【作者】 张红梅；

【导师】 董同力嘎（DONG Tungalag）； 成培芳；

【作者基本信息】 内蒙古农业大学 ， 农业硕士（专业学位）， 2022， 硕士

【摘要】 本论文以鲜食葡萄为研究对象,花椒、牛至精油为抑菌、保鲜剂。首先采用喷雾干燥法制备花椒、牛至及复配精油微胶囊,并通过单因素及响应面试验优化微胶囊的制备工艺。然后利用扫描电镜、傅立叶红外光谱等表征微胶囊的包埋和释放情况。最后将三种微胶囊分别置于无纺布中结合PCL/PLLA包装薄膜对葡萄在12℃,90%RH的环境下进行贮藏,使花椒、牛至及复配精油缓慢释放,达到长效抑菌、保鲜目的。结果表明:（1）以海藻酸钠为壁材制备精油微胶囊时,在芯壁比1:3（w/w）、均质时间50s、喷雾干燥进口温度180℃的条件下,包埋率最高,达到58.79%（v/v）。通过傅立叶红外光谱测试发现,花椒精油2856 cm^-1的特征吸收峰、牛至精油2960 cm^-1特征吸收峰均能在对应的微胶囊中出现,说明花椒、牛至及复配精油被成功包埋;释放试验发现,存放20天后花椒、牛至及复配精油微胶囊组的精油释放率较未包埋组分别降低31%、32%及33%,说明微胶囊化操作可以有效减缓精油的释放速率;体外抑菌试验发现,制备好的花椒、牛至及复配精油微胶囊放置15天后,对大肠杆菌的抑制率分别达到71.97%、77.41%及71.13%。表明喷雾干燥操作并未对精油抑菌性能产生明显影响,且微胶囊化操作可使精油达到长效抑菌效果。（2）将制备好的精油微胶囊应用于茉莉香葡萄的采后贮藏保鲜。结果表明:在PCL/PLLA包装基础上引入花椒、牛至及二者复配的精油微胶囊能够有效延缓葡萄呼吸代谢,提高感官品质。从理化指标来看,PCL/PLLA+CEOM组将贮藏24天后葡萄的腐烂率由PCL/PLLA气调组的14.87%（w/w）降低至2.97%（w/w）;同时PCL/PLLA+CEOM组也能够将贮藏20天后葡萄的总酚、类黄酮保留率分别较CK组提高23.89%（w/w）和18.26%（w/w）,较PCL/PLLA+PEOM组提高2.91%（w/w）和2.03%（w/w）。从微生物指标来看,PCL/PLLA+CEOM组能将贮藏28天后引起腐烂变质的优势菌青霉属（Penicillium）和根霉属（Rhizopus）的丰度由34%和38%降低为0,物种总数由204降至111,PCL/PLLA+PEOM组和PCL/PLLA+OEOM组则将青霉属的丰度降为1%和2%。此外,贮藏20天PCL/PLLA+CEOM组葡萄的苯丙氨酸解氨酶活性才达到最大值33.64 U/g,与PCL/PLLA组相比显著提高葡萄的抗病能力（P<0.05）。综上所述,采用喷雾干燥法成功制备了花椒、牛至及复配精油微胶囊。同时,在PCL/PLLA包装环境下引入花椒精油、牛至精油及复配精油微胶囊可长效抑制葡萄主要腐败菌的生长,同时可保持葡萄采后良好的感官品质和理化品质,且PCL/PLLA+CEOM组效果优于PCL/PLLA+PEOM和PCL/PLLA+OEOM处理组。更多还原

【Abstract】 In this thesis,fresh grapes were studied and pepper and oregano essential oils were used as antibacterial and preservative agents.The microcapsules of pepper,oregano and compound essential oils were firstly prepared by spray drying method,and the preparation process of microcapsules was optimized by single-factor and response surface tests.Then the microcapsules were characterized by scanning electron microscopy and Fourier infrared spectroscopy for encapsulation and release.Finally,the three microcapsules were placed in non-woven fabric combined with spontaneous air-regulated packaging film to store grapes at 12 ℃ and 90% RH,so that the pepper,oregano and the compound essential oil could be released slowly to achieve long-lasting antibacterial and freshness preservation.The results showed that(1)when the essential oil microcapsules were prepared with sodium alginate as the wall material,the highest encapsulation rate of 58.79%(v/v)was achieved at the core-to-wall ratio of 1:3(w/w),homogenization time of 50 s and spray drying inlet temperature of 180 ℃.The FTIR spectra showed that the characteristic absorption peaks of pepper essential oil at 2856 cm-1 and oregano essential oil at 2960 cm-1 could be found in the corresponding microcapsules,indicating that pepper,oregano and the compound essential oils were successfully encapsulated;the release test showed that the release rates of pepper,oregano and compound essential oils in the microcapsule group were31%,32% and 33% lower than those in the unencapsulated group after 20 days of storage,respectively.The in vitro inhibition test showed that the inhibition rate of E.coli was 71.97%,77.41% and 71.13% after 15 days of storage for the prepared pepper,oregano and compound essential oil microcapsules,respectively.It showed that the spray drying operation did not significantly affect the antibacterial properties of the essential oils,and the microencapsulation operation could achieve long-lasting antibacterial effects.(2)The prepared essential oil microcapsules were applied to the postharvest storage and preservation of jasmine grapes.The results showed that the essential oil microcapsules with the introduction of pepper and oregano and their combination on the basis of PCL/PLLA package could effectively delay the respiratory metabolism of grapes and improve the sensory quality.In terms of physicochemical indexes,the PCL/PLLA+CEOM group reduced the decay rate of grapes after 24 days of storage from 14.87%(w/w)to 2.97%(w/w)in the PCL/PLLA gas-conditioned group;meanwhile,the PCL/PLLA+CEOM group was also able to increase the retention rate of total phenols and flavonoids by 23.89%(w/w)and 18.26%(w/w),respectively,compared with the CK group after 20 days of storage.and 18.26%(w/w),and 2.91%(w/w)and 2.03%(w/w)higher than the PCL/PLLA+PEOM group.In terms of microbial indicators,the PCL/PLLA+CEOM group was able to reduce the abundance of Penicillium and Rhizopus,the dominant bacteria causing spoilage after 28 days of storage,from 34% and 38% to 0,with the total number of species reduced from 204 to 111,while the PCL/PLLA+PEOM and PCL/PLLA+OEOM groups groups reduced the abundance of Penicillium spp.to 1% and 2%.In addition,the phenylalanine aminolytic enzyme activity of grapes in the PCL/PLLA+CEOM group only reached a maximum value of 33.64 U/g at20 days of storage,significantly improving the disease resistance of grapes compared to the PCL/PLLA group(P<0.05).In summary,pepper,oregano and compound essential oil microcapsules were successfully prepared by spray drying method.Meanwhile,the introduction of pepper essential oil,oregano essential oil and compound essential oil microcapsules in PCL/PLLA packaging environment could inhibit the growth of major spoilage bacteria of grapes for a long time,while maintaining good organoleptic and physicochemical quality of grapes after harvest,and the effect of PCL/PLLA+CEOM group was better than PCL/PLLA+PEOM and PCL/PLLA+OEOM treatment groups.更多还原