Study on the mechanism of preservation and alteration of green color in vegetables

蔬菜保绿变色机理研究

• 批准号: 13660030
• 负责人: TERAI Hirofumi
• 金额: $ 2.3万
• 依托单位: Faculty of Agriculture, Kobe University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13660030/
• 关键词: Postharvest; Senescence; Ripening; Broccoli; Sweet pepper; Chloroplast; Electron microscope; Ethanol treatment; 緑色保持; エタノール蒸気処理; エチレン; ACC; ACC酸化酵素

1) Broccoli (Brassica oleracea L.var. Italicd) senesces rapidly and the florets turn yellow at room temperature after harvest. As a result, this vegetable has a short shelf life. A simple and cost-effective ethanol vapor treatment with powdery alcohol was conducted to inhibit the senescence in harvested broccoli and to clarify the mechanism involved in the preservation of the green color in stored broccoli florets. Some branchlets of the broccoli were stored in a perforated polyethylene bag together with 0, 3, 6, or 12 g powdery alcohol at 20℃ in the dark. Results showed that ethanol vapor treatment with 3 g powdery alcohol was very effective in delaying the yellowing of broccoli florets. However, higher concentration of ethanol vapor with 12 g powdery alcohol produced off-odor and softened the florets, and darkened the green color of florets. Results also indicated that ethylene production increased rapidly after 2 to 3 days in storage and simultaneously, ACC oxidase activity increase … More d in untreated broccoli florets but not in broccoli samples treated with powdery alcohol during storage. These results revealed that powdery alcohol treatment was simple and cost-effective method for prolonging the shelf life of broccoli since it suppresses ethylene production by inhibiting ACC oxidase activity.2) Further study was conducted using transmission electron microscope (TEM) to elucidate the mechanism involved in the occurrence of these anomalous phenomena with higher concentration of ethanol vapor. The structural changes in the cells and chloroplasts in the sepal tissues of broccoli florets during storage were examined. We found that the treatment with adequate concentration of ethanol vapor evaporated from 3 g powdery alcohol did not induce the structural changes of broccoli sepal cells but retarded the conversion of chloroplasts to chromoplasts. On the contrary, higher concentration of ethanol vapor induced 'false' plasmolysis, plasma membrane breaks and modified plastids, resulting in production of off-odor and the appearance of darkened green color in the florets.3) Red-colored sweet peppers are well-ripened fruit, which have been recently sold in the market. This study was investigated to improve the quality of pepper fruit harvested at mature green stage during storage at room temperature. In this experiment, the ultrastructural changes of plastids were examined to elucidate the transfomation mechanism of chloroplasts to chromoplasts during ripening in sweet peppers by using scanning electron microscope (SEM) and TEM. Based on SEM observation, disorganization of grana and stroma thylakoids appeared as the ripening progresses. At the developed stage of ripening, a large number of tubules with nods occupied in the plastids, which were probably derived from the thylakoid membranes. Based on TEM observation at the same stage, the greater parts of the plastids were filled with aggregated tubules. At fully-ripened stage, the appearances of fibril structures were observed. The morphometrical analysis showed that the ratios of grana thylakoids and stroma thylakoids to plastids decreased with ripening whereas the ratios of single thylakoids, vesicles, oil droplets, tubular structures, and fibril structures increased. The results of morphometrical analysis confirmed the quantitative changes of sub-organelles during ripening. Less

1)花椰菜（Brassica oleracea L.var.在室温下，收获后的小花迅速衰老并变黄。因此，这种蔬菜的保质期很短。采用一种简单、经济的乙醇蒸汽处理方法，以抑制采收后青花菜的衰老，并阐明其贮藏期间保持绿色的机理。将西兰花的一些小枝与0、3、6或12 g粉末状乙醇一起储存在20℃下的带孔聚乙烯袋中。结果表明，用3g粉末状乙醇蒸汽处理对延缓青花菜花的黄化有显著效果。而12 g粉末状乙醇的高浓度乙醇蒸气产生异味，软化小花，使小花的绿色颜色变深。贮藏2 ~ 3d后，乙烯释放量迅速增加，ACC氧化酶活性也随之增加 ...更多信息 d在未经处理的花椰菜小花中，但在储存期间用粉末状乙醇处理的花椰菜样品中没有。这些结果表明，粉末乙醇处理是延长西兰花货架期的一种简单而经济的方法，因为它通过抑制ACC氧化酶的活性来抑制乙烯的产生。2）利用透射电子显微镜（TEM）进一步研究了高浓度乙醇蒸汽发生这些异常现象的机制。研究了青花菜花萼组织细胞和叶绿体在贮藏过程中的结构变化。我们发现，用3g粉末乙醇蒸发出的足够浓度的乙醇蒸汽处理青花菜萼片细胞不会引起结构的变化，但延缓了叶绿体向色素体的转化。相反，较高浓度的乙醇蒸汽诱导了假质体的形成，质膜断裂，质体发生了结构改变，导致了异味的产生，小花颜色变深，呈绿色。3）红色甜椒果实成熟度高，最近上市销售。以提高成熟绿色期采收的辣椒果实常温贮藏品质为研究对象。本试验利用扫描电镜和透射电镜研究了甜椒成熟过程中质体超微结构的变化，探讨了叶绿体向色素体转化的机制。扫描电镜观察表明，随着成熟过程的进行，基粒和基质类囊体逐渐解体。在成熟发育阶段，质体中出现大量由类囊体膜衍生而来的小管，这些小管中含有大量的微管。透射电镜观察表明，在同一时期，质体大部分被聚集的小管所充满。在完全成熟期，观察到原纤维结构的出现。形态计量学分析表明，基粒类囊体和基质类囊体与质体的比例随着成熟而降低，而单个类囊体、小泡、油滴、管状结构和纤丝结构的比例则随着成熟而增加。形态计量学分析结果证实了成熟过程中亚细胞器的数量变化。少

项目成果

Terai,H., T.Nagatomo, and Y.Suzuki: "Plastid morphogenesis during ripening in sweet pepper fruit"J.Hlectr.Microsc.Technol.Med.Biol.. 17 (2) (In press). (2003)

Terai, H.、T.Nagatomo 和 Y.Suzuki：“甜椒果实成熟过程中的质体形态发生”J.Hlectr.Microsc.Technol.Med.Biol.. 17 (2)（印刷中）。

Terai H., Nagatomo T., Suzuki Y: "Plastid morphogenesis during ripening in sweet pepper fruit"J. of Electron Microscopy Technology for Medicine and Biology. (Accepted). (2003)

Terai H.，Nagatomo T.，Suzuki Y：“甜椒果实成熟过程中的质体形态发生”J。

Terai, H., T.Nagatomo, Y.Suzuki: "Plastid morphogenesis during ripening in sweet pepper fruit"J.Electr.Microsc.Technol.Med.Biol.. 17(In Press). (2003)

Terai, H., T.Nagatomo, Y.Suzuki：“甜椒果实成熟过程中的质体形态发生”J.Electr.Microsc.Technol.Med.Biol.. 17（正在出版）。