不同干燥方式对明胶特性的影响

系统研究了不同干燥方式(热风干燥,真空冷冻干燥和喷雾干燥)对明胶性质的影响,包括得率、色差、十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(sodium dodecyl sulfate-polyacrylamide gel electrophoresis,SDS-PAGE)、凝胶强度、凝胶持水力、疏水性以及傅里叶变换红外光谱(Fourier transform infrared spectroscopy,FTIR)。结果表明,由于贴壁行为和涡旋分离损失的影响,使得喷雾干燥明胶的得率明显较低(P<0.05)。喷雾干燥和真空冷冻干燥可减轻不良色泽的产生,并且降低干燥过程中明胶的氧化和降解,保留更多的高分子亚基,进而增加了明胶的凝胶强度和凝胶持水力。此外,喷雾干燥的明胶由于疏水基团的暴露以及较多的亚基组分可能含有更多的疏水基团,显示出最高的疏水性(P<0.05),冷冻干燥的明胶次之,热风干燥的明胶最低。红外结果表明,热风干燥和真空冷冻干燥破坏了明胶的构象,而喷雾干燥更有利于明胶在凝胶过程中,形成类三螺旋结构。该文可为绿色明胶的干燥方法和工业化应用提供理论依据和指导意义。

The effect of different drying methods on properties of gelatin

The effects of different drying methods(hot air drying,vacuum freeze-drying and spray drying)on the properties of gelatin were studied systematically,including the yield,color,sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE),gel strength,the water holding capacity of gel,hydrophobicity and Fourier transform infrared spectroscopy(FTIR).The results showed that the yield of spray-dried gelatin was significantly lower(P<0.05)due to wall sticking and the dissipation in vortex separation.Spray drying and vacuum freeze drying could reduce the formation of bad color,reduce the oxidation and degradation of gelatin during drying the process,retain more polymer subunits,resulting in the increased of gel strength and water holding capacity of gel.Furthermore,the spray drying gelatin showed the highest hydrophobicity due to the exposure of hydrophobic groups and more subunit components might contain more hydrophobic groups(P<0.05),followed by freeze-drying gelatin and the hot air-drying gelatin.The FTIR results showed that the conformation of gelatin was destroyed by hot air drying and vacuum freeze drying,while spray drying was more conducive to the formation of three helix-structures in the gel formation process.Therefore,this paper can provide a theoretical basis and guiding significance for the drying method and industrial application of green gelatin.