Abstract Climacteric fruits such as papaya are characterized by changes in the pigment composition during fruit ripening. Therefore, information on the degree of fruit ripeness with respect to the pigment composition using proper monitoring tools is important to growers for determining the appropriate harvest time associated with best quality. This study is aimed at exploring the applicability of spectroscopic probes such as laser-induced fluorescence (LIF) and confocal Raman microspectroscopy for the nondestructive, extraction free and rapid evaluation of pigment changes associated with the growth and ripening of papaya fruits. The laser-induced fluorescence spectra of the papaya show that as the fruit ripening progresses, there is a decrease in intensity of the chlorophyll bands with a simultaneous increase in intensity of carotenoid bands. This phenomenon can be regarded as a characteristic feature of the ripening of papaya. To obtain additional insight about the carotenoid dynamics during ripening, confocal Raman microspectroscopy has been utilized. The Raman spectra show strong spectral signature of carotenoids in both pericarp and mesocarp whose intensity increases as the fruit ripens. In addition, the bands of carotenoids are more prominent in the spectra of the mesocarp than in the pericarp. These facts are supported by the quantitative estimation of pigments in the papaya fruits by ultraviolet-visible spectroscopy. The determined spectral signatures can be used as indices for effective monitoring of ripening of fruits and commercial application for the phenotyping of important plant parts, screening, grading, shelf life estimation and quality standardization.

中文翻译：

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非破坏性光谱探针研究成熟和成熟期间木瓜果实的胡萝卜素生成过程

摘要 更年期水果如木瓜的特点是果实成熟过程中色素成分发生变化。因此，使用适当的监测工具了解与色素成分相关的水果成熟度信息对于种植者确定与最佳质量相关的适当收获时间很重要。本研究旨在探索激光诱导荧光 (LIF) 和共聚焦拉曼显微光谱等光谱探针在无损、免提取和快速评估与木瓜果实生长和成熟相关的色素变化方面的适用性。木瓜的激光诱导荧光光谱表明，随着果实成熟的进行，叶绿素带的强度降低，同时类胡萝卜素带的强度增加。这种现象可以看作是木瓜成熟的一个特征。为了获得有关成熟过程中类胡萝卜素动力学的更多信息，已使用共聚焦拉曼显微光谱。拉曼光谱显示果皮和中果皮中类胡萝卜素的强烈光谱特征，其强度随着果实成熟而增加。此外，类胡萝卜素的谱带在中果皮光谱中比在果皮中更显着。这些事实得到了通过紫外-可见光谱法对木瓜果实中色素进行定量估计的支持。确定的光谱特征可用作有效监测水果成熟度和商业应用的指标，用于重要植物部分的表型、筛选、分级、保质期估计和质量标准化。