High Efficient Synthesis of Enzymatic 2-Ethylhexyl Ferulate at Solvent-Free and Reduced Pressure Evaporation System

The use of immobilized lipase from Candida antarctica (Novozymò 435) to catalyze ferulic acid of esterification was investigated in this study. The synthesis product was analyzed using HPLC. The results revealed that the major product was 2-ethylhexyl ferulate. Response surface methodology and 3-level-3-factor central composite rotatable design were adopted to evaluate the effects of synthesis variables, including reaction temperature (60℃- 80℃), enzyme amount (500 - 1500 PLU) and reaction time (8 - 24 h) on the percentage molar conversion of 2-ethylhexyl ferulate. The results showed that reaction temperature and reaction time were the most important parameters on percentage molar conversion. Based on ridge max analysis, the optimum conditions for synthesis were: reaction time 23 h, reaction temperature 71℃?and enzyme amount 1422 PLU. The molar conversion of actual experimental values was 98% under optimal conditions.

Changes in color and rheological behavior of pineapple concentrate through various evaporation methods

The objective of this study was to investigate the effect of various concentration methods namely microwave vacuum evaporation(MVE),microwave heating evaporation(MHE),and rotary vacuum evaporation(RVE)on the concentrate change,the kinetic of color degradation,and the rheological behavior of pineapple juice.The concentrated behavior of pineapple juice from the experimental data of concentration rate was fitted with three types of exponential models for evaluating a suitable prediction.The four-parameter exponential model was found to agreeably explain the concentrated change of pineapple juice during each concentration methods.The Kinetics of color change during concentration processes was evaluated.The color changing from three different evaporations was measured by lightness values(L*),redness values(a*)and yellowness(b*)values,total color difference(TCD)and brown pigment formation index(A420).The result indicated that the change in Hunter parameters,L*and b*,fitted well with the first-order kinetic model while a*,TCD,and Browning index followed the zero-order kinetic model.The observed apparent viscosities(μa)of pineapple concentrate at 55-85℃through the three different evaporation methods were also measured.In relation to temperature and shear rate,the viscosity decreased as these two parameters increased,for all concentrated pineapple juice.On comparing the values ofμa of pineapple concentrate from different concentration methods,pineapple concentrate from MHE has higher values than those from MVE and RVE.The Duncan test,applied to the experimental results,indicates no significant difference in theμa of pineapple juice concentrate by MVE and by RVE.