Volume 31,Issue 3,2023 Table of Contents

1 Research progress on the effect of small molecular sugars on starch properties(Online First, Recommended Article)

SONG Jin-hong , CHEN Long , ZHAO Jian-wei

2023, 31(3):1-8.

[Abstract](175) [HTML](209) [PDF 483.21 K](454)

Abstract:
Small molecular sugars are a group of sugars with low molecular weight, mainly including monosaccharides, disaccharides, and other oligosaccharides with low degree of polymerization. Small molecular sugars are commonly used as food additives in the food industy, including providing sweetness, improving food texture and optimizeing food processing adaptability. In addition, some small molecular sugars also have unique physiological functions that can be used to regulate the nutritional quality of food. Starch is the most common staple component in food, and starch and its modified derivatives are also widely used as food ingredients in food categories such as sauces, dairy products, beverages, and meat products. The composite system of small molecular sugar and starch is widely used in food. The addition of small molecular sugar has an important impact on the properties of natural starch, and plays an important role in regulating the quality of starch-based foods. This article mainly introduces the common small molecular sugars in food and their effects on the main physical and chemical properties of starch (gel texture, transparency, coagulation, gelatinization, freeze-thaw stability, aging, digestion, etc.), with emphasis on the impact of different types and amounts of small molecular sugars on the properties of starch from different sources. This paper aimed to provide reference for the application of small molecular sugars in starch based foods.

2 Effects of processing conditions and key components on the quality of baked foods(Online First, Recommended Article)

LIN Qian-zhu , CHEN Yue , YU Xiang , QIU Chao

2023, 31(3):9-14.

[Abstract](138) [HTML](223) [PDF 489.64 K](315)

Abstract:
Baked foods with a huge market scale play an important part in people's daily diet, and the market scale maintains a trend of rapid growth. The quality of baked foods is affected by many factors, such as raw material composition and processing conditions, so understanding the factors affecting the quality of baked foods is of great significance to process and produce high-quality baked foods. This paper reviewed the effects of fermentation conditions, processing conditions, and raw material composition on the quality of baked foods, and it also involved research on functional baked foods with the addition of special nutritional ingredients or low / no sugar content. These new types of baked foods are more in line with the current people's pursuit of the concept of nutritious and healthy diet. This paper could provide the reference for the design and production of high-quality baked foods, and promote the development and upgrading of the baked food industry.

3 Study on the preparation of V-type porous starch with high oil absorption capacity(Online First, Recommended Article)

MENG Yue , CHANG Qing , LIANG Xiao-li , LI Jia-xin , JIN Zheng-yu , ZHOU Xing

2023, 31(3):15-23.

[Abstract](101) [HTML](206) [PDF 1.53 M](291)

Abstract:
In this research, V-type porous starch (VPS) with high oil absorption capacity was obtained by enzymatic hydrolysis of V-type granular starch (VGS) in ethanol aqueous solution. Firstly, the reaction condition of V-type granular starch (VGS) was optimized with oil absorption capacity and V-type crystal crystallinity as indexes. In 50% ethanol, aqueous solution the oil absorption capacity of VGS obtained by reaction 100 ℃ was the highest (176.23%). Then, the influence of enzymatic hydrolysis time, temperature and speed on the degree of hydrolysis, yield and oil absorption capacity of VPS were investigated. The optimal preparation conditions of VPS were obtained through single factor and orthogonal experiments: enzymatic hydrolysis time 4 h, temperature 25 ℃, and enzymatic hydrolysis speed 300 r/min. The oil absorption capacity of the optimal VPS was the highest (550.28%). Finally, the difference in the crystalline structure, granular morphology, specific surface area and bulk density were compared among normal maize starch (NMS), traditional A-type porous starch, VGS and VPS. VPS exhibited a unique sponge shaped irregular dense honeycomb structure, the highest specific surface area (39.94 m2/g) and the lowest bulk density (0.19 g/cm3), which were the reasons for its higher oil absorption capacity.

4 Study on the pre-cooking process and physicochemical properties of red bean(Online First, Recommended Article)

CAO Ge , CHEN Chu-yao , HAN Yong-bin , LI Dan-dan

2023, 31(3):24-32.

[Abstract](103) [HTML](202) [PDF 4.07 M](535)

Abstract:
Aiming at the disadvantages of thick seed coat and difficult cooking of red beans, a red bean product that can be co-cooked with white rice was developed through the pre-cooking technology of "microwave pretreatment-soaking-steaming". Based on the optimization of pre-cooking process by response surface methodology, the appearance, color, pasting properties, texture and re-cooking properties of pre-cooked red beans with different gelatinization degree were characterized. The results showed that the increase of microwave time, microwave power, soaking time and cooking time could significantly increase the gelatinization degree of red bean. Compared with raw red beans, the color of pre-cooked red beans became dark, and the volume expanded several times. The hardness and pasting viscosity of pre-cooked red beans also decreased, but their rehydration increased by 7.5-8.8 times. In addition, there was no white core after re-cooking under simulated cooking conditions of white rice. However, with the increase of gelatinization degree, the red bean granules swelled, and the epidermis seriously ruptured. The sensory score decreased, and the rehydration first increased but then decreased. In summary, the optimal pre-cooking process was determined as: microwave power 640 W, microwave time 30 s, soaking time 6.5 h, cooking time 20 min. Under these conditions, the gelatinization degree of pre-cooked red bean was 57.52%.

5 Study on properties of walnut protein emulsion modified by limited enzymatic hydrolysis(Online First, Recommended Article)

CHEN Si-rui , HUANG Zi-lin , XING Ruo-yu , WANG Yu-qing , JIN Ya-mei , XU Xue-ming , KONG Xiang-zhen

2023, 31(3):33-40.

[Abstract](47) [HTML](205) [PDF 3.10 M](288)

Abstract:
The application of walnut protein is limited due to its poor water solubility and low yield. Five proteases, neutral protease, papain, bromelain, trypsin and protein glutaminase, were selected to carry out limited enzymatic hydrolysis reaction on walnut protein, and the modified walnut protein was applied to prepare the emulsion. The results showed that the solubility and emulsification of walnut protein were significantly improved after modification. Neutral protease modified protein (WP-Z) had the best emulsification and high stability. SDS-PAGE results showed that the macromolecular subunits of walnut protein were partially decomposed after limited enzymatic hydrolysis. After the modification, the particle size of the emulsion was reduced to 5~8 μm, and micro-volume of oil droplets was reduced. In addition, the dispersion was more uniform, and the emulsion index was greatly reduced, which did not exceed 10% in 30 days. By comprehensive analysis, the particle size of the emulsion prepared by WP-Z was moderate, which was more suitable for the preparation of emulsion.

6 Impact of flaxseed oil concentration on stabilization of mayonnaise-like emulsion co-stabilized by WP and KGM(Online First, Recommended Article)

ZHANG Yan-qiu , XU Chang , PEI Ya-qiong

2023, 31(3):41-47.

[Abstract](44) [HTML](216) [PDF 9.12 M](308)

Abstract:
Traditional mayonnaise has some dietary health problems such as high cholesterol, high fat and high calories. In this work, the mayonnaise-like emulsions with cholesterol-free and high omega-3 unsaturated fatty acid were prepared with whey protein (WP) and Konjac glucomannan (KGM) instead of egg yolk, and linseed oil as the oil phase. The effect of flaxseed oil concentration on the physical stability, such as appearance, droplet size and microstructure, stacking and extrusion formability, and rheological properties of mayonnaise-like emulsions were investigated. The results showed that the droplets size was decreased from 30.8 µm to 17.1 µm and the uniformity of droplet-size increased with the increase of oil phase concentration. The microstructure observation showed there was no flocculation among droplets indicating a good dispersion. Moreover, when the oil phase concentration was increased from 40% to 80%, the rheological properties of the mayonnaise-like emulsion were changed from fluid properties (G′>G″ at 40%) to solid gel properties (50%~80%, G′>G″). The viscosity, elastic modulus and viscous modulus were all increased with the increase of oil phase concentration, suggesting the ability to resist deformation under a certain external force and to return to the original state after deformation was gradually enhanced. The stacking property and extrusion formability were also increased with the increase of oil phase concentration. In conclusion, by adjusting the concentration of flaxseed oil, mayonnaise-like emulsion( flaxseed oil concentration: 40%~60%) with low viscosity and strong fluidity could be prepared for use in sauces and condiments with high fluidity and dispersity requirements, or mayonnaise-like emulsion (flaxseed oil concentration: 70%~80%) with high viscosity and strong stacking property could be prepared for use in condiments with molding and coating requirements.

7 Study on the influencing factors of corn starch saccharification reaction

LEI Ying-jie , YU Xiao-ming , REN Yuan-yuan , ZOU De-jun , MENG Zi-kuan , ZOU Yu , LI Yu-hang

2023, 31(3):48-54.

[Abstract](70) [HTML](213) [PDF 550.50 K](644)

Abstract:
At present, in the industrial production process of corn starch sugar, there are some problems in the saccharification reaction stage, such as low initial starch milk concentration, long reaction time, poor enzymatic hydrolysis effect, low yield of final product, and more miscellaneous sugar components. Aiming at the above phenomena, the optimal saccharification conditions were obtained by orthogonal design with the parameters of the saccharification reaction stage, such as temperature, pH value, and the amount of enzyme added by using starch milk with 40% concentration as raw material. At the same time, the effect of DE value of glycosylated substrate on the glycosylation reaction and the composition of glycosylated products was analyzed. The results showed that the main factors affecting the glycosylation reaction were pH > enzyme amount > substrate DE value. The optimum conditions for the reaction of glycosylase were temperature 60 ℃, pH 4.5, enzyme dosage 200 U/g and substrate DE 15. Under this condition, the viscosity of the saccharification solution was moderate, which was more conducive to the enzymolysis reaction. The DE value of the final product could reach 95% and the glucose content (DX value) could reach 96.86%. Meanwhile, the content of other components was only 1.30%. The conclusion of this study can provide theoretical reference for the industrial production of corn starch sugar to improve product yield and reduce cost.

8 Effect of high hydrostatic pressure on physicochemical and functional properties of millet flour

BAI Tao , FU Li-hong , ZHANG Hong-li , LI Zhang-rong , ZHAO Lu-yao , WANG Xiao-wen

2023, 31(3):55-61.

[Abstract](53) [HTML](219) [PDF 2.40 M](327)

Abstract:
Millet was treated at 600 MPa for 15 min and 30 min, respectively (millet: water=1∶1 or 1∶2 (w/w). The effects of different treatment conditions on physicochemical and functional properties of millet flour were investigated to provide a theoretical basis for optimizing the quality characteristics of millet powder. The results showed that high hydrostatic pressure (HHP) treatment affected the morphology, particle size, and crystal characteristics of the four different millet powders. The morphology of starch particles in the whole flour changed from a scattered irregular sphere to complex and bonded to block structure with other substances, and the average particle size decreased significantly. The overall particle size shrank, and the crystal structure changed from natural A type to B type. The effect on the microstructure was particularly significant when the ratio of millet to water was 1∶2. The dynamic rheological tests showed that Gʹ and tanδ of millet paste after HHP treatment were higher than those of original powder, and Gʺ was lower than that of original powder. The results showed that HHP treatment could improve the elasticity and viscosity of millet starch, and this technology could be used as an effective physical modification method to improve the physical properties of millet powder.

9 Physicochemical and functional properties of water-soluble dietary fiber from different sources of cereal bran

CHENG Zhuo , WU Na-na , DING Wen-ping , TAN Bin

2023, 31(3):62-70.

[Abstract](54) [HTML](208) [PDF 1.32 M](287)

Abstract:
Water-soluble dietary fiber was extracted from ten kinds of cereal bran, such as rice fragrance rice bran, long grain fragrant rice bran, indica rice bran, millet rice bran, wheat bran thick bran, wheat bran thin bran, oat bran, sweet buckwheat skin powder, tartary buckwheat skin powder, millet skin powder. The physicochemical characteristics, functional characteristics and molecular structure of these SDF samples were studied. SDF from tartary buckwheat skin powder had the strongest water holding capacity. SDF from millet skin powder had the strongest oil holding capacity. SDF from wheat bran thin bran showeds the strongest water expansion. SDF from rice fragrance rice bran, long grain fragrant rice bran, millet rice bran and sweet buckwheat skin powder did not have water absorption expansion ability. The glucose binding abilities of ten kinds of SDF were between 56.95~432.83 mg/g. The cholesterol adsorption capacity of SDF from Grain bran was significantly different in the range of 0.41~66.21 mol/g. The antioxidant ability of ABTS and DPPH for SDF from wheat bran was the highest, and the antioxidant ability of hydroxyl for SDF of millet rice bran was the highest. The total antioxidant capacity of the ten kinds of SDF was significantly varied with the range of 2.00~5.59 μmol/g. SEM results showed some uneven surface with granular and smooth with porous structure, and Fourier infrared absorption spectrum results show different weak peaks. In conclusion, there were obvious differences in the molecular structure, physical and functional properties of SDF from different sources, and SDF with different structural and functional properties can be selected according to the specific utilizations.

10 Assessment of bioactive and antioxidant capacities of water-extraction substances from black waxy corn silk with different ingredients with different mass ratios

ZHANG Bo-fan , ZHAO Wen-xin , WANG Jiu-jiang , LIU Ze-yu , TIAN Ya-jing , XUE Jian-fu

2023, 31(3):71-78.

[Abstract](48) [HTML](217) [PDF 2.77 M](281)

Abstract:
Corn silk is rich in a variety of biologically active ingredients. The development of tea products based on corn silk and supplemented by other auxiliary materials could be of great significance for alleviating high blood pressure, high blood fat, and high blood sugar. The main ingredients of corn silk tea products on dominating online shopping APPs were sorted out in current study. Then, in order to assess the bioactive substances and antioxidant capacities in the water-extraction of corn silk tea products, an experiment was carried out with corn silk as the main material and other ingredients as supplements under different mass ratios with 1∶2, 1∶1, and 2∶1. The results showed that thirteen ingredients were sorted out by analyzing 139 kinds of corn silk tea products sourced from 8 shopping APPs, occurrence times of which were more than 20% of total products number, such as mulberry leaves, hawthorn and pueraria. Under the mass ratio of black corn silk to most ingredients with 2∶1, the contents of total polysaccharides, total saponins and total flavonoids in the water-extraction were higher, but the antioxidant capacity did not show an advantage. The integrated effects of bioactive substances and antioxidant capacities were assessed by subordinate function value method, and it was concluded that corn silk with pueraria, gardenia, chrysanthemum, pericarpium citri reticulatae and tartary buckwheat had better comprehensive effect under the mass ratio of 2∶1. Therefore, 1.5 g corn silk with 0.75 g pueraria, gardenia, chrysanthemum, pericarpium citri reticulatae and tartary buckwheat could be used as potential products for corn silk tea.

11 The impact of environmental factors on the production of bongkrekic acid in fermented glutinous rice flour

LU Yu-jian , QIAO Xin , CHEN Yu-jie , LIU Hua-liang , ZHOU Yong-lin

2023, 31(3):79-84.

[Abstract](44) [HTML](223) [PDF 540.51 K](375)

Abstract:
This study aimed to explore the characteristics of bongkrekic acid (BA) produced by Burkholderia gladioli pathovar cocovenenans (BGC) and the effects of ambient temperature and humidity on BA production in the fermented glutinous rice flour (FGRF). In the specific environment with various ambient temperatures (10±1, 15±1, 20±1, 25±1, 30±1, 36±1 ℃) and relative humidity (20%, 40%, 60%), The FGRF was incubated with different bacteria counts of BGC (103, 105, 107 CFU/mL), and BA in the FGRF was measured with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The results revealed that BA could be detectable after only one day of incubation. The BA produced and accumulated by BGC with an initial bacteria count of 103 CFU/mL was more than that in the groups with the initial bacteria counts of 105 and 107 CFU/mL (with a difference of 1-3 μg/kg between groups). Lower temperatures (10±1, 15±1, 20±1 ℃) and humidity (20%) were found to reduce the BA production of BGC in the FGRF. To minimize the risk of foodborne BA poisoning, it is recommended to consume freshly prepared FGRF promptly and avoid storing it for extended periods under hot and humid conditions.

12 A review of preparation, efficacy and application of acer truncatum seed oil

ZHANG Xiao-qing , LI Xin-rong , JIA Min , XIA Yuan-jun , XU Tong-cheng

2023, 31(3):85-90.

[Abstract](84) [HTML](216) [PDF 513.71 K](1134)

Abstract:
As a new resource food in China, acer truncatum seed oil is rich in oleic acid, linoleic acid and neuroic acid and other components, and their nutritional value and medicinal health care effects are prominent, which has been increasingly valued by the industry and consumers. In recent years, the new preparation and application development technology of Acer truncatum seed oil has been continuously presented. It has not only been developed for food, but also appeared successively in the flavoring of Acer truncatum seed oil, complex dairy products,tablet candy, etc. It has also been applied in the fields of daily chemical industry, medical care and so on. This paper reviewed the current research progress and the existing problems in the preparation, efficacy evaluation, industrial application and development, and putted forward some suggestions for these problems, which could promote the development and perfection of Acer truncatum seed oil industry.

13 Analysis of fatty acid composition and volatile flavor composition of different parts of beef tallow

WANG Chong , WANG Qiao-jun , MA Guo-li , ZHANG Yi-xian , JIN Jun , WU Gang-cheng

2023, 31(3):91-97.

[Abstract](196) [HTML](208) [PDF 504.90 K](560)

Abstract:
To smelt beef tallow by using 1 000 kg as the mass of each sample of beef fat, and the fatty acid composition of the obtained butter including perirenal fat, abdominal fat and segmented fat was analyzed by gas chromatography (GC), and the volatile flavor components were detected by gas chromatography-olfactory mass spectrometry (GC-O-MS). The results showed that the saturated fatty acids (SFA) of the three kinds of beef tallow were mainly palmitic acid and stearic acid, and the unsaturated fatty acids (UFA) were mainly oleic acid. In addition, there was no significant difference (P>0.05) in palmitic acid content among three kinds of beef tallow. Although there were no significant differences in the stearic acid and oleic acid contents between perirenal tallow and belly tallow (P>0.05), there were significant differences in the stearic acid and oleic acid contents between partitioned tallow and waist oil and belly tallow (P<0.01). The volatile flavor components of the three kinds of butter were aldehydes, acids, alcohols, ketones, esters and heterocyclic compounds, in which the sum of aldehydes and acids accounted for more than 70% of the total. Moreover, there were significant differences in volatile flavor components among different parts of butter (P<0.05). Among the three kinds of beef tallow, the total amount of volatile flavor substances in perirenal tallow was the highest. The aldehydes in belly tallow accounted for 59.90%; At the same time, partitioned tallow had the most volatile flavor components, and esters and heterocyclic volatile flavor components accounted for 8.49% and 7.61%, respectively. Fatty acid determination and volatile flavor component analysis revealed the characteristics and differences of different parts of beef fat. It can provide reference for rational development and flavor quality control of beef tallow.

14 Analysis of flavor composition in different peanut varieties᾽ butter(Online First, Recommended Article)

HU Jun-jing , LIU xiao-cheng , LU ze-yu , LI Jin-zhuang

2023, 31(3):98-105.

[Abstract](44) [HTML](197) [PDF 1.19 M](363)

Abstract:
In this paper, the flavor substances of five varieties of peanut butter were mainly studied by gas chromatography-mass spectrometry (GC-MS). The results showed that the total number of flavor substances was 62, 55, 46, 46 and 44 in “Baisha”, “Luohan”, “Kainong 80”, “Chuantong” and “Lu Hua 8”, respectively The main flavor substances of these five peanut varieties were alcohols, aldehydes, hydrocarbons and pyrazines. Among them, "Baisha" had many kinds of flavor substances, but few pyrazines, and the aroma of nuts was weak. The other four peanut butter varieties had higher pyrazines content, but “Lu Hua 8” peanut butter had a high content of acetic acid, which leads to acrimonious sour and poor aroma. Therefore, among the five peanut varieties, Kainong 80, Luohan and Chuantong were the best varieties for processing peanut butter.

15 Influencing factors of micellar casein concentrate composition and its application in cheese production(Online First, Recommended Article)

YAN Qing-quan , BIAN Yan-fei , ZHAO Zhong-hua , LI Ying-yu , ZHAO Yue , ZONG Xue-xing

2023, 31(3):106-111.

[Abstract](81) [HTML](196) [PDF 395.94 K](493)

Abstract:
At present, casein can be isolated from skim milk by membrane filtration technology, and micellar casein concentrate could be obtained by concentration, sterilization, drying. In this paper, the factors affecting the composition of micellar casein concentrate and its application in cheese production were reviewed. It was found that pH value, temperature and diafiltrant during membrane filtration all affected the composition of micellar casein concentrate, resulting in different concentrations of casein, whey protein, lactose and calcium. It is also possible to standardize raw milk by micellar casein concentrate to produce cheese with the same composition and quality. It is also possible to obtain different raw milk compositions by micellar casein concentrate having different components to produce cheese with desired quality and function. In conclusion, the addition of micellar casein concentrate could affect the composition, texture and flavor of cheese during cheese production, but these problems could be solved by adjusting the process parameters of membrane filtration and cheesemaking. Further research will be still required to find an economic way to preserve micellar casein concentrate and give it extended shelf life, good rennet properties to ensure cheese quality and yield.

16 Analysis of the current evelopment of lectromagnetic cooking equipment

WANG Qiao , SHEN Chan-duo , LIU Yong-xin , SHEN Yi-jian , LIU Yi , MENG Ling-qing

2023, 31(3):112-119.

[Abstract](34) [HTML](204) [PDF 1.79 M](414)

Abstract:
In this paper, the overall development of electromagnetic heating food technology and even electromagnetic cooking technology was analyzed from multiple perspectives by means of literature date summary, and questionnaire survey analysis. This paper focused on the main components and functions, technical elements, core technical indicators and research hotspots of electromagnetic heating food equipment, and the current overall research situation of electromagnetic cooking food technology was also summarized and analyzed. For the commercial electromagnetic cooker products, this paper summarized and analyzed the market application situation and main use problems of electromagnetic cooker based on the questionnaire survey analysis method. Finally, based on the current situation of increasingly prominent problems of electromagnetic cooking products, the future development suggestion of standardizing market order and improving technology foresight was pointed out.

17 Influence of climate factors on quality characteristics of cereals

YUE Zhong-xiao , FENG Nai-hong

2023, 31(3):120-126.

[Abstract](62) [HTML](200) [PDF 461.99 K](343)

Abstract:
Climate change significantly affects the quality characteristics of cereals. Climate factors such as accumulated temperature, daily temperature difference, rainfall and gas concentration and ratio affect the growing environment of cereals to varying degrees, leading to the changes of physiological and biochemical metabolic pathways of plants, and changes the traits of plants, which could have a series of effects on the quality of cereals. This paper summarized the research progress of different climatic factors affecting on the appearance quality, cooking quality, nutritional quality and eating quality of cereals. Many studies showed that climate factors had different effects on the color luster, particle size, grain integrity, water absorption, swelling rate, iodine blue value, solid content, microscopic changes of grain morphology, volatile components, protein, fat, starch and trace nutrients in grains. There are single and compound effects of various climatic factors on the quality of cereals, but the regulation mechanism of the compound interaction of various climatic factors still needs to be further studied.

18 The rapid determination of aflatoxin B1 in peanut and its products by colloidal gold method

BI Ting-ting , ZHANG Hai-hong , TIAN Hong-yun , WEI Ke-yan , WANG Jun

2023, 31(3):127-136.

[Abstract](32) [HTML](197) [PDF 1.12 M](306)

Abstract:
By investigating the absolute sensitivity and maximum dilution ratio of commercially available kits, three kinds of rapid detection kit products with the best effect were selected. Fried peanuts, roasted peanuts and peanut butter were taken as representative substrates to optimize the pre-treatment conditions of samples and the reaction conditions of kits. Unified technical evaluation was conducted according to the performance indexes in The Technical Specification for Evaluation of Rapid Food Detection Methods, and the detection limit, sensitivity, specificity, false negative rate, false positive rate, relative accuracy and consistency analysis of reference methods of all brands of rapid test kits were investigated. Our findings could provide scientific basis for the rapid determination and evaluation standard of aflatoxin B1 colloidal gold in peanut and its products.

19 Determination of 19 phthalate acid esters in vegetable oil by freezing method combined with GC-MS/MS

PENG Xing-xing , GENG Li-na , GAO Hai-jun , LU Hui-li

2023, 31(3):137-146.

[Abstract](27) [HTML](224) [PDF 551.92 K](238)

Abstract:
In order to establish a rapid, efficient and convenient method for the determination of 19 phthalate esters in vegetable oil, a method for the determination of 19 phthalate acid esters in vegetable oil by freezing method combined with GC-MS/MS was developed. The results showed that: the pretreatment method of freezing for 24 hours at –18 ℃ was changed to freezing for 12 hours at –36 ℃ which could reduce the sample pretreatment time. In addition to the determination of 8 phthalate ester compound in LS/T 6131—2018, this method also determined 11 phthalate ester compounds, including DAP, DMEP, BMPP, DEEP, DPP, DHXP, BBP, DBEP, DPhP, DNOP and DNP. Compared with the external standard method of LS/T 6131—2018, this method added the isotope internal standard method. GC-MS/MS was used to compare differences between the internal standard method and the external standard method in determining the content of phthalate esters in vegetable oil.The results showed that there was a good linear relationship between the chromatographic peak responses values of 19 phthalate esters in vegetable oil on GC-MS/MS and their mass concentrations. The correlation coefficients of the regression curve equations of the external standard method and the internal standard method were greater than 0.990, and the detection limit and quantitative limit were lower than LS/T 6131-2018. The method met the requirements of 19 PAEs analysis. The precision and accuracy of internal standard method are better than that of external standard method, mainly because the internal standard method can avoid the content loss in the extraction process. The experimenter can use the corresponding quantitative method according to the actual situation.

20 Effects of different pretreatment methods on the determination of benzo (a) pyrene in vegetable oil

TAO Ru-qing , DU Li-juan

2023, 31(3):147-152.

[Abstract](39) [HTML](196) [PDF 518.97 K](381)

Abstract:
Three pretreatment methods, including direct extraction method, neutral alumina column method and molecular imprinted column method, were established for the determination of benzo (a) pyrene in vegetable oil by high performance liquid chromatography-fluorescence detector. The results showed that the linear relationship between the concentration of benzo (a) pyrene standard curve and the corresponding hromatographic peak area was good, and the correlation coefficient was 0.9993, when the concentration was in the range of 0.5~50 ng/mL. The blank vegetable oil was used as the matrix to carry out the spike recovery experiment. When the addition levels of benzo (a) pyrene were 2, 15 and 25 μg/kg, the average recoveries of direct extraction method, molecular imprinted column method and neutral alumina column method were 98.8%~102.8% and 91.1%~101.0% and 91.8%~113.7%, respectively, and the relative standard deviations (RSD) were 0.8%~2.0%, 2.3%~7.3% and 1.9%~8.8%, respectively. The direct extraction method has the advantages of simple pretreatment, good precision, high accuracy and sensitivity, and low cost, and is suitable for the detection of benzo (a) pyrene in vegetable oil.

21 Comparative study on the determination of aflatoxin B1 in edible oil by automated immunomagnetic beadpurification method and immunoaffinity column purification method

CAO Jing-jing , LIU Ying , WANG Ya-nan , ZHAO Sheng-nan , WU Xiu-yuan , GAO Hai-jun

2023, 31(3):153-158.

[Abstract](50) [HTML](202) [PDF 560.04 K](348)

Abstract:
In this experiment the pretreatment methods of automatic immunomagnetic bead purification and immunoaffinity chromatography purification were used to quantitatively detect aflatoxin B1 in different edible oils by ultra-high performance liquid chromatography, and the accuracy, spike recovery and detection time of the two pretreatment methods were compared. The results showed that the results of automatic immunomagnetic bead purification and immunoaffinity chromatography purification for the determination of vegetable oil standard materials were 15.59 μg/kg and 14.64 μg/kg, respectively, both of which were within the standard range. Different amounts of aflatoxin B1 standard materials were added to different kinds of edible oils, and the recovery rate of spikes was between 88%~110%, and the relative standard deviation was within 5%. The Bland-Altman method was used to analyze differences between the automatic immunomagnetic bead purification method and the immunoaffinity chromatography purification method, and the results showed that differences between the two purification methods were within the acceptable range. Both methods could meet the experimental requirements in purification and enrichment of aflatoxin B1 in edible oil and can be used instead of each other. Through the comparison of detection time, automatic immunomagnetic bead purification combined with mycotoxin automatic purification instrument pretreatment method can process multiple samples at the same time, and the average purification time of one sample is less than 3 min, indicating that the treatment time is shorter, and the experimental efficiency is higher.

22 Determination of 19 succinate dehydrogenase inhibitor fungicides pesticide residues in green coffee by quechers-liquid chromatography tandem mass spectrometry

MAO Jing-chun , WU Xu-dong , LUO Fa-mei , ZHOU Qin , PU Hong-jun , DENG Hong-yan , CHENG Long

2023, 31(3):159-167.

[Abstract](30) [HTML](214) [PDF 3.81 M](248)

Abstract:
This study establishes an analytical method for simultaneous determination of 19 Succinate dehydrogenase inhibitor fungicides pesticide residues in Green coffee by QuEChERS-Liquid chromatography tandem mass spectrometry. The Green coffee powder samples were extracted with acetonitrile by Homogenizer, the supernatant were purified by Magnesium sulfate anhydrous、PSA and C18, liquid chromatograhy - tandem mass spectrometry were used for analyzing 19 Succinate dehydrogenase inhibitor fungicides pesticide residues at positive ion mode. The results showed that the calibration curves of 19 targets showed good linearity with correlation coefficients of above 0.995 0 in the range of 1~100 ng/mL, the recoveries of 19 pesticides were 79.6%~109.4% and the relative standard deviations(RSD, n=6) were in the range of 1.4%~9.7% at spiked levels of 0.01、0.05 and 0.1 mg/kg. Limit of quantitation (LOQ) of all the tested pesticides were 0.51~4.60 μg/kg. This method has good linear relations, excellent stable and sensitive, accuracy and precision meet the requirement of quantitative analysis, it is suitable for quantitative analysis of 19 Succinate dehydrogenase inhibitor fungicides pesticide residues in Green coffee.

23 Study on the construction and control of microbial food safety objective(FSO) in baked food

LE Zhen-qiao , ZHANG Xi-ling

2023, 31(3):168-174.

[Abstract](40) [HTML](202) [PDF 575.32 K](231)

Abstract:
International Commission on Microbiological Specification for Foods (ICMSF) proposed the establishment of Food Safety Objective (FSO) and the formula. Through the establishment of microbial Performance Objective (PO) and Food Safety Objective (FSO) with FSO formula, it is expected to explain how to collect and analysis the data information to reduce the microbial level H0 & ΣR and increase the microbial level ΣI, to find the key elements and key values of product microbial control, to provide strong data support for the specific execution of GMP and HACCP was provided, which could ensure the product qualification ratio is 100%.

24 Study on ventilation resistance characteristics of different grains

LEI Cong-lin , LI Yan , ZHANG He-ying , ZHANG Lai-lin , WU Dong-liang , FANG Jiang-kun

2023, 31(3):175-182.

[Abstract](105) [HTML](201) [PDF 1.54 M](335)

Abstract:
The results of resistance characteristics in different grains during ventilation experiments showed that the resistance of unit grain layer was positively correlated with the surface wind speed of grain, and the polynomial quadratic function had the higher fitting degree for them. When the surface wind speed of grain was at the same level, the resistance of unit grain layer in soybean was lower, followed by corn but that of rice and wheat was higher, indicating that the resistance of unit grain layer was related to grain structure、surface smoothness and porosity. The resistance of net was positively correlated with the surface wind speed of grain, with the increase of surface wind speed and the resistance of net during ventilation process. The resistance of net could increase sharply when the surface wind speed increased to a certain extent. In order to avoid the waste of energies, the large volume shouldn’t choose blindly during the process of ventilation. The ventilation uniformity of grain increased gradually with the increase of the grain layer thickness, which was less affected by the ventilation volume when the ventilation uniformity of different grains was compared, rice was lower, follow by wheat, and soybean and corn was higher, which was related to grain shape and stacking structure.

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