红枣贮藏期果面微生物多样性

以2种成熟度不同的红枣(Zizyphus jujuba Mill.)为试验材料在入库前采用保鲜剂处理,未采用保鲜剂处理的红枣为试验对照,研究红枣不同贮藏时期果面微生物多样性。结果表明:红枣贮藏期果面微生物种群中,细菌是优势类群,占微生物总数80%以上,真菌较少;采摘期红枣果面上就携带微生物,真菌优势菌株属于链格孢(Alternaria),其次为镰刀菌(Fusarium)和木霉(Trichoderma),贮藏期优势菌株属于链格孢(Alternaria)、青霉(Penicillium)、木霉(Trichoderma)和镰刀菌(Fusarium),曲霉(Aspergillus)、毛霉(Mucor)和根霉(Rhizopus)次之。红枣贮藏期果面微生物种群动态失衡是导致贮藏病害发生的主要原因,成熟度较高的红枣果面微生物总数、真菌和细菌的数量明显高于成熟度较低的红枣,使用保鲜剂后有效地降低了红枣贮藏期果面微生物的多样性,贮藏时间越长红枣果面微生物的多样性越明显。

Microbial diversity of the jujube(Zizyphus jujuba Mill.) fruits surface during harvesting and storage stages

Post harvest diseases of jujube(Zizyphus jujuba Mill.) fruits are serous problem during storage. Many microbes including benefit and harmful organisms, and pathogens are associated with jujube. The aim of the study was to characterize the microbial diversity in stored jujube fruits and their potential effect on the storage diseases. Microbial diversity of the Ningxia jujube (Zizyphus jujuba Mill.) fruit surface at different mature levels during the harvesting and storage stages was investigated. The jujube maturity was graded based on the percentage of erubescent area of the jujube fruit surface and the tenth grade was with the 100% of the area erubescent and the eighth grade was with 2 third of the area erubescent. The samples were collected at the picking time, and after storages of 15 d, 30 d, and 45 d. The result showed that 80% of the microbes isolated on the jujube surface are bacteria. Fungi including species of Alternaria, Fusarium, Penicillium, Trichoderma, Aspergillus, Mucor and Rhizopus were detected at all sampling stages. Alternaria spp. were the dominant and Fusarium spp. and Trichoderma spp. were common at the picking stage and the storage stages, while species of Alternaria, Penicillium, Trichoderma and Fusarium were dominant and species of Aspergillus, Mucor and Rhizopus were common at the storage stages. The preservative treatment was significantly reduced the fungi colonized on the jujube surface during the storage compared with non-treatment. More microbial diversity was found on the full mature jujubes than that on the eighth grade mature jujubes. Microbial diversity and their effect on the jujube quality were significantly increased along with the time of jujube storage. The biodiversity analysis showed that microbial diverse index of the jujube surface increased during the storage period. The Shannon-Wiener index has increasing tendency for all test treatments and reached to the highest at the storage of 45 d. The Simpson index was significantly inhibited at the picking time and earlier storage stages by the preservative treatment and reached the same as the non-treatment at the storage of 45 d. Although our current result was preliminary, it provided comprehensive understanding on the microbial community of jujube fruits and their effect on the jujube storage diseases. Our performance encouraged that the microbial community of other fruits should be conducted and investigated during storage, and the microbial community function should be determined. The antagonistic microbes may find from the community and are potential in biocontrol of fruit post harvest diseases.