Luo Wen, Guo Jinrong, Zhou Jia, Yang Mingjun, Wang Yonggang
School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou 730050, China.
Gansu Food Inspection and Research Institute, Lanzhou 730199, China.
Biology (Basel). 2025 Aug 1;14(8):963. doi: 10.3390/biology14080963.
Rhubarb, a medicinal herb in Gansu Province, China, undergoes significant quality changes during sun-drying. This study investigated color changes, drying kinetics, anthraquinone (AQ) content, metabolic profiles, and enzyme activity during the process. Results showed that drying induced enzymatic browning, with the browning index (BI) progressively increasing over extended drying periods (4-16 h) and with greater slice thickness (2-8 mm). Catalase (CAT) activity first decreased and then increased, while polyphenol oxidase (PPO) activity decreased throughout drying. Slice thickness significantly affected AQ content, with the highest in 2 mm slices and the lowest in 4 mm slices. The drying process followed a logarithmic model (R = 0.99418, RMSE = 0.02310, and χ = 0.0005). Metabolomics analysis identified 631 differential metabolites, with 8 key metabolites linked to flavonoid biosynthesis, phenylalanine biosynthesis, and tyrosine metabolism. Fifteen enzymes were involved in metabolite synthesis and decomposition, though some enzyme activity trends contradicted metabolite changes. This study provides insight into rhubarb drying mechanisms and a basis for optimizing the drying process.
大黄是中国甘肃省的一种草药，在晒干过程中会发生显著的质量变化。本研究调查了该过程中的颜色变化、干燥动力学、蒽醌（AQ）含量、代谢谱和酶活性。结果表明，干燥会引发酶促褐变，褐变指数（BI）在较长干燥时间（4 - 16小时）和较大切片厚度（2 - 8毫米）下逐渐增加。过氧化氢酶（CAT）活性先降低后升高，而多酚氧化酶（PPO）活性在整个干燥过程中均降低。切片厚度显著影响AQ含量，2毫米切片中含量最高，4毫米切片中含量最低。干燥过程符合对数模型（R = 0.99418，RMSE = 0.02310，χ = 0.0005）。代谢组学分析鉴定出631种差异代谢物，其中8种关键代谢物与黄酮类生物合成、苯丙氨酸生物合成和酪氨酸代谢有关。15种酶参与代谢物的合成与分解，尽管一些酶活性趋势与代谢物变化相矛盾。本研究为大黄干燥机制提供了见解，并为优化干燥过程提供了依据。
