茶梗木质纤维素对儿茶素类吸附动力学研究

以茶梗为原料制备木质纤维素,通过静态吸附,研究茶梗木质纤维素在绿茶提取物溶液中对儿茶素类的吸附动力学。结果表明,茶梗木质纤维素对儿茶素类总量的吸附等温线符合Freundlich经验方程,随着温度的升高,茶梗木质素纤维素对儿茶素类的平衡吸附量降低;动力学研究数据用拟一级速率方程和拟二级速率方程模拟,其中拟二级速率方程拟合程度更高,在不同温度下利用拟二级速率方程计算的总儿茶素类饱和吸附量与实测值吻合。随着温度的升高,速率常数k1和k2提高,而总儿茶素类的初始吸附速率降低。     

木质纤维素吸附分离法纯化茶多酚研究

选用经过预处理的白杨树、杉木、松树的木屑、铁观音乌龙茶茶梗及大孔树脂、活性炭(颗粒)作为吸附剂,对直接采用鲜叶提制的茶多酚浓缩液进行静态和动态吸附及常温纯净水洗脱试验,以筛选出较好的木质纤维素吸附剂,实验结果表明,杉木木屑是首选的木质纤维素制备原料,选用经过酸碱预处理的杉木木屑作为吸附剂,对茶多酚浓缩液进行动态吸附,进液流速控制在3 mL·min-1,总儿茶素的平衡吸附量为107.93 mg·g-1;再用常温纯净水进行洗脱,控制流速2 mL· min-1,总儿茶素的解吸率为26.21％.     

茶籽苗儿茶素类、嘌呤碱及游离氨基酸分布规律的研究

应用HPLC-PDAD和氨基酸自动分析仪对4～5叶初展的福云6号沙培茶籽苗各部位儿茶素类、嘌呤碱、氨基酸(茶氨酸)进行分析测定。结果表明:儿茶素类、嘌呤碱(咖啡碱、可可碱)主要分布于茶籽苗叶片及嫩茎,子叶下部含量明显降低;EGCG、茶氨酸在茶籽苗嫩叶中含量较高,并随叶片成熟不断减少,但茶氨酸以侧根和主根最为富集,其代谢前体氨基酸(Glu、Ala)在根部亦具较高含量。随着茶籽萌发,茶氨酸在胚根大量合成,初露紫红色嫩茎的茶籽苗根系茶氨酸含量达13.429mg/g鲜重。据此认为培育茶籽及其无性系幼苗,并以幼嫩根系为材料,有望成为茶籽综合利用及天然茶氨酸获取的新途径。     

茶儿茶素类物质对大豆脂肪氧化酶活性的影响

油脂和含油脂的食品在贮存和加工期间会发生酸败而产生醇、醛、酮、酸类物质,使食品的色、香、味发生劣变。酸败主要是因有脂肪的存在而发生自动氧化、酶促氧化和脂肪分解。自动氧化反应的最初引发,如形成氢过氧化物,涉及光、γ射线和χ射线,光敏染料,过渡金属离子和游离基等,因此冷藏、避光、添加抗氧化剂有利于食品保存。由于抗氧化剂可以抑制油脂的自动氧化,延缓氧化物的生成而被广泛应用于食品行业。然而,自动氧化并不是油脂和含油脂食物变质的唯一原因,解脂变质也     

茶树发根中茶氨酸和儿茶素类含量的分析

茶树发根在LG₀培养基和添加1βmg/L IBA的1/2MS培养基上生长迅速,但只在一个培养于LG₀培养基的发根克隆中检测到高含量的茶氨酸,含量达到23.12βmg/g鲜重,高于未转化根的18.77βmg/g鲜重。除茶氨酸外,该发根克隆中也检测到高含量的天门冬氨酸、谷氨酸、天门冬酰胺、谷氨酰胺和精氨酸。发根克隆培养于添加1βmg/L IBA的1/2MS培养基,茶氨酸的含量则显著降低,说明培养基组成也是影响发根中茶氨酸的含量的因素之一。茶树发根中也含有少量的儿茶素类单体,主要为儿茶素和表儿茶素。     

茶尺蠖幼虫取食提高茶树儿茶素代谢响应强度

研究了茶尺蠖幼虫为害茶树叶片对儿茶素合成途径的影响。采用3龄茶尺蠖幼虫取食茶树新梢芽下第二叶,测定了儿茶素合成相关基因的表达水平和儿茶素含量。研究结果表明,与对照相比,茶尺蠖幼虫为害后3、6、12βh显著诱导了CsANR基因的相对表达水平,且在为害后3βh和12βh达到了极显著差异。CsLAR基因在茶尺蠖为害后6βh和12βh,与对照具有显著差异。茶尺蠖幼虫为害后24βh显著诱导了没食子酸、没食子儿茶素、表儿茶素、表没食子儿茶素没食子酸酯和表儿茶素没食子酸酯含量的升高,而茶尺蠖为害后48βh仅没食子酸和没食子儿茶素的含量显著高于对照;儿茶素、表没食子儿茶素和没食子儿茶素没食子酸酯在茶尺蠖为害后24βh和48βh均没有被显著诱导。上述结果表明茶尺蠖幼虫为害提高了茶树儿茶素合成途径的代谢强度和儿茶素类化合物的积累。     

四种茶儿茶素在蒸馏酒和水中的变化研究

儿茶素作为茶叶中尤为重要的功能成分备受关注,探讨其在食品体系中的变化对于儿茶素的应用和含儿茶素类食品品质尤为重要和必要.针对食品硬饮料中茶儿茶素变化相关研究缺乏,选用茶叶中四种主要儿茶素(EGCG、EGC、ECG、EC)单体和茶多酚,采用统一浓度添加法,分别探讨在蒸馏酒(酒精度45.5％)和水两种体系中于25℃避光、密封条件下的稳定性.结果表明,四种儿茶素无论是在蒸馏酒还是水体系中均有所下降;在蒸馏酒中四种单体含量呈线性下降趋势且推测降低原因而非单体间转化导致,按初始浓度降低50％的时间排序为EGCG相似文献   

茶儿茶素对鱼油的抗氧化活性

研究了添加茶儿茶素对鱼油中多烯脂肪酸（ＤＨＡ、ＥＰＡ）分解和过氧化物形成的抑制效果。结果表明，茶儿茶素可有效地抑制鱼油的过氧化物形成和多烯脂肪酸分解，在相同的温度（３０℃）条件下，茶儿茶素的抗氧化活性优于维生素Ｅ     

茶儿茶素类和生物碱成分的HPLC分析

建立了以恒组成溶液为流动相的ＨＰＬＣ同时分析茶中５种儿茶素类（Ｃ、ＥＣＧ、ＥＣ、ＥＧＣ、ＥＧＣＧ）和３种生物碱（Ｃａｆ、Ｔｐ、Ｔｂ）的定量方法，色谱条件为：ＯＤＳ（１０μｍ）柱，以０．０４ｍｏｌ·Ｌ柠檬酸水溶液─Ｎ，Ｎ─二甲基甲酰胺─四氢呋喃（９０：１６：４：）为流动相，ＵＶ检测器（２７８ｎｍ），以二氯磺胺为内标。讨论了这些成分的提取方法和分离测定条件，此法分离效果好，操作简便，重现性好，分析结果准确。     

Influence of alkali treatment on the structure and properties of hemp fibers

Alkali treatment may change the structures and properties of cellulosic fibers. The aim of this work was to study the mechanism of structural changes of hemp fibers treated with different alkali concentrations and time by SEM, FTIR, tensile and bending tests. The results showed that the alkali treatment removed some of non-cellulosic materials from the surface of fibers and caused many cracks along the axis of fibers. The crystalline order index increased firstly followed by decreased with the increase of concentration. The deconvolution spectra in OH stretching region showed that the alkali treatment decreased the amount of hydrogen bonding firstly and then increased. The S/G ratio results also support the removal of non-cellulosic materials. The tensile strength of the fibers increased with the alkali concentration. Furthermore, the suitable chemical treatment not only slenderized the hemp fibers, but also softened the fibers dramatically.     

Effect of alkali and silane treatments on mechanical and thermal behavior of Phormium tenax fibers

The effect of different treatments on the mechanical (tensile), thermal behavior (TGA), FTIR, and morphology of Phormium tenax fibers has been studied with the aim to investigate methods to improve their compatibility with polymer matrices. Applied treatments included sodium hydroxide (NaOH), silane (APTES, 3-aminopropyltriethoxysilane), and the combined application of silane treatment after NaOH. The effectiveness of the treatments in the removal of non-structural matter from the fibers was confirmed by FTIR investigation and TGA measurements, suggesting also that the alkali treatment has a strong effect on their thermal behavior. The study of tensile properties of the fibers performed using Weibull statistics indicates that the tensile properties are somewhat reduced by chemical treatment. The morphological investigation of treated fibers through scanning electron microscopy indicates that silane treatments, both on raw fibers and on alkalized ones, result in limited fiber degradation.     

Effect of alkali treatments on the nutritive value of common bean (Phaseolus vulgaris)

The effect of alkali treatments of common bean seeds with red seed coat on the stability of antinutritional factors such as tannins, phytates and trypsim inhibitors, vitamins such as niacin and riboflavin and on protein quality has been studied. The samples were processed by soaking and soaking and pressure cooking in alkalies such as sodium hydroxide, sodium carbonate and sodium bicarbonate. At low temperature sodium carbonate and at high temperature sodium bicarbonate were found to be most effective in the extraction of tannins. At both low and high temperatures sodium carbonate was found to be more efficient in destruction of phytates. In the case of trypsin inhibitors, extraction at both low and high temperatures with sodium bicarbonate was most effective. Sodium hydroxide treatment was found to be better as far as the retention of niacin and riboflavin was considered.     

Lignocellulosic nanofiber prepared by alkali treatment and electrospinning using ionic liquid

Nano-size fibers from lignocellulosic biomass were successfully obtained by akali-treatment and electrospinning using ionic liquid. The effects of the lignin and the hemicelluloses content on the spinnability, the web morphology, the micro-structure and the thermal stability of the electrospun fibers were investigated. The lower lignin content resulted in better spinnability, fine and uniform fiber diameter, higher crystallinity and decrease of thermal stability. This study reveals the possibility of the utilization for the lignocellulosic biomass other than pulp or cotton.     

Effect of inulin with different degree of polymerization on water redistribution of steamed bread

The aim of this work was to study the influences of three types of inulin with different degree of polymerization on the water state of steamed bread during production and storage. The addition of inulin reduced the moisture content of the dough and facilitated the migration of free water to bound water. In the fermentation process, inulin had little impact on the bound water content in the dough, but could speed up the fermentation process. During the storage time, the freezable water content in steamed bread crumb decreased faster in the presence of inulin. The weaker interaction of freezable water with starch and protein chains became stronger, while the stronger interaction of tightly bound water with starch and protein chains decreased compared to the control. The changes of melting and vaporization enthalpies suggested that inulin could accelerate water migration of steamed bread from the inside to the outside.     

Multi-stage Bagasse pulping by using alkali/Caro’s acid treatment

Bagasse delignification by using separate alkali and Caro’s acid treatments is considered as a promising process to prepare high-yield bagasse pulp. This could be achieved via two-stage technique (NaOH/Caro’s acid) and three-stage technique (NaOH/Caro’s acid/NaOH). The two techniques were practiced at low temperatures and atmospheric pressure. Three-stage techniques provide a possibility to produce chemical pulps, which have the advantages of both mechanical pulp (high-yield pulp), and chemical pulp (good strength properties). At moderate concentration of Caro’s acid used (3.0, 4.5% based on raw materials), three-stage technique has higher delignification selectivity than that of two-stage technique Three-stage techniques produced pulps of higher breaking length and burst factor than that produced by two-stage techniques. Tear factor of pulps produced by two-stage techniques has the superiority.     

不同富营养化程度下Cd和百草枯对浮萍部分生理指标的影响

研究了不同富营养化程度下百草枯和Cd对浮萍（Lemna minorLinn）可溶性糖含量、植物组织中游离氨基酸含量、丙二醛（MDA）含量的影响。结果表明：随富营养化程度的升高,在百草枯和Cd单一及复合污染条件作用下,可溶性糖含量显著下降,而氨基酸和MDA含量随污染物浓度的增加而显著提高。百草枯和Cd单一及复合污染对浮萍的毒害作用也很大,尤其是两者复合污染作用时,效果更显著。     

Structural factors and physical properties of needle-punched nonwovens based on Co-PET/PA bicomponent fibers via alkali treatment

Needle-punched nonwovens are widely used in industrial fields. However, they are limited to some applications such as high-efficiency filters, high-performance synthetic leathers, and high-absorption wipes because of their low surface area and large pore size. In this study, needle-punched nonwovens composed of Copolyethylene terephthalate (Co-PET)/Polyamide (PA) sea-island bicomponent fibers were treated in NaOH solution with various conditions for preparing nonwovens composed of ultra-fine fibers. The effect of NaOH concentration and treatment temperature on the structural factors and physical properties of nonwovens was investigated. The morphological structures of Co-PET and PA components were analyzed by scanning electron microscope. After alkali treatment, fiber diameter was significantly reduced from 23.65 to 3.95 μm, specific surface area of nonwovens increased more than five times, calculated and experimental mean pore diameter decreased by 83.6 % and 20.8 %, respectively. By increasing NaOH concentration and treatment temperature, pore diameter was reduced, thereby decreasing the air permeability of nonwovens. Meanwhile, tensile strength increased and tearing strength decreased as NaOH concentration and treatment temperature were increased in both machine and cross direction, respectively. The treatment temperature of alkali treatment was significantly influenced by the physical properties of nonwovens.     

盐碱对水稻生产的危害及防治对策

阐述了凌海市沿海地区水稻遭受盐碱危害的状况,分析了盐碱灾害发生的原因,并提出了选种抗盐品种、培育壮秧、提高田间工程标准、科学用水、适当施肥、调节盐碱、培肥地力等防治措施。