Abstract：
Previously, we showed that water extract (soymilk, except pH was increased to 8 from 6.5) of whole soybean could be used directly as a raw material for producing edible soy films by deposition of the film-forming solution (soy extract with enhancers). However, the strength of such soy films needed improvement because they were weak. The purpose of this study was to investigate how transglutaminase (TG) cross-linking reactions and film enhancers, including pectin (low- and high-methoxyl pectin), whey protein isolate (WPI), and soy protein isolate (SPI), improve the physical properties of soy films. Soy films prepared with TG had tensile strength (TS) of 3.01 MPa and puncture strength (PS) of 0.78 MPa, which were higher by as much as 51% and 30% than that of soy films without TG treatment, respectively. Pectin showed significant effects on the mechanical properties of TG-added soy films in terms of TS, PS, and % elongation. On the other hand, only TS and PS were increased by the addition of WPI or SPI. Heat curing had a significant effect on soy film\'s physical properties. TG treatment significantly reduced film solubility when soaked in water and various levels of acid (vinegar) and base (baking soda) solutions. Under the experimental conditions of 35 unit TG and 28 min of reaction, the degrees of cross-linking were evidenced by the disappearance of individual protein subunits, except the basic subunit of glycinin, and the reduction of 21% of lysine residues of the proteins. HIGHLIGHTS: Edible soy films were made with transglutaminase and about 21% lysine cross-linked. The mechanical strength of soy films was increased by incorporating film enhancers. Transglutaminase enhanced the mechanical properties of soy films.
摘要：
以前,我们表明水提取物(豆浆，除了pH值从6.5增加到8）的整个大豆可以直接用作通过沉积成膜溶液（带有增强剂的大豆提取物）来生产可食用大豆膜的原料。然而,这种大豆膜的强度需要改进，因为它们很弱。本研究的目的是研究转谷氨酰胺酶（TG）交联反应和膜增强剂，包括果胶（低和高甲氧基果胶），乳清分离蛋白（WPI），和大豆分离蛋白（SPI），提高大豆膜的物理性能。用TG制备的大豆膜的拉伸强度（TS）为3.01MPa，穿刺强度（PS）为0.78MPa，比未经TG处理的大豆薄膜高出51%和30%，分别。在TS方面，果胶对添加TG的大豆膜的机械性能具有显着影响，PS,和%伸长率。另一方面,仅TS和PS通过添加WPI或SPI而增加。热固化对大豆膜的物理性质有显著影响。当浸泡在水和各种水平的酸(醋)和碱(小苏打)溶液中时,TG处理显著降低膜的溶解度。在35单位TG和28min反应的实验条件下，交联程度由单个蛋白质亚基的消失证明，除了大豆球蛋白的基本亚单位,蛋白质赖氨酸残基减少21%。要点:用转谷氨酰胺酶和约21%赖氨酸交联制备可食用大豆膜。通过掺入膜增强剂提高了大豆膜的机械强度。转谷氨酰胺酶增强了大豆膜的机械性能。
