高压均质对豆腐皮特性及微观结构的影响

Effect of High Pressure Homogenization on Properties and Microstructure of Yuba

研究经不同均质压力（20-140MPa）处理的豆乳制成豆腐皮的感官特性、质构特性及其微观结构变化规律。结果表明：随着均质压力增加,豆腐皮颜色由浅金黄色变为金黄色;均质压力大于100MPa时,豆腐皮的成膜速率加快,耐煮性增强,豆腐皮品质更加稳定。TPA分析表明,高压均质提高了豆腐皮的断裂延伸性和抗拉强度。扫描电镜观察表明,豆腐皮的内部结构是蛋白-脂肪复合物形成的网状层层叠加的结构;在20MPa和60MPa豆腐皮的网状结构中存在游离脂肪球,而脱脂后豆腐皮结构中未出现游离脂肪球;均质压力高于100MPa时,豆腐皮的网状结构中不存在游离脂肪球,豆腐皮的结构更加均匀、致密;140MPa的豆腐皮脱脂前后微观结构无明显变化,蛋白-脂肪复合物更加稳定。这种结构使其贮存过程中减少＂浸油＂现象,防止其氧化产生＂哈喇味＂,有利于延长产品的货架期。

The effect of different homogenization pressures （20-140 MPa） on Yuba properties and microstructure was studied. By increasing the homogenization pressure, the color of Yuba turned from light golden yellow to golden yellow. At a homogenization pressure larger than 100 MPa, the formation of Yuba was speeded up, with enhanced cooking tolerance and stable quality. TPA analysis showed that high-pressure homogenization improved the tensile strength and elongation at break of Yuba. Scanning electron microscopy showed that the internal structure of Yuba was protein-fat complex forming superimposed layers of mesh-like structure. Free fat globules appeared in the mesh-like structure of Ynba homogenized at 20 MPa or 60 MPa rather than in the structure of degreased yuba. But the free fat globules were degraded when using a homogenization pressure larger than 100 MPa, resulting in more homogenous and compact structure. In addition, Yuba treated at 140 MPa had no significant change in microstructure before and after defatting treatments, and the protein-fat complex was more stable. This structure reduced the ＂oil-exuding＂ phenomenon and prevented its oxidative rancidity, thereby extending the shelf life.