Abstract:In order to clarify the role of lactic acid bacteria and yeast in the yak yogurt quality formation, by using the yak milk powder as the raw material, the yak yogurt as the fermentation agent, and inhibiting the yeast and lactic acid bacteria in fermention, respectivly, the indexes, for the flavor, taste and texture, were determined, and compared in the ordinary fermentation, inhibition of lactic acid bacteria, inhibition of yeast fermentation yogurt. The results showed that lactic acid bacteria and yeast had a key role in the formation of yak yogurt quality. The lactic acid bacteria had a great contribution to acidity, texture, amino acid nitrogen, organic acid, V_B1, ketones and acid flavor compounds, and yeast has a greater contribution to ethanol, V_B2, alcohol and ester flavor compounds. Through exploiting the fermentation agents, mixed the lactic acid bacteria and yeast strains, it will help produce high quality yak yogurt.

Abstract:Interactions between Streptococcus salivarius and Streptococcus mutans play important roles in the development of dental biolms in oral cavity. S. salivarius BD3900, isolated from the oral cavity of a healthy voluteer, displayed the potential to be an oral probiotics in vitro. Strong hydrophobicity (95.8%) and high surface charges(≥88.6%) endure the strain to be easily adhered in oral cavity. The strain BD3900 was tolerant to 100 μg/mL lysozyme(2.0×104 U/mg), indicating the high ability for the strain to survive in oral cavity. Besides, the strain was determined to be with high auto-aggregating ability(15%～20%) as well as co-aggregating abiltity with Streptococcus mutans.in the presence of sucrose at a concentration dependant manner, with a highest co-aggregation rate of 64.3% at a sucrose level of 5 g/100 mL, while no obvious effect of sucrose was observed on the auto-aggregation of the strain BD3526. Furthermore, when co-cultured with the strain BD3900, the formation of S. mutans biofilm could be reduced by 67.1%. Therefore, the strain S. salivarius BD3900 is a candidate of oral probiotics with potential in prevention of dental caries.

Abstract:Beef longissimus dorsi muscle with different high temperature treatment (110 ℃, 115 ℃ and 121 ℃, respectively, heating 3, 6, 9, 12 and 15 min) were tested for time and temperature-related changes in different solubility and structural proteins, total nitrogen and non-protein nitrogen, amino nitrogen content, proteolysis index and SDS-PAGE patterns of total muscle protein during high temperature processing. The results showed that the contents of water-soluble protein and salt-soluble protein decreased distinctly with the increase of heating temperature and time. After heating at 121 ℃ for 15 min, the content of sarcoplasmic protein in the beef longissimus dorsi muscle was decreased by 86.9%, myofibrillar protein decreased by 89.88%. The content of total nitrogen and amino nitrogen increased first and then decreased. The effect of heating time on non-protein nitrogen and protein hydrolysis index was significant (P＜0.05). The myosin heavy chain band of 200 kDa gradually disappeared as the heating time prolonged, while the actin band of 44.3 kDa did not change significantly during the high temperature treatment.

Abstract:In order to degrade protein of tobacco and improve the smoking quality of tobacco, 18 protein degrading bacterias from flue-cured tobacco of Henan, Fujian, Yunnan province were isolated through protein degrading selective medium. The activity of protease was detected, and the strain with highest protease-producing was identified by the 16S rRNA gene sequence and physiological-biochemical tests. Orthogonal experiment was further designed to get the optimal fermentation conditions of protein degrading in the tobacco leaf. And then the sensory quality of tobacco leaves after treatment was investigated The results showed that: (1) Strain HN-3 was the preferred strain with the highest activity of protease enzyme producing (3 417 U/mL). (2) Strain HN-3 was identified as Bacillus pumilus by the 16S rRNA gene sequence and physiological-biochemical tests. (3) The orthogonal experiment results suggested that, by adding 3% culture medium (with strain HN-3) to the surface of tobacco leaf, the degrading rates of protein could reach 29.66% after 84 hours fermentation under the 37 ℃. (4) The sensory evaluation results showed that after fermentation, the aroma of tobacco leaves was changed well. The amount of aroma and smoke increased, while the gas content decreased, the aftertaste improved, and the overall sensory quality of tobacco was improved obviously.

Abstract:In this paper, the effect of different mixing (vacuum, conventional and manual) and kneading (machine kneading, hand kneading and non-kneading) methods on the quality of frozen cooked noodles were studied. The different processing methods on the cooking and texture properties of the frozen cooked noodle were investigated, and by NMR analyzed the water changes, use SE-HPLC to analyze the changes in protein. The results showed that the frozen cooked noodlemixed in vacuum condition had the best texture and cooking properties, the highest percentage of A₂₁ and the lowest SDS extractability. It showed that vacuum condition could promote the cross-linking of gluten protein, make the gluten more continue and evenly, and combined with water more tightly; kneading process especially manual kneading could make the noodle with better cooking and texture properties, and the higher percentage of A₂₁, reduced the SDS extractability, showed that kneading specially by hand could make the gluten more complete and promote the combination of gluten with water.

Abstract:The components of the provided E-cigs liquids were analyzed by solvent extraction-gas chromatography/mass spectro-metry and headspace GC/MS (HS-GC/MS). Under the standard suction (ISO) condition, the atomization behavior of E-cigs was studied. The results indicated: ① The content of PG, glycerol, and nicotine in E-cigs liquid was higher than the other components. The other components were mainly tobacco essences and extracts. ② The component of PG in mainstream cigarette aerosol was highest, which up to 588.5 mg/g. The glycerol content was up to 290.2 mg/g, and the nicotine content was 10.4 mg/g. ③ E-cigs liquid was atomized and trapped by Cambridge pad, and the mainstream cigarette aerosol was mainly particulate matter. The average atomizing efficiency was 11.99%, and the efficiency in every puffing smoke was 0.30% under the standard puff conditions. The pretreatment process of static headspace analysis is simple and convenient, and it has advantages in qualitative analysis. However, pyrolysis will lead to the generation of aldehydes and ketones with small amounts of molecular weight. Therefore, the use of solvent extraction and GC-MS is more suitable for quantitative analysis.

Abstract:To determine the antibacterially effective fraction from Peristrophe japonica (Thunb.) Brem.and to clarify its chemical components. The ethanol extract of Peristrophe japonica (Thunb.) Brem. was separated by macroporous resin column chromatography eluted with water, 80% ethanol and acetone, respectively, to give the fractions A-C. The in vitro antibacterial effects of the fractions were determined by the disc diffusion test. The anti-bacterial potencies of the active fraction was then assessed in vitro by determining the MICs and MBCs. The chemical structures and relative contents of the components present in the antibacterially effective fraction were determined by gas chromatography-mass spectrometry (GC-MS). Each fraction from Peristrophe japonica (Thunb.) Brem showed different levels of antibacterial activity with fraction C (the acetone fraction) being the most active fraction. Twenty-six compounds were identified by GC-MS in the effective fraction, these compounds are fatty acid and its derivatives. The fatty acid and its derivatives is the main antibacterially active ingredients in Peristrophe japonica.

Abstract:The physicochemical characteristics and digestibility of native starch from Dioscorea opposite Thunb. cv. Huaiqing and its resistant starch produced by autoclave process preparation method have been analyzed and compared in the paper. Results showed that the shape of native starch granules from Dioscorea opposite Thunb. cv. Huaiqing was irregular ellipsoid and triangle with a smooth surface. The crystal form of naitive starch was type C. Resistant starch losing particle characteristic exhibited a lamellar structure with loose surface. Both of them were similar in chemical structure without new functional group in resistant starch granules. Compared with the native starch, the molecular weight distribution of resistant starch was more concentrated. The peak temperature of resistant starch gelatinization was higher than that of naitive starch, and the resistant starch had better thermal stability. The transparency of resistant starch was lower than naitive starch. When bath temperature was lower than 75 ℃, the water-holding capacity of resistant starch was greater than that of naitive starch, and while bath temperature was above the gelatinization temperature of native starch, water-holding capacity of naitive starch, which was much higher than that of resistant starch. The results of simulating human digestion based on In-Vitro mode showed that resistant starch was more resistant to digestion than naitive starch.

Abstract:The cut tobacco moisture content, smoke moisture content, tar, nicotine, carbon monoxide and 70 kinds of smoke components of cigarettes with different environmental humidity were measured, and the cigarette feature indexes and quality indexes were evaluated. ① In general, with increasing of the environmental humidity, the contents of mainstream smoke components increased. ② With the increasing of the environmental humidity, the features indexes were overall increased firstly and then decreased, and the maximum value appeared at 50% humidity. In quality characteristics, the total score were increased first and then decreased, the maximum value appeared in 60% humidity, and the comfort indexes showed a increasing trend. However, aroma, smoothness, aroma abundance showed a increasing first and then decreasing trend, and the maximum value appeared in 60% and 70%. The smoke concentration and strength showed a decreasing trend. The influence of environmental humidity on the quality characteristics of cigarette was greater than that of feature characteristics, and the slightly drier environment, was more suitable for the performance of feature characteristics.

Abstract:The high resolution mass spectrometry database of weight-loss illegally added drugs was established base on liquid chromatography-diode array detector-ion trap-time of flight tandem mass spectrometry (LC-DAD-MS-IT-TOF)．The analytes in samples were extracted with acetonitrile and the extract was purified with the mixed QuEChERS sorbents. In the chromatographic analysis, target compounds were separated on a ZORBAX Eclipse AAA column (150 mm × 4.6 mm, 4.5 μm) with the gradient elution using the mobile phases of acetonitrile and water containing 0.1% acetic acid. The results showed that the screening detection limit (SDL)of the target compounds were ranged from 0.10～0.75 mg/kg. The method validation was carried out at SDL levels，and the recoveries were 49.4%～88.1%. with the relative standard deviations(RSDs) of 5.0%～14.8%．The characteristic absorption wavelength of illegally added drugs was determined by UV spectrum. The screening of analytes was performed by precision mass matching and library searching. The retention time, isotopic abundance and multiple-stage ion mass spectral was employed to the confirmation. Moreover, the ion fragmentation patterns of these drugs can be exploited to predict the chemical formula and the fragmentation pathway.This method is simple, fast, credible and high sensitivity, which can be applied to simultaneous screening and identification of illegally added drugs in health foods.

Abstract:As the defects of the existing detection methods for Salmonella, a fast, simple, low cost and highly sensitive new rapid detection technology has been developed. The CdTe quantum dots were synthesized by water method, and then the display DNA was used to connect hundreds of quantum dots to a gold nanoparticle. After preparing the amination Fe₃O₄ magnetic nanoparticles by using a water hot-solvent hot method, the principle of avidin-biotin specific was used to bind with the capturing probes. Finally the fluorescence intensity of Salmonella DNA was detected. The results showed that the fluorescence intensity and Salmonella DNA concentration had good linear relationship in the range of 10～1 000 fmol/L, and the regression equation was I_F=0.198 \[DNA\]+55.00, R²=0.997, with the detection limit of 8 fmol/L. Moreover, it also showed good accuracy, with the minimum detection limit of 4 fmol/L, in the detection of milk samples contaminated with salmonella.

Abstract:A method was developed for the simultaneous determination of arsenic acid \[As(Ⅴ)\], arsenious acid \[As(Ⅲ)\], arsenobetaine (AsB), monomethyl arsonic acid (MMA) and dimethylarsinic acid (DMA) in aquatic animals and their products by high performance liquid chromatography and inductively coupled plasma mass spectrometry (HPLC-ICP-MS). The extraction reagent was 0.15 mol/L nitric acid with heat-assistant condition for 30 min at 80 ℃. Then, the five arsenic species were separated by a anion exchange column (Hanmilton PRX-X100 250 mm×4.1 mm, 10 μm) and detected by ICP-MS. The effects of different elution methods on the separation of five arsenic forms were compared, and the chromatographic conditions on the separation of arsenic were studied and optimized. The recoveries of the five arsenic species spiked in aquatic animals at three levels ranged from 87.8%～97.5%, and the relative standard deviations (n=6) were 1.5%～4.5%. The five arsenic species showed good linearity in the range of 0～100 μg/L, and the limits of detection for the five arsenic species were 0.002～0.010 mg/kg. This method was simple, accurate and durable for the detection of arsenic species in aquatic animals and their products.

Abstract:The method of measuring rice protein with fully automatic Kieldahl azotometer by single-factor experiment and orthogonal experiment was investigated. It defines the best experiment conditions through examining such key factors as sample weight, additive amount of sulfuric acid, digesting temperature and digesting time. The results showed that when the sample weight is 0.40 g, the added amount of sulfuric acid was 12 mL, digested at is 420 ℃ and for 50 min, the experimental effect was the best. The standard deviations of 6 determinations of 5 kinds of rice were 0.050 2～0.101 1, and the recoveries of nitrogen of urea were 99.9%～100.5%. The ratios of protein obtained by semi-micro distillation method were between 1.023 4～1.079 4, and the time of determination could be shortened to 1 hours. The method was found stable and accurate.

Abstract:To establish a LC/MS-MS method for determination of 4 kinds of rodenticide residues in plant-origin food, the effects of different mobile phase and purification on the recovery was studied. The grain samples were extracted by acetontrile and then determined by LC/MS-MS, while the samples with fruit or vegetable matrix were purified with PSA+GCB after the extraction. LC/MS-MS was used for determination. The recoveries were all above 70% at spiked levels of 0.002～0.050 mg/kg, and the relative standard deviation of the methods were 4.1%～9.5%. The LOD of warfarin and coumatetralyl were 0.001 mg/kg while the other two reach 0.005 mg/kg which was in accordance with the requirement of technical parameters for analysis, with fast and simple determination and high sensitivity.

Abstract:A method to the determination of Iodide, Thiocyanate, Perchlorate and Glyphosate in drinking water by flow injection on-line preconcentration and Ion chromatography Spectrometry with activated carbon fiber as adsorbent was developed. Using the activated carbon fiber as adsorbent flow injection on-line preconcentration, and by flow injection in the laboratory (FIA)-ion chromatography (IC) combined with technology of adsorption column enrichment of Iodide, Thiocyanate, Perchlorate and Glyphosate were determined. The linear range of the method for trace Iodide, Thiocyanate, Perchlorate and Glyphosate was 0.01～5.00 mg/L, the correlation coefficients were 0.997 9, 0.999 0, 0.998 7 and 0.998 1, and the average recoveries were 94.9%～99.2%.

Abstract:The effects of different pretreatments, NaCl concentration and pickling temperature on nitrite formation in the traditional pickling process of Toona sinensis were studied. Moreover, the change rules of the content of nitrite in the pickling process after adding VC, glucose and ginger respectively were also discussed, and the control conditions were optimized. The results showed that blanching materials with Zn(Ac)₂ and EDTA-2Na mixture could greatly reduce the content of nitrite in the product; the higher the NaCl concentration, the later the peak of nitrite occurred and the higher the concentration and the peak value of nitrite; the lower the pickling temperature was, the slower the nitrite produced, the higher the content was and the longer the peak duration was. When added 0.47‰ VC, 0.34% glucose and 1.75% ginger, the nitrite content in the conditions was 3.74 mg/kg. The products could be accepted by consumers.

Abstract:One vegetable processing production line was used based on ultrasonic pesticide degradation machine as experimental equipment in this study. By controlling the different ultrasonic power and ultrasonic radiation time parameters, the pesticide degradation effects of organic phosphorus and carbamate remaining on the surface of a small green vegetables with different ultrasonic power and ultrasonic radiation time were analyzed. The results showed that the ultrasonic power for organic phosphorus and carbamate pesticide degradation effect was very obvious. However, when the ultrasonic power reached to a certain degree, the pesticide degradation tend to be changless. The relationship between the ultrasonic irradiation time and the degradation of organic phosphorus and carbamate pesticides was as follows: the degradation rate increased with the increase of ultrasonic irradiation time. From the consideration of production efficiency, for the degradation of organic phosphorus and carbamate pesticides ultrasonic power was 2.4 kW, with ultrasonic radiation for 4 min, the degradation rate could reach 80%.

Abstract:The ice-temperature vacuum drying processing dose little damage to the nutrition of food products, and helps to preserve their high quality. However, the precise control of ice-temperature is difficult in this field. On the basis of analyzing the principles of ice-temperature vacuum drying process and the features of drying equipment, the ice-temperature vacuum drying system with improved control flow was set up and the experiments with the sample of white radish wear were carried out. The results showed that this system could operate steadily at the set sample temperature value ±0.5 ℃, and provided a platform for the follow-up study of the ice-temperature vacuum drying process.

Abstract:In order to reduce the high degree of dependence on human resources in the process of hamburger-making, an automatic hamburger-making machine was designed. The machine consisted of mechanical system and control system. The mechanical system included an oven, an overhead travelling crane system, a meat storage cabinet, a manipulator, a pallet trolley, an assembly line, a hamburger sauce adding mechanism and a vegetable adding mechanism. The control system included a touch screen, a communication system and a PLC (Programmable Logic Controller). The control system could regulate the mechanical system to complete a five-step task, including adding bread, adding meat, adding hamburger sauce, adding lettuce and adding bread. The automation and efficiency of hamburger-making was increased by using the automatic hamburg-making machine. The feasibility and rationality of automatic hamburg-making machine were verified by experiments.

Abstract:In order to solve the problem of low weight detection precision of belt type weight detection equipment at high speed. Firstly, the model of weight detection system was modeled, and then the checkweigher in static, no-load operation, the normal work of the state of the system was checked to analyze time frequency signals.The source of interference and its frequency were found out, then an analysis of its causes and changes were analyzed, determining the index filtering. According to the index, the FIR digital filter was designed to denoise the data. After filtering, two methods were adopted as follows. The weight estimation of asymmetric trimmed mean (Trimmed-mean mass estimator, referred to as TME) was investigated. After taking the last N data and sorting by size, this sequence was cut in an asymmetrical way for average. Moreover, the arithmetic average weight estimation (Averagemassestimation, referred to as AME) used to intercept the last N data, and the average was adopted. The results showed that the weight error of TME was less than 0.3%, and the average error is 0.155%, with the average error of AME 0.758%. It was concluded that the FIR filtering could fast denoise the wave, and the TME weight estimation had higher detection accuracy.

Abstract:To improve the dehulling rate and reduce the damage rate, a peeling machine for potato was designed according to the principle of rubbing. The machine consisted of waterworks, discharge control device, locking device, peeling roller, spiral brush roller and so on. It adopted rubbing of peeling roller and spiral brush roller for potato peeling. The main factors influenced peeling were studied, including rotating speed, time and feeding rate, and a peel test was carried out. The results showed the mass loss rate increased significantly with the increase of rotating speed and time. However, with the increase of feeding rate, the mass loss rate decreased. The suitable working parameters of the peeling machine were as follows: The rotating speed and time should be about 205 r/min and 3.5 min respectively, with feeding speed at about 105 kg/h. The mass loss rate could reach only 11.1%. Meanwhile, the lifting scheme of the full automatic mechanical peeling machine was controlled by the main motor, water pump, inlet baffle, discharging mouth damper using PLC and frequency converter.

Abstract:The bacteriostatic activity and bacteriostatic mechanism of thymol to Listeria monocytogenes were studied and the thymol-chitosan composite membrane was prepared to study the properties of the composite membrane and its preservation effect on pork. The results showed that the minimum inhibitory concentration of thymol on Listeria monocytogenes was 12.5 μg/mL. The experimental study of conductivity, nucleic acid and protein leakage found that thymol caused by mononuclear proliferative Leptospira cell membrane damage, so that bacterial cell inclusions caused by bacterial death. With the increase of thymol concentration (0.25%, 0.50%, 1.00%) in the thymol-chitosan composite membrane, the hardness and puncture strength of the membrane gradually decreased. The temperature and thymol concentration affected the removal of DPPH free radicals by composite membranes. At 25 ℃, the scavenging rate of 1.00% thymol-composite membrane was the highest at 25 ℃; the growth and reproduction of microbes in pork were reduced by the thymol-chitosan composite membrane, the total number of colonies decreased and the chilling period of pork was prolonged.

Abstract:The two compounds of methyl p-hydroxybenzoate and propyl p-hydroxybenzoate were added into LDPE to make antibacterial masterbatch. The masterbatch were prepared for different formula antimicrobial films using of extrusion casting methods, and then the antibacterial and mildew resistance properties, as well as the mechanical and barrier properties of the films were studied. Methyl p-hydroxybenzoate and propyl p-hydroxybenzoate were found showing synergistic antibacterial effect. When the ratio was 23, the antibacterial rate reached 99.67% (E.coli) and 99.59% (Staphylococcus aureus) respectively, and the mold mildew grade reached Level 1, with a strong anti-bacterial and anti-mildew effect. The addition of p-hydroxybenzoate had little effect on the mechanical properties, which was slightly better than that of LDPE at the ratio of 23, and the water permeability decreased by 34.73%, with the air permeability decreased by 5.32% and barrier performance improved. When the ratio of the two was 23, the antibacterial and mouldproof LDPE film had the best application effect, and it was expected to be used in the inner layer of low water activity food package.

Abstract:Changsha kiln was famous in history for specializing in the production of civilian ceramic utensils since the Tang Dynasty. It not only reflects the spiritual meaning of the Huxiang culture , but also mixes the cultural traits of western Asia, northern Africa and Europe in the 9th century during the long-term foreign trade. Starting from ceramic types of Changsha kiln, the traditional plain and modest modeling elements can be extracted, and an innovative packaging design for a fish sauce can be achieved. This packaging can not only convey the cultural implication of traditional food, but also serve as a caster for kitchen and table and thus realize its secondary utilization.

Abstract:In order to prolong the shelf life of semi-dried noodles at normal temperature, In this paper, the effects of different water activity lowering agents on water activities were investigated，A combination of 3% sorbitol solution, 0.10% propylene glycol, 2% salt, 0.8% complex phosphate reduced the water activity of semi-noodles from 0.945 to 0.867. Then changes in total plate count (TPC), water content, water activity, texture and sensory quality of the semi-dried noodles of the reducing the water activity group, the deoxygen packaging group and the combined action group were measured. The results showed that compared with the control group, the three experimental groups effectively prolonged the shelf life of the semi-dried noodles, and extended for 3 days, 7 days and 48 days, respectively. The combined action group synergistically inhibited the growth of microorganisms, and the speed of water dispersion was slow, while the speed of deterioration of texture and sensory was obviously slowed down.

Abstract:The preservation at room temperature of fresh bean curd using polyamide (PA) packaging films with different concentrations of sugar, vinegar and salt was researched in this study. The single factor experiment was used to determine the optimal concentration of sugar, vinegar and salt. The orthogonal test showed that preservative solution ratio of 1 g/L sugar, 3 g/L vinegar, 7 g/L salt, treated with boiling water for 0.5 min, the freash bean curd could be stored longest.

Abstract:In order to realize the detection of mango size, maturity and degree of decay, a test platform based on DSP6437 development board was constructed. Image acquisition was carried out on this platform, with conversion and collection of the data stream. Therefor, the RGB and grayscale images were obtained, the super neighborhood average method for smoothing the image was used to detect the region of interest, and according to the regional average gray degree of maturity, the classification of mango was determined. The edge points of mango were calculated by Laplace transform, and the minimum envelope rectangle was rotated to judge the size. Combining the visual inspection with gray histogram statistics and the taste sensor, the ripeness of mango was determined. The experimental results showed that the detection platform was small, stable, accurate and more suitable for actual production detection, and was also practicable for the inspection of mango production.

Abstract:Hyperspectral images of egg samples were obtained using a hyperspectral system of 400~1 000 nm. The anomalous samples were detected by Monte Carlo method, and the original spectra were processed by three kinds of pretreatment methods. The characteristic wavelengths were extracted from the spectral data after pretreatment using competitive adaptive reweighed sampling (CARS), Genetic Algorithms PLS (GAPLS) and Interval Random Frog (IRF). The Partial Least Squares Regression (PLSR) and Least Squares Support Vector Machine (LS-SVM) eggs freshness prediction models based on full spectrum and characteristic wavelength were established respectively. The results showed that the standardized normal variate (SNV) method was the best pretreatment method. CARS, GAPLS and IRF were used to select 8, 35 and 74 characteristic wavelengths respectively. LS-SVM model based on characteristic wavelengths by GAPLS method was the best, and correlation coefficient of correlation (Rc) and prediction(Rp) of the model were 0.899 and 0.832 respectively. It was indicated that the non-destructive measurement for egg freshness based on hyperspectral imaging technology was feasible.

Abstract:The aim of this work was to fulfill the objective and rapid assessment of quality and flavor of fresh orange juice with different storage time. An electronic tongue system that based on virtual instrument technology was developed and used to the qualitative and quantitative analysis of fresh orange juice samples with six kinds of storage time. According to the characteristics of electronic tongue respond signal, it was first preprocessed by the principal component analysis (PCA) method and discrete wavelet transform (DWT) method, respectively. According to the classification result, the DWT was selected as a recommended feature extraction method. Then the linear discriminant analysis (LDA) was used to the qualitative analysis of fresh orange juice samples with different storage time. Moreover, the least squared-support vector machines based on particle swarm optimization method (PSO-LSSVM) was applied to quantitative forecast the different storage time. The results showed that the cumulative contribution rate of LD1 and LD2 was reached 95.7% when the linear discriminant analysis was employed, and the fresh orange juice samples with the six kinds of storage time were effectively discriminated; The PSO-LSSVM prediction model had high prediction precision for different storage time of fresh orange juice, the correlation coefficient (R²) root mean square error (RMSE), mean absolute error (MAE) were 0.999 1, 0.287 7, and 0.232 8, respectively. This study could provide technical reference for quality evaluation and monitoring of fresh fruit juice.

Abstract:The effects of different drying methods on the quality and antioxidant properties of seedless purple grapes were investigated in this study. Four different drying techniques including natural drying, hot-air drying, drying in the shade and vacuum freeze drying was used to dry fresh seedless purple grapes. Moreover, the total sugar, reducing sugar, fructose glucose, total acid, vitamin C, total phenol, total phenolics, total flavonoid, total flavanols, anthocyanins and sensory indicators, antioxidant capacity were detected, in order to compare the effects of different drying methods. The results showed that different drying methods obviously influenced the quality and antioxidant properties of the seedless purple grapes. The time of vacuum freeze drying and hot-air drying were found to be the shortest, 3.5 days and 3 days respectively. Drying in the shade needed the longest time, lasting for 35 days. The total sugar content, total acid content, total phenolic, total flavonoids, total flavanols and anthocyanins of vacuum freeze drying were significantly higher than those of other drying methods, and the antioxidant capacity was also strongest. The correlation analysis showed that the content of phenols was related to the antioxidant capacity. In combination, vacuum freeze-drying was suitable for the drying of non-nuclear purple grapes, and could retain its nutritional and antioxidant content, and the strong antioxidant activity better. Therefore, it could be used as a suitable drying method of purple grapes.

Abstract:The effect of the drying properties on hot air drying by relative humidity control of Chinese yam was studied. The test material was treated with high humidity after the hot air drying, and factors on the drying characteristics and rehydration characteristics were investigated, including the treatment time of humidity, slice thickness, dying temperature, and drying air velocity. The L9(3⁴) orthogonal test was used to get the best drying process parameters on energy consumption. the content of polysaccharide and the color of two kind of yam (prepared by the best drying process parameters on energy consumption and hot air drying without relative humidity) were determined. The results showed that, compared with direct hot air dying, high relative humidity control could not only greatly shorten the drying time, but also improve the rehydration characteristics. Moreover, the energy consumption was the minimum of 19 056 kJ/kg·H2O when material under the conditions of constant temperature and humidity ( Slice thickness of 3 mm, temperature of 60 ℃, relative humidity 40%, treat time 30 min), hot air drying treatment (air temperature of 60 ℃, air velocity of 3.5 m/s). Under this condition the ΔE value of yam chip and polysaccharide content were 8.17% and 5.14%, respectively, while those of directly hot-drying were 12.35% and 4.96%.

Abstract:The active ingredients of crude propolis from Yongzhou were extracted by graded ethanol method and investigated the scope of their activity. With flavonoids content as index, content and the antioxidant activity of them in the crude propolis from different extraction conditions was evaluated. The results showed that the quality and content of flavonoids in the crude propolis extracted with 40%～60% ethanol were higher. The content of flavonoids in the extracts by graded ethanol method reached 41.2% and the extraction yield of flavonoids was 25.81%. The antioxidant activity of flavonoids of crude propolis extracted with 50% and 60% ethanol were better than Vc, but the one in the crude propolis extracted with 30% ethanol was the worst. It illustrated the crude propolis contained different types of flavonoids. To obtain high active flavonoids of crude propolis, water should be chosen as extraction solvent to water-soluble flavonoids and 40%～70% ethanol should be chosen as extraction solvent to medium polarity flavonoids.

Abstract:To study the lipopolysaccharide (LPS) of Aeromonas hydrophila, LPS was extracted by hot phenol-water method, purified by enzymatic hydrolysis and chloroform/methanol precipitation. The yield of LPS and the contents of protein, DNA were determined. The purity of LPS was analyzed by SDS-PAGE and silver staining．Ana-1 cell model was established to evaluate the toxicity and biological activity of LPS samples. The results showed that the yield of LPS was 1.22%, and the contents of protein and nucleic acid were 1.53% and 0.79% respectively. The main bands of SDS-PAGE were clear and located at same position as the LPS standard. After LPS treatment, the viability of Ana-1 cells decreased by 21.20%, and the fluorescence intensity of Ca²⁺ was 1.67±0.19, without significant difference compared with LPS standard. The LPS samples extracted from Aeromonas hydrophila had high purity, toxicity and biological activity. This study provided technical support for the development of subsequent extraction and detection methods.

Abstract:The ultrasonic-assisted ethanol-ammonium sulfate aqueous two-phase system was adopted to extract polyphenols from finger millet. The extraction process was optimized by single factor test and response surface analysis, polyphenols yield as the index. The results showed that the optimum extraction process was determined as follows: ethanol volume fraction of 41%, ammonium sulfate concentration of 0.3 g/mL, ultrasonic temperature of 42 ℃, liquid-solid ratio of 60 mL/g, and treated for 29 min. By adopting the process, the extraction yield of polyphenols was 319.15 mg/100 g. Finger millet polyphenols had strong antioxidant activity in vitro, the total reducing capacity, DPPH radical scavenging activity, hydroxyl radical scavenging ability reached 91.84%, 96.79% and 89.03% of V_C at the same concentration, respectively.

Abstract:This research studied microwave assisted extraction process of germinated brown rice polysaccharides (GBRP). The extraction process was optimized by response surface methodology. Antioxidant activities of the germinated brown rice polysaccharides (GBRP) were also studied. On the basis of single factor experiment, the microwave assisted extraction rate of GBRP from germinated brown rice was optimized by Box-Behnken model. The antioxidant activities of the GBRP (in vitro) were investigated based on reducing force to Fe³⁺, scavenging rate to DPPH·, O-2·, and ·OH, and inhibition to lipid peroxidation five testing factors. The results showed that the optimal conditions were as followed: extraction temperature 40 ℃, microwave power 604 W, ratio of solvent to material 24 mL/g, and microwave time 3.83 min. The optimized extraction conditions led to 2.82% extraction rate of the GBRP. The absorbance of the reducing force to Fe³⁺ of the GBRP was 0.196. The DPPH· scavenging rate of the GBRP reached to a maximum value of 52.71%, resulting half maximum effective concentration (EC₅₀) value 0.34 mg/mL. The clearance rate of O^-₂reached to 40.18%, resulting EC₅₀ value 0.23 mg/mL. The maximum scavenging rate to ·OH was 88.41%, resulting EC₅₀ value 0.211 mg/mL. The scavenging rate is 1.37 times higher than that of Vitamin C (V_C). The maximum value of inhibition to lipid peroxidation was 60.86%, getting EC₅₀ value 0.077 mg/mL. The inhibition ability is 1.5 times stronger than that of Vitamin C. Testing results showed that germinated brown rice polysaccharides (GBRP) possesses relatively strong antioxidant ability (in vitro).

Abstract:The optimum conditions for the preparation of sorghum gliadin by ultrasonic assisted enzymatic method were studied by single factor and response surface test. The effects of standing time and temperature on the oil retention and water holding capacity of gliadin were studied. The results showed that the optimum conditions were as followed: enzyme dosage 1%, enzyme action time 3 h, ultrasonic action time 19 min, ethanol concentration 60%, the maximum extraction rate under the conditions of (7.19±0.36)%. At the temperature of 35 ℃and standing time of 40 min, the maximum oil holding capacityof sorghum gliadin was (2.84±0.15) g/g and the maximum water holding capacity was (2.78±0.09) g/g.

Abstract:The pigments were obtained from leaves of Ginkgo biloba L. using ultrasound-assisted ethanol extraction method. The main influence factors of pigments extraction were selected from the results of single factor test and optimized by orthogonal experimental design, and its stability to pH, temperature, metal ions and light was studied. The optimum extraction technology was using the ethanol concentration of 95%, with the pH value 6.0, extracted at 60 ℃ for 2 h. Under this condition, the absorbance of pigments was 0.831. The stability results indicated that the pigments was stable in acidic and alkine media, and was stable to Na⁺ and Ca²⁺, but unstable to Fe³⁺, Cu²⁺ and Mg²⁺ relatively. It would accelerate the pigments decomposition when the temperature was higher than 70 ℃, and it had instability to the sunlight and indoor light, so it should be stored away from light.

Abstract:In order to prepare original material for developing low phenylalanine special food, the peanut protein was degraded by Alcalase2.4L and papain, the hydrolysis by Flavourzyme and the removal of phenylalanine by activated carbon were determined by signal and orthogonal tests separately. The optimal parameters were found to be hydrolysis temperature 50 ℃, pH 6.5, enzyme/substrate 3 500 U/g and time 5 h, which resulted in a content of free phenylalanine of 28.65 mg/100 mL in hydrolysates. The removal of phenylalanine with 7 g/100 g activated carbon powder was conducted at 35 ℃, pH 3.0 for 2.5 h and the removal rate of phenylalanine could reach 98.64% under these parameters. The amino acids and molecular weight analysis showed a significant decrease for the content of phenylalanine (0.61 mg/100 mL) and the molecular weight was blow 600 Da, mainly including oligopeptides and free amino acids. The resulting product could be used to prepare special medical formula foods in the future.

Abstract:In order to study the effects of common high temperature treatment methods such as pan-frying, frying and broiling on eating quality of meat. pork, chicken and duck were used as research object. The meat color, texture profile analysis and shear force were determined to evaluate the eating quality. Results indicated that pan-frying, frying and broiling had a significant influence on the eating quality of all the samples (P＜0.05). After treatments, the L^*and b^* value of the three kinds of meat increased (P＜0.05), the a^* value of pork decreased (P＜0.05), conversely, the a^* value of chicken increased (P＜0.05); After the high temperature treatments, the shear force of pork and duck increased (P>0.05), nevertheless it had no influence on chicken (P＜0.05); After treatments, the hardness of pork increased significantly (P＜0.05), for white meat, except pan-fried 2 min, 3 min, fried 3 min, the hardness has increased significantly (P＜0.05). After the three kinds of high temperature treatments, the springiness of red and white meat both increased significantly (P＜0.05). The results of these studies provide a theoretical basis for improving the eating quality of meat products, and have a certain guiding significance for consumers to choose scientific cooking time and temperature.

Abstract:To explore the solvent extraction to reduce cigarette harm and tar, the optimal extraction conditions of tobacco, according to the change of release amount of HCN and ammonia treated tobacco pyrolysis simulation, were determined by optimizing the conditions such as extraction solvent, broken wall, and extraction times. Additionally, reduction mechanism of the solvent extraction on the reduction of hydrogen cyanide and ammonia was discussed. Tobacoo treated with optimal extraction conditions could significantly reduce the release of HCN and ammonia in tobacco because of the solvent extraction to extract the precursor of HCN and ammonia content in tobacco. The results showed that moisture retention ability of tobacco was almost unchanged, and the tar, CO, benzopyrene and phenol of tobacco were also decreased, whereas the degree of softness, aftertaste and irritant were improved. The study could provide new ideas and methods for cigarette industry enterprises to reduce the harm and tar and use the low-grade tobacco.

Abstract:In order to investigate the effects of online laser perforation parameters on physical and chemical indexes of fine cigarette, the cigarette samples were prepared with different laser perforation positions, different hole numbers and different laser perforation time, and the relationships of the said parameters were also analyzed with cigarette ventilation rate,the consistence of ventilation rate and the deliveries of routine smoke constituents. The results showed that: ① Compared with normal cigarettes, the positions of online laser pulse had little influence on physical and chemical indexes of fine cigarette, the change of physical and chemical indexes of fine cigarettes with different positions was smaller, while the ventilation rate was the highest in the middle of the filter (14 mm from the lip end), and the minimum amount of mainstream smoke was released. ② Laser pulse hole number and time could affect physical and chemical indexes of fine cigarettes obviously, the mean value of ventilation rate increased with the increase of hole number and laser pulse time, meanwhile, the amount of mainstream smoke emission decreased significantly. The suitable ventilation rate and smoke index could be obtained by adjusting the parameters of online laser perforation of fine cigarette.

Abstract:Aquatic products are of high protein value, which are rich in polyunsaturated fatty acids, essential amino acids and other nutrients, and the aquatic products are extremely susceptible to microbial contamination. In the paper, based on the analysis of modern aquatic product preservation technology, combined with physical, chemical and microbiological indicators, the different preservation methods of aquatic products were reviewed in detail in the view of combination of physics, chemistry and biological preservation technology. At the same time, preservation technology of aquatic products are also proposed, the keeping fresh method tends to develop the combination of compound biological preservative, physical and chemical preservation technology in the future.

Abstract:The swim bladder is rich in collagen, and contains bioactive components such as peptides and glycosaminoglycans. It has the functions of supplementing kidney and filling the blood and so on. It is one of the tonic of medicinal and edible products. It was reviewed the chemical composition, traditional medicinal value, clinical efficacy, functional factor and utilization of swim bladder in this study, in order to provide a reference for its further development and utilization.

Abstract:The wide applications of ultra violet stabilizers and absorbers in industry caused the elevation of the contaminated levels in environmental media and livings. Because of many violet stabilizers and absorbers have estrogenic effects on livings, and more concerns are attracted on them. In order to prevent the aging process of plastic food contact materials, violet stabilizers and absorbers are employed in the process of manufacture. Therefore, these chemicals could migrate into food when the plastic food contact materials were used for food package. The migration quantity needed to be determined to prevent proceeding the limits. In this paper, the research progress for the contaminated level, hazardous effects of ultra violet stabilizers and absorbers was carried to imply that the migration from plastic food contact materials to food could cause food safety problem. Finally, the relative determination methods for ultra violet stabilizers and absorbers were reviewed to prospect the surveillance technique and measures for the ultra violet stabilizers and absorbers in plastic food contact materials.