| Ferulic acid (4-hydroxy-3-methoxy cinnamic acid, FA), is a phenolic compound that is abundant in plant cell walls. It has been shown to have many physiological functions, including antioxidant, antimicrobial, anti-inflammatory, anti-allergic, antiviral, anti-carcinogenic, free radical scavenging, and UV filter properties, which made FA widely used in the food, cosmetics, and pharmaceutical industries. However a major obstacle in the application of FA in oil-based food processing and other corresponding industries is its low solubility and stability in hydrophobic media. To overcome this limitation the modification of FA through esterification with aliphatic alcohols or transesterification with triacylglycerols has been widely reported. Chemical synthesis of feruloylated lipids is difficult due to heat-sensitivity and susceptibility of ferulic acid to oxidation at high temperature and under certain pH conditions. The advantages associated with enzymatic synthesis include mild-operating reaction conditions, high specificity, and easy recovery of the end-product.Lipase-catalyzed synthesis of functional feruloyl-oleyl-glycerol (FOG), consisted of 1(3)-feruloyl-monooleyl-glycerol (FMOG) and 1(3)-feruloyl-dioleyl-glycerol (FDOG), in toluene was investigated in this study. First, ferulic acid was chemically modified to ethyl ferulate and vinyl ferulate in order to make the substrate more soluble in the fatty alcohols. Second, feruloy-oleyl-glycerol was synthesis through transesterification between ethyl ferulate or vinyl ferulate and triolein using Novozym 435 as catalyst. The optimal reaction conditions were obtained by investigation of reaction factors, including substrate molar ratio, reaction time, temperature, water activity, enzyme content and enzyme stability. Meanwhile, under the same conditions, the synthetic efficiency of ethyl ferulate and vinyl ferulate was compared in this study.The optimal conditions confirmed when vinyl ferulate was used as sustrate were:3.0 mL toluene,3 molar ration of vinyl ferulate to triolein, enzyme loading 60mg, reaction temperature 55℃, reaction time 62h, agitation speed 210 r/min, water activity 0.02. Under these optimal conditions, the highest reaction conversion achieved was 90.2%, which was composed of 1(3)-feruloyl-monooleyl-glycerol 32.5% and 1(3)-feruloyl-dioleyl-glycerol 57.6%. The optimal conditions confirmed when ethyl ferulate was used as sustrate were:3.0 mL toluene,3 molar ration of vinyl ferulate to triolein, enzyme loading 100mg, reaction temperature 50℃, reaction time 96h, agitation speed 210 r/min, water activity 0.07. Under these optimal conditions, the highest reaction conversion achieved was 61.9%, which was composed of 1(3)-feruloyl-monooleyl-glycerol 30.4% and 1(3)-feruloyl-dioleyl-glycerol 31.4%. The high synthetic efficiency of vinyl ferulate as substrate has been confirmed by the comparative studies. Furthermore, the residual activity of enzyme was keep about 75% after 13 runs when vinyl ferulate was used as substrate.The radical scavenging properties of feruloyl-oleyl-glycerol were evaluated using several different tests, including hydroxyl radical scavenging, superoxide anion radical scavenging, 1,1-diphenyl-2-picrylhydrazyl (DPPH-) radical scavenging and using tocopherol as check sample. The results showed that feruloyl-oleyl-glycerol had strong radical scavenging ability and their abilities increased with the increase of their concentration. The experiment results indicated that the DPPH·scavenging properties of feruloyl-oleyl-glycerol in decreasing order was tocopherol> 1(3)-feruloyl-monooleyl-glycerol>1(3)-feruloyl-dioleyl-glycerol; for·OH radical the decreasing order was tocopherol> 1(3)-feruloyl-monooleyl-glycerol> 1(3)-feruloyl-dioleyl-glycerol; for O2·radical the decreasing order was tocopherol> 1(3)-feruloyl-monooleyl-glycerol> 1 (3)-feruloyl-dioleyl-glycerol.Fast-dissolving ultrafine membranes (FDMs) were prepared with the water-soluble polymer polyvinylpyrrolidone (PVP) K90 as the filament-forming matrix and ferulic acid and feruloyl-oleyl-glycerol as a poorly water-soluble drug. The influence of PVP concentration and the applied voltage on the morphology of fibers were investigated. Wetting time tests were conducted to evaluate fast-dissolving properties. For preparation of ferulic acid-loaded PVP ultrafine membranes, the optimal conditions are:ferulic acid 5 (w/w)%, PVP 40 (w/v)%, solvent anhydrous ethanol, applied voltage 12 kV, distance from the syringe tip to aluminium foil 12cm, feed rate 0.8 mL/h. Under the optimal conditions, the fibers with the diameter ranging from 800 to 1000 nm were obtain, wetting time 3.4±1.5 s; For preparation of feruloyl-oleyl-glycerol-loaded PVP ultrafine membranes, the optimal conditions are:PVP 5(w/v)%, feruloyl-oleyl-glycerol 25 (w/w)%, mixed solvent V(CHCl3):V(C2H5OH)= 4:1, applied voltage 14 kV, distance from the syringe tip to aluminium foil 12 cm, feed rate 0.8 mL/h. Under the optimal conditions, the fibers with the diameter ranging from 800 to 1000 nm were obtain, wetting time 2.0±1.5 s... |
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