精油对柑橘采后致腐真菌的抑菌活性及主要成分研究

发布时间：2018-08-27 17:44

【摘要】：柑橘作为世界四大水果之一,是全球产量第一、被新鲜食用量第一的水果。但是,由于柑橘类果实组织柔软多汁且富含糖分,在摘采后的贮存运输过程中易发生机械损伤,受到多种侵染性病害,因而导致腐烂变质。不仅影响水果质量,造成严重的经济损失,还会引起食品安全问题。柑橘的腐烂变质多数由真菌引起,目前常见的防腐措施仍以化学药剂为主,化学药剂杀菌虽然有效,但药剂残留会对消费者有影响,对环境也会造成污染,并且病原微生物耐药性的增加也会使得化学药剂使用效果下降。寻找新的天然抗菌剂成为人们的研究目标。精油是从植物的花、叶、茎、根或果实中提炼萃取的挥发性芳香油状液体的总称。研究表明,精油具有广谱强抗菌性,对细菌、真菌和病毒都有很好的抑杀作用,因此可以作为天然防腐抑菌剂用于食品中对微生物污染的控制。目前国内对于精油对微生物的抑制作用研究很多,部分也分析了精油的主要组成成分及含量,但是对于这些主要组分对于微生物的抑菌活性研究并不多。为了探究精油对柑橘采后致腐真菌的抑菌活性及有效抑菌成分,本研究从发霉柑橘中分离出5种真菌,经ITS测序鉴定分别为可可毛色二孢菌Lasiodiplodia theobromae、芽枝状枝孢菌 Cladosporium cladosporioides、芸苔生链格孢Alternaria brassicae、指状青霉 Penicillium digitatum、青霉 Penicillium sp.13 BRO-2013。采用滤纸片法测定肉桂(Cinnamomum zeylanicum)精油、百里香(Thymusvulgaris)精油、香茅(Cymbopogon nardus)精油、天竺葵(Pelargonium graveolens)精油、(Eucalyptus globulus)精油、广藿香)(Pogostemon cablin)精油、雪松(Cedrusatl antica)精油和香橼(Citruslimon)精油等8种精油对分离纯化得到的5种柑橘采后致腐真菌的抑菌活性。结果表明,肉桂精油和百里香精油具有较强的广谱抗真菌活性。气质联用分析两种精油的组分及含量,肉桂精油共检测出61种成分,主要含有丁香酚(70.38%)、β-石竹烯(7.52%)、苯甲酸苄酯(6.23%)和肉桂醛(4.65%),百里香精油检测出67种成分,主要含有百里香酚(48.97%)、对伞花烃(22.95%)、3-甲基-4异丙基苯酚(12.41%)和萜品烯(3.19%)。采用液体培养基稀释法测定6种精油成分(丁香酚、苯甲酸苄酯、肉桂醛、百里香酚、对伞花烃和3-甲基-4异丙基苯酚)对5种病原真菌的最低抑菌浓度(MIC)和最小杀菌浓度(MFC),结果显示液体化合物中肉桂醛对 5 种真菌的 MIC 和 MFC 范围均为 0.016-0.125μL/mL 和 0.016-0.125μL/mL,均有极好的抑杀作用且无抗药性;固体化合物中百里香酚对5种真菌的MIC和MFC 为 51.2μg/mL-204.8μg/mL 和 102.4μg/mL-819.2μg/mL,有显著的抑菌作用,部分真菌对其有抗药性。研究表明,百里香精油和肉桂精油均具有良好的广谱抗真菌活性,其各自含有的百里香酚和肉桂醛成分也均有显著的抑菌作用,为柑橘类果实天然抑菌剂的研制提供理论依据。
[Abstract]:Citrus is one of the four largest fruits in the world. However, due to the soft and juicy tissue and rich in sugar, citrus fruits are prone to mechanical damage during storage and transportation after picking and harvesting, and suffer from various infectious diseases, which lead to decay and deterioration. Not only affect fruit quality, cause serious economic losses, but also cause food safety problems. The decay and deterioration of citrus is mostly caused by fungi. At present, the common anticorrosion measures are still mainly chemical fungicides. Although chemical fungicides are effective in sterilization, pesticide residues will have an impact on consumers and will also cause pollution to the environment. And the increase of drug resistance of pathogenic microorganisms will also reduce the use of chemical agents. Finding new natural antimicrobial agents has become a research goal. Essential oil is a general term for volatile oils extracted from flowers, leaves, stems, roots, or fruits of plants. The results showed that the essential oil had broad spectrum and strong antibacterial properties, and could be used as a natural anticorrosive and bacteriostasis agent to control the microbial contamination in food because of its good inhibitory effect on bacteria, fungi and viruses. At present, there are a lot of studies on the inhibition of essential oils on microorganisms, some of which have also analyzed the main components and contents of essential oils, but there are few studies on the bacteriostatic activities of these main components to microorganisms. In order to investigate the antimicrobial activity and effective antimicrobial components of essential oil against postharvest rot fungi, five fungi were isolated from moldy citrus. By ITS sequencing, they were identified as Lasiodiplodia theobromae, Lasiodiplodia theobromae, Cladosporium spp., Cladosporium cladosporioides, Brassica, Alternaria Alternaria brassicae, Penicillium digitalis, Penicillium digitatum, Penicillium Penicillium sp.13 BRO-2013., respectively. The essential oil of cinnamon (Cinnamomum zeylanicum) thyme (Thymusvulgaris) citronella (Cymbopogon nardus), (Eucalyptus globulus) essential oil of geranium (Pelargonium graveolens) and) (Pogostemon cablin) essential oil of patchouli were determined by filter paper method. The antimicrobial activity of eight essential oils, such as cedar (Cedrusatl antica) essential oil and Citron (Citruslimon) essential oil, against five citrus postharvest rot fungi isolated and purified. The results showed that cinnamon essential oil and thyme essential oil had strong broad-spectrum antifungal activity. The composition and content of the two essential oils were analyzed by GC-MS. 61 components were detected in the essential oil of cinnamon, which mainly contained eugenol (70.38%), 尾 -caryophyllene (7.52%), benzyl benzoate (6.23%) and cinnamaldehyde (4.65%). Thyme phenols (48.97%), 3-methyl-4-isopropyl phenol (12.41%) and terpenes (3.19%) were mainly found in this paper. The main contents were thymol (48.97%), para-cymene (22.95%), 3-methyl-4-isopropyl phenol (12.41%). Six essential oils (eugenol, benzyl benzoate, cinnamaldehyde, thymol) were determined by liquid medium dilution method. The results of minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MFC),) for 5 pathogenic fungi showed that the MIC and MFC ranges of cinnamaldehyde to 5 fungi in liquid compounds were 0.016-0.125 渭 L/mL and 0.125 渭 L/mL, respectively. 0.016-0.125 渭 L / mL, all of them had excellent inhibition and killing effect and had no resistance. The MIC and MFC of thymol in solid compounds were 51.2 渭 g/mL-204.8 渭 g/mL and 102.4 渭 g/mL-819.2 渭 g / mL, respectively. The results showed that thyme essential oil and cinnamon essential oil had good broad-spectrum antifungal activity, and the thyme phenol and cinnamaldehyde contained in thyme and cinnamaldehyde also had significant bacteriostatic effects, which provided theoretical basis for the development of natural antibacterial agents for citrus fruits.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S436.66

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