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| LED红光萎凋对红茶关键酶活性、理化性质及挥发性物质的影响 |
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杨涵越1, 李永焜1, 谢侗1, 王龙华1, 付佳音1, 曲东1,2, 习林杰1,2, 燕飞1,2,3,4
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1.陕西理工大学 生物科学与工程学院，陕西 汉中 723000;2.陕西省资源生物重点实验室，陕西 汉中 723000;3.陕南秦巴山区生物资源综合开发协同创新中心，陕西 汉中 723000;4.陕西省“四主体一联合”茶产业校企联合研究中心，陕西 汉中 723000
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| 摘要: |
| 【 目的】研究LED红光对红茶萎凋过程中关键酶活性、理化性质及挥发性物质动态变化的调控作用， 为优质红茶的萎凋加工提供参考。【 方法】以室内自然萎凋为对照（CK），设置LED红光（650 nm，2 000 lx）萎凋处理 组（RL），分别在萎凋处理后0，2，4，6，8和10 h取样，测定多酚氧化酶（PPO）、过氧化物酶（POD）、β-葡萄糖苷酶 （β-GC）活性及茶多酚、游离氨基酸、可溶性糖、总黄酮含量，结合GC-IMS技术分析挥发性物质组成，并通过主成分分 析明确不同萎凋阶段的品质差异。【 结果】红光萎凋8 h时茶叶中的PPO活性最高，为15.65 U/g，较CK提升8.70%； 萎凋10 h时茶叶中的POD活性达16.26 U/g，较CK提升25.08%；萎凋4 h时茶叶中的β-GC活性达到最高，为4.58 U/g；红光萎凋下，茶多酚含量在2，4和8 h时极显著减少（P<0.01），黄酮含量在8和10 h时极显著下降（P<0.01），而可溶性糖和游离氨基酸含量分别在红光萎凋10 h和8~10 h时极显著增加（P<0.01）；红光萎凋10 h时，游离氨基酸含量为3.58%，较CK提升20.95%。通过GC-IMS共鉴定出 85 种挥发性物质，在红光萎凋4 h时，加速青味物质（如水杨酸甲酯、（Z）-4-庚烯醇）减少，果香物质（如柠檬烯、α-松油烯）增加，较CK提前2 h完成。红光萎凋后期（6~10 h）果 香、酒香类物质（2-己酮、3-甲基丁醇）显著增加，酸味物质（乙二醇单丁醚）减少，内含物及香气种类在10 h最丰富。主 成分分析表明，红光萎凋8和10 h时样品主成分差异显著（累计解释率为68.9%）。【 结论】LED红光萎凋通过激活 β葡萄糖苷酶及调控氧化酶活性，显著促进糖苷类前体物质水解和果香物质生成，其中萎凋4 h为香气转化的关键节点。 红光萎凋10 h时游离氨基酸和可溶性糖等内含物和挥发性物质种类、含量最丰富。 |
| 关键词: 红茶 LED红光萎凋 关键酶活性 气相-离子迁移谱（GC-IMS）技术 |
| DOI：10. 13207/j. cnki.jnwafu. 2026. 05. 006 |
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| 基金项目:陕西省重点研发计划项目（2024NC-YBXM-038）；陕西理工大学研究生创新基金项目（SLGYCX2532） |
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| Effects of LED red light withering on key enzyme activities，physicochemical properties and volatile compounds of black tea |
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YANG Hanyue1, LI Yongkun1, XIE Tong1, WANG Longhua1, FU Jiayin1, QU Dong1,2, XI Linjie1,2, YAN Fei1,2,3,4
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1.College of Biological Science and Engineering，Shaanxi University of Technology，Hanzhong，Shaanxi 723000，China;2.Shaanxi Bio-Resources Key Laboratory，Hanzhong，Shaanxi 723000，China;3.Coordination and Innovation Center for
Comprehensive Development of Qinba Biological Resources，Hanzhong，Shaanxi 723000，China;4.Shaanxi Province Four Subjects and One Joint Tea University & Enterprise Alliance Research Center，Hanzhong，Shaanxi 723000，China
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| Abstract: |
| 【 Objective】The study aimed to explore the role of LED red light in regulating the dynamic changes of key enzyme activities，physicochemical properties and volatile compounds during the withering process of black tea，providing a reference for the withering processing of high-quality black tea.【Method】Natural indoor withering was used as the control（ CK），with an LED red light（650 nm，2 000 lx） withering treatment group（RL） established for comparison. Samples were collected at 0，2，4，6，8， and 10 h，respectively，to determine the activities of polyphenol oxidase（PPO），peroxidase（POD），and β-glucosidase（ β-GC），along with the contents of tea polyphenols，free amino acids，soluble sugars，and flavonoids. Volatile compounds were analyzed using the GC-IMS technology，and principal component analysis was performed to clarify the quality differences between different withering stages.【Result】During red-light withering，PPO activity in tea leaves peaked at 8 h，reaching 15.65 U/g，an 8.70% increase compared to CK. POD activity reached its maximum at 10 h，reaching 16.26 U/g，a 25.08% increase of compared to CK. β -GC activity in tea leaves reached its peak of 4.58 U/g at 4 h. Under red light withering，tea polyphenols content decreased significantly at 2，4，and 8 h（P<0. 01）. Flavonoid content decreased significantly at 8 and 10 h（P<0. 01）. Soluble sugar and free amino acid contents significantly increased at 10 h and 8? 10 h of red light withering（P<0. 01）. After 10 h of red light withering treatment，free amino acid content rose to 3.58%，representing a 20.95% increase compared to CK.GC-IMS identified 85 volatile compounds. At 4 h of red light withering，the reduction of green-tasting substances（ e. g. ，methyl salicylate and（Z）-4-heptenol） accelerated，while fruit-scented substances（ such as limonene and α-pinene） increased，completing the process 2 hours earlier than CK. During the late withering stage（6 to 10 h），fruit and wine-like substances （e. g. ，2-hexanone and 3-methylbutanol） significantly increased，whereas acidic substances（ ethylene glycol monobutyl ether） decreased. The content and variety of constituents and aromas were most abundant at 10 h. Principal component analysis（PCA） showed that there were significant differences in the principal components of the samples at 8 h and 10 h，with a cumulative explanatory power of 68.9%.【Conclusion】LED red light withering significantly promoted glycosidic precursor hydrolysis and the generation of fruity aroma compounds by activating β-glucosidase and modulating oxidative enzymes，with the 4 h identified as the key node for aroma transformation. At 10 h of red light withering，the variety and content of free amino acids，soluble sugars，other constituents，and volatile compounds were most abundant. |
| Key words: black tea LED red light withering key enzyme activities GC-IMS technology |
