不同储藏条件下鲜湿糙米线品质变化动力学模型研究

    Study on the kinetic model of quality changes of fresh brown rice noodles during storage at different temperatures

    • 摘要: 为了预测鲜湿糙米线在储藏期间的品质变化,测定了其在4、25、37 ℃储藏的pH值、蒸煮损失率、蒸煮前硬度和蒸煮后硬度,并借助化学反应动力学方程,结合Arrhenius方程,建立了各指标的动力学模型。结果表明:随着储藏时间的延长,鲜湿糙米线的pH值和蒸煮后硬度逐渐减小,而蒸煮损失率和蒸煮前硬度则逐渐增大;储藏温度越高,鲜湿糙米线的pH值、蒸煮损失率和蒸煮后硬度变化越快;在4 ℃储藏时,鲜湿糙米线蒸煮前硬度增加最快,这主要与淀粉在4 ℃易回生有关。鲜湿糙米线的pH值、蒸煮损失率的变化符合一级反应,且模型的拟合系数分别为0.955 0和0.999 5;蒸煮前硬度和蒸煮后硬度的变化符合零级反应,且模型的拟合系数分别为0.963 2和0.984 8。4个模型均得到较好的验证,可用于预测鲜湿糙米线在4~37 ℃储藏过程中的品质变化。

       

      Abstract: As a whole grain food with high content of moisture and rice bran, fresh brown rice noodles are perishable, including retrogradation and rancidity. The quality of fresh brown rice noodles deteriorates rapidly and the shelf life is short, which seriously affects its market circulation. It is of great significance for the quality management and control of fresh brown rice noodles to establish a dynamic model of quality change for brown rice noodles. However, there are few studies on predicting the quality change and shelf life of fresh brown rice noodles. In the study, the pH value, cooking loss rate, hardness before and after cooking of fresh brown rice noodles were determined after stored at 4 ℃ for 0, 24, 48, 72, and 120 h, 25 ℃ for 12, 24, 36, 48, and 60 h, and 37 ℃ for 6, 12, 18, 24, and 30 h, respectively. Each data and the logarithm of each data were analyzed by linear regression, and the reaction rate constant k and the determination coefficient R2 were obtained to determine the reaction order of index changes. According to the reaction rate constant k of each index at different storage temperatures, lnk and the reciprocal of thermodynamic temperature were substituted into the Arrhenius equation, and Ea and A were calculated according to the Arrhenius equation. Ea and A were brought into the equation combined with the reaction kinetic model equation and Arrhenius equation, and the reaction kinetic model equation of the index was obtained. Finally, the reaction kinetic model equation was validated by calculating the percentage error between the true and predicted values. The results showed that the pH value and hardness after cooking of fresh brown rice noodles were gradually decreased, and cooking loss rate and hardness before cooking of fresh brown rice noodles were gradually increased with the increase of storage time. The storage temperature was higher, and the changes of pH value, cooking loss rate, and hardness after cooking of fresh brown rice noodles were higher. The hardness before cooking of fresh brown rice noodles was significantly increased when fresh brown rice noodles were stored at 4 ℃, which was mainly attributed to the easy retrogradation of starch stored at 4 ℃. The changes of pH value and cooking loss rate of fresh brown rice noodles were accorded with the first-order reaction, and the fitting coefficient R2 of the model was 0.955 0 and 0.999 5, respectively. The changes of hardness before and after cooking were accorded with the zero-order reaction, and the fitting coefficient R2 of the model was 0.963 2 and 0.984 8, respectively. The four models have been well verified, and can be used to predict the quality changes of fresh brown rice noodles during storage process at 4-37 ℃.

       

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