基于动态机械分析仪的馒头玻璃化转变温度测定条件的研究

Study on testing condition of the glass transition temperature of steamed bread

食品的玻璃化转变温度是控制食品质量和稳定性的关键。食品在玻璃化转变温度下进行保存,可最大限度保存其原有色、香、味、形及营养成分,从而延长食品保存期,提高食品保存过程中质量。基于此,研究用动态机械分析仪(DMA)对馒头的玻璃化转变温度进行了测定。结果表明:在不同测定条件下得到的馒头玻璃化转变温度不同。在振幅变化,其他测定条件不变时,馒头的玻璃化转变温度随振幅的增大而减小;在温度变化速率改变,其他测定条件不变时,馒头的玻璃化转变温度随温度变化速率的增大而增大。综合得出在振幅20μm,温度变化速率2℃/min下测得的馒头玻璃化转变温度较客观准确。因此,最佳测定是其他条件不变,振幅20μm,温度变化速率2℃/min。

The glass transition temperature of food was the key to control food quality and stability. The food was preserved at the glass transition temperature, which could maximize preservation of its original color, fragrance, taste, shape and nutrition, extend shelf life, and improve the quality in food preservation process. Based on this, the glass transition temperature of steamed bread by dynamic mechanical analyzer （DMA） were determined. The results showed that., in different measurement conditions, the glass transition temperatures of steamed bread were different; when the amplitude varied but other conditions unchanged, the glass transition temperature decreased with the amplitude increasing~ when the temperature changing rate varied but the other conditions unchanged, the glass transition temperature increased with the rate increasing. It was find that glass transition temperature of steamed bread measured in the amplitude of 20 μm and temperature changing rate of 2℃/min was objective and accurate. Therefore, the optimum determination conditions were as： the amplitude of 20 μm, temperature changing rate of 2℃/min and the other conditions remained unchanged.