红芸豆浸泡过程中吸水特性及吸水动力学变化

Changes in Water Absorption Characteristics and Kinetics of Red Kidney Beans during Soaking

摘要:

为探讨红芸豆籽粒在浸泡过程中温度、时间等条件对其吸水特性及水分子动态变化的影响，采用低场核磁共振技术（LF-NMR）、Peleg模型、质构分析技术和核磁共振成像技术（MRI）等分析了浸泡后红芸豆吸水率、硬度、体积膨胀率、Peleg常数、弛豫时间、水分分布的变化。结果表明，红芸豆吸水率随着浸泡温度的升高，平衡所需时间缩短，硬度在吸水前2 h快速下降，降低至最低点后逐渐上升至稳定状态；体积膨胀率随温度的升高而增加，与吸水率呈正相关性。Peleg方程模拟获得相对误差E均小于10%，证明模型可靠，常数K1随温度的升高呈下降趋势；红芸豆浸泡过程中出现三种状态的水（结合水、游离水、弱结合水），含量随着温度的升高先增加后平衡，且温度越高，达到平衡时间越短；确定最佳浸泡温度为45 ℃，浸泡时间为4 h，浸泡后红芸豆的水分含量为56.61%，硬度57.80 N，体积膨胀率122.22%。研究结果为红芸豆经浸泡工艺的加工利用提供一定依据及参考。

Abstract:

Red kidney beans were soaked at different temperatures for different durations to determine the effects of several factors on their water absorption characteristics and kinetics. Low-field nuclear magnetic resonance, Peleg modeling, texture profile analysis, and magnetic resonance imaging were used to analyze changes in the water absorption rate, hardness, volume expansion, Peleg constants, relaxation time, and water distribution of red kidney beans after soaking. The results showed that increasing the soaking temperature increased the water absorption rate of red kidney beans, thereby shortening the time to reach equilibrium. The hardness rapidly decreased in the first 2 h of soaking and slowly increased to a stable state after reaching a minimum. Volume expansion increased with temperature and was positively correlated with the water absorption rate. The relative error of the results simulated by the Peleg model was within 10%, demonstrating the reliability of the model. K1 showed a decreasing trend with increasing temperature. During soaking, three forms of water (bound water, free water, and weakly bound water) were observed in red kidney beans. At the optimal soaking temperature (45 ℃) and time (4 h), the soaked red kidney beans had a moisture content of 56.61%, hardness of 57.80 N, and volume expansion of 122.22%. These results provide a reference for the processing and utilization of soaked red kidney beans.