龙陵紫皮石斛色素的提取及其稳定性

以3 种类型的龙陵紫皮石斛（Dendrobium devonianum）茎为试材,用溶剂法提取色素,并研究其稳定性。结果表明：3 种类型龙陵紫皮石斛色素溶液在可见光533.0 nm波长处有吸收峰,其色素的主要成分为花色苷。紫鞘型、紫条型和血草型紫皮石斛花色苷含量分别为39.65、35.05、15.85 mg/L。温度的改变对紫皮石斛花色苷影响较大,随着温度升高,颜色逐渐加深;在阳光照射下,花色苷极不稳定,Mg2+和Al3+对花色苷有很好的增色、稳定作用;Cu2+、Zn2+和Fe3+使花色苷明显褪色,并伴有沉淀;随着H2O2 和VC、Na2SO3浓度的增大,颜色逐渐消退;食盐对紫皮石斛花色苷有一定的增色作用;蔗糖和柠檬酸使花色苷明显褪色。     

6种石斛的化学成分对比分析与质量评价

目的 挖掘石斛属植物的药用和食用价值, 根据不同石斛中化学成分含量的差异对其进行质量评价。方法: 采用硫酸蒽酮比色法、热浸法、凯氏定氮法、硝酸铝显色法和高效液相色谱法对石斛属植物顶叶组鼓槌石斛(Dendrobium chrysotoxum)、密花石斛(Dendrobium densiflorum), 石斛组苏瓣石斛(Dendrobium harveyanum)、黄花石斛(Dendrobium dixanthum), 黑毛组翅萼石斛(Dendrobium cariniferum)、翅梗石斛(Dendrobium trigonopus) 6种石斛的可溶性糖、多糖、粗蛋白、黄酮、酚类和氨基酸含量进行测定, 结合层次分析法对6种石斛的品质进行综合评价。结果: 6种石斛中, 化学成分含量存在较大差异。可溶性糖含量在12.616%~58.572%之间, 含量最高的是翅梗石斛, 高达58.572%; 多糖含量均低于中国药典所规定, 最高的是翅梗石斛, 为4.867%, 是黄花石斛的5倍; 粗蛋白含量在0.949%~5.059%之间, 含量最低的是翅萼石斛, 仅有0.949%; 总黄酮含量在0.113%~0.357%之间, 鼓槌石斛和翅萼石斛居于前两位; 总多酚含量在0.674%~2.317%之间, 共检测了5种酚类化合物, 芹菜素和石斛酚在6种石斛中均被检测到; 共检测到16种氨基酸, 含量在3.83%~6.98%之间。氨基酸主成分分析结果表明: 组氨酸、丝氨酸、精氨酸是6种石斛的特征性氨基酸。层次分析结果表明, 翅梗石斛的综合评分最高。结论: 本研究所测定的6种石斛来自石斛属不同组, 相关分析表明石斛不同组别, 不同物种存在差异, 化学成分含量不同其药理作用和功效不同, 应根据其不同成分和含量有针对性地进行生产和应用; 综合评价结果表明, 翅梗石斛的品质最佳。     

铁皮石斛多糖水解工艺优化及甘露糖含量的测定

优化高温高压辅助硫酸水解铁皮石斛多糖工艺,测定了不同栽培方式的铁皮石斛不同部位多糖及甘露糖含量。利用苯酚-硫酸法测定3种栽培方式的铁皮石斛茎、叶、花多糖的含量;以单因素实验为依据,固定料液比、硫酸浓度,根据中心组合试验设计（Central Composite Design,CCD）原理建立两因素五水平响应面法优化硫酸水解铁皮石斛多糖的温度及时间,采用柱前衍生化-高效液相色谱法测定甘露糖含量。结果表明,以1 mol/L的硫酸溶液为催化剂,料液比1:1.5、水解温度112 ℃（压强0.15 MPa）,水解44 min,甘露糖含量达64.35%±0.76%;同一栽培方式的铁皮石斛茎、叶、花多糖、甘露糖含量表现出极显著差异（P<0.01,茎>叶>花）,茎的多糖及甘露糖含量分别在29.32%~33.78%、18.17%~21.05%;叶分别在15.91%~17.31%、10.28%~11.11%,花分别在8.37%~8.68%、5.30%~5.75%之间。高温高压辅助硫酸水解铁皮石斛多糖工艺高效可行,铁皮石斛茎、叶、花是制备甘露糖的优质天然资源。     

汉中绿茶中6 种矿质元素含量及其溶出特性

采用原子吸收光谱法测定汉中绿茶主栽地区的7 个品种茶叶消化液和茶叶水浸出液中Mn、Zn、Fe、Cu、Ni、Cr 6 种矿质元素的含量。以这些矿质元素的含量及其溶出率作为另一种分析评价汉中绿茶品质的依据,实验回收率在92.70%～102.55%之间,相对标准偏差在10%以下。结果表明：采用原子吸收光谱法能准确测定绿茶及绿茶水浸出物中的矿质元素的含量,且方法简单、快捷;从溶出率和矿质元素的含量来看,相对其他几个供试品种而言,有机锌硒茶、鹏翔茶粉、汉中仙毫和汉中绿茶品质较好。     

溪头滴水香绿茶化学成分分析与品质评价

目的 分析溪头滴水香绿茶的化学成分并进行品质评价。方法 采用相关性分析和主成分分析，对溪头滴水香绿茶的感官指标和化学成分进行综合评价。结果 6份溪头滴水香绿茶的感官品质综合得分从高到低排序为：溪头>竹岭>汪满田=西坡>大北山>岱岭。不同产区的茶叶品质化学成分存在一定的差异，水浸出物含量为49.5%~52.4%，游离氨基酸含量为4.4%~5.8%，茶多酚含量为17.1%~19.1%，儿茶素总量为10.67%~14.24%，水分含量为1.86%~8.55%，咖啡碱含量为3.0%~3.7%。相关性分析结果显示，滴水香绿茶的色、香、味等品质与氨基酸、水浸出物、酚氨比、儿茶素、酚碱比等有较强的关系。采用主成分分析建立综合品质得分数学模型，6件样品综合品质得分由高到低顺序为溪头>西坡>汪满田>竹岭>大北山>岱岭。结论 溪头滴水香绿茶具有优良的品质，化学成分含量丰富，滋味鲜爽、香气高，但溪头滴水香绿茶的加工生产需要形成标准化工艺流程。本研究结果可为溪头滴水香绿茶的工艺、品质提升及宣传推广提供数据支撑和一定的理论依据。     

干燥方式对铁皮石斛糖类成分的影响

以浙产铁皮石槲为原料,探讨自然晾干、热风干燥、真空干燥和真空冷冻干燥4种方式对铁皮石斛糖类成分含量的影响。结果表明,铁皮石斛干燥后多糖、甘露糖含量大小排列为真空冷冻干燥>热风干燥>真空干燥>自然晾干。考虑到成本及工艺繁琐程度问题,在品质接近情况下,于90℃热风干燥6 h,铁皮石斛中的多糖含量为35.61%,甘露糖含量为19.04%,甘露糖与葡萄糖比值在4.68左右,可被广泛用于浙产铁皮石斛加工。     

不同发育时期柿叶品质的变化规律研究

柿叶含丰富的营养成分,具多种保健功能,为探讨适合加工柿叶茶的原料,本文研究了不同品种不同发育阶段柿叶的品质变化。结果表明,4~10月间,柿叶水浸出物含量在26.84%~42.78%之间变化,最低值一般出现在9月,最高值一般出现在5月;多酚和VC含量于5月份达最高水平,平均分别为9.62%和23.82 mg/g,7月后显著下降至最低水平;可溶性糖含量各月都维持在10%以上,以5月最高,平均达15.31%。感官品质分析结果显示,7月份之前的柿叶滋味较酸,7~8月大多柿叶粗青气明显,9~10月柿叶大多为薯香或甜香,滋味较醇和。不同品种、不同发育阶段的柿叶的理化成分和感官品质差异明显,故对柿叶进行加工利用时应进行合理选择。     

龙陵紫皮石斛多糖的硒化修饰及其抗氧化活性

以云南龙陵紫皮石斛鲜条为原料,采用微波辅助-浸提法提取紫皮石斛多糖（Dendrobium devonianum Paxt.polysaccharide,DDP）。以亚硒酸钠为硒化剂,冰醋酸为催化剂对DDP进行硒化修饰获得硒化紫皮石斛多糖（Se-DDP）。通过电感耦合等离子体原子发射光谱（inductively coupled plasma atomic emission spectrometer,ICP-AES）法测定硒含量,由傅里叶变换红外光谱法对Se-DDP进行表征。以硒含量为指标,通过单因素和正交试验优化硒化反应条件,并测定Se-DDP和DDP对1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）、OH和O2-自由基的清除能力。结果表明,Se-DDP 的最佳制备工艺为 DDP∶亚硒酸钠=1∶2.0（g/g）,反应温度 90 ℃,DDP∶冰乙酸=1∶4.0（g/mL）,反应时间48 h,此时Se-DDP的硒含量为12.37 mg/g。Se-DDP的抗氧化试验结果表明,当浓度高于4 mg/mL时,Se-DDP对DPPH自由基、OH自由基和O2-自由基的清除能力均强于DDP;当浓度为8 mg/mL时,Se-DDP的抗氧化能力与VC相当。     

基于生化成分的铅山群体种茶树鲜叶品质分析

为了明确铅山群体种茶树春梢鲜叶生化品质特性,为其适制性、新品种选育及合理开发利用提供科学依据。以28份铅山群体种单株的春季新梢鲜叶为研究对象,对其主要生化成分进行测定。结果表明：铅山群体种生化成分多样性丰富,多样性指数范围为1.44～2.04,均值为1.83,水浸出物含量范围为41.6%～47.72%,茶多酚含量范围为12.83%～23.07%,游离氨基酸范围为2.77%～5.16%,咖啡碱含量范围为3.22%～4.94%。聚类分析将28份单株分为5类,每一类均含有不同的亚组,各类均有典型的生化特征。依据儿茶素品质与苦涩味指数,初步筛选出4份优良单株,其中No.17和No.18适制绿茶,No.5和No.3为红绿茶兼制。最终从铅山群体种中筛选出5份高水浸出物、1份高游离氨基酸、1份高儿茶素、6份低茶多酚等特异资源。     

冷泡红茶微波干燥工艺的优化研究

冷泡红茶是一款具有便捷、健康特点的新兴品种茶叶。为探讨冷泡红茶微波干燥最优工艺,通过单因素实验研究冷泡红茶微波干燥工艺中不同的微波功率、铺盘厚度和干燥时间对茶叶品质的影响,以水浸出物含量、感官得分为综合评判指标,得到较合适的微波工艺参数为微波功率12000W、铺盘厚度1.5cm、干燥时间8min。在此基础上,通过三因素三水平的正交试验优化,结果显示干燥时间、微波功率分别是影响冷泡红茶水浸出物含量、感官得分的最主要因素;冷泡红茶最优微波干燥工艺为微波功率12000W、铺盘厚度2.0cm、干燥时间10min,此时冷泡红茶水浸出物含量为31.4%,感官得分为96分、水分含量为6.3%,符合标准GB/T13738.2-2017中小叶种功夫红茶的要求。     

Influence of the dehydration process on active compounds of okara during its fractionation

Okara (residue of the soymilk manufacture) is rich in proteins, fibres and lipids. It also contains isoflavones that possess health‐promoting properties. A new method has been developed for the valorization of fibres from okara by hydrolysis of insoluble proteins with a protease and removal of the oil. Three different processes were investigated: the first one involved delipidation and drying prior to proteolysis and led to the highest content of fibre (80%) in the final product. The second used proteolysis on crude okara followed by solvent delipidation–dehydration and gave an intermediate content of fibre (75%). The last process was totally enzymatic (proteolysis and lipolysis) and gave the lowest content of fibre in the final product (50%). Fibre water‐holding capacity was correlated to the total dietary fibre content of each sample. It was preferable to use crude okara for hydrolysis, since oven‐drying during the process decreased the water‐holding capacity and modified the isoflavone profile of okara. Copyright © 2005 Society of Chemical Industry     

Microwave drying of lucerne and grass samples

Microwave drying of fodder crop samples appeared to be a suitable technique, especially when the organic components are to be determined. Eleven lucerne and 17 pasture grass samples were dried by both oven drying at 80°c and microwave drying. The dry matter content of the samples dried by microwaves was 0·8% higher on average than that of the oven-dried samples; the carotene and xanthophyll contents were almost twice as high in the samples dried by microwaves. The digestibility coefficient of the organic matter, determined in vitro, was 1·6 units lower on average in the oven-dried samples; this was due partly to the higher crude fibre content and much lower content of soluble carbohydrates in these samples. There were no significant differences in the total ash and crude protein contents of the samples dried by the two methods. A 500 g sample of fresh grass can be dried in 10 min in the microwave energy apparatus; the moisture content of about 10% obtained after drying guarantees a good grinding and storage ability of the samples.     

Chemical composition and physical properties of modified dietary fibre sources

The influence of thermal treatments on the chemical composition and the physical properties of yellow pea hulls, apple pomace and depectinised apple pomace were determined. The chemical composition of yellow pea hulls and apple pomace was altered only slightly. With depectinised apple pomace, however, the heat treatments led to a significant loss of the total dietary fibre (TDF) content. Water uptake, water binding capacity, rheological behaviour in the farinograph and oil absorption were determined before and after boiling, autoclaving and extrusion cooking. The physical properties of all samples were considerably affected by the thermal modifications. Whilst in cooked dietary fibre samples the water uptake, the water binding capacity and the oil absorption was always enhanced, the influence of autoclaving and extrusion cooking on the physical properties depended very much on the dietary fibre source. Yellow pea hulls showed unchanged or slightly increased values, while the results for the two apple pomace preparations were lower compared with the untreated samples. The differences in the farinogramsiwere less obvious since the dietary fibre content in the dough mixtures was only in the range of 10–20%.     

霍山石斛不同提取物抗小鼠亚急性酒精性肝损伤活性的比较研究

目的：比较霍山石斛不同提取物抗小鼠亚急性酒精性肝损伤的活性。方法：制备霍山石斛冷冻干燥物、水提物、水提醇溶物、水提醇沉物、水提粗多糖5 种提取物;以连续灌胃30%乙醇的小鼠为亚急性酒精性肝损伤模型,以霍山石斛不同提取物连续灌胃30 d后,称量小鼠体质量及肝质量,测定血清中谷丙转氨酶（alanineaminotransferase,ALT）、谷草转氨酶（aspartate aminotransferase,AST）、碱性磷酸酶（alkaline phosphatase,ALP）活性,以及总胆固醇（total cholesterol,TC）、甘油三酯（triglyceride,TG）、高密度脂蛋白胆固醇（highdensity lipoprotein cholesterol,HDL-C）、低密度脂蛋白胆固醇（low density lipoprotein cholesterol,LDL-C）含量,同时测定肝脏中乙醇脱氢酶（alcohol dehydrogenase,ADH）、乙醛脱氢酶（acetaldehyde dehydrogenase,ALDH）、谷胱甘肽过氧化物酶（glutathione peroxidase,GSH-Px）、超氧化物歧化酶（superoxide dismutase,SOD）活性,丙二醛（malondialdehyde,MDA）、谷胱甘肽（glutathione,GSH）水平,并检查肝组织损伤病理变化。结果：霍山石斛水提醇溶物抗亚急性酒精性肝损伤的活性最差,醇沉物、水提物、冷冻干燥物具有一定的肝损伤保护活性,水提粗多糖各个剂量组均可显著改善肝脏组织损伤和脂肪变性（P＜0.05）,降低血清ALT、AST、ALP活性和LDL-C、TC、TG水平,提高血清HDL-C含量,增强肝组织ADH、ALDH、SOD、GSH-Px活性,减少肝组织GSH损耗并抑制肝组织MDA含量增加。结论：多糖是霍山石斛抗小鼠亚急性酒精性肝损伤的功能因子。     

体外模拟消化液对金钗石斛的作用

采用体外模拟消化液,分别对金钗石斛超微/普通粉、水/醇提物、粗石斛碱和多糖进行实验,探究实 验组模拟消化液中化学成分的变化。实验测定石斛碱、多糖溶出率;运用高效液相色谱、3,5-二硝基水杨酸法 和阴离子色谱对多糖消化产物的分子质量、还原糖质量浓度和单糖组成进行分析;采用液相色谱-质谱联用仪对 多酚类化合物成分进行分析。结果表明：消化组中石斛碱溶出率不断增大,超微粉肠道消化液组溶出率最高达 （21.46±0.52）%,粗石斛碱消化液最低为（8.74±0.50）%;水提物组多糖溶出率高,在口腔和胃消化液中,超 微粉多糖溶出率比普通粉高;肠道消化液中的情况与之相反;多糖在消化过程中分子质量降低,还原糖质量浓度上 升,无单糖检出;多酚类物质的质量浓度普遍在模拟胃液中升高,在模拟肠液中降低。     

Dietary fibre and components of the nitrogen-free extract of almond kernels

Determinations of neutral and acid detergent fibre residues (NDF and ADF), hemicellulose, cellulose and lignin in almond nuts (Prunus amygdalus) were carried out. The NDF content was about 5% while the crude fibre content was only approximately 2%. The composition of several components of nitrogen-free extract (NFE) such as soluble sugars, starch, gums and mucilages and pectins were also determined, and the results are discussed.     

Combined Effect of Drying Time and Slice Thickness on the Solar Drying of Okra

The effect of slice thickness and drying time on colour, viscosity, microbial load, moisture, crude fibre, vitamin C and ash contents of okra (Hibiscus esculentus) during solar drying was studied using three slice thicknesses (5·0 mm, 10·0 mm, 15·0 mm) obtained from a survey and five drying times (0, 24, 48, 72 and 96 h). The results showed that slice thickness had a significant effect (P<0·01) on moisture, crude fibre and ash contents but not on vitamin C content, viscosity, colour and microbial load. However, the effect of drying time was highly significant (P<0·01) on all the parameters determined. The combined effects of slice thickness and drying time were observed to be highly significant (P<0·05) on ash, crude fibre and moisture contents, viscosity and microbial load but had no significant effect (P<0·05) on colour and vitamin C content. There was a strong correlation between moisture content and ash (R=-0·926), crude fibre (R=-0·94), vitamin C contents (R=0·928) and viscosity (R=-0·963) in all samples during drying. The study showed that a slice thickness of 10·0 mm and a drying time of 48 h was suitable for the solar drying of okra. © 1997 SCI.     

干燥工艺对重庆沱茶及其毛茶风味品质的影响

以重庆地产茶鲜叶为原料加工重庆沱茶,比较60 ℃烘干（1号）、80 ℃烘干（2号）、晒3 h＋60 ℃烘干（3号）、晒3 h＋80 ℃烘干（4号）4 种干燥工艺对重庆沱茶及其毛茶风味品质的影响。结果表明,1、2号毛茶、沱茶综合感官品质好于3、4号毛茶、沱茶。3号毛茶茶多酚质量分数较低为31.3%,游离氨基酸、水浸出物、香气物质质量分数较高分别为2.2%、43.9%、182.57 μg/L,烯、醇类较多分别为16、7 种。1号毛茶香气种类数量和含量均最多分别为54 种、190.27 μg/L,2、4号毛茶香气含量较少。经压制后,各沱茶游离氨基酸、醇、醛、烯、酸含量降低,咖啡碱含量升高,3号沱茶茶多酚、游离氨基酸、水浸出物含量无显著变化,香气种类数量以及含量均最多分别为50 种、252.11 μg/L,酮类、酯类含量增加较多分别为64.6%、113%,1号沱茶酮类增加2 种,2、4号沱茶香气种类、含量减少。正交偏最小二乘法判别分析共识别出11 种差异性香气物质,其中烯类5 种,1、3号毛茶差异性香气物质种类较多,其对应的沱茶正二十一烷含量较高。β-紫罗酮在各茶样中的气味活度值（odor active value,OAV）大于10,芳樟醇在1号、3号毛茶及沱茶中的OAV均大于1。综上所述,1号、3号毛茶及沱茶综合品质较好,其对应的干燥工艺更适合于重庆沱茶加工。