珈白丽珍珠属于近年来研发出的三角帆蚌外套膜位淡水有核珍珠。本文以该类珍珠为研究对象,辅以类胡萝卜标样(β-胡萝卜素和虾青素)为参照物,采用激光拉曼光谱仪及显微红外光谱仪重点针对该类珍珠的致色机理进行研究,旨在为该类珍珠的品质评价和养殖技术提供科学的理论依据。研究结果表明:对于淡水彩色有核珍珠的珍珠层,由类胡萝卜素结合蛋白的ν₁(C=C)和ν₂(C—C)伸缩振动引起的拉曼较强锐峰分别出现在1509 cm ^-1和1126 cm ^-1附近,1017 cm ^-1处的拉曼弱峰与CH₃的平面摆动振动(ν₃)有关,在2100~3800 cm ^-1拉曼位移范围内出现的强弱不等的5组拉曼峰是由ν₁、ν₂、ν₃的倍频和组合频振动引起的。类胡萝卜素分子中共轭双键的数量及其结合蛋白复合体与淡水有核珍珠颜色之间存在一定的关系,是导致该类有核珍珠颜色多样性的缘由之一。

Gabriel pearls are freshwater-nucleated pearls developed in recent years cultured in the mantle of Hyriopsis cumingii. In response to its coloration mechanism, scholars have proposed diversified viewpoints. In our research, both laser Raman spectroscopic and micro-infrared spectroscopic analyses were performed on Gabriel pearls with carotenoid standard samples (β-carotene and astaxanthin) as reference materials for a better understanding of the coloration mechanism, which was expected to provide a scientific theoretical basis for quality evaluation and cultivation technology of these pearls. The results confirmed the strong 1509 and 1126 cm ^-1 Raman peaks of the nacre of freshwater colored nucleated pearls attributed to ν₁(C=C) and ν₂(C—C) stretching vibration modes of carotenoid-binding protein, respectively. The presence of a weak peak at 1017 cm ^-1 was associated with the plane oscillation of CH₃ (ν₃). Raman spectra in the range of 2100--3800 cm ^-1 revealed five groups of peaks with varying intensities, which were attributed to frequency multiplication and combined frequency vibration of ν₁, ν₂, and ν₃. Notably, there was a correlation between the number of conjugated double bonds of carotenoid molecules or carotenoid-binding proteins and the color of freshwater-nucleated pearls, indicating one of the reasons for the coloration diversity of pearl color.