發(fā)布時間：2018-03-28 02:14

  本文選題：生物酶保鮮紙　切入點：固定化葡萄糖氧化酶　出處：《浙江理工大學》2017年碩士論文

【摘要】：楊梅是我國的特色水果,果實成熟時期高溫多雨,且無外果皮包裹,人們常說,楊梅“頭日采收,二日色變,三日味變”,由此可見其變質(zhì)速度之快。楊梅的貯藏與運輸問題是限制楊梅產(chǎn)業(yè)發(fā)展的瓶頸,因此,研究楊梅的保鮮技術,延長楊梅的保鮮時間具有十分重要的意義。本文利用葡萄糖氧化酶(GOD)制備具有除氧作用的生物酶保鮮紙對楊梅進行保鮮,首先對GOD的固定化,優(yōu)選載體及優(yōu)化工藝條件后,制備固定化GOD;然后將固定化GOD與糊化陰離子淀粉混合制備成楊梅保鮮涂料,再將制備的涂料涂布在食品包裝紙表面,自然風干得到生物酶保鮮紙;最后研究了生物酶保鮮紙的物理性能、除氧性能以及在楊梅保鮮上的應用。首先,得出固定化GOD的最佳載體是比表面積為300m~2/g的氣相法SiO_2;最佳工藝條件為:反應溫度30℃,pH值5.1,加酶量0.5mg,戊二醛濃度0.10%,交聯(lián)時間3h,該條件下固定化效果最好,固定化GOD的酶活力回收率達到75%;GOD經(jīng)固定化后,分散穩(wěn)定性得到明顯提高,貯藏穩(wěn)定性相對于游離的GOD也有較明顯的提高,在貯藏60d后,固定化GOD活性仍保持原酶活力的90%以上,而游離GOD活性降低至原酶活性的70%;經(jīng)FT-IR分析可知,固定化GOD的紅外光譜中,在1637cm~(-1)、1110cm~(-1)、1540cm~(-1)處出現(xiàn)特征峰,其中1637cm~(-1)處出現(xiàn)的C=N伸縮振動峰主要是因為形成Schiff堿所導致,說明GOD被固定在氣相法SiO_2載體上,且酶蛋白的二級結構沒有發(fā)生改變。然后,研究了生物酶保鮮紙的制備技術,得到生物酶保鮮紙涂料配方:固定化GOD用量為6g、蒸餾水74g以及15%陰離子淀粉32g混合配制成涂料,得到涂料的固含量為9.6%。隨著楊梅保鮮涂布量的增加,保鮮紙除氧效果逐漸增強,當涂布量為8g/m~2,固定化GOD的含量為4.4g/m~2時,常溫(25℃)條件下,250min內(nèi)氧氣含量降低了56%,除氧效果顯著。最后,用涂布量為8g/m~2生物酶保鮮紙對楊梅進行保鮮研究,通過空白對照實驗表明,利用生物酶保鮮紙對楊梅進行保鮮,其貯藏環(huán)境中的氧氣含量和乙烯產(chǎn)生量明顯減少;通過對楊梅生理變化的研究表明,使用生物酶保鮮紙對楊梅進行保鮮,楊梅貯藏到第4d才開始腐爛變質(zhì),貯藏6d后,其好果率是未使用生物酶保鮮紙的2倍以上,有效的延長了楊梅的保鮮期。
[Abstract]:Bayberry is a characteristic fruit of our country. It is hot and rainy in ripening period, and there is no outer pericarp wrapped in it. People often say that bayberry is "harvested in the first day and changed in color in two days." It can be seen that the speed of deterioration is so fast. The storage and transportation of bayberry is the bottleneck restricting the development of bayberry industry. Therefore, research on the preservation technology of bayberry, It is of great significance to prolong the preservation time of Myrica rubra. In this paper, the biological enzyme paper with deoxygenation effect was prepared by using glucose oxidase oxidase to keep myrica rubra fresh. Firstly, the immobilization of GOD, the selection of carrier and the optimization of technological conditions were carried out. Then the immobilized GOD and gelatinized anion starch were mixed to prepare the preservative coating of Myrica rubra, and then the coating was coated on the surface of the food packaging paper, and the bio-enzyme preservation paper was obtained by natural air drying. Finally, the physical properties, deoxygenation and application in the preservation of Myrica rubra were studied. The best carrier for immobilized GOD was the gas phase method SiOs _ 2 with specific surface area of 300m~2/g. The optimum conditions were as follows: reaction temperature 30 鈩，

本文編號：1674298