【摘要】：谷朊蛋白是生產(chǎn)小麥淀粉的副產(chǎn)品,來源廣泛,具有獨特的粘彈性,良好的生物相容性及生物可降解性,是制備蛋白膜的理想原料。谷氨酰胺轉(zhuǎn)氨酶(TGase)可催化蛋白間發(fā)生ε-(γ-谷氨酰基)賴氨酸共價轉(zhuǎn)移,進而發(fā)生交聯(lián)反應(yīng)。谷朊蛋白可被TGase催化改性。本課題以谷朊蛋白為原料,利用TGase的催化作用,引入含有多個伯胺基的α-聚賴氨酸,通過增加谷朊蛋白的作用位點,提高谷朊蛋白的反應(yīng)性能,并與絲素蛋白交聯(lián)改性制備蛋白復(fù)合膜,以克服單一谷朊蛋白膜機械性能較差,水溶失率較大的缺點。主要探討了谷朊蛋白膜的制備方法以及酶促反應(yīng)的工藝條件,考察了α-聚賴氨酸對酶促谷朊蛋白的增效作用;研究了酶促改性對蛋白膜的水穩(wěn)定性性、疏水性、熱穩(wěn)定性及微觀形態(tài)的影響,并考察蛋白膜在食品保鮮中的應(yīng)用。研究結(jié)果表明:當?shù)鞍缀繛?%(g/mL),甘油濃度為1%(g/mL)時,蛋白溶液具有較好的成膜性能。TGase用量為20 U/g谷朊蛋白,蛋白反應(yīng)液pH值為7.0,反應(yīng)溫度為40℃,反應(yīng)時間為3 h時,對谷朊蛋白進行改性后制得的谷朊蛋白膜的拉伸性能較好,為4.36 MPa。α-聚賴氨酸使TGase催化單一谷朊蛋白及谷朊/絲素蛋白共混體系中氨氣的釋放量有所提高;十二烷基磺酸鈉-聚丙烯酰胺凝膠電泳(SDS-PAGE)結(jié)果顯示,引入α-聚賴氨酸的蛋白酶促反應(yīng)體系中,蛋白大分子生成量明顯增加;谷朊/絲素蛋白混合體系中含有α-聚賴氨酸時,TGase酶促反應(yīng)后谷朊蛋白中所含絲素的特征氨基酸含量上升。谷朊/絲素蛋白復(fù)合膜較單一谷朊蛋白膜機械性能有所提高,當α-聚賴氨酸存在時,谷朊/絲素蛋白經(jīng)TGase酶促改性后所得到的復(fù)合膜的機械性能增加至5.21MPa,同時,蛋白膜的疏水性和熱穩(wěn)定性提高,水溶失率降低,且對小番茄貯藏效果較好。掃描電鏡(SEM)顯示TGase及α-聚賴氨酸的作用使單一谷朊蛋白膜及谷朊/絲素蛋白膜材料的表面變得粗糙,截面結(jié)構(gòu)更加緊密。
[Abstract]:Glutenin, a by-product of wheat starch production, is an ideal raw material for the preparation of protein film, because of its unique viscoelasticity, good biocompatibility and biodegradability. Glutamine aminotransferase (TGase) can catalyze 蔚-(緯 -glutamyl) lysine covalent transfer between proteins, which leads to cross-linking reaction. Glutenin can be modified by TGase. Using glutenin as raw material and using TGase as catalyst, 偽 -Poly (lysine) containing several primary amino groups was introduced to improve the reactivity of glutenin by increasing the interaction sites of glutenin. Protein composite membrane was prepared by crosslinking with silk fibroin to overcome the disadvantages of poor mechanical properties and high water solubility of single glutenin membrane. The preparation method of glutenin membrane and the conditions of enzymatic reaction were discussed, the synergistic effect of 偽 -polylysine on enzymatic glutenin was investigated, and the water stability and hydrophobicity of enzyme modified glutenin membrane were studied. The effects of thermal stability and micromorphology, and the application of protein film in food preservation were investigated. The results showed that when the content of protein was 5% (g / mL) and the concentration of glycerol was 1% (g / mL), the dosage of TGase was 20 渭 g glutenin, the pH value of protein reaction solution was 7.0, the reaction temperature was 40 鈩，

本文編號：2130894