【作者】 张欣；

【导师】 侯汉学； 刁恩杰；

【作者基本信息】 山东农业大学 ， 食品加工与安全（专业学位）， 2019， 硕士

【摘要】 淀粉具有来源广泛、价格低廉、可再生、可生物降解并且降解产物对环境友善等优点,成为公认的制备可生物降解塑料制品的理想原材料。本文研究了淀粉三层复合膜的降解过程及降解周期,淀粉复合膜中间层为添加50%聚乙烯醇(PVA)的淀粉层,两边为聚乳酸(PLA)/聚己二酸/对苯二甲酸丁二酯(PBAT)外层。通过测定淀粉复合膜在受控堆肥条件下其排放的二氧化碳量来确定其最终需氧生物分解能力及其崩解程度,通过测定失重率、扫描电镜(SEM)、X-射线衍射(XRD)、红外光谱(FTIR)、差示扫描量热(DSC)等方法观察降解前后淀粉复合膜的形貌、结晶度、化学结构等变化,并利用其优良的阻氧性能进行高油食品的包装应用研究,拓展淀粉复合膜在食品包装上的应用范围。主要研究结果如下:1.淀粉复合膜在受控堆肥条件下表现出良好的生物降解性,在降解前36 d二氧化碳生成总量和降解速率基本与淀粉/PVA膜持平,说明这段时间主要是淀粉复合膜中的淀粉层在降解;36 d后淀粉复合膜生物降解达到平稳阶段,说明这段时间中间层可降解物质基本降解完全,开始降解PLA/PBAT外层,56 d后生物分解率可达47.23%。2.淀粉复合膜在土埋降解的56 d内,外观和微观形貌都发生了显著变化,出现孔洞和裂缝,并且分层现象严重;淀粉复合膜前42 d失重较快,之后进入缓慢失重阶段;X-射线衍射结果显示淀粉复合膜降解过程中其结晶度降低;红外结果显示淀粉复合膜降解前后没有产生新的基团,只是大分子分解为小分子的过程;DSC结果显示淀粉复合膜降解过程中晶体结构被破坏。3.淀粉复合膜可以有效的阻隔氧气进入包装内部,在50℃高温加速氧化和常温贮藏条件下,随贮藏时间的延长,淀粉复合膜包装的烘焙小麦胚芽酸价、过氧化值、丙二醛含量升高程度都明显小于高阻隔膜包装的烘焙小麦胚芽,DPPH自由基清除率、ABTS自由基清除率、碘值和总酚含量的降低程度也明显小于高阻隔膜包装的烘焙小麦胚芽。淀粉复合膜能够很好地延缓烘焙小麦胚芽的氧化变质,与常规包装膜相比更有利于延长烘焙小麦胚芽的货架期,为拓展淀粉膜在高油食品包装上的应用奠定了基础。更多还原

【Abstract】 Starch has the advantages of a wide range of sources,low cost,renewable,biodegradable and environmentally friendly degradation products,and is recognized as an ideal raw material for the preparation of biodegradable plastic products.In this thesis,the degradation process and degradation cycle of starch three-layer composite film were studied.The intermediate layer of the starch composite film is a starch layer to which 50% polyvinyl alcohol(PVA)is added,and the outer layer consists of polylactic acid(PLA)and poly(butyleneadipate-co-terephthalate)(PBAT).Through measuring the emitting amount of carbon dioxide by the starch composite film under the controlled composting conditions,this research has determined the ultimate aerobic biodegradability and its degree of disintegration.Besides that,this research expand the application field of starch composite film on food packaging by observing the morphology,crystallinity and chemical structure of the starch composite film before and after degradation through scanning electron microscopy(SEM),X-ray diffraction(XRD),infrared spectroscopy(FTIR),and differential scanning calorimetry(DSC),as well as the study on packaging application of high oil foods by using its excellent oxygen resistance,in order to expand the application of starch composite film in food packaging.The main findings are as follows:1.The starch composite film showed good biodegradability under controlled composting conditions.The total carbon dioxide production and degradation rate were basically the same as the starch/PVA film in degradation of 36 days,indicating that the starch layer was the main degradation part in the starch composite film during this period.After 36 days,the biodegradation of the starch composite film reached a stationary stage,indicating that the degradable material in the intermediate layer was basically degraded and began to degrade the outer layer of PLA/PBAT.After 56 days,the biodegradation rate reached 47.23%.2.Within 56 days of the degradation of starch composite film,the appearance and microscopic morphology have significantly changed,holes and cracks appeared,and the stratification was serious.The weight loss of the starch composite film was faster in the first 42 days,and then it went into slow weight-loss process;X-ray diffraction results showed that the crystallinity of the starch composite film was reduced during the degradation process;the infrared results showed that no new groups were produced before and after degradation of the starch composite film,but the process of decomposition of macromolecules into small molecules;DSC results showed that the crystal structure was destroyed during the degradation of the starch composite film.3.The starch composite film can effectively prevent the oxygen from entering the interior of food packaging.Under the conditions of accelerated oxidation at 50°C and storage under normal temperature,the increase of the solanic acid value,peroxide value and malondialdehyde content of the baked wheat germ in the starch composite film was significantly lower than that of the high-barrier film packaged baking wheat germ,as well as the decrease in DPPH free radical scavenging rate,ABTS free radical scavenging rate,iodine value and total phenolic content.The results indicated that the starch composite film could delay the oxidative deterioration of baked wheat germ.By inference,compared with conventional packaging film,it is more conducive to prolonging the shelf life of baked wheat germ.All in all,these research results provide a foundation for expanding the application of starch composite film in high oil food packaging.更多还原