【作者】 陈莹；

【导师】 穆韡；

【作者基本信息】 哈尔滨工业大学 ， 化学工程与技术， 2022， 硕士

【摘要】 微生物可引起严重的食源性疾病,开发抗菌可食用食品包装膜是解决食品安全问题、延长保质期的有效策略。然而,大多数食品包装膜不满足抗菌要求。为提升可食用包装膜的抗菌性,本论文以玉米/木薯淀粉膜为基底膜、丁香酚为抗菌剂、甘油为增塑剂,制备了不同浓度丁香酚的抗菌可食用膜。同时,为提高丁香酚在复合膜中的相容性,以明胶微球为载体,制备了不同浓度的丁香酚/明胶微球抗菌可食用淀粉基复合膜。实验以成膜性和机械强度作为性能指标,通过单因素试验确定基底膜的最佳成膜工艺:玉米淀粉与木薯淀粉的质量比为1:6,甘油含量为3%。通过在基底膜中直接添加不同剂量的丁香酚,由实验成品的成膜性判断出丁香酚的最大添加量为1.1 mg/mL;结果表明,丁香酚使复合膜粗糙程度、亲水性、含水量和水蒸气透过率降低,水溶解性增加;丁香酚有助于提高薄膜的致密性,使得复合膜的拉伸强度增加,当丁香酚浓度为0.8 mg/mL时强度达到最大值,但削弱了聚合物链在应力下的运动,使膜的柔韧性降低;丁香酚的掺入赋予了复合膜优异的抗氧化活性,由于复合膜对直接添加的丁香酚承载能力有限,所以复合膜的抑菌活性提升不高。为进一步提升复合膜的抑菌活性,以明胶微球作为丁香酚载体,以解决丁香酚精油与聚合物基质的相容性问题。基底膜中掺入丁香酚/明胶微球,实验结果表明,复合膜丁香酚添加量提高到3.62 mg/mL;同时,丁香酚/明胶微球可以填充聚合物的束状结构,使复合膜微观表面平整,掺杂了丁香酚/明胶微球的复合膜拉伸强度可增加到31.87 MPa,有更强的抵抗外力的能力;随着丁香酚/明胶微球含量的增加,复合膜的溶解性和水蒸气透过率增加、含水量降低、对紫外光的屏蔽性能增强;含16%丁香酚/明胶微球的复合膜抗氧化活性可达到86.7%;含8%、16%丁香酚/明胶微球的复合膜在5 h内就可以杀死所有受试细菌,与大肠杆菌相比,丁香酚对金黄色葡萄球菌的抑制效果更明显,复合膜用于苹果包覆实验,其在7天内依然不腐坏证明了复合膜具有优异的抑菌性。丁香酚淀粉复合膜利用天然生物聚合物制备、具有优异的抗氧化和抗菌活性,使其在食品包装方面显示出良好的实际应用前景,为不可降解的包装膜提供了一种可行的替代品。更多还原

【Abstract】 Microorganisms can cause serious foodborne illness,and the development of antimicrobial edible food packaging films is an effective strategy to address food safety issues and extend shelf-life.However,most edible packaging films is insufficient to meet antimicrobial applications.Herein,the antibacterial edible films were prepared based on corn/cassava starch with eugenol as antibacterial agent and glycerol as plasticized agent.Meanwhile,to improve the compatibility of eugenol in the composite films,eugenol is loaded into microspheres to fabricate different concentrations of eugenol/gelatin microspheres added antimicrobial edible starch-based composite films.The optimum film formation process of the base film is determined by single-factor test using film formation and mechanical strength as performance indexes.The ratio of corn starch to tapioca starch was 1:6 and the glycerol content was 3%.Eugenol was added directly to the base film,and the maximum addition amount of eugenol was determined to be 1.1 mg/mL based on the film-forming property.The addition of eugenol reduced the roughness,hydrophilicity,water content and water vapor transmission rate of the composite film,and increased the water solubility.Eugenol helped to improve the denseness of the film,resulting in an increase in the tensile strength of the composite film,reaching a maximum at a concentration of 0.8 mg/mL of eugenol;however,it weakened the movement of the polymer chains under stress,resulting in a decrease in the flexibility of the film.The incorporation of eugenol imparted excellent antioxidant activity to the composite films,and the antibacterial activity of the composite films was weak due to the limited carrying capacity of the composite films for direct addition of eugenol.The compatibility of eugenol essential oil with the polymer matrix was solved by using gelatin microspheres as a carrier to load eugenol.The incorporation of eugenol/gelatin microspheres in the substrate film can increase the addition of eugenol to3.62 mg/mL in the composite film.Eugenol/gelatin microspheres can fill the bundle structure of the polymer and make the microscopic surface of the composite film flat.The tensile strength of the composite film doped with eugenol/gelatin microspheres can be increased to 31.87 MPa,which has stronger resistance to external forces.With the increase of eugenol/gelatin microspheres content,the solubility and water vapor transmission rate of the composite film increased,the water content decreased,and the shielding performance against UV light was enhanced.The antioxidant activity of the composite film containing 16% eugenol/gelatin microspheres could reach 86.7%.The composite film containing 8% and 16% eugenol/gelatin microspheres could kill all the tested bacteria within 5 h.Compared with Gram-negative bacteria(Escherichia coli),the inhibition effect of eugenol on Gram-positive bacteria(Staphylococcus aureus)was more effective.The apple wrapping experiment of the composite film also proved that the composite film possessed excellent antibacterial property.Eugenol starch composite film is prepared by natural biopolymer and has excellent antioxidant and antibacterial activity,which holds potential in food packaging and provides a feasible substitute for nondegradable packaging films.更多还原