【作者】 陈杨；

【导师】 李喜宏；

【作者基本信息】 天津科技大学 ， 营养与食品卫生学， 2009， 硕士

【摘要】 本课题以研制透湿效果好、食品生物安全性强的聚乙烯保鲜膜为目标,通过CaCO₃微孔材料交链改性,研究聚乙烯保鲜膜新配方、新工艺,形成专利新产品2种。并通过蔬菜保鲜试验和微生物培养试验2种方式,评价保鲜膜的食品生物安全性。研究结果表明:新材料试验。选用钛酸酯偶联剂对CaCO₃进行表面改性,测定了改性前后CaCO₃粉体的活化度、沉降体积、粘度、吸油值,并用IR对改性粉体进行了表征。结果表明:改性后的CaCO₃粉体在有机介质中的分散性得到了提高,钛酸酯偶联剂TC-2用量为2%时产品可以达到95%的活化度。改性剂与碳酸钙很好的结合,提高了CaCO₃粉体作为填料的功能性。新配方试验。将改性后的CaCO₃添加到LDPE基材中,通过向上吹塑成膜的方法,制备透湿性薄膜。测试了该保鲜膜的拉伸强度,以及透气、透湿性能。结果表明:LDPE中添加CaCO₃可在薄膜中形成微孔,从而制得透湿性能较好的薄膜。其中经TC-2改性的CaCO₃的添加量为20份时,保鲜膜综合效果最佳。透湿保鲜膜生菜保鲜试验。测定贮藏期间生菜的失重率、维生素C、亚硝酸盐、可溶性固形物等理化指标,以及贮藏过程中保鲜袋内O₂和CO₂的变化规律。通过这些指标,可以确定透湿保鲜膜可明显延长生菜的贮藏时间,保持生菜的营养价值和食用安全性。最后,通过聚乙烯透湿保鲜膜的洗涤液对大肠杆菌的微生物培养,初步分析微生物的安全性。更多还原

【Abstract】 The PE film with moisture permeability and good security of food biology was developed in this study and CaCO₃ was added as an additive agents.New material and new composition was developed,2 patents was formed.We evaluate the the security of food biology from 2 ways.The results indicated that,The experimentation of new material.The surface modification of CaCO₃ was made by using titanate coupling agent.The activation grade,sedimentation volume and the viscosity of calcium carbonate before and after the modification were determined,and IR was used to characterize the modified calcium carbonate.The results indicated that the disperse ability of the modified calcium carbonate in organic medium was improved.The activation grade of the modified calcium carbonate reached 95%,when the dosage of titanate coupling agent TC-2 was 2%.The modification of calcium carbonate improved the function of calcium carbonate as filler.Add the modified CaCO₃ to LDPE,the film with moisture permeability was made. Various properties of the film were examined,such as tensile strength,O₂ permeability and moisture permeability.The results indicated that add calcium carbonate can bring countless small deficiency to make film with good moisture permeability.Consider from mechanical performance and moisture permeability of the film,when the amount of CaCO₃ was made by using titanate coupling agent is 20,the film is the best film.The film was used to package lettuce for examining fresh-keeping affections.The percentage of losting-weight,vitamin C,nitrate,SSC were examined,the content of CO₂ and O₂ in the plastic bag were tested,and the appearance change of lettuce was observed everyday,which were used to investigate the affections of the film to lettuce.According to the data we could know the film can make the storage time longer than before,it is good for the nutrition and eating quality of lettuce.Finally,according to the microorganism cultivation of the lotion of PE fresh-keeping film to colon bacillus,the analysis of the security of microorganism was made.更多还原