基于花色苷/类胡萝卜素组成、比例、呈色的硫磺熏蒸枸杞子增色作用机制研究

The abuse of traditional sulfur fumigation (SF) method violated of the original intention and principles of Traditional Chinese Medicine (TCM) processing, and the illegal sulfur-fumigated Gouqizi (Lycium barbarum) is a more serious TCMs. However, this fact cann’t be ignored that sulfur fumigation, at present, is the only way to effectively solve the mildew and discoloration of fresh fruit, when it suffers from rainy weather or cann’t be processed in time after harvest. Therefore, it is of great significance to understand and explain color protection and color enhancement mechanism of sulfur-fumigated Gouqizi for the development of alternative technologies.. In the study, Gouqizi, a medicinal and edible material, was used as the research object to discusses color enhancement mechanism of sulfur-fumigated sample. The main ingredients from non-sulfur fumigated samples and other different ingredients by characterized between before and after SF from sulfur fumigated samples were isolated, identified and prepared with modern separation and analysis technologies. The SF reactions were designed and simulated to describe the conversion mechanism of different ingredients in SF process. Meanwhile, the showing colors of the prepared compounds in different conditions was tested, and an attempt was made to combine compounds for restoring the color of real samples. On this basis, the correlation between sample color and SF level, the content and proportion of anthocyanin/carotene, the showing color of the compounds, related enzyme activities, and so on, was analyzed dynamically in SF process. The study will deepen the understanding of conversion mechanism of chemical ingredients and discover the characteristic SF ingredients, and also explain color enhancement mechanism of sulfur-fumigated Gouqizi to provide ideas for the development of alternative technologies and to take targeted measures in poverty alleviation.

传统硫磺熏蒸加工方法的滥用，违背了中药炮制的初衷，非法硫熏枸杞子是其中较为严重的一种。然而这个事实不能被忽视：目前仅有硫熏才能有效解决枸杞采收后，遇到阴雨天及难以及时加工时出现的霉变、变色问题。因此深入认识、阐述硫熏枸杞的护色增色机制对替代技术开发有重要意义。.本项目以药食两用枸杞子为研究素材，探讨其硫熏增色机制。运用现代分离分析手段分离、鉴定和制备色素类成分(花色苷和类胡萝卜素)以及所表征的硫熏前后其它色素差异性成分；设计、模拟硫熏反应，阐述成分硫熏转化规律。同时，测试所制备单体化合物的呈色，并尝试组合单体化合物、模拟还原真实样品色泽。在此基础上，动态分析硫熏过程中样品色泽与硫熏水平、花色苷/胡萝卜素含量与比例、单体化合物呈色、相关酶活性等的关联性。本项目研究既有助于加深对成分转化的认识和发现硫熏特征性成分；也有助于理解硫熏枸杞子增色作用机理，为枸杞替代技术开发提供思路，为精准扶贫服务。

传统硫磺熏蒸加工方法的滥用，违背了中药炮制的初衷，非法硫熏枸杞子是其中较为严重的一种。深入认识硫熏枸杞的护色增色机制对替代技术开发有重要意义。本研究通过现代分离纯化技术从中药枸杞子中分离鉴定了48个化合物，其中新化合物2个；并富集了硫熏机制研究所需色素单体成分。机制研究结果显示：相比于未硫熏枸杞样品，硫熏显著防止了总类胡萝卜素以及玉米黄素二棕榈酸酯等单体成分的过度损失，而花色苷（枸杞中类胡萝卜素的含量是花色苷的数百倍）的种类与含量都有所减少、降低。视觉分析结果显示硫熏较好的保护了枸杞样品中呈现红色和亮色的物质，而对呈现黄色的物质并无明显影响。硫熏模拟反应进一步表明硫熏对玉米黄素二棕榈酸酯等单体成分并无显著的影响。显微和其它研究显示：硫熏处理可使有色体破裂、溶解并均匀分布于细胞中；由于硫熏较好抑制了酶促褐变，加热干燥中较好保持了其红色。因此，硫熏枸杞子护色、增色的机制与其不同程度的防止类胡萝卜素类成分的损失，及所导致的类胡萝卜素类成分比例发生变化密切相关。这一结果与前期“硫熏改变花色苷/类胡萝卜素组成、比例、呈色”的设想不一致。本研究为开发品相更好的枸杞子替代加工技术提供了新思路。