海沃德猕猴桃货架期预测模型的建立

Establishment of Prediction Model of Hayward Kiwifruit Shelf-Life

为建立海沃德猕猴桃货架期品质变化动力学模型,以实现对海沃德猕猴桃货架期的预测。本试验将经0.5μL·L^-1 1-甲基环丙烯(1-MCP)处理(处理组)与不处理(对照组)的猕猴桃于0、4、15、25℃条件下贮藏,测定其硬度、可溶性固形物含量、可滴定酸含量、Vc含量;并基于Arrhenius理论建立货架期预测模型,选取20℃样本对该模型进行验证。结果表明,1-MCP对试验设置温度条件下贮藏的海沃德猕猴桃硬度、可滴定酸含量和Vc含量的降低以及可溶性固形物含量的升高均有一定的延缓作用;同时对其硬度和Vc含量变化情况进行拟合,比较拟合后的反应速率常数k,发现温度越高Vc含量和硬度变化越快。比较零级反应和一级反应线性回归决定系数R2可知,对照组和处理组Vc含量变化动力学方程遵循一级反应动力学,对照组R2≥0.97,处理组R2≥0.94;对照组和处理组硬度含量变化动力学方程遵循零级反应动力学,对照组R2≥0.96,处理组R2≥0.92。对照组硬度下降及Vc含量下降的lnk和1/T的R2>0.98,处理组硬度下降及Vc含量下降的lnk和1/T的R2>0.89。将预测值和实测值进行比较,结果显示,对照组猕猴桃货架期预测值和实测值相对误差均在±10%以内。综上表明,用硬度变化预测猕猴桃货架期,操作简单,相对误差较低。本研究结果在猕猴桃贮藏、销售中具有较好的应用价值。

In order to establish a dynamic model of quality changes during the shelf life,and realize the prediction for the shelf life of Hayward kiwifruit,kiwifruit processed with 0.5μL·L^-11-MCP(processing group)and unprocessed(control group)were stored at 0,4,15,and 25℃,and its firmness,soluble solids content,titrate acid content and VC content were measured.Based on Arrhenius theory to establish a shelf-life prediction model,which was verified by samples at 20 oC.The results showed that the kiwifruit processed with 1-MCP had a certain retardation effect on the reduction of the firmness,the increase of the titrate acid content,the Vc content and the soluble solid content of the Hayward kiwifruit under the temperature set in the experiment.At the same time,the firmness and Vc content were fitted,and the reaction rate constant k after being fitted was compared.It was found that the higher the temperature,the faster the Vc content and firmness changed.Comparing the zero-order reaction and the linear regression determination coefficient R2 of the first-order reaction could be known that the kinetic equation of Vc content in the control group and the processing group followed the first-order reaction kinetics with R2≥0.97 and R2≥0.94 for the control group and processing group,respectively.The kinetic equation of content of the firmness changes followed the zero-order reaction kinetics with R2≥0.96 and R2≥0.92 for the control group and processing group,respectively.The firmness of the control group decreased and the Vc content decreased by lnk and 1/T of R2>0.98.The firmness of the processing group decreased and the Vc content decreased by lnk and 1/T of R2>0.89.Compared the predicted value with the processing value,it was found that the relative error of the predicted value and the processing value of the kiwifruit in the control group were within±10%.The shelf life of kiwifruit was predicted by the change of firmness.The operation was simple with relative low error.The results had good application value in the storage and sale of kiwifruit.