Advanced Materials Research Vols. 554-556

Abstract: A micellar electrokinetic electrophoresis-laser induced fluorescence detection (MEKC-LIF) method was applied for the profiling of native fluorescence in three different kinds of Chinese green teas. The running buffer was 100 mM sodium borate (pH9.8) containing 20 mM SDS, and tea infusion was injected at the pressure of 0.5 psi for 5 seconds. The applied voltage was set at 25 kV, and the excited wavelength was 488 nm, and the detected wavelength was 520 nm. Ten tea samples were collected and analyzed by the developed method. Eighteen common peaks in the MEKC-LIF profiling of green teas were selected and these samples were classified into 3 groups by cluster analysis and partial least square discriminant analysis (PLS-DA). Our primary results indicated that the developed method could be applied for the classification of three different Chinese green teas

Abstract: The effects of temperature, time, pH, calcium concentration and the ratio of shelling buckwheat and sodium glutamate were studied while using dipping treatment to accumulate γ-aminobutyric acid (GABA) in north-shaanxi shelled buckwheat. The results were as follows: Glutamate decarboxylase activity is 3.694u/g. The yield of GABA achieves in the largest respectively under the following conditions: Soaking temperature at 40°C, time of 10h, pH6.0, calcium concentration at 0.3mmol/L, the ratio of shelled buckwheat and sodium glutamate at 1800g/mol.

Abstract: Corn residue is used as raw material, and through the study of corn juice processing, we can optimize the machining process, reduce processing costs, increase economic efficiency. It is found through the test that the optimum corn processing time for the precooking is 1h, liquefaction enzyme dosage is 30 activity unit every gram, reaction time is 1.5h, glucoamylase ratio is 120 activity unit every gram, saccharification time is 1.5h, 40MPa homogeneous for two times, sterilization at 135 °C ultra high temperature for 10s. Under these conditions, the production of maize corn residue has high sugar content with a small amount of enzyme dosage, the production cost is reduced, the product stability is greatly enhanced, and the shelf life is effectively extended.

Abstract: The effects of different antioxidants on anti-oxidative protection of the Tengjiao (Zanthoxylum schinifolium) oil during its conservation were studied by Schaal-oven test according to the peroxide value(PV) and acid value(AV) of the oil. The results indicate that TBHQ and TBHQ+AP compound antioxidant, have good anti-oxidative protection on Tengjiao oil, the antioxidant activity of BHA+AP was the lowest, and citric acid exhibited great anti-oxidative protection and synergistic antioxidant effect.A positive interaction was found between TBHQ and AP; whereas a negative interaction was observed between AP and BHA.The positive interaction of TBHQ and AP was higher than TBHQ and BHA. TBHQ(0.02%) and TBHQ(0.01%)+AP(0.01%) have the same antioxidant activity on the Tengjiao oil.

Abstract: The enzymolysis to defatted carps with trypsin protease can obtain enzymatic hydrolysate with Calcium chelation activity. The best hydrolysis condition is as follows: 45 °C, 3000(U/g substrate), 1:40（w/V）, and pH8.0. Moderate dephosphorization treatment on roes( rate:20% to 50%) can significantly improve the degree of hydrolysis and the Ca-binding capacity of enzymatic hydrolysate, up 31.05% and 6.8 (mg Ca/g protein) respectively.

Abstract: The bittern soy sauce was investigated. Two kinds of the vegetable bittern –the mustard tuber and potherb mustard were added in the fermentation respectively. After the fermentation, physical, chemical and sensory quality attributes were monitored. As a result, the physicochemical property was not influenced significantly by the vegetable bittern and the free amino acids were higher. The soy sauce was proved to be consistent with the standard.

Abstract: The objective of this study was to propose a method that the residues of avermectins (Abamectin, Emamectin Benzoate, Ivermectin, Eprinomectin and Doramectin) derived from the food plant were determined by UPLC-MS/MS. The avermectins were extracted with acetonitrile, purified by Alumina B or GCB/NH2 SPE cartridge, and then determined by ultra high-performance liquid chromatography with tandem mass spectrometry. Tests for recovery (Recovery rate: 80.6%～99.8%, RSD's: 0.22%～6.4%) were made by addition of avermectin standards at three different concentration levels (4, 20 and 100μg/kg) to five kinds of food plant as matrixes. The sensitivity, accuracy and precision of this method were able to meet the requirements for pesticide residue analysis.

Abstract: Protein hydrolysates from Tuna frame (TFPH) and Pollock frame (PFPH) were prepared by papain, respectively.The yield, the basic composition content, the antioxidant activity and functional properties (solubility, emulsifying and foaming ability) and the degree of hydrolysis of the protein hydrolysates were evaluated. Results suggest that solubility, antioxidant activity of protein hydrolysate from Pollock frame are better than that of tuna frame, but the yield is lower than that of tuna frame.

Abstract: To investigate behavior of osmotic dehydration and mass transfer of tilapia fillet in sucrose solution, the changes of moisture content (MC), solid gain (SG) were quantitatively determined during osmotic treatments of fresh tilapia fillets with the sucrose solution concentration (20-40%), temperature (20-30°C), fillet thickness (1-5mm) and osmotic time (1-8h) as the independent treatment factors. Results were as follows: First, MC of fish fillet decreased, and SG of fish fillet increased with increasing of the concentration of sucrose solution. Second, the osmotic dehydration of fish fillet was fast during the first hour and slowed during the 2nd or 4th hour. Third, the dehydration and SG of fish fillet increased with increasing of treatment temperature, but influence of temperature on osmotic dehydration and SG was decreasing with increasing of the concentration of sucrose solution. Finally, a thinner fillet was found to own higher of dehydration and SG than a thicker one.

Abstract: Based on the determination of physiological indexes of chestnut stored in the refrigerator, i.e. SOD (Superoxidize dismutase), CAT (Catalase), MDA (Malondialdehyde), Vc (Vitamin C) and GSH (Glutathione), damage rate and decay rate, by Factor Analysis and Canonical Correration Analysis, decay mechanism of the chestnut is that leaking of electrons results the formation of O2., which promote the SOD activity and Vc content; O2. damages mitochondrial membrane, its electrons transfer to H2O and then form H2O2 which damages the membrane, finally result in chestnut decay. By Comparison of the membrane and the mitochondrion in electron microscope photos of chestnut cell, this conclusion is also proved.