挤压刺梨牛肉干中维生素C损失预测模型

Prediction model for vitamin C loss in extruded prickly Rosa roxburghii Tratt beef jerky

为了探索挤压刺梨牛肉干中维生素C(VC)的损失规律,解决挤压过程中营养物质损失的“黑箱”问题,本文使用双螺杆挤压机生产刺梨牛肉干,采用高效液相色谱法测定物料挤压前后的VC含量,得到挤压前后的VC损失率。以碳粉为示踪剂,测定物料在挤压机内的停留时间,将平均停留时间(MRT,记作t m)视为不同条件下物料在挤压机内的反应时间,对不同挤压条件下VC损失率进行动力学分析,通过多项式回归分析得到不同机筒温度、螺杆转速条件下的VC损失率预测模型。结果表明,挤压过程中VC损失率与机筒温度、螺杆转速均呈显著负相关,与刺梨添加量影响不显著。动力学分析表明,不同挤压条件下VC的损失速率常数(k)为0.00354~0.00605 s-1,通过多项式回归分析得到k、t m对不同机筒温度、螺杆转速条件下的预测模型,相关系数R 2分别为0.7564和0.9712,模型拟合度较高,可实现对挤压过程中营养物质损失规律的合理预测。

The purpose of this paper is to explore the principle of vitamin C loss in extruded Rosa roxburghii Tratt beef jerky and investigate the“black box”problem of nutrient loss during the extrusion process.By using Rosa roxburghii Tratt beef jerky produced with a twin-screw extruder,we measured the vitamin C contents before and after extrusion by HPLC,then calculated the vitamin C loss rate during this process.Moreover,we collected the residence time of the material in the extruder by using toner as the tracer,and the mean value was considered to be the reaction time.Based on the kinetic analysis of VC loss rates under different extrusion conditions with various barrel temperatures and screw speeds,a VC loss rate prediction model was established using polynomial regression analysis method.As a result,the VC loss rates were negatively correlated with barrel temperatures and screw speeds,despite the amounts of Rosa roxburghii Tratt.In addition,dynamic analysis could generate the vitamin C loss rate constant,which was between 0.00354 and 0.00605 s-1 under different extrusion conditions.Further polynomial regression analysis provided the prediction models of k and t m for different barrel temperatures and screw rotation speeds,with the R 2 values as 0.7564 and 0.9712,respectively.The well-fitted models could reasonably predict the nutrient loss in the extrusion process.