柚果皮果胶浸提过程及动力学分析优化设计

Optimization design based on kinetic model and extraction process of pectin from pomelo(Citrus grandis L. Osbeck) fruit peel

以琯溪蜜柚果皮为原料,采用果胶酸解浸提法,基于果胶在浸提过程中包括原果胶转变为果胶、果胶从组织扩散到溶剂、果胶大分子降解等进程,以同步串联反应法构建果胶浸提动力学模型,获得基于浸提工艺优化和果胶同步降解影响的浸提动力学方程,进而进行模型验证分析及参数优化.有效性(残差分析及F检验)检验表明:该模型可应用于分析柚果皮果胶浸提动力学过程,在温度70～90℃,浸提过程表观活化能Ea为31.34 kJ·mol-1;优化分析获得在浸提液pH=2.0,浸提温度90℃,浸提时间90.25 min,料液质量与体积比为1∶40时,柚果皮果胶浸提得率11.83%,此结果与正交设计优化结果吻合.

The pectin extraction of pomelo （ Citrus grandis L. Osbeck） fruit peel was investigated by the method of acid hydrolysis. The kinetic model of the processes of protopectin hydrolysis to pectin, pectin diffusion from tissue to solvent, degradation of some pectin macromolecules was established by synchronous series reaction method to estimate the most important mass transfer coefficients. Based on the effects of degradation and extraction of pectin, and optimization of simultaneous extraction conditions, the kinetic equations were obtained to realize model validation and optimization parameter. The validations of resi- dual error analysis and F test show that the model can be applied to the kinetic analysis of pectin extraction from pomelo fruit peel. The apparent activation energy of extraction process is 31.34 kJ · mol-1 at temperature of 70 - 90 ℃. According to the optimization analysis, the pectin extraction yield from pomelo fruit peel is 11.83% of dried peel at the optimized conditions with pH value of 2.0, extraction temperature of 90 ℃, extraction time of 90min and solid to liquid ration of 1 ： 40. The optimization condition and the maximum yield from kinetic model are confirmed by the results from orthogonal experiment.