豆浆处理工艺改善内酯豆腐的质构特性

Treatment technology of soy milk improving texture characteristics of lactone tofu

豆浆的粒子大小可以通过一定的处理工艺加以改变，从而提高内酯豆腐质构特点。该文研究了胶体磨磨齿间隙（10～30μm）、超声波功率强度（1～3 W/g）、匀浆机转速（1000～5000 r/min）对内酯豆腐质构特点的影响。结果表明胶体磨处理能显著（p＜0.05）提高内酯豆腐的弹性和内聚性。但在间隙为10μm的情况下，长时间研磨会降低硬度。在不同超声波功率强度条件下，内酯豆腐的硬度和弹性都是先上升后下降。超声波处理会显著（p＜0.05）降低内酯豆腐的内聚性。匀浆处理对内酯豆腐的质构特点均产生先上升后下降的影响。通过Topsis法进行多指标综合评价，得出较好的豆浆处理工艺是匀浆处理1000 r/min处理8 min。粒径分析结果证明处理工艺能降低豆浆粒径大小。豆浆处理工艺可以改善内酯豆腐的质构特点，从而满足人们的不同需求。

Tofu is a nutritional, gel-like soy food. Its preparation generally includes soaking and grinding of soybeans in water, filtering, boiling and coagulation of soy milk, molding and pressing in the same basic methods. It is consumed in significant amounts in Asian countries like China and Japan because of their inexpensive, high quality protein. Because of its bland taste, the textural properties markedly influence its food quality and consumer acceptability. The textural properties are governed by soy milk concentration, coagulant type and concentration, gelation pressure and temperature, and gelation time. The textural properties of tofu also varied with the density of the gel network, the size of protein granules in the network from microscopic view. The particle size of soy milk was changed by some treatments to improve the texture characteristics of lactone tofu. Effect of plate gap （10-30μm）, ultrasound power （1-3 W/g） and homogenate speed （1 000-5 000 r/min） on texture characteristics of lactone tofu were studied in this article. The results showed that treatment with colloid mill significantly （p〈0.05） increased elasticity and cohesion of lactone tofu. However, grinding for longer time lowered hardness of lactone tofu under the condition of plate gap of 10μm. Treatment of soy milk for 2 min under the plate gap of 10μm effectively improved the quality and texture characteristics of lactone tofu. Hardness and elasticity of lactone tofu all offered upgrade firstly then descending latter tendency under different intensities of ultrasound power. Cohesion of lactone tofu was decreased significantly （p〈0.05） by ultrasound treatments. Treatment with ultrasound powder of 2 W/g for 3 min exhibited better quality of lactone tofu. All texture characteristics of lactone tofu showed descending following its ascending under homogenate conditions. Soy milk treated by homogenate at 1 000 r/min for 8 min was better choice. By multi-index comprehensive evaluation of Topsis, the results showed that homogenate at 1 000 r/min for 8 min was more suitable for soy milk as its improvement of texture characteristics of lactone tofu. The size of particle was shifted from 8.6 to 4.2, 1.6, 1.4μm when soy milk treated by colloid mill, homogenate and ultrasound, respectively. The results of particle size analysis showed that the processing could reduce the particle size of soy milk, which played an improvement role in texture characteristics of lactone tofu. The texture characteristics of lactone tofu were improved by processing technology of soy milk to meet the different requires. The result can provide a reference for the processing technology of lactone tofu.