Pakchoi (Brassica rapa L. Chinensis) is an important cruciferous vegetable crop in East and Southeast Asia. This research aimed to investigate the change of microbial community and antibacterial effect of 405 nm light-emitting diode (LED_405 nm) illumination (15 μ mol/(m² · s)) against spoilage bacteria on the surface of agar media and fresh-cut pakchoi. High-throughput community sequencing was used to quantify bacterial abundance and 16S rRNA was used to analyze the bacterial community composition on fresh-cut pakchoi treated with or without LED_405 nm storage at 4°C. And alkaline phosphatase (AKP) activity and metabolic inhibition assays were selected to measure the mechanism of bacterial inhibition. The results showed that Pseudomonas spp. were able to multiply and cause spoilage of fresh-cut pakchoi at 4°C. Nevertheless, the majority of Pseudomonas spp. isolated from spoilage pakchoi were Pseudomonas reinekei and Pseudomonas palleroniana which were considered as representative specific spoilage microorganisms in pakchoi. Furthermore, 405 nm light treatment retarded sensory deterioration, inhibited microbial growth. AKP activity and metabolic inhibition assays confirmed the inhibitory effect of light treatment. In brief, 405 nm LED illumination has potential as a preservative to maintain quality, extend the shelf life for 6 days of fresh-cut pakchoi and abled to control P. reinekei and P. palleroniana growth on fresh-cut pakchoi at 4°C.

中文翻译：

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405 nm 发光二极管处理对鲜切小白菜微生物群落的影响及对雷氏假单胞菌和巴勒罗尼亚假单胞菌的抗菌作用

小白菜（芜菁大号。羊草）是在东亚和东南亚地区的重要十字花科蔬菜作物。本研究旨在探讨 405 nm 发光二极管（LED _{405 nm}）照明（15 μmol/(m ² · s)）对琼脂培养基和新鲜培养基表面腐败菌的影响及抗菌作用。切小白菜。高通量群落测序用于定量细菌丰度，16S rRNA 用于分析用或不用 LED _{405 nm}处理的鲜切小白菜的细菌群落组成4°C 保存。并选择碱性磷酸酶 (AKP) 活性和代谢抑制试验来测量细菌抑制的机制。结果表明，假单胞菌属。能够在 4°C 下繁殖并导致鲜切小白菜腐败变质。尽管如此，大多数假单胞菌属。从腐败小白菜中分离出的有Pseudomonas reinekei和Pseudomonas palleroniana被认为是小白菜中具有代表性的特定腐败微生物。此外，405 nm 光处理延缓了感官恶化，抑制了微生物生长。AKP 活性和代谢抑制试验证实了光处理的抑制作用。简而言之，405 nm LED 照明具有作为防腐剂保持质量、延长 6 天鲜切小白菜的保质期并能够控制P 的潜力。Reinekei和P . 4°C 下鲜切小白菜上的巴勒罗尼亚生长。