P<0.05). The content of neochlorogenic acid and cryptochlorogenic acid increased first and then decreased. The degradation rate of isochlorogenic acid A was significantly higher than that of isochlorogenic acid B and isochlorogenic acid C. The degradation rate of chlorogenic acid and 5-ferulicquinic acid was relatively stable compared with the other six kinds of chlorogenic acid. Through the study of the content changes of seven kinds of chlorogenic acid compounds under different baking degrees can further evaluate the efficacy of chlorogenic acids in coffee, and provide a reference basis for the quality control of coffee baking.

15 Study on Sample Representative Guarantee Factors of Heavy Metal in Grain for Unmanned Detection

ZHANG Jie-qiong , ZHOU Ming-hui , LI Li , YANG Ming-he , WANG Song-xue

2023, 31(4):111-117.

[Abstract](45) [HTML](104) [PDF 715.89 K](212)

Abstract:
Sample representativeness is the premise to ensure the authenticity and accuracy of test results. The application scenario of unmanned detection is taken as the research object. Through the research on the uniformity of major heavy metals content detection in the sample processing of unmanned sample sampler, it is clear that mixing operation and sampling control are the necessary steps to ensure the representativeness of samples. By the method of combining dyeing simulation and actual sample verification, the key parameters such as the blending operation mode and parameters, the amount of samples crushed and tested for automatic sampling were systematically studied, and an optimal blending sampling scheme was obtained to ensure the representativeness of samples for unmanned heavy metal testing. The results showed that, the anchor type mountain paddle was used to stir 100 laps in revolution mode or repeat mix and separate samples for 3 times, and the minimum sample sampling amount for crushing was 150 g. The maximum crushed particle size of the sample was 1 mm and the minimum weight was 0.5g. This scheme was suitable for the representative detection of lead and cadmium elements in rice and wheat samples less than 6 kg. The research results provide technical supports for ensuring the representativeness and accuracy of heavy metal detection results in grain.

16 Determination of Ethyl Maltol Added in Edible Vegetable Oils by Ultra Performance Liquid Chromatography-tandem Mass Spectrometry

LIN Cui-hua

2023, 31(4):118-122.

[Abstract](31) [HTML](126) [PDF 478.34 K](271)

Abstract:
The content of ethyl maltol in special sampling samples of edible vegetable oils was determined by ultra performance liquid chromatography-tandem mass spectrometry to understand the illegal addition of ethyl maltol. The chromatographic column used in this method was ZORBAX SB-C18 column (2.0×100 mm, 1.8 μm), and mobile phase was 0.1% formic acid solution-acetonitrile with gradient elution. The flow rate was 0.2 mL/min, and the column temperature was 40 ℃. The results showed that ethyl maltol had a good linear relationship in the concentration range of 10~100 ng/mL with the correlation coefficient R2 0.999 8, and the average recovery rate of added standard was 99.9% with and the relative standard deviation (RSD) 0.31%. Ethyl maltol in 83 batches of edible vegetable oil was determined by liquid chromatography-tandem mass spectrometry, and the content of ethyl maltol in 1 batch of peanut oil was 36.4 μ g/kg. This study could be used for the quality control of edible vegetable oil and also provide scientific reference for the supervision of edible vegetable oil.

17 Determination of Morpholine Residues in Lettuces by UPLC-MS/MS and Its Uncertainty Evaluation

LI Tong-hui , YUAN Li-jie , SHANG Wei , ZHANG Pei-yi

2023, 31(4):123-129.

[Abstract](30) [HTML](125) [PDF 610.46 K](216)

Abstract:
To establish a method for the determination of morpholine guanidine residues in lettuce, ultra performance liquid chromatography-tandem mass spectrometry and uncertainty evaluation of the established method were studied. After samples were extracted and purified, the morpholine guanidine was quantified by scanning with positive ions from an electrospray ionization source in multiple reaction monitoring mode. The uncertainty was synthesized by building a mathematical model to analyze the sources of measurement uncertainty and quantify each uncertainty component. The morpholinoguanidine showed a good line in the range of 0.1~20 mg/L with a correlation coefficient R2 of 0.999 3. The spiked recoveries at the three levels of 0.5, 5.0 and 10.0 μg/kg ranged from 84.08% to 98.06% (n=6) with the relative standard deviations of 3.58% to 5.26% (n=6), and the extended uncertainty was 2.84 μg/kg (k=2) at 95% confidence interval for the determination of morpholine guanidine in the sample at 17.5 μg/kg. The method was rapid and efficient, highly accurate and reproducible, and the recovery and precision can meet the test requirements. The uncertainty was mainly caused by the standard solution, the establishment of the standard curve and the recovery of the sample spiking. The experimental results could provide a reference for the determination of morpholine guanidine residues in lettuce by UPLC-MS/MS and the uncertainty evaluation.

18 Research Progress of Adsorption Materials for Heavy Metals Analysis in Food

WANG Yue , CHEN Xi , WU Yan-xiang , YANG Ming-he , ZHOU Ming-hui

2023, 31(4):130-137.

[Abstract](27) [HTML](125) [PDF 1.10 M](212)

Abstract:
Food safety problems caused by excessive metals have potential health hazards related to people’s heath. The development of rapid detection technology for heavy metals in food is an effective means to prevent food with excessive heavy metals from entering the market. However, the accuracy and stability of the rapid detection of heavy metals in food is difficult to be guaranteed due to the low limit of the target element and the interference of sample matrix after pretreatment. Adsorption materials could have good accumulation on heavy metals, and are effective to remove the matrix of food, which provides technical support for the realization of rapid detection of heavy metals in food. Based on the analysis and summary of the current research on the application of adsorption materials for detecting heavy metals in food, the advantages and disadvantages of adsorption materials including absorbability and limit of detection were discussed, and the development trend in the future was also prospected.

19 Study on Process Optimization of Recovery of D-p-hydroxyphenylglycine from Crystallization Mother Liquor(Online First, Recommended Article)

XU Ping , DIAO Yu-duan , HU Xiao-xia , ZHANG Xiang-zhi , LIU Xiao-jie

2023, 31(4):138-144.

[Abstract](33) [HTML](123) [PDF 604.69 K](179)

Abstract:
D-p-hydroxyphenylglycine (D-HPG) is an important intermediate for the synthesis of sweeteners and drugs. An innovative continuous chromatographic process was developed to recover D-HPG from crystallization mother liquor, with the aim of reducing the process cost and improving the quality of D-HPG. The thickening properties of different nanofiltration membranes on mother liquor were investigated by pre-treatment test, and the Applexion NF200 nanofiltration membrane was selected to enrich D-HPG. The separation properties of different resins were analyzed by single column experiment, and the separation degree of Applexion XA945 resin to D-HPG and ammonium sulfate could reach 16. Based on the results, the way of sequential simulated moving bed separation was further studied. The results showed that after separation by the sequential simulated moving bed, the average purity of D-HPG in feeding was increased from 42.2% to 96.3%, and the average yield was 91%. The continuous chromatographic system is a promising method for the recovery of D-HPG from crystallization mother liquor. Compared with the traditional process, the new process not only ensures the total yield of D-HPG, but also greatly reduces the process cost and improves the product quality.

20 Bacterial Diversity and Their Correlations with the Properties of Traditional Tianpei from China(Online First, Recommended Article)

REN Fei , TAN Bin , LIU Ming , LI Wen-yi

2023, 31(4):145-153.

[Abstract](70) [HTML](109) [PDF 5.55 M](239)

Abstract:
The high-throughput amplicon sequencing technology was used to study the microbiota of the the traditional fermented whole grain Tianpei from the typical regions of our country. The correlations between the bacteria communities and the properties of Tianpei were also analyzed. The results showed that Firmicutes were most abundant. At genus level, the abundance of Weissella, Lactobacillus and Staphylococcus was the highest ones. Principal coordinate analysis (PCoA) showed that the compositions of bacterial community among three kinds of Tianpei were different. According to Lefse analysis, the related biomarkers were found in each Tianpei, including Lactobacillus and Staphylococcus. By the distance-based redundancy analysis (db-RDA), it is illustrated that the bacterial community of Tianpei was significantly correlated with the properties of Tianpei (lactic acid, flavone, amino acid, protein, starch, free fatty acid and reducing sugar content). The prediction of bacterial functions in Tianpei based on 16S rDNA mainly involved in amino acid transport and metabolism and carbohydrate transport and metabolism etc. This study laid a theoretical foundation for the exploration of microbial resources of traditional whole grain fermented food, the improvement of the quality of Tianpei and the industrial production etc. It also could provide a reference for the research on the microbiota of other fermented foods.

21 Optimization of Fermentation Process for Taq DNA Polymerase Production by Recombinant Escherichia coli

XIAO Yun , CHEN Jie

2023, 31(4):154-161.

[Abstract](88) [HTML](129) [PDF 1.09 M](325)

Abstract:
Taq DNA polymerase is a thermostable enzyme and widely used in PCR technology. In order to improve the production of Taq DNA polymerase by recombinant Escherichia coli, in this study the enzyme yield and specific activity of the enzyme were taken as the inspection indicators. The single factors producing Taq DNA polymerase content were optimized through single factor test: fermentation temperature, pH, amount of IPTG inducer, induction time, and inoculation amount. The results showed that fermentation temperature, pH, concentration of IPTG inducer had a significant impact on the specific enzyme activity of Taq DNA polymerase produced by the genetic engineering strain, while induction culture time and inoculation amount had no significant impact on the specific enzyme activity of Taq DNA polymerase produced by the genetic engineering strain. So fermentation temperature, pH and IPTG inducer concentration were selected as three factors of response surface to optimize the fermentation process of recombinant Escherichia coli for Taq DNA polymerase production. The response surface analysis results showed and that the order of significance for the specific activity of enzymes were: IPTG inducer concentration>fermentation temperature>pH, and the optimal fermentation process parameters were: fermentation temperature 37.2 ℃, pH 7.5, IPTG inducer concentration 0.800 mmol/L. Under this condition, the specific activity of Taq DNA polymerase reached (43.822±0.878) kU/mg.

22 Research on the Key Control Points and Suggestions forGrain Storage Management in the New Period(Online First, Recommended Article)

SONG Xiao-jie , AN Chun-mei , HOU Yan , LI Chun-hua , LI Jian

2023, 31(4):162-169.

[Abstract](79) [HTML](132) [PDF 485.69 K](453)

Abstract:
Grain reserve is the important material basis for food safety, and the grain storage management is core business for grain reserve security. In this paper, the whole process of grain storage management was classified into preparation, input, storage and output such 4 process and 23 steps, which can match the problems occurring in each process with 6 essential factors including human, machine, material, method, environment and measurement and 15 subdivision factors based on the matrix graph method. Six key control points, such as warehouse tidiness, personnel technical ability, grain origin investigation in the preparation, technology and equipment, operation rules and regulations in the storage, and quality control of sample determination in the warehouse link, were identified through by the Pareto chart. This study put forward some countermeasures and suggestions to ensure the quality of grain reserves and improve the standardization of storage management in the new period based on the key control points.

23 Effects of Two Air-conditioning Temperature Control Modes on the Safe Storage of Rice in High-temperature and High-humidity Areas

CHEN Yue-yin , HUANG Dong-yang , WU Wen-jun , WEI Hai-shan , ZHONG Wei-xian , CAI Qing-chun , ZHENG Yuan-xin , GUO Chao

2023, 31(4):170-176.

[Abstract](60) [HTML](114) [PDF 3.39 M](244)

Abstract:
The temperature changes of grain piles during rice storage in high-temperature and high-humidity grain storage areas were studied under the air-conditioning temperature control mode with a temperature of 22 ℃ and a daily opening time of 13 h and a temperature of 24 ℃ and a daily opening time of 24 h. The changes of rice moisture and fatty acid values before and after temperature-controlled storage were compared, and the differences in temperature changes in each layer in the horizontal direction of grain piles at different depths were analyzed. The results showed that the average temperature and the maximum grain temperature of the grain pile increased slowly under different air-conditioning operation modes. Air-conditioned temperature-controlled grain storage had a greater impact on the surface temperature of the grain pile, but less impact on the middle layer grain temperature. During the air-conditioned temperature-controlled storage period, the lower layer grain temperature may be affected by the floor temperature. The temperature control mode that lowered the temperature control temperature but shortened the temperature control time was more economical and efficient. The temperature control mode of 22 ℃ + 13 h could save about 12.4% of electricity costs compared with the temperature control mode of 24 ℃ + 24 h. At the same time, the control effect of the warehouse temperature, surface grain temperature and average grain temperature of the grain pile with a lower basic grain temperature was more obvious, and the basic grain temperature of the grain pile played an important role in the implementation of temperature-controlled grain storage technology.

24 Research on the Trade Characteristics and Development Path of Chinese Grain Machinery Industry under the “Belt and Road” Background(Online First, Recommended Article)

GUAN Jia-chen , LI Teng-fei

2023, 31(4):177-184.

[Abstract](40) [HTML](123) [PDF 514.54 K](216)

Abstract:
As an important part of agricultural foreign cooperation, promoting the export of grain machinery industry is an important starting point for strengthening agricultural foreign cooperation and implementing the “the Belt and Road” initiative. Based on the UN CONTRADE database, combined with statistical analysis and case studies, this research made an in-depth analysis of the opportunities, development status and existing problems faced by Chinese grain machinery export under the background of the “the Belt and Road Initiative”. The analysis found that the “the Belt and Road” initiative has brought good opportunities for Chinese grain machinery exports. With comparative advantages such as technology and price, Chinese grain machinery exports in countries and regions along the “the Belt and Road” have continued to grow, and showed the characteristics of increasingly concentrated market structure and stable product structure. However, with the deepening development of foreign cooperation, Chinese grain machinery exports were also facing development difficulties such as a single export model, excessive competition in export prices, shortcomings in core technology, and outdated brand construction. In the future, grain machinery can expand its foreign cooperation paths by strengthening independent research and development, strengthening brand construction, and enriching foreign trade methods and models. At the same time, the government can start by optimizing top-level design and strengthening overseas information services. The foundation of cooperation between grain machinery enterprises and countries along the “the Belt and Road” will be further consolidated, and the level and level of foreign cooperation in grain machinery industry will be improved.

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