发芽对糙米理化特性的影响

Effect of germination on physicochemical properties of brown rice

采用富集γ-氨基丁酸(GABA)的优化糙米发芽工艺条件,研究糙米发芽前后内部结构和理化特性的变化,主要包括膨胀度、透明度、冻融稳定性、凝沉特性、糊化特性及质构特性等。结果表明:糙米发芽后,膨胀度增大,且随温度的升高而提高;透光率比发芽前升高了20%;冻融稳定性提高,凝沉特性得到改善,这说明发芽使糙米不易老化,有助于食品货架期的延长;峰值黏度降低,糊化温度基本不变;糙米发芽后凝胶黏性有所提高,硬度和胶凝性均降低;电镜分析结果显示,发芽后整个米粒结构变得较疏松。通过对糙米淀粉酶活力的测定,表明发芽后糙米淀粉酶活力上升。综上得出,发芽对糙米的理化特性有一定的改善作用。

With the optimal conditions of GABA enrichment for brown rice germination, the changes of internal structure of brown rice and physicochemical properties after germination were studied, including swelling capacity, transparency, freeze-thawing stability, retrogradation, pasting properties and textural characteristics. The results showed that after germination, the swelling capacity was increased and more higher with temperature rise. The transparency was increased by 20 % after germination;the retrogradation was inhibited obviously and the freeze-thawing stability was enhanced strongly after germination. These indicated that thegermination of brown rice made it not＇easy to aging and was helpfu.1 to extend the shelf life of food. The peak viscosity was reduced and the pasting temperature basically unchanged. The adhesiveness of brown rice was increased after germination, the hardness and the gelatinization were both decreased. The analysis by electron microscopy showed that the rice grain structure became looser after germination. The activity of brown rice amylase was increased after germination. In summary, the germination could improve the physicochemical properties of brown rice.