米饭质构特性测定方法的研究(Ⅱ)——米饭样品放置时间、环境温度对硬度值的影响

Study on Determination of Texture Characteristics of the Cooked Rice(Ⅱ)——Impact of Storage Time and Environmental Temperature on the Cooked Rice Hardness

用不同品质的大米,参照GB/T 15682—2008的米饭样品制备方法制作米饭样品,并利用质构测试仪采用TPA模式对米饭样品的质构特性进行测定试验,探讨了米饭质构测定值的分散特征及米饭样品放置时间与测试环境温度对测定值的影响。用电饭煲炊饭和米饭样品预压8 mm方法制作米饭样品并用Φ25.4mm圆球探头进行的多次重复试验结果表明:硬度值的稳定性和精确性明显优于黏着性值,适宜将硬度值作为米饭质构特性测定的主要考察指标。结果还表明:随着米饭放置时间的延长,籼米米饭硬度值逐渐减小的趋势明显,粳米米饭在放置时间12 h范围内有硬度值缓慢增大的总体趋势;米饭制作、放置和测定过程的温度对米饭硬度值有较大影响,建议在进行米饭质构(硬度)测定时应当保持米饭制作、放置和测定全过程的温度恒定。

The cooked rice was produced from different kind of rice according to GB/T 15682—2008 method,and the texture characteristics of the cooked rice were determined by a food texture analyzer and the TPA model to investigate the dispersion character of the texture measured value and the impact of storage time and environmental temperature on measured hardness values.The rice samples were produced by cooking in the electric rice cooker,pressed down to 8 mm,and repeated the test by a Φ25.4 mm global plunger.The results showed that the stability and accuracy of measured hardness were better than those of adhesiveness,which suggested that hardness values should be chosen as criterion of the texture characteristics determination.The results also indicated that,with the extension of storage time,the hardness values of the cooked indica rice tended toward decrease gradually,and those of the japonica rice increased slowly during 12 h.The influences of the production method,storage and temperature of the cooked rice on the cooked rice hardness are great.Therefore,it is suggested that all the measured conditions including rice production,placement and temperature,must be constant during the texture determination.