Immunostimulating activity of a crude polysaccharide derived from green tea (Camellia sinensis) extract

Green tea extract is well-known to reduce the risk of a variety of diseases. Here, we investigated the immunostimulating activity of tea polysaccharide (TPS), one of the main components in green tea extract. The water extracts from mature or immature tea leaves were precipitated by using ethanol at room temperature. The sediment was washed with ethanol and acetone alternately and then dried. We used the phagocytic activity of macrophage-like cells as an indicator of immune function activation. Chemical components were analyzed by HPLC. The immunostimulating activity of TPS from immature leaves extract was higher than that of TPS from mature leaves, and its activities were dependent on the content of strictinin in the leaf extract. Futhermore, a mixture of catechin and TPS that removed polyphenols did not increase the immunostimulating activity. These results suggest that the catechin-polysaccharide complex is a very important molecule in the immunomodulating activity of tea extracts.     

Compositional analysis and preliminary toxicological evaluation of a tea polysaccharide conjugate

Tea polysaccharide conjugate is one of the main bioactive constituents of tea (Camellia sinensis L.). The chemical composition and preliminary toxicological evaluation of a tea polysaccharide conjugate was investigated to determine the possibility of using it for human consumption. Chemical analysis of tea polysaccharide conjugate showed that the tea polysaccharide conjugate was a nonstarch protein bounded acidic polysaccharide. The protein, neutral sugar, and uronic acid content of the tea polysaccharide conjugate was 3.5%, 44.2%, and 43.1%, respectively. The contents of iron, magnesium, zinc, and selenium in the tea and its polysaccharide conjugate were measured by inductively coupled plasma-optical emission spectrometry (ICP-OES). Results showed that the contents of four elements in tea polysaccharide conjugate were much higher than that of tea power. Especially, the content of iron in tea polysaccharide conjugate was increased 5.9 times. The tea polysaccharide conjugate, when fed to mice, was found to have no toxicity to the liver, kidney, heart, thymus, or spleen of the mice and none of the mice died throughout the period of the experiment. There was no significant difference between the thymus index, spleen index, and liver index of the mice from the test and control groups (P>0.05). On the basis of the study, the tea polysaccharide conjugate may be classified either as a very low toxicity substance, that is, GHS Category 5 (globally harmonized system), or as unclassified when orally administrated to mice. It might be a candidate of dietary supplements besides the bioactivities as a polysaccharide.     

雅安藏茶茶多糖对~(60)Co-γ射线辐照损伤小鼠抗氧化和造血功能的防护作用

为探究雅安藏茶茶多糖对~(60)Co-γ射线辐射损伤小鼠抗辐射作用的影响,从雅安藏茶中提取茶多糖,用不同浓度(50、100、200 mg·kg-1·d-1)的茶多糖连续15 d灌胃小鼠,在第6天采用5Gy的~(60)Co-γ射线一次性全身辐照各组小鼠,灌胃第16天测定各组小鼠外周血细胞、肝脏组织总抗氧化能力(T-AOC)、总超强氧化物歧化酶(T-SOD)活性和总蛋白(TP)含量等指标。结果表明,与单纯辐照组相比,雅安藏茶茶多糖能显著提高辐照损伤小鼠的外周血细胞数量,极显著提高肝脏组织T-AOC、T-SOD活性和股骨骨髓DNA含量,极显著降低肝脏MDA含量,缓解了免疫器官胸腺的萎缩;且随着茶多糖浓度的增加,其抗辐射作用效果增强。综上,雅安藏茶茶多糖对~(60)Co-γ射线辐照损伤小鼠抗氧化功能和造血功能具有较强的防护作用,且具有一定的剂量效应。本研究结果为进一步深入探究茶多糖防辐射作用机理提供了新参考,也为雅安藏茶辐照保健功效研究提供了一定的理论依据。     

Quantification of uronic acids in tea polysaccharide conjugates and their antioxidant properties

A technique of high-performance liquid chromatography (HPLC) was described for the measurement of total uronic acids in tea polysaccharide conjugates. This method was applied to polysaccharide conjugate extracts obtained from green tea after most of the components that produce interference were removed. The preliminary extraction process was according to the procedure of isolation of polysaccharide conjugates. The uronic acid content of different polysaccharide conjugate fractions was quantified by HPLC on a Sugar-Pak I column with a 1.0 x 10(-)(4) mol x L(-)(1) calcium disodium ethylenediaminetetraacetic acid solution as the mobile phase and refractive index detection. The validation study showed high recoveries (>97.0%) and low coefficients of variance (<3.0%). The minimum detectable limit concentration of uronic acid was 10 microg x mL(-)(1). The analysis of a standard range of galacturonic acid concentrations (100-4000 microg x mL(-)(1)) yielded linear results. The use of the method on different polysaccharide conjugate fraction samples confirmed its effectiveness. With the high content of uronic acids in polysaccharide conjugates, the stronger reactive oxygen species scavenging activities were found.     

响应面法优化茉莉花茶茶多糖提取工艺

本实验以茉莉花茶为供试材料,优化茶多糖的提取工艺,旨在提高茶多糖的提取率,为茶叶深加工提供理论依据。在单因素实验的基础上,利用Box-Benhnken的中心组合设计,选定温度、水料比和沉淀茶多糖时所用的乙醇浓度3个因素分别选3水平进行中心组合实验,通过响应面分析实验,拟合出数学模型：Y=6.55＋1.30A＋0.83B＋1.10C-0.092AB＋0.11AC＋0.34BC-1.56A2-0.64B2-1.48C2。利用该函数关系来优化茶多糖提取条件,最终确定茶多糖的最佳浸提条件为：浸提温度100℃;水料比为26.8;乙醇浓度为90%。在该条件下茶多糖得量有所提高,且验证值为7.8610mg/g,比单因素最高提取率高25.6%,表明响应面法可有效用于茶多糖提取方法的优化。     

Radical scavenging conserves from unused fresh green tea leaves

Green teas were made by inactivating the enzymes present in fresh leaves of coarse/pruned (unused) and normal (used for tea) grades using different sources of thermal energies. Green teas were extracted in a Soxhlet using different solvents. The obtained miscella was subjected to concentration to give the extract. The extract was subjected to solvent-solvent extraction. Solvent extract was concentrated to obtain conserve. The yields of conserves are 17 +/- 0.8 and 15 +/- 0.8% from green teas of normal and coarse tea leaves, respectively. The radical scavenging activity of these extracts was evaluated using a DPPH in vitro model system. The total polyphenol content was also determined and found to be higher in conserves from normal tea leaves. However, radical scavenging activity of conserves from coarse and normal green tea leaves was found to be >90% at 15 ppm concentration. The HPLC profiles of these conserves were used to quantify the total catechin content with the help of calibration curves prepared using authentic samples at known concentrations. The total catechin content is found to be in the range of 55-85%. Results indicated that the extracts from coarse leaves also possess potential biological activity and could be used as nutraceuticals as well as for preservation purposes in food formulations.     

Effects of soluble tea polysaccharides on hyperglycemia in alloxan-diabetic mice

The effects of tea water extracts (TWE), crude tea polysaccharides (CTP), and a tea polysaccharide fraction (TPF) were tested on hyperglycemic diabetic mice. Results indicated that TWE, CTP, and TPF could significantly decrease fasting blood glucose (FBG) and glucosylated serum protein (GSP) in alloxan-induced diabetic mice compared to the control group. In vitro antioxidant activities of TWE, CTP, and TPF for scavenging hydroxyl radicals and superoxide radicals decreased with the degree of purification and were lowest for TPF. High-performance gel permeation chromatography (HPGPC) and component analysis revealed the molecular mass distribution and constituents of TWE, CTP, and TPF, indicating that a 100-120 kDa fraction contained the hypoglycemic activity. This fraction was essentially composed of polysaccharides (approximately 90%) with substantial amounts of arabinogalactan proteins. The second-derivative IR spectra of TWE, CTP, and TPF with peak intensity around 1075 and 1045 cm(-1), which characterize galactopyranose in the backbone and arabinofuranose units in side branches, respectively, further substantiated the importance of the arabinogalactan proteins. Taken together, the results indicate that a soluble tea polysaccharide is the major hypoglycemic factor in tea and that this polysaccharide may be developed to a potential natural hypoglycemic functional ingredient.     

脱氢表雄酮对肉鸡脂类代谢和相关激素的影响

将180羽1日龄Arbor Acres(AA)肉鸡随机分为饲料中不添加脱氢表雄酮(DHEA)的对照组,添加20和5mg/kgDHEA的高、低剂量组,饲喂至42日龄时分别从各组随机取12只公鸡和母鸡,采集血样、肝脏、腹脂、左侧胸肌和腿肌,分别测定血清葡萄糖(BG)、甘油三酯(TG)、总胆固醇(TC)、高密度脂蛋白(HDL-C)、低密度脂蛋白(LDL-C)、非酯化脂肪酸(NEFA)、三碘甲腺原氨酸(T3)、甲状腺素(T4)、游离三碘甲腺原氨酸(FT3)、游离甲状腺素(FT4)、胰高血糖素(glucagon)和瘦素(leptin)含量。结果表明,与对照组相比,DHEA显著降低肉鸡体重、腹脂重和腹脂率,显著降低TG、TC、HDL-C、FT3和FT4含量,显著升高瘦素含量,而对血糖和LDL-C没有影响;DHEA使公鸡血清NEFA含量升高,母鸡血清NEFA含量降低;DHEA使公鸡血清LPL活性和胰高血糖素含量显著升高,血清T4显著降低。DHEA可能通过提高肉鸡体内脂类分解代谢相关酶的活性及激素水平,对脂类代谢起调节作用。     

不同遮荫水平对茶树光合环境及茶叶品质的影响

试验研究了夏秋季80%、61%、37%遮光率遮阳网覆盖处理对茶园生态环境、茶树光合作用特性和茶叶内含成分的影响。结果表明:与露地对照茶园相比,3种遮光率遮荫处理茶园夏秋季气温、叶面温度、地面温度和土壤温度均明显降低;茶园土壤水分含量、茶园空气湿度明显提高。遮荫改善了茶园生态环境,且遮光率越高,效果越明显。与对照茶园比较,80%、61%、37%遮光率遮阳网覆盖处理日平均净光合速率增加了365%、283%和68%;茶叶新梢的叶绿素a含量增加了57.5%、29.3%和15.9%,叶绿素总量增加了52.2%、29.2%和14.3%;茶叶氨基酸含量增加了68.6%、33.5%和2.16%;茶叶茶多酚含量降低了15.3%、12.5%和5.4%。80%遮光率处理1芽2叶新梢制作的茶叶酚氨比达到名优绿茶标准,61%遮光率和37%遮光率处理的茶叶酚氨比也均达到高档绿茶标准,茶叶品质明显优于对照茶园。     

Effects of spraying rare earths on contents of rare Earth elements and effective components in tea

Rare earth (RE) fertilizer is widely applied in China to increase the yield and the quality of crops including tea. However, the effects of spraying RE fertilizer on the contents of rare earth elements (REE) and effective components in tea are unknown. The results from basin and field experiments show that the values of the REE concentrations in new shoots of tea plants and the concentration of REE in the soil (REE/REEs) either from control basins or from treatment basins were smaller than those in other parts of tea plant and similar between control and treatment. The longer the interval between spraying RE fertilizer and picking the shoots of tea plants, the less the effects from spraying. About 80% summation operator REE (the sum of the concentrations of 15 REE) in tea, whether it came from spraying or not, was insoluble in the infusion. About 10% the soluble REE of summation operator REE in tea infusion was bound to polysaccharide, and the amount of REE bound polysaccharide decreased over time. At least a 25 day safety interval is needed between spraying and picking if the microelement fertilizer is used, in order to enhance tea output and to ensure tea safety.     

硒、锌及其交互作用对不同季节茶叶多酚氧化酶活性的影响

通过喷施不同浓度的亚硒酸钠和醋酸锌,研究了硒、锌及硒锌交互作用对不同季节茶叶叶片硒、锌含量以及多酚氧化酶活性的影响。结果表明:(1)茶叶硒、锌含量均在春季最高,夏季次之,秋季最低。3季茶叶硒含量都在中高浓度(200~400μg/ml)的硒和低中浓度(0.2%~0.4%)的锌处理下相对较高;而锌含量在中高浓度(0.8%~1.2%)的锌和低中浓度(50~100μg/ml)的硒处理下较高;各季节茶叶硒、锌含量都在中浓度的硒(100~200μg/ml)和锌(0.4%~0.8%)配比下较高。(2)茶叶多酚氧化酶活性在夏季最高,春季次之,秋季最低。3季茶叶该酶活性均在中浓度的硒(100~200μg/ml)和锌(0.4%~0.8%)处理及其配比下相对较高;而高浓度的硒(400μg/ml)和锌(1.2%),以及低浓度(0.2%)的锌处理对春茶和夏茶多酚氧化酶活性的提高效应不甚明显,秋茶多酚氧化酶活性则在低浓度的硒(50μg/ml)和低浓度的锌(0.2%)以及高浓度的硒(400μg/ml)、锌(1.2%)处理下均无明显提高效应,同时低硒与低锌配比、高硒与中高浓度(0.2%~0.8%)的锌配比对春、夏、秋3季茶叶PPO活性的促进效应均不明显。     

Distribution of ascorbic acid in potato tubers and in home-processed and commercial potato foods

HPLC was used to analyze the content of ascorbic acid (AA) in tubers of four Korean potato cultivars (Chaju, Sumi, Deso, and Dejima), in a series of baked, boiled, braised, fried, microwaved, pressure-cooked, and sauteed potato slices from the Dejima cultivar and in 14 commercial Korean and 14 processed potato foods sold in the United States (chips, snacks, mashed potatoes, fries). The AA content for the four cultivars ranged from 16 to 46 mg/100 g of fresh weight. The distribution of AA in each of the eight potato slices (sticks, plugs) cut horizontally from the stem end of the Dejima potato ranged from 6.8 to 19.3% of the total. The corresponding distribution in seven sticks cut vertically was much narrower, ranging from 11.7 to 17.5% of the total. Losses of AA in water (pH 5.2) were significantly greater than in 5% metaphosphoric acid (pH 1.0). Less degradation occurred in water solutions of the vitamin stored at 1 degree C than at 25 degrees C. Losses of AA observed during home-processing of three varieties with low (Dejima, 16 mg/100 g), intermediate (Sumi, 32 mg/100 g), and high (Chaju, 42 mg/100 g) AA contents were as follows: boiling in water, 77-88%; boiling in water containing 1-3% NaCl, 61-79%; frying in oil, 55-79%; sauteing, 61-67%; pressure-cooking in water, 56-60%; braising, 50-63%; baking, 33-51%; and microwaving, 21-33%. The content of the Korean foods ranged from trace amounts to 25 mg/100 g and that of the U.S. foods from 0.4 to 46 mg/100 g. These results permit optimization of the vitamin C content of the diet by (a) using high-vitamin C potato varieties such as Chaju, (b) selecting sticks cut horizontally for frying, (c) baking or microwaving rather than boiling or frying, and (d) selecting commercial potato foods with a high vitamin C content.     

手掌参多糖对60Co-γ射线辐射小鼠造血和抗氧化功能损伤的治疗作用研究

为研究手掌参多糖对电离辐射损伤小鼠造血和抗氧化功能的治疗作用,本试验选用48只健康雌性昆明小白鼠,随机分为8组,分别为空白组,辐射组,手掌参多糖低、中、高给药组(150、300、600 mg·kg^-1 组)和辐射低、中、高给药组;辐射组和辐射给药组分别用⁶⁰Co-γ射线进行辐射,辐射剂量5.0 Gy(剂量率0.8 Gy·min^-1)。分别在照射后 30 min内灌胃相应剂量的手掌参多糖和生理盐水(空白组、辐射组),连续5 d。末次灌胃后48 h内测定所有小鼠外周血细胞计数、脾脏指数、肝脏超氧化物歧化酶(SOD)活性、总抗氧化能力(T-AOC)、丙二醛(MDA)含量、骨髓DNA含量、骨髓嗜多染红细胞微核 (MN) 数目及脾脏T淋巴细胞亚群。结果表明,与空白组相比,给药组小鼠抗氧化能力和造血系统得到不同程度的改善,辐射组外周血细胞计数、脾脏指数、骨髓DNA含量、肝脏抗氧化能力及T淋巴细胞亚群极显著降低,MDA含量与MN数目显著升高; 与辐射组相比,辐射给药组小鼠脾脏指数和T-AOC、SOD活性极显著升高,DNA含量、外周血细胞计数也有所升高,CD3⁺、CD4⁺、CD8⁺ T淋巴细胞比率升高,MDA含量、MN数目显著降低。上述试验结果表明,手掌参多糖对⁶⁰Co-γ射线照射造成的小鼠造血、抗氧化功能损伤具有治疗作用。本研究为手掌参多糖对辐射损伤的治疗提供了技术参考。     

机械超微粉碎与不同粒度常规粉碎对红茶理化特性的影响

为探究机械超微粉碎对茶叶物性及功能成分浸出特性的影响,该文通过超微粉碎和常规粉碎2种方法制备超微红茶粉和4种粒度的粗粉红茶粉,研究了5种茶粉的粒度分布、微观形貌、比表面积、结晶度、表面氧碳元素比、中红外图谱和功能成分的浸出特性。结果表明:常规粉碎不同粒度茶粉间差异较小,而超微粉碎较大程度地改变了茶叶的物料性质。超微粉碎后,茶粉粒度减小至微米级,比表面积增大,茶粉的结晶度降低,表面暴露的纤维素和半纤维素相对含量增多,而中红外谱图显示超微粉碎茶粉的官能团结构并没有改变。沸水浸提过程中茶多酚、咖啡因、可溶性糖和水浸出物的溶出结果表明:5种茶粉功能成分的浸出量都随时间的增加而增加,经过一段时间后达到平衡。在达到浸出平衡时,不同粒度茶粉的茶多酚和咖啡因含量差异不显著,超微茶粉的可溶性糖含量为4种粗粉的2倍左右,水浸出物比粗粉茶粉提高10%以上。上述研究结果表明:超微粉碎能够有效减小茶粉的粒度,破坏植物的细胞壁结构,使内部成分暴露于表面,此外,组织结构和细胞壁的破坏使不溶的纤维成分转化成可溶性成分,可溶性糖和水浸出物显著增多,超微粉碎能够在一定程度上提高茶粉的有效利用率。     

Textural and Bile Acid‐Binding Properties of Muffins Impacted by Oat β‐Glucan with Different Molecular Weights

Water‐soluble β‐glucan (BG) extracted from a high‐BG oat line was treated with different amounts of lichenase (1→3)(1→4)‐β‐d ‐glucanase) enzyme to yield three different molecular weight (MW) BG extracts. Low (LMW‐BG, 157,000), medium (MMW‐BG, 277,000), and high (HMW‐BG, 560,000) MW BG extracts were added to plain muffin formulations at a level of 0.52% (0.42% in the batter, 0.52% in the resultant muffins) to investigate the effect of MW of BG on textural and bile acid (BA) binding properties of the muffins. In addition, treatments were prepared containing LMW‐BG, MMW‐BG, and HMW‐BG extracts in amounts providing equivalent batter firmness as determined on a texture analyzer. Resultant BG concentrations (and per serving amounts) of these muffins were 1.36% (0.81 g/60 g muffin), 1.05% (0.63 g/60 g muffin), and 0.52% (0.31 g/60 g muffin), respectively; thus, the LMW treatment complied with a U.S. Food and Drug Administration health claim requiring 0.75 g of BG per serving. The firmness, springiness, and BA‐binding capacity of the muffins were unaffected by the MW of BG. However, when added at the maximum limit for equivalent batter firmness, the LMW treatment was more firm and less springy than the HMW treatment. Furthermore, BA‐binding capacities of LMW and MMW fractions tended to be greater than that of the HMW fraction when added at the maximum limit. These results add further evidence to the importance of fine‐tuning BG structure to provide maximum health benefits while maintaining high product quality.     

Effects of Pearling,Grinding Conditions,and Roller Mill Flow on the Yield and Composition of Milled Products from Hull‐less Barley

Two hull‐less barley cultivars, one with waxy starch and the other with high‐amylose starch, were roller‐milled unpearled and after 15% pearling. Flows of varying length, with diverse roll settings and roll surfaces were used to determine effects on the yield, composition, and properties of milled products. Similar trends were noted for the two cultivars. When using a short flow comprising four break passages and a sizing passage, power consumption during grinding was reduced by 10% when roll flute orientation was changed from dull‐to‐dull (D/D) to sharp‐to‐sharp (S/S). Flute orientation had minimal effects on the yield and brightness of flour, but SS grinding gave a higher yield of a fiber‐rich fraction (FRF). FRF yield and composition are of particular interest because FRF has potential as a functional food ingredient due to elevated levels of β‐glucans (BG) and arabinoxylans (AX). When using smooth frosted rolls (SM) for the sizing passage, power consumption increased by several times over using fluted sizing rolls with little advantage for either yield or BG content of FRF. FRF starch damage increased when smooth sizing rolls were used, and water swelling, a measure of water hydration capacity, also increased. Setting break and sizing rolls sharp‐to‐sharp significantly lowered the mean particle size of the FRF fraction, accompanied by moderate declines in FRF BG and AX contents. FRF yield decreased ≤50% when milling flow was lengthened to three sizing passages with intermediate impact passages, with only a moderate accompanying increase in FRF fiber content, regardless of roll conditions. Pearling 15% before milling reduced the yield of FRF by ≈30% while moderately reducing flour yield. Flour brightness was improved by pearling. When barley was pearled, FRF contained higher amounts of BG, but lower amounts of AX, phenolics, ash, and protein.     

Wet Processing of Barley Grains into Concentrates of Proteins, β‐Glucan,and Starch

An improved wet method was developed to process barley into fractions concentrated in protein, (1‐3)(1‐4)‐β‐d ‐glucan (BG), starch, or other carbohydrates (CHO). Alkaline concentration, solvent to barley flour ratio (SFR), and extraction temperature were evaluated for their effects on concentration and recovery of protein, BG, starch, oil, ash, and other CHO in each fraction type. Results show that the three parameters and their interactions all had significant effects, resulting in varying nutrient concentrations and recovery rates in each type of fractions. For protein fractions, protein content varied from 37.7 to 75.2%, protein recovery from 8.5 to 75.7%, and increasing alkaline concentration and SFR improved nutrient recovery. For BG fractions, BG content ranged from 21.5 to 87.0%, BG recovery from 28.6 to 78.0%, and increasing alkaline concentration decreased BG content but increased its recovery significantly. For starch fractions, starch content varied from 76.9 to 93.9%, starch recovery from 33.6 to 63.9%, and all parameters had little effect on the nutrient concentrations, but alkaline concentration and SFR improved recovery of starch, other CHO, and mass. Overall, the improved wet method was effective in concentrating the major nutrients from barley into their respective fractions, but process optimization through manipulating the three parameters is necessary to achieve a maximum concentration or recovery rate of a nutrient of interest in a specific fraction.     

Breast cancer prevention by green tea catechins and black tea theaflavins in the C3(1) SV40 T,t antigen transgenic mouse model is accompanied by increased apoptosis and a decrease in oxidative DNA adducts

Tea consumption is associated with a reduced risk of mammary cancer as reflected by epidemiological studies and experiments in carcinogen-induced rodent models of mammary carcinogenesis. We tested the hypothesis that green tea catechins (GTC) or theaflavins from black tea (BTT) interfere with mammary carcinogenesis in C3(1) SV40 T,t antigen transgenic multiple mammary adenocarcinoma (TAg) mice and that GTC/BTT affect tumor survival or oxidation status. TAg mice received GTC/BTT (0.05%) in drinking water for their lifetime. As compared to control mice, they survived longer and had smaller tumors. On microscopic inspection, the size of the largest tumor per mouse was decreased by 40-42% (p<0.01). GTC (0.01%) and BTT (0.05%) increased levels of cleaved caspase 3 in tumor tissue by 67 and 38%, respectively (p<0.05), intimating increased apoptosis. Tumor levels of the malondialdehyde-DNA adduct M1dG in mice receiving GTC or BTT (0.05%) were reduced by 78 (p<0.001) or 63% (p<0.05), respectively, as compared to controls. The results render the exploration of the breast cancer chemopreventive properties of tea preparations in humans worthwhile.     

不同种类茶叶冲泡前后中红外光谱变化探析

为建立一种快速无损评价茶叶/茶汤化学品质和色泽的方法,本试验选取7种代表性茶叶样本为材料,利用傅里叶变换中红外光谱(FTIR)技术,以开水冲泡方式制备茶汤冻干粉,对茶叶与茶汤共14个样本进行FTIR光谱采集分析。通过聚类分析、光谱曲线拟合、定性分析,并结合常规化学法检测茶多酚、茶多糖、可溶性糖、游离氨基酸、主要儿茶素类和生物碱含量。结果表明,不同茶叶光谱明显不同,由于茶叶加工工艺造成的脂类、儿茶素类、咖啡碱、游离氨基酸及叶绿素含量差异,利用1 800~1 170 cm^-1狭窄区域的光谱特征,可实现茶叶分类。茶叶与对应茶汤的光谱也存在明显差异,体现了茶叶在冲泡过程中的物质变化。主要特征峰区(位)为:2 925/2 855 cm^-1代表脂类饱和烃链-CH₂振动,1 700 cm^-1峰位对应儿茶素类和咖啡碱,1 534 cm^-1对应着叶绿素脱镁过程,1 551/1 556 cm^-1和1 500/1 497 cm^-1为叶绿素中亚甲基桥的伸缩振动,1 516/1 517 cm^-1为木质素中的苯环C=C伸缩振动。本研究为市场中茶叶、新型速溶茶粉样品化学品质检测提供了一种有效、快速的无损分析方法。     

亚热带红壤丘陵茶区茶-杉复合系统生态经济效应探析

定位试验研究结果表明,亚热带红壤丘陵区茶-杉复合茶园比单一茶园光照强度降低31.1%~50.1%,且园内气温、地表与土壤温度、茶树叶面温度及其高温危害产生的频率等均低于单一茶园,园内湿度和土壤含水量分别高于单一茶园,茶树主要害虫天敌种群数量比单一茶园多118.75%,而其害虫数量仅为单一茶园的45.4%,且茶叶产量提高,其品质亦明显改善。