FOOD CHEMISTRY
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2024
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IF 8.5
Qiuyan Liu,Wenjing Huang,Caiyan Sheng,Yida Wu,Mingxia Lu,Tiehan Li,Jixin Zhang,Yuming Wei,Yujie Wang,Jingming Ning
Large-leaf yellow tea (LYT) is processed from both leaves and stems, resulting in a distinctive rice crust–like aroma. Tea stems may contribute differently to the aroma of LYT than leaves. This study aimed to clarify the specific contribution of stems to LYT. The volatile compounds in different components of LYT were extracted and analyzed using a combination of headspace solid-phase microextraction and stir bar sorptive extraction coupled with gas chromatography-olfactory-mass spectrometry. The results revealed high concentrations of compounds with roasty attributes in stems such as 2-ethyl-3,5-dimethylpyrazine (OAV 153–208) and 2-ethyl-3,6-dimethylpyrazine (OAV 111–140). Aroma recombination and addition experiments confirmed that the roasty aroma provided by stems plays a pivotal role in the formation of the distinctive flavor of LYT. This study offers novel insights into the contribution of stems to the aroma of LYT, which can be used for processing and quality enhancement of roasted tea.
研究领域:
食品科学
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茶叶加工学
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产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2025
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IF 8.5
Pei-Ru Zhou,Xiao-Ping Zheng,Ya-Peng Du,Yu Chai,Yu-Cang Zhang,Yan-Zhen Zheng
In this study, polyethylene glycol 200 (PEG200) was employed as hydrogen bond acceptor, while organic acids served as hydrogen bond donors, to formulate poly-deep eutectic solvents (PDESs), which were utilized to pretreat tea stem. Specially, combining PEG200 and oxalic acid (OA) exhibited a notably high cellulose retention (82.03 %) and most efficient hemicellulose (97.02 %) and lignin removal (70.89 %). The removal of amorphous lignin enhanced the crystallinity of the residues and improved the conversion efficiency of cellulose into levulinic acid. Additionally, the structural alterations in lignin samples were analyzed in comparison to milled wood lignin (MWL). The PEG200-OA system facilitated the cleavage of β-O-4 and β-5 linkages and resulted in the degradation of S-type lignin, accompanied by increased condensation of G units. The resulting lignin displayed a reduced molecular weight (Mw of 1283 g/mol, Mn value 531 g/mol) and nanoscale particle size (D 50 212 nm). Furthermore, fluorescent lignin was synthesized through simple oxidation and was used to detect metal ions. Density functional theory (DFT) calculations supported that both PEG200 and OA played a significant role in lignin dissolution, with the weak interactions between DES and lignin primarily driven by hydrogen bonding (characterized as weak, closed-shell, and electrostatic) and van der Waals forces.
研究领域:
生物化学
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材料科学
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环境工程
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产品关联
DOI
PubMed
高影响因子
FOOD CHEMISTRY
·
2025
·
IF 9.8
Ye-Ting Wang,Yu Chai,Xiao-Ping Zheng,Ya-Peng Du,Yu-Cang Zhang,Yan-Zhen Zheng
In this study, novel biocompatible choline-organic carboxylic acid ionic liquids (Ch-OAC-ILs) were developed for pretreatment of tea stems. Among them, the combination of Ch + and levulinate achieved highest cellulose retention and most efficient lignin removal. The pretreatment mechanism were systematically explored using advanced characterization techniques and density functional theory calculations. The Ch-OAC-ILs preferentially targeted β-O-4 and β-5 linkages, yielding regenerated lignin enriched with H units. Both the cation and anion played critical roles in lignin dissolution. Furthermore, the enzyme digestibility of the pretreatment residue was significantly enhanced. The IL-lignin solution obtained after pretreatment was directly incorporated into chitosan films, where the ILs acted as plasticizers and lignin functioned as an active additive. These composite films exhibited superior UV-blocking properties with potential in functional packaging applications. This study highlights the efficacy of Ch-OAC-ILs as a sustainable and efficient method for lignin dissociation, offering a promising strategy for biomass fractionation and valorization.
研究领域:
生物质工程
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材料科学
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产品关联
DOI
PubMed
高影响因子
Food Chemistry-X
·
2024
·
IF 6.5
Wenjing Huang,Qiuyan Liu,Jingming Ning
In this study, the stems (ST) and leaves (LT) isolated from Large-leaf yellow tea (LYT) were used for sensory evaluation and quantitative analysis of flavor metabolites by sensomics and flavoromics. The results showed that the flavors of ST and LT in LYT were significantly different, and ST had stronger roasty and nutty aroma and sweet taste, which was mainly due to the accumulation of higher theanine and soluble monosaccharides in ST, and provided more substrates for the production of more pyrazine by the Maillard reaction; whereas LT contributed to the mellow and thick taste quality of LYT, and the abundance of catechins and caffeine were the main reason. The metabolic patterns of flavor metabolites indicated that the flavor differences between ST and LT were mainly due to biological metabolism in tea plants. This study provides the selection of raw materials for LYT in the future and product development of tea stems.
研究领域:
食品科学
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茶叶科学
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农业化学
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感官评价
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产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2025
·
IF 13.2
Ye-Ting Wang,Qing-Ping Zheng,Yu Chai,Yu-Cang Zhang,Yan-Zhen Zheng
In this study, an efficient and environmentally friendly pretreatment system was developed by combining the biocompatible ionic liquid choline levulinate (ChLA) with monoethanolamine (MEA) to enhance the fractionation and valorization of tea stems (TS). Under optimized conditions (140 °C, 2 h, 20 % water content, ChLA:MEA molar ratio of 1:2), the system achieved high retention of cellulose (89.2 ± 1.4 %) and hemicellulose (76.6 ± 1.4 %), alongside substantial lignin removal (76.9 ± 0.7 %). Spectroscopic and morphological analyses (FTIR, XRD, SEM) confirmed effective disruption of the lignin-carbohydrate complex, a reduction in cellulose crystallinity, and enhanced substrate accessibility. Consequently, enzymatic hydrolysis of the pretreated biomass yielded glucose and xylose at 93.7 ± 0.6 % and 85.7 ± 0.7 %, respectively, representing a more than 212 % improvement in saccharification efficiency compared to untreated TS. Furthermore, the pretreatment selectively cleaved lignin-carbohydrate ester linkages, enabling the recovery of lignin nanoparticles (LNPs) characterized by a high β-O-4 linkage content, low condensation degree, and low molecular weight. These LNPs were incorporated into polyvinyl alcohol (PVA)-based nanocomposite films, which exhibited improved mechanical properties, hydrophobicity, and UV-shielding performance. Overall, this work presented a sustainable and integrated strategy for the comprehensive utilization of lignocellulosic biomass into high-value multifunctional materials.
研究领域:
生物质转化
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绿色化学
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材料科学
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纳米复合材料
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可再生资源利用
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生物基材料
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纤维素降解
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）