Xihong Yang

Synthesis and characterization of chitosan quaternary ammonium salt and its application as drug carrier for ribavirin

Abstract N-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride (HTCC) is hydro-soluble chitosan (CS) derivative, which can be obtained by the reaction between epoxypropyl trimethyl ammonium chloride (ETA) and CS. The preparation parameters for the synthesis of HTCC were optimized by orthogonal experimental design. ETA was successfully grafted into the free amino group of CS. Grafting of ETA with CS had great effect on the crystal structure of HTCC, which was confirmed by the XRD results. HTCC displayed higher capability to form nanoparticles by crosslinking with negatively charged sodium tripolyphosphate (TPP). Ribavrin- (RIV-) loaded HTCC nanoparticles were positively charged and were spherical in shape with average particle size of 200 nm. More efficient drug encapsulation efficiency and loading capacity were obtained for HTCC in comparison with CS, however, HTCC nanoparticles displayed faster release rate due to its hydro-soluble properties. The results suggest that HTCC is a promising CS derivative for the encapsulation of hydrophilic drugs in obtaining sustained release of drugs.

Identification of Sensory Quality of Rapid Fermented Fish Using Electronic Nose

In order to shorten the production cycle of traditional fermented fish, cured fish was fermented by Lactobacillus plantarum and Staphylococcus xylosus. Considering sensory quality of products affected the acceptance of consumer, electronic nose (E-nose) and sensory evaluation by human taste panel were used to analysis fish flavor. The results of principal component analysis (PCA) indicated the flavor quality of rapid fermented fish was close to the traditional fermented fish, even though cured fish had more response value of sensor. When traditional fermented fish was acted as standard, rapid fermented fish located nearer accepted range than cured fish by analysis of Statistical Quality Control (SQC). The result was explained by sensory evaluation of human taste panel: only cured fish had strong fishy smell, peculiar flavor of salted fish, and little aroma; traditional fermented fish had thick aroma and a little bad smell for oil oxidation; rapid fermented fish had obvious aroma. The result indicated that rapid fermentation for production of traditional fish was possible. The differences of flavor among three groups of fish were distinguished by E-nose, same as sensory evaluation. So E-nose acted as a new method could be successfully used in aroma identification of foods.

Effects of different inoculation densities on growth and toxin production of Alexandrium minutum

Effects of different inoculation densities on growth and toxin production of Alexandrium minutum were studied.Experiments were conducted under conditions of varying inoculation densities(0.05×104,0.10×104,0.15×104,0.30×104 cells/mL).Higher inoculation densities always resulted in shorter lag phase of A.minutum,and an earlier setting in of the steady growth phase.However,the specific growth rate and maximum cell concentration of A.minutum decreased with increasing inoculation densities.The multiplication models developed correlated well with the observations,as the inoculation density increased,the initial-density dependent parameter a also deceased and the reduction of environmental capacity,instantaneous multiplication included.According to MBA analysis,toxicity of A.minutum is typically highest when cells are growing fast in early exponential phase and lowest as growth slows and eventually stops in plateau phase.The PSP-toxin congeners,GTX1(2.14 fmol/cell),GTX2(2.08 fmol/cell),GTX3(4.97 fmol/cell),GTX4(5.04 fmol/cell)were analysed by high-performance liquid chromatography with fluorescence diction(HPLC-FLD).Result of this study implied that toxin production of the dinoflagellate A.minutum is better in 0.10×104-0.15×104 cells/mL than other condition of inoculations densities.

Evaluation of the Flavor Development Based on Sensors and Actuators Technology and SPME-GC-MS Analysis

This paper was focused on the usage of modern electronic noses (E-nose) and SPME-GC-MS to classification the aroma compounds in food flavorings. Two kinds of shrimp flavorings were prepared, using shrimp Penaeus Vannamei head as raw materials. SPME-GC-MS was adapted to analysis the characteristic volatile of the flavorings. Then E-nose was used to detect overall product aroma as a kind of sensory array fingerprint analysis method. Principal component analysis (PCA) and linear discriminate analysis (LDA) were used to investigate the different of the two samples. Among the volatiles identified by GC-MS, hydrocarbons, alcoholics, ketones, aldehydes, esters, furans, pyrroles and pyrazines were the primary constituents of shrimp flavorings, and difference in volatile aroma profiles were observed between the two flavorings. There are more compounds of pyrazines produced after MR, which have characterized bake, nut, and meat flavor, and more pyrroles provide characterized full-bodied shrimp flavor. RSD of E-nose is under 3% and the similarity 71.5%. E-nose can able to successfully differentiate and identify the flavor between the two different flavorings. According to these results, it can be concluded that the combination of sensors and actuators technology with SPMEGC-MS analysis provides a great deal of information and a more complete picture of the shrimp flavorings. KeywordsElectronic Nose (E-nose); Penaeus Vannamei Shrimp head; Flavor; SPME-GC-MS