采用单因素筛选试验考察了氢化温度、pH值、氢气压力、氢化时间、催化剂用量、浸膏中异α-酸浓度对异α-酸氢化的影响。再利用Plackett-Burman设计研究了各因素对异α-酸氢化的影响。结果表明,底物异α-酸浓度、氢气压力和pH对异α-酸酒花浸膏氢化效果影响显著;在此基础上,采用L9(34)正交设计法对影响异α-酸酒花浸膏氢化的3个主要因素异α-酸浓度、氢气压力、pH进行了参数优化试验。结果表明,影响异α-酸酒花浸膏氢化的主次因素顺序为异α-酸浓度>氢气压力>pH值,异α-酸氢化的最佳工艺参数为:异α-酸的浓度55mg/mL,氢气压力0.2 MPa,pH值10,催化剂Pb/C用量3%,氢化时间4h。浸膏中四氢异α-酸的浓度达到58.89%,异α-酸氢化转化率达到89.73%。

The factors influencing the hydrogenation of isomerized α-acid were inspected by using the single factor screening experiment,including hydrogenation temperature,pH,hydrogen pressure,hydrogenation time,the catalyst amount and the concentration of isomerized a-acid in hops extracts.Plackett-Burman design was employed to evaluate the effects of the 5 factors mentioned above on hydrogenation of iso-α-acid.It showed that concentration of isomerized a-acid,hydrogen pressure and pH were the three most important factors.On the basis of that,the technological parameter of hydrogenation of isomerized α-acids was optimized by adopting the orthogonal design L9(34).The results showed that the order of affecting hydrogenation of iso-α-acid was the concentration of iso-α-acid>hydrogen pressure>pH,and the optimum technological parameter of hydrogenation was respectively the concentration of iso-α-acid 55mg/mL,hydrogen pressure 0.2MPa,pH10,the amount of catalyst 3%.The content of tetrahydro iso-α-acid in hydrogenation extracts was up to 58.89%,and the hydrogenation percent conversion of iso-α-acid was 89.73%.