TP-CS-PAA纳米粒抑制枇杷采后病原微生物的研究

发布时间：2018-05-01 14:26

本文选题：壳聚糖 + 茶多酚　；参考：《浙江工商大学》2015年硕士论文

【摘要】：壳聚糖是一种天然的碱性多糖,具有良好的相容性、降解性和成膜性等生物特性,安全无毒,并且具有广泛的抑菌活性。然而壳聚糖的抑菌能力相对有限,限制了其广泛应用。将壳聚糖和其他物质一起制备成壳聚糖纳米粒以提高抑菌活性,是近年来的研究热点之一。本研究利用壳聚糖CS和聚天冬氨酸PAA之间离子交联作用制备CS-PAA纳米载体,装载茶多酚TP,制备TP-CS-PAA纳米粒,研究其对引起采后枇杷果实贮藏期间腐烂的病原真菌的抑菌能力,探索其在果蔬真菌病害防治中应用的可能性。结果如下：(1) CS/PAA质量比、搅拌时间、TP浓度对TP-CS-PAA纳米粒的粒径、Zeta电位、包埋率都有较大的影响。制备TP-CS-PAA纳米粒的最佳工艺为：CS/PAA质量比为4,搅拌时间为75 min,TP浓度为4 mg/mL时,制备出的TP-CS-PAA纳米粒的平均粒径为167.1nm, PDI为O.152和Zeta电位为47.8 mV,平均包封率为24.73%。(2)运用形态学和分子生物学等方法对采后枇杷果实病害菌进行了分离鉴定,结果表明：尖孢炭疽菌(Colletotrichum acutatum)、三隔镰孢菌(Fusarium tricinctum)、互隔交链孢霉(Alternaria alternata)、亮青霉(Penicillium crustosum)、可可毛色二孢菌(Lasiodiplodia theobromae)和葡萄座腔菌(Botryosphaeria dothidea)等6种病原真菌是引起枇杷果实采后病害的主要病原菌。(3)通过测定菌丝生长速率和孢子萌发抑制率,研究了TP-CS-PAA纳米粒对枇杷果实采后6种致病真菌的抑菌活性。结果表明：TP-CS-PAA纳米粒对这6种病原真菌的菌丝生长和孢子萌发均有抑制作用,且抑制作用与浓度正相关。相同浓度下,TP-CS-PAA纳米粒对病原真菌的抑菌效果明显优于CS-TP-PAA复合物、CS-TP复合物、CS和PAA。扫描电镜观察表明：含0.6 mg/mL CS的TP-CS-PAA纳米粒对C. acutatum和F. tricinctum菌丝形态有明显的影响。(4)含CS浓度为3、6 mg/mL的TP-CS-PAA纳米粒和CS-TP-PAA复合物处理枇杷果实后,能够明显降低果实的自然发病率以及针刺接种C. acutatum和F. tricinctum的发病率,抑制了针刺接种后病斑直径的扩大,TP-CS-PAA纳米粒处理的效果明显优于CS-TP-PAA复合物处理的效果。
[Abstract]:Chitosan is a natural alkaline polysaccharide with good biocompatibility, biodegradability and film-forming properties. It is safe and non-toxic, and has a wide range of bacteriostatic activities. However, the antimicrobial ability of chitosan is relatively limited, which limits its wide application. The preparation of chitosan nanoparticles with other substances to improve antibacterial activity is one of the hot research topics in recent years. In this study, CS-PAA nanoparticles were prepared by ionic cross-linking between chitosan CS and polyaspartic acid (PAA). The TP-CS-PAA nanoparticles were prepared by loading tea polyphenols. The inhibitory effect of TP-CS-PAA nanoparticles on pathogenic fungi that caused rot in postharvest loquat fruits during storage was studied. To explore the possibility of its application in the prevention and control of fruit and vegetable fungal diseases. The results are as follows: (1) the mass ratio of CS/PAA and the concentration of TP in stirring time have a great influence on the particle size and the entrapment rate of TP-CS-PAA nanoparticles. When the mass ratio of TP-CS-PAA / PAA was 4 and the stirring time was 75 min TP was 4 mg/mL. The average diameter of the prepared TP-CS-PAA nanoparticles was 167.1 nm, PDI was 0.152, Zeta potential was 47.8 MV, and the average entrapment efficiency was 24.73mV.) morphological and molecular biological methods were used to isolate and identify postharvest loquat fruit disease bacteria. The results showed that six pathogenic fungi such as Colletotrichum acutatumum, Fusarium tricinctuma, Alternaria alternata, Penicillium crustosumsuma, Lasiodiplodia theobromaeand Botryosphaeria dothidea were the main pathogens causing postharvest diseases of loquat fruits. The growth rate of hyphae and the inhibition rate of spore germination were measured. The antimicrobial activity of TP-CS-PAA nanoparticles against 6 pathogenic fungi in postharvest loquat fruit was studied. The results showed that TP-CS-PAA nanoparticles could inhibit the hyphal growth and spore germination of the six pathogenic fungi, and the inhibitory effect was positively correlated with the concentration. The inhibitory effect of TP-CS-PAA nanoparticles on pathogenic fungi at the same concentration was obviously superior to that of CS-TP-PAA complexes, CS-TP complexes, CS and PAA. SEM observation showed that TP-CS-PAA nanoparticles containing 0.6 mg/mL CS significantly affected the morphology of C. acutatum and F. tricinctum mycelium. 4) TP-CS-PAA nanoparticles with CS concentration of 3 mg/mL and CS-TP-PAA complex were used to treat loquat fruit. The natural incidence of fruit and the incidence of C. acutatum and F. tricinctum after acupuncture inoculation were significantly decreased, and the effect of TP-CS-PAA nanoparticles treatment on the diameter of disease spot after acupuncture inoculation was obviously better than that of CS-TP-PAA compound treatment.
【学位授予单位】：浙江工商大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;TS255.3

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