Abstract:In this study, the gelatinization of heat-moisture treated (HMT) corn starch was investigated by rheometer (RHE) and differential scanning calorimeter (DSC) under the same condition of excessive water (starch∶water=1∶10) with heating-rate dependent gelatinization and time-temperature gradient gelatinization tests. DSC and RHE results showed that multiple endothermic transitions (G and M₁) and two viscosity peaks (PV₁ and PV₂) were observed in viscosity curves and DSC traces even in excess water for HMT starches. The gelatinization process of HMT starch could be divided into three stages by correlation analysis of thermal and viscosity characteristics as follows. The first stage of swelling corresponded to the G endotherm, and the second stage of swelling corresponded to the M₁ endotherm, followed by swelling non-corresponding to any endotherm. The temperature-dependent behaviors of corn starch gelatinization were evidenced by RHE results and starch gelatinization has different temperature thresholds at different stages. The degree of time- and temperature- dependence was closely related to these temperature thresholds.

Abstract:The nano-emulsions and microcapsules were used to improve the hydrophilicity of cinnamaldehyde, which were then added to whey protein concentrate solution. Protein gel was produced by heat-induced method. The rheological property, water holding capacity, texture and microstructure of protein gels were characterized to investigate the influence of encapsulated cinnamaldehyde on the property of protein gels. The results showed that the water holding capacity of protein gel significantly increased with the addition of cinnamaldehyde. When cinnamaldehyde was encapsulated by emulsions, the properties of heat-induced protein gels including viscoelasticity, water holding capacity, texture characteristics and network structure were positively correlated with the content of cinnamaldehyde. The addition of cinnamaldehyde microcapsules significantly enhanced the viscoelasticity, water holding capacity, texture characteristics and network structure compactness of protein gels. Whereas, the influence was independent on cinnamaldehyde content. Compared with the two forms, cinnamaldehyde added in the form of microcapsules could more effectively regulate the water holding capacity and texture properties of protein gel.

Abstract:In order to study chromatographic retention time (RT) of aroma components from pineapple, molecular valence connectivity index (^mX^V_t), molecular shape index (ⁿK) and electrotopological state index (E_i) of 44 aroma components were calculated. ²X^V_p and ⁴X^V_c of the molecular valence connectivity indices, and ¹K and ²K of the molecular shape indices, E₈ and E₁₃ of the electrotopological state indices were optimized. The six parameters were used as input variables of neural network and the chromatographic retention time was used as output variable，and the 6∶3∶1 network structure was adopted and BP neural network method was used to establish a satisfying QSRR prediction model. The total correlation coefficient was 0.995. The predicted values by the model were in agreement those of the experiment values. A good nonlinear relationship between the chromatographic retention time and the six molecular structure parameters was found. The model could better elucidate the changing rule of chromatography retention time of the aroma components.

Abstract:Gas chromatography-mass spectrometry (GC-MS) was used to determine the chemical composition of Ravansaravolatile oil. The in vitro bacteriostasis experiment was carried out by the paper diffusion method and the microdilution broth method. And its inhibitory effect on pancreatic lipase and α-glucosidase activity was determined. The results characterized 17 chemical components, accounting for 98.5% of the total volatile oils. The main components were 1,8-cineole (30.89%), camphor (21.67%), (-)-allo-aromadendrene (12.38%), p-cymene (10.14%), β-pinene (6.01%). The minimum inhibitory concentrationrange of volatile oils for 18 tested bacteria was 1.25~40.00 mg/mL. At the concentration of 100 mg/mL, the inhibition rates of pancreatic lipase and α-glucosidase activity were 84.50% and 93.67%, respectively and the half-inhibitory concentration (IC₅₀) was 37.20 mg/mL and 6.81 mg/mL. Experiments showed that the main chemical components of Ravansaravolatile oil were terpenes, alcohols, aromatic hydrocarbons, etc., which had a significant inhibitory effect on Gram-positive bacteria, Gram-negative bacteria and fungi, and had a slightly poorer inhibitory effect on pancreatic lipase activity, but a trong inhibitory activity on α-glucosidase.

Abstract:In this study, Xylose and Lysine were used as raw materials. The browning level of Maillard reaction and the antioxidant activity of reaction products (MRPs) were taken as evaluation indexes, combined with response surface method to optimize and obtain optimal preparation conditions for Maillard reaction products (XL-MRPs) of the xylose-lysine system. In addition, the antibacterial properties of XL-MRPs have also been studied.The results showed that the optimal preparation conditions were: reaction time 120 min, pH 9.0, reaction temperature 109 ℃, Xylose to Lys molar ratio of 2.1∶1.0, XL-MRPs had the strongest oxidation resistance, and FRAP value was 1.33±0.16. XL-MRPs have antibacterial effects on Staphylococcus aureus, Escherichia coli and Bacillus subtilis, and the minimum inhibitory concentration of XL-MRPs solution was 10^-6.

Abstract:As a device for evaluating the taste quality of rice, rice taste analyzer has been used more and more widely. However, the pretreatment conditions for different rice have always been fixed. In this study, the effects of a series of pretreatment conditions such as rice water ratio, soaking time, cooking time, rice braising time and rice temperature for taste quality evaluation of southern Jiangsu japonica rice was explored. It was found that under different conditions of rice-water ratio, the taste scores of four kinds of japonica rice tend to increase and then decrease, and the highest scores were obtained at the rice-water ratios of 1.0∶1.2 and 1.0∶1.3. The effect of soaking time on the rice taste meter score is more remarkable. The taste meter score increased significantly from 0 to 30 min and reached the maximum value at 30 min, after which the taste meter score decreased slightly. The four kinds of southern japonica rice had no significant difference on the taste score under different cooking time. The taste scores of four types of rice all reached the maximum after cooking for 30 to 40 minutes. Within the range of braising time from 0 to 60 min, the tarte scores of the four types of rice increased till 20 min and then decreased. Besides, the taste scores of 9 southern japonica rice were measured at both 75 and 25 ℃. The taste scores of all hot rice samples were about 2 points higher than that of the cold rice. Overall, the change of rice pretreatment conditions for rice taste analyzer brought out scores much more consistent with the results of sensory evaluation. This indicated that the rice pretreatment conditions could be adjusted to make the taste analyzer scores more effective for Chinese eating habits.

Abstract:The longissimus muscle from chilled beef was used as raw material to preliminary study the purification and characteristics of metmyoglobin reductase. The effect of temperature, pH and metal ions on the metmyoglobin reductase activity was investigated. Results revealed that the metmyoglobin reductase of longissimus muscle could be crudely purified with ammonium sulfate (65% saturation) and ultrafiltration (>50 kDa). SDS-PAGE analysis showed that the molecular weight of the metmyoglobin reductase of longissimus muscle was 29.0~66.4 kDa, mainly. The proper temperature of the metmyoglobin reductase of longissimus muscle was 40 ℃, with the proper pH 6.0. Cu²⁺ could inhibit the activity of the metmyoglobin reductase obviously.

Abstract:The free fatty acids and the flavor characteristics of the time-honored sauced duck, Huangshanghuang sauced ducks and Xiangtang sauced duck in Jiangxi province were investigated by gas chromatography-mass spectrometry (GC-MS) and amino acid analysis. The results showed that twenty-three kinds of free fatty acids were detected in the three kinds of sauced duck, which cis-9-oleic acid, palmitic acid and linoleic acid were the main free fatty acids in Jiangxi sauced duck. The glutamic acid content of Xiangtang sauced duck was higher than that of the other two sauced duck significantly, which was 9.27 g /100 g. Ninety-two volatile flavor compounds were identified from the three brands of sauced ducks, including hydrocarbons, aldehydes, esters, alcohols, phenols, ketones. And hydrocarbons were the main volatile flavor substances in the three sauced ducks. Eighteen main volatile flavor compounds were obtained by odor activity value, which (E,E)-2, 4-decadienal, linalol and nonaldehyde were the largest contribution in the time-honored sauced duck, Huangshanghuang sauced ducks and Xiangtang sauced duck respectively.

Abstract:In this study, in order to evaluate the effect of three kinds of sports drinks on the color stability of light cured composite resin materials after 1 and 6 months of immersion, the reference color values (L^*, a^*, b^*) of four kinds of resin composites were measured, and samples from each group of composite materials were randomly selected and immersed in sports drinks and distilled water for 1 month and 6 months. The color values of the samples after immersion were re measured, and the color change value (DE) was calculated. The data were evaluated by Kruskal - Wallis and Mann-Whitney methods. The resin composite showed a color change over a 6-month evaluation period, with the highest color change observed in APX samples immersed in burn at 1 month (P＜0.01); after 6 months, Posterior showed less discoloration (P＜0.001). Among the composite materials tested, Burn sports drink showed the highest fading level (P＜0.01). During the 6-month evaluation period, the color stability of the test samples in this study was mainly affected by the solution type, soaking time and composite composition. The results showed that long-term in-taker of sports should pay attention to their dyeing effect and potential corrosion.

Abstract:Studied the changes of polyphenols including chlorogenic acid, neochlorogenic acid, 4-O-coffee-D-quinic acid, scopoletin, rutin, kaempferol glycoside and polyphenols content in Sichuan Liangshan flue-cured tobacco leaves under different key parameters of threshing and redrying (a1 was one wetting process outlet temperature; a2 was redrying zone 1 temperature~a5 was redrying zone 4 temperature) and alcoholization duration. The results show that: ① one wetting process outlet temperature have a certain positive correlation with polyphenols content, and redrying zone 1 temperature~ redrying zone 4 temperature are not significantly correlation. ② Chlorogenic acid, neochlorogenic acid, rutin, kaempferol glycoside and polyphenols content decrease with the increase of the alcoholization time, and 4-O-caffeo-D-quinic acid, scopoletin content increased with the increase of alcoholization time. ③ The effect of alcoholization time on the polyphenols content is greater than that of threshing, redrying. ④ The best aroma sensory quality of B0~B5, C0~C5, X0~X5 were a1: 60 ℃, a2: 50 ℃, a3: 79 ℃, a4: 67 ℃, a5: 70 ℃, and 12 months of alcoholization time. At this time, a1 and a5 were the highest, and the polyphenol content was high, which was in harmony with the optimal sensory quality.

Abstract:In this paper, regulation of self-assembly properties of thiacyanine dye (Dye2) by nucleic acid aptamer (T30695) was used to construct a specific recognition unit for detecting Pb²⁺. G-quadruplexes were formed to interact with dye 2 monomers, which could disassemble dimers of Dye2 into monomer, in the presence of Pb²⁺. The absorption vales at 422 nm via 445 nm was used as a specific recognition signal to achieve the purpose of specificity and high sensitivity identification of Pb²⁺ only by UV-vis spectra. This system has a good linear relationship from 0.25 to 10.00 μmol/L (R² = 0.992 7), and the detection limit is 0.115 μmol/L.

Abstract:A general QuEChERS purification method was used to establish an HPLC-MS/MS method for the determination of Bentazone and its metabolites 6-hydroxymetazone and 8-hydroxymetazone residues in rice and flour. The results showed that the calibration curves had a good linear relationship between bentazone and its metabolites in the range of 0.1 to 100.0 μg/kg, and the linear correlation coefficients (R²) were all greater than 0.995, with the limits of quantification were all 0.2 μg/kg. Methods at the levels of 0.2 μg/kg, 0.4 μg/kg and 2 μg/kg, the average recovery rates were between 89.6% and 106.9%, and the relative standard deviations were between 1.4% and 11.7% (n=6). The detection method was fast, high sensitivity, accurate and accurate, and the results are stable. It was suitable for the determination and confirmation of Bentazone and its metabolites 6-hydroxy-10-propafenone and 8-hydroxy-1-propafenone residues in rice and flour.

Abstract:A method for the quantitative determination of icariin, hypericin and Psoralen in mix liquor, beverage sample and tea substitutes were established by ultra-high-performance liquid chromatography tandem mass spectrometry. Samples were extracted by methanol water solution, diluted, purified, extracted, centrifuged, filtered, and determined by Thermo Acclain RSLC C₁₈ (2.6 μm, 2.1 mm×100 mm) chromatographic column. The determination was carried out under the mode of electrospray positive and negative ion multi-reaction monitoring scanning (MRM) with acetonitrile and water. The maximum linear detection concentration of 20 compounds was 500 ng/mL, the correlation coefficient (R²) was greater than 0.99, and the quantitative limit was 0.5～5.0 mg/kg. The recovery test of standard addition was carried out at three levels of 1, 2 and 10 times limit of quantitation. The average recovery rate of 20 compounds was between 72.80%～107.75%, and the relative deviation was less than 10%. Conclusion: The method is easy to operate, simple, fast, clean, high sensitivity and good repeatability.

Abstract:Using the principle of enzyme-linked immunosorbent assay, a method for quantitative determination of carbendazim residues in fruits, vegetables, tea, and tobacco was established. First, the carbendazim hapten was prepared through acid-base neutralization chemical reaction, and then the anti-carbendazim monoclonal antibody was screened out by immunizing mice to prepare the enzyme-labeled goat anti-mouse anti-antibody, and finally the prepared anti-carbendazim Monoclonal antibodies and enzyme-labeled goat anti-mouse anti-antibodies were used in the development of enzyme-linked ELISA kits. The results showed that within the linear range of 0.1~8.1 μg/L, the target carbendazim had a good linear relationship, and the correlation coefficient (R²) could reach 0.995. The recoveries of the kits at the addition levels of 300, 600, and 1 200 μg/kg were 76.0%~102.2%, and the relative standard deviations were all less than 10%. The kit detected carbendazim in tobacco leaves, apples, cabbage, and tea samples, and the detection limits were 266.3, 421.0, 349.1, and 484.4 μg/kg (n=20). This method was a rapid detection method and suitable for the determination of carbendazim residues in fruits, vegetables, tea, and tobacco leaves.

Abstract:Based on the hyperspectral imaging technology, a non-destructive detection method for pesticide residues on fruit surfaces is proposed. By preprocessing the collected data and extract features, finding the optimal least squares support vector machine parameters through the bacterial population chemotaxis algorithm, a pesticide residue detection model was established, which was compared with the least squares support vector machine model to verify the superiority and accuracy the model. The results showed that the detection model had the highest detection accuracy based on the characteristic wavelength of the continuous projection method combined with the detection model, and its accuracy rate was 97.92%, which had certain application value.

Abstract:In the environment of large data, the application value of data mining and neural network technology in food safety supervision is discussed to provide ideas for the innovation of supervision mode in this field in China. Several important safety supervision models of Chinese traditional food first analyzed. Based on the analysis of the deficiencies of current supervision, the more mature supervision strategy of developed countries such as the United States is used to apply big data related technology to the food safety supervision, so as to make the data information timelier and more open. BP neural network is applied to the analysis of food testing data to predict the risk coefficient of a certain type of food in the subsequent multiple regulatory cycles, and to give early warning.

Abstract:In the process design of falling film evaporator, there are uncertainties in the design parameters and heat transfer model, which increases the difficulty of falling film evaporator design. Therefore, based on the Monte Carlo uncertainty method, the influence of the uncertainty of the parameters and the model in the three-effect falling film evaporator of dairy products on the design results is studied. The results showed that, compared with parameter uncertainty, the change of evaporator heat transfer performance caused by model uncertainty was more significant. By comprehensively considering the influence of parameter uncertainty and model uncertainty, a model ensembling method was proposed to reduce model uncertainty and improve model prediction reliability. The heat transfer area of the evaporator was selected based on different design probabilities, which provided a theoretical basis for the design and operation of the evaporator under different design conditions and different operating conditions.

Abstract:To solve the problem that many temperature fluctuations occur in cold chain logistics from catching to selling Bonito, a new analog cutting system was designed under -18 ℃ environment based on wide-temperature PLC. Results showed that the design was superior to the traditional manual processing under room temperature and mechanical cutting after ultra-low temperature defrosting whether in low-temperature preservation or cutting speed, which reduced the cutting and exposure links and the temperature fluctuations effectively. After being assembled between the processing and quick-frozen cabins of the ocean-going fishing vessel, the synchronization of cutting and quick freezing could be realized, which could provide an effective way to keep fresh for the cold chain logistics of Bonito.

Abstract:In order to solve the problem that the high-pressure sterilization system cannot remove multiple strains at the same time, this article uses a modular design to establish a sterilization system structure that eliminates three strains (Penicillium, yeast, Escherichia coli), and establishes a bipolar square wave and a high-frequency pulse with adjustable frequency Equivalent model of power supply and processing room, respectively. The system can output multiple bipolar square wave waveforms with different peak values when the frequency is 100~1 000 Hz with the pulse width of 10 μs, and can sterilize different pathogens separately. Simulation results show that the power supply can generate three pulses with amplitudes of 4.417, 6.153 and 9.663 kV, respectively, at 100 Hz stable operation, and can generate three pulses with amplitudes of 4.272, 6.082 and 9.393 kV, respectively, at 1 000 Hz stable operation. When the treatment room spacing is 3 mm, the best treatment voltage peaks of Penicillium, yeast, and E. coli are 3.75, 6.00 and 9.00 kV, respectively. Therefore, the three voltage pulses generated during stable operation of the power supply can meet the requirements for simultaneous eradication of Penicillium, yeast and E. coli.

Abstract:In order to solve the problem that the fish belly is easy to scratch by the existing dirt-removing device , a kind of dirt-removing device for freshwater fish with reciprocating operation is designed. Taking carp as the test object, a sensory evaluation model of dirt-removing effect was established with visceral removal degree and fish belly integrity degree as evaluation indexes. The influences of process parameters such as starting position, feed speed and feed quantity of reciprocating operation of dirt-removing tool on dirt-removing effects were analyzed, and the process parameters were also optimized. By increasing the starting position and feeding rate, decreasing the feeding rate were beneficial to the improvement of the degree of internal organs removal, but the possibility of abdominal injury was increased. The order of influence of process parameters on the comprehensive effects of dirt-removal was operational speed >feed rate> starting point. When the starting position was 27 mm, the feed rate was 0.23 m/s, and the feed rate was 64 mm, the internal organs removal degree and the fish abdomen integrity degree score were 4.65 and 4.82, respectively. The comprehensive dirt-removal effect of this scheme was the best.

Abstract:Aiming at the problems of large-scale food waste treatment production line, such as large capital investment, high cost of equipment operation and maintenance, and single operation form of small-scale food waste treatment equipment, based on SolidWorks, a kind of food waste treatment equipment, which integrates feeding, crushing, compression and dehydration, is designed to realize high integration, high automation, low energy consumption and low operation cost of food waste resource utilization Slag liquid separator. The particle model was established by EDEM software, and the particle motion parameters of kitchen waste were analyzed and optimized by RNG k—ε turbulence model in Fluent. The results show that when the screw speed of the separator is 150 r/min, the operation of the separator is stable and the speed is kept at 0.05~0.07 m/s. In the range of 4.75~4.90 s, the velocity of particles reaches the maximum value of 0.14 m/s, and the force reaches the maximum value of 1.49 N, which can achieve fast and effective solid-liquid separation, significantly reduce the retention of harmful substances, and obtain higher resource recovery.

Abstract:To determine the freshness change of Channel catfish fillets during freeze-thaw cycles and establishprediction model using near infrared spectroscopy, Near Infrared(NIR) reflectance spectroscopy was used to collect spectral data of Channel catfish meat during 5 times freeze-thaw processing, meanwhile the contents of ATP-related compounds of fish samples were obtained by HPLC (High Performance Liquid Chromatography) to calculate the freshness of K value, then the quantitative prediction model of K value was established based on the optimal wavelengths using PLS (Partial least squares regression) method and verified by t-test. The results showed that ATP content declined rapidly (P＜0.05) from 2.15 to 0.55 μmol/g after the first freeze-thaw cycle and then stabilized until the end of processing; IMP content increased from the initial value of 4.07 μmol/g to the peak value of 5.97 μmol/g (P＜0.05) after the first freeze-thaw cycle and then decreased gradually (P＜0.05); Hx content increased slightly until the 4th freeze-thaw cycle and then increased greatly (P＜0.01) from 4.29 to 19.65 μmol/g after the 5th freeze-thaw cycle. K value significantly increased (P＜0.05) throughout the freeze-thaw processing, and the catfish meat showed decompose after 3th freeze-thaw while the K value was 67.95%(overlimitation of 60%). The near-infrared spectral data was pre-processed by filter fitting method (SG) and Standard Normal Variate (SNV), which obtained the best the prediction result, with the model predictive value determination coefficient (R²) of 0.938 1, and root mean square errors of prediction (RMSEP) of 1.49. Therefore, the established model was capable to predict the freshness of fish samples.

Abstract:After opening the shell with steam, the microorganisms on the surface of fresh mussel meat (FS), frozen mussel meat at -18 ℃ for 1 week (FS-1), frozen mussel meat for 3 weeks (FS-3) and frozen mussel meat for 9 weeks (FS-9) were extracted with DNA extraction kit and then analyzed by high-throughput sequencing. The effective sequences in all samples ranged from 31 896 to 42 812, and the operational taxonomic unit (OTU) ranged from 289 to 681. Among them, the OTU of FS-9 was the lowest, and the OTU of FS was the highest. Diversity index analysis showed that the lowest microflora richness was found in FS-3. At the genus level, the predominant flora of each sample contains Vibrio spp. With the extension of frozen storage time, the proportion of Staphylococcus was gradually decreased. The Shewanella was newly added and relatively abundant after frozen for 9 weeks. In addition, Acinetobacter was only found in samples of FS and FS-9.

Abstract:To study the effects of 1-MCP (0.00, 0.08, 0.16, 0.32 g/L) on the quality of banana in Hekou, Yunnan Province The changes of soluble solids, hardness, disease index, yellowing index, pod enzyme (peroxidase), weight loss rate, respiration rate and titratable acid of banana during storage were studied. The results showed that: 1-MCP + PBI modified atmosphere preservation bag delayed soluble solids, disease index, yellowing index, pod enzyme activity compared with other treatments (P ≤ 0.05); 1-MCP + microporous membrane significantly delayed the decline of fruit firmness (P ≤ 0.05), inhibited the increase of titratable acid content (P ≤ 0.05), but had no significant effect on weight loss rate and soluble solid content of banana. Among them, 0.16 g/L 1-MCP + PBI modified atmosphere bag treatment was the best way to keep banana fresh.

Abstract:In this study, three kinds of disease images of jujubes, black spots, broken heads and dry strips with high classification difficulty were used as research materials. The color moment and gray level co-occurrence matrix were used to extract 14-dimensional eigenvectors of the color and texture features of jujube, and the principal component analysis method was used to optimize the features. Four principal factors of eigenvectors were obtained and then used as the input of support vector machine. The crossover algorithm was used to determine the optimal support vector machine penalty parameter c and kernel function parameter g, which was used as the parameter of the support vector machine multi-classification model to train the model. Using the trained model to perform multi-classification experiments on the jujube, the results proved that the three kinds of defects of jujube could recognized quickly and accurately, with the recognition rate at 93.3%, 100.0% and 96.6%, respectively. The classification accuracy of this model for jujube defects could reach 97.2%, with high efficiency.

Abstract:In order to obtain the image of seedless white grape, the influence of background paper color, light source structure and lighting mode on the image was fully considered on the self-made acquisition platform. Firstly, the optimal level of each factor is determined by single factor test, then the acquisition platform is optimized by orthogonal test, and finally the optimal value level of each factor is determined by subjective and objective comprehensive evaluation image method. The results showed that the best values of the machine vision imaging system of seedless white grape were: the background paper is white, the light source structure is strip light source -60°, the lighting mode is open field mode. Under the conditions, the image quality is the best.

Abstract:To realize the rapid detection of normal peppers and defective peppers (dark spots, insect marks and stripe skin), image acquisition and median filtering were used for denoising. 24 color feature variables and 20 texture feature variables of sample images were extracted. Threshold segmentation in the Otsu algorithm was used to extract two morphological feature variables. The Successive Projections Algorithm (SPA) was used to optimize 14 feature variables. Modeling was done based on the Least Squares Support Vector Machine (LS-SVM) method. The detection result of SPA-LS-SVM model is 98.67%, which is the best.

Abstract:Taking Tie Guanyin residues as the research object, through single factor experiment and response surface methodology, the effects of extrusion water content, sleeve temperature and screw frequency on its assisted alkaline-enzyme combined extraction of tea residue protein hydrolysates (TPH) were discussed, and the functionalities of TPH was then investigated. The optimal extrusion assisted extractions were water content of tea residue material 15%, sleeve temperature 97 ℃, screw frequency 40 Hz. Under the conditions the extraction rate of TPH was improved to (71.37±0.09)%, which was close to the predicted result. The results of TPH antioxidant activity showed the IC₅₀ values of DPPH· and ABTS⁺· were 23.4 μg/mL and 111.4 μg/mL, respectively, which were 18% and 32% lower than those of directly extracted sample; and except the decrease of emulsion stathe, the solubility, emulsifying activity index and foaming properties of TPH were all significantly improved (P＜0.05). The results indicated that the extrusion assisted extraction process could well improve the functionalities of TPH, which makes its application in food system valuable and possible.

Abstract:Taking substitution rate as an index, the effects of concentration of sulfuric acid, reaction temperature and reaction time on sulfation of Pleurotus ostreatus polysaccharides were studied by concentrated sulfuric acid method. On the basis of single-factor results, the optimum preparation process of P. ostreatus polysaccharide sulfate was obtained by L₉(3⁴) orthogonal test. Secondly, the polysaccharide and sulfates of P. ostreatus polysaccharide were characterized by FT-IR spectrometer. Finally, the reductive power of V_C and the scavenging rates of DPPH radical, superoxide anion radical and hydroxyl radical were determined to explore the antioxidant activity of P. ostreatus polysaccharide sulfate. The optimum preparation process of polysaccharide sulfate of P. ostreatus was as follows: the mass of P. ostreatus polysaccharide was 1.00 g; the volume of sulfuric acid was 10 mL, reacting at 60 ℃ for 90 min, and the degree of substitution was 0.48. FT-IR spectrum results showed that sulfate group and P. ostreatus polysaccharide formed polysaccharide sulfate. The IC₅₀( scavenging rate) of polysaccharide sulfate from P. ostreatus were 0.816, 1.882 and 1.611 mg/mL for DPPH radical, superoxide anion radical and hydroxyl radical, respectively. The reductive power and scavenging ability to three free radicals of P. ostreatus polysaccharide sulfate were higher than those of polysaccharides, which suggested that P. ostreatus polysaccharide sulfate had a better antioxidant activity than that of polysaccharides.

Abstract:Arecoline was extracted from the core of betel-nut by acid water extraction method. Based on the effects of time, temperature, ratio of material to liquid, hydrochloric acid concentration and extraction times on arecoline by single factor method, a quadratic polynomial model of time, temperature and hydrochloric acid concentration was established by box-Behnken response surface design method to optimize the extraction process. The arecoline extraction was applied to betel-nut products to investigate its effect on the quality of areca products. The results showed that the optimum extraction process conditions were solid-liquid ratio 1∶15 (g/mL), extraction times 2, extraction time 45 minutes, temperature 80 ℃ and hydrochloric acid concentration 0.22%. The arecoline extraction amount obtained under this process condition was (8.330±0.109) mg/g. The arecoline extraction can enhance the flavor of areca products, thus enhancing the market competitiveness of betel-nut products.

Abstract:Taking 10 kinds of vine tea samples collected as objects, 15 related physicohemical quality indexes of vine tea were measured. Four core indexes of tea infusioninflavonoids(A₁₁), polyphenols(A₁₂), soluble sugar(A₁₃), and brightness(A₅) were determined by variation analysis, correlation analysis, and principal component analysis. After that, the index weight was determined by the entropy method, and the grey correlation analysis was used to construct the evaluation model of the physicohemical quality: φ_imodelscore=ξ_A11×0.181 1+ξ_A12×0.224 2+ξ_A13×0.415 4+ξ_A3×0.179 3, and the fitting degree between the model score and the sensory score is 0.822. Finally, according to the score of the model, the vine tea samples were divided into three levels by cluster analysis.

Abstract:The basic physical and chemical indexes, cooking characteristics, gelatinization characteristics and texture characteristics of different combinations of japonica rice and indica rice were studied. The results showed that the content of amylose had an important influence on food quality. In terms of cooking characteristics, the lower the amylose content and the smaller the water absorption and expansion volume was, the higher the rice soup pH , the rice soup iodine color value and the rice soup dry matter content would be, and the better the cooking and brewing properties was. In terms of gelatinization characteristics, the lower the amylose content was, the higher the peak viscosity and disintegration value was; the lower the recovery value and the attenuation value was, the better taste would be achieved. In terms of texture characteristics, the lower the amylose content was, the hardness and viscosity was; the higher the cohesion, recovery and elasticity was, the higher eating quality would be. Therefore, regardless of the influence of other auxiliary materials, using only the North-east pearl rice could make the infant rice noodles have better taste and eating quality.

Abstract:Chinese yam, Coix chinensis Tod. and Euryale ferox were added to wheat flour, the effect of mixed powder with different addition amount on the gelatinization characteristics, thermomechanical properties of dough and texture characteristics of steamed bread were analyzed by using rapid viscosity analyzer, Mixolab hybrid experiment instrument and texture analyzer. The results showed that as the amount of mixed powder added increased. The gelatinization viscosity, disintegration value, retrogradation value, gelatinization temperature, gelatinization time, dough water absorption, formation time and stability time of wheat flour gradually decreased, and cooking stability and protein weakening gradually increased. The hardness and chewiness of steamed bread increased significantly (P < 0.05), and elasticity increased first and then decreased. The sensory evaluation was consistent with the results of the texture analyzer. When the added amount of mixed flour was 10%, the gelatinization properties of wheat flour were the best, and the quality of steamed bread was the best. The added amount of mixed powder, gelatinization properties, and dough thermomechanical properties were significantly related to the texture properties of steamed bread (P＜0.05). The texture properties of steamed bread could be predicted by the thermomechanical properties and gelatinization properties of the dough.

Abstract:In order to investigate the quality characteristics of banana dried by ultrasound combined with far-infrared radiation drying, the banana slices were dried using ultrasound combined far-infrared radiation drying, and the drying was operated using the radiation temperature of 150, 210, 270 ℃ under the ultrasound power of 0, 30, 60 W. The effect of drying conditions on structure, rehydration ratio, shrinkage, color difference, total phenol content, VC content and antioxidant activity of banana slices were compared. The results showed that as the increases of radiation temperature and ultrasound power, the hardness values and shrinkage rate of banana slices decreased, and the rehydration ratio increased. At radiation temperature of 210 ℃, the color difference of banana slices was smaller, the contents of total phenol and VC were higher, and the antioxidant activity was stronger. The application of ultrasound can improve the physical and chemical quality of banana slices dried by far-infrared radiation. The results of weighted comprehensive score analysis showed that radiation temperature of 210 ℃ and ultrasonic power of 60 W were the optimal parameters for ultrasound combined far-infrared radiation drying of banana slices.

Abstract:This review summarized the microstructure, gelation process and the mechanism of gel properties of heat-induced from egg albumin. The effects of glycosylation, salt, enzymes, pH, adding NaCl or adjusting pH to synergistic glycosylation or enzyme on heat-induced gelation of egg white protein were discussed emphatically, and the research direction and application of heat-induced gelation of egg albumin were also prospected.

Abstract:The principles, advantages and disadvantages of the traditional and novel freezing and thawing methods were elaborated, and the research status of the applications of freezing and thawing technologies in aquatic products were also summarized. The development direction of freezing and thawing technologies was then prospected in this review.

Abstract:This study reviews the preparation process, properties (mechanical properties, thermal properties, barrier properties, etc.), modification methods, and applications of fish scale collagen films. The performance of the film can be significantly improved through molecular blending, but it is critical that the factors have not been studied in depth. Future research must solve the problems of film modification mechanism, aging mechanism, edibility, biodegradability, barrier property, safety, etc. from the perspective of industrial scale and commercialization, so as to make fish scales collagen films industrially feasible.