Efficient microwave-assisted production of biofuel ethyl levulinate from corn stover in ethanol medium

Levulinate esters are versatile chemicals that have been used in various fields. Herein, the production of ethyl levulinate（EL） from corn stover was investigated under microwave irradiation. Several reaction parameters, including acid concentration, reaction temperature, reaction time, and liquid-to-solid mass ratio, were investigated to evaluate the reaction conditions. Response surface methodology（RSM） was employed to optimize the reaction conditions for the production of EL. A quadratic polynomial model was fitted to the data with an R2 value of 0.93. The model validation results reflected a good fit between the experimental and predicted values. A high conversion yield（58.1 mol%） was obtained at the optimum conditions of 190℃, 30.4 min, 2.84 wt% acid, and 15 g/g liquid-to-solid mass ratio. Compared with conventional heating, microwave irradiation facilitated the conversion of corn stover to EL by dramatically shortening the reaction time from several hours to ～30 min. Thus, microwave-assisted conversion of corn stover to EL is an efficient way of utilizing a renewable biomass resource.

Vibration spectroscopic technique for species identification based on lipid characteristics

Due to the widespread of adulteration of lipid in food and feed industry,the quality and safety of lipid are of public concern gradually.Firstly,the current article presents theory and mechanism of species identification of lipid by spectroscopic technique.Potential of near-infrared reflectance spectroscopy(NIR),Fourier transform infrared spectroscopy(FT-IR),and Fourier transform Raman spectroscopy(FT-Raman)applied to species identification of lipid were summarized.In addition,the relationship between lipid and spectroscopy as well as the recent advances of species identification of lipid were discussed.Research showed that FT-IR and FT-Raman spectroscopies possessed more efficient potential for species identification of lipid.Finally,prospects for future lipid detection and relative practical application,and combination of spectroscopy and other technique were further discussed.

Effects of xanthan gum on the rheological properties of soy protein dispersion

This study focused on the effects of addition of xanthan gum(XG)on the rheological properties of soy protein isolate(SPI)solution.Three types of tests(steady shear test,strain sweep test,and frequency sweep test)were performed to figure out the influences of shear rate on the viscosity of the SPI-XG hybrid system,the effects of strain variable on the storage modulus of the hybrid system,and the effects of frequency on both the storage modulus and the loss modulus of the hybrid system,respectively.SPI-XG hybrid system showed more obvious shear-thinning properties compared to pure SPI and pure XG solution.Meanwhile,it was found that the critical point of hybrid system was highly related to the XG concentration.XG can postpone the critical point strain amplitude to a higher value,and the addition of XG can enhance the strain resistance of hybrid system.The concentration of XG influenced the viscoelastic frequency dependence of the hybrid system significantly and complicatedly.After the addition of XG,the correlation between G′and frequency changed from negative to positive.