茶多酚绿色荧光特性研究

以茶多酚为材料,研究了茶多酚浓度、溶液pH、溶剂、金属离子（Ca²⁺、Al³⁺）和热处理对茶多酚绿色荧光特性的影响。结果表明：以上各因素对荧光强度的影响都极为显著,当溶液pH=7.4±0.2、茶多酚浓度为3βmg/ml或溶剂采用50%乙醇水溶液时,荧光强度达到最大值;金属离子（Ca²⁺、Al³⁺）的直接影响不明显,主要通过影响游离茶多酚浓度而降低其荧光强度;加热处理能显著增大荧光强度。当茶多酚浓度过高（>3βmg/ml）或pH>8时,能导致最大发射峰位置显著红移,其它因素对其影响较小;此外,溶剂极性显著地影响激发峰的形状和荧光强度,但对最大发射峰位置影响较小。     

海藻酸钠茶多酚复配涂膜对滇橄榄贮藏品质的影响

采用不同浓度的茶多酚和海藻酸钠对滇橄榄进行涂膜保鲜单因素试验,根据测定结果,选择浓度为0.10%、0.20%的海藻酸钠与浓度为0.75%、1.00%、1.50%的茶多酚进行复配涂膜,研究其对滇橄榄贮藏品质的影响。结果表明:经涂膜处理后的滇橄榄贮藏品质优于CK组,在6组不同浓度配比下,以0.10%海藻酸钠与1.50%茶多酚复配保鲜液的保鲜效果较好,可保持滇橄榄较好的感官品质,延缓果实失重率、可溶性固形物含量的升高和VC含量的下降,保持较高的好果率,抑制呼吸强度,能将滇橄榄保鲜期延长至15 d。     

Effects of germination and cooking on polyphenols and in vitro protein digestibility of horse gram and moth bean

Changes in polyphenols and in vitro protein digestibility due to germination and cooking were studied in horse gram and moth bean. Horse gram had higher amounts of polyphenols than moth bean. Polyphenol content in horse gram decreased from 1.6% to 1.1% at 48h germination, but in moth bean there was a reduction in polyphenol content from 1.3% to 1.0% at 24 h germination with a significant increase from 1.0% to 1.7% at 36 h germination. Seeds germinated for 48 h also exhibited higher amounts of polyphenols than in raw moth bean. The germination had no effect on total protein content, but a progressive increase in free amino acid content was observed in both legumes. In the ungerminated form, horse gram protein was more digestible than moth bean protein. The in vitro protein digestibility of both the legumes increased during germination. Cooking decreased the protein digestibility of horse gram either in ungerminated or germinated form, but such a decrease was noticed in moth bean at only 36 h germination. Moth bean either in raw form or germinated for 24 h did not exhibit a decrease in in vitro protein digestibility after cooking. Cooking decreased polyphenol content by 20%–50%. The apparent decrease in polyphenols in moth bean and horse gram due to cooking has been attributed to a decrease in assayable polyphenols.     

Algal-oligosaccharide-lysates prepared by two bacterial agarases stepwise hydrolyzed and their anti-oxidative properties

Twenty algal-oligosaccharide-lysates (AOLs), derived from six agars and four algal polysaccharide extracts (APEs), were treated first with agarases with 250 or 500 agarase activity units (AU), which were produced from the agar-liquefying bacterial strain Pseudomonas vesicularis MA103, named MA103-agarases. The AOLs were then treated with agarases (250 or 500 AU) derived from the agar-softening bacterial strain Aeromonas salmonicida MAEF 108, named MAEF 108-agarases. Anti-oxidative properties of the AOLs were evaluated by five in vitro methods. The AOL obtained from the APE of Porphyra dentate, digested by 250 AU of MA 103-agarases, and by 250 AU of MAEF 108-agarases, designated as A₂₅₀-Por, showed better results than the 19 other AOLs. This result is in accordance with the level of soluble total polyphenols (STP) of A₂₅₀-Por, which was also higher than the remainder of the AOLs tested. The AOL derived from the APE of P. dentate, digested by 500 AU of MA103-agarases and then 500 AU of MAEF108-agarases, and designated as B₅₀₀-Por, displayed the second highest data in four potential evaluation methods, except in H₂O₂ scavenging capacity. In this study, certain agars or APEs digested by specific agarases can present an increasing antioxidative capacity. These agars include Bitek agar, Agar powder, Bacteriological, Agar Bacteriological, and Guanghui agar, plus APEs of Gracilaria sp. and Monostroma nitidum decomposed stepwise by two agarases. The fraction of polyphenols (<1 kDa) that were derived from A₂₅₀-Por showed anti-oxidative activities on α, α-diphenyl-β-picrylhydrazyl (DPPH) assay and reducing power determination, while the remaining four agar-lytic fractions obtained from A₂₅₀-Por did not exhibit anti-oxidative activity. This phenomenon may suggest that anti-oxidative properties of AOLs originate in polyphenols. Algal-oligosaccharide-lysates may have potential use as a health food.     

茶树鲜叶品质成分浸提方法比较及应用

代谢组学和系统生物学研究要求数据丰富、重复性好,简单易行、浸提效率高的样品前处理方法是获得较好的试验结果的关键步骤。比较了不同浸提剂（甲醇、乙醇和高氯酸）和不同研磨方法（球磨机和研钵研磨）对茶树叶片品质成分的浸提效果,结果表明,70%乙醇和70%甲醇对茶鲜叶氨基酸的浸提效率显著高于无水甲醇和无水乙醇,而对鲜叶茶多酚的浸提效率以100%乙醇和70%乙醇最好;3 mol·L^-1高氯酸对鲜叶氨基酸浸提效率最高,超过70%乙醇,但对茶多酚的浸提效率最低。优化出一种针对茶树鲜叶浸提的快速前处理方法（70%乙醇,球磨机研磨5 min）。对鲜叶经冷冻干燥和微波杀青处理后浸提的茶多酚和氨基酸含量进行了比较,发现冷冻干燥可以更好地保持茶树叶片中特征代谢产物成分。     

Polyphenol-Rich Extract of Fenugreek Seeds Protect Erythrocytes from Oxidative Damage

A polyphenol-rich extract from the seeds of fenugreek was evaluated for its protective effect against hydrogen peroxide(H₂O₂)-induced oxidation in normal and diabetic human erythrocytes (RBCs). RBCs, preincubated with increasing amounts of fenugreek seed extract and challenged with H₂O_2, were analyzed for hemolysis and lipid peroxidation. RBCs from diabetic subjects were more susceptible to oxidative hemolysis and lipid peroxidation than those from normal subjects. However preincubation with the polyphenol-rich extract significantly reduced the oxidative modifications in both the groups. The inhibition of lipid peroxidation was concentration-dependent up to 100 l of extract, which contained 0.75mM gallic acid equivalent (GAE) of phenolic compounds. These findings demonstrate the potent antioxidant properties of the fenugreek seeds.     

Drought Tolerance in Cotton: Involvement of Non-enzymatic ROS-Scavenging Compounds

Compounds with reactive oxygen species (ROS)-scavenging ability were studied. High-performance liquid chromatography (HPLC) pattern of polyphenols, contents of proline and carotenoids, and antiradical (AR) capacity were determined. The malonyldialdehyde (MDA) level was also assessed. Tolerant and sensitive cotton genotypes were compared, grown in the Aegean region of Turkey at normal (field capacity) and limited (1/3 field capacity) water supply. Chlorogenic acid isomers and flavonoids were identified in HPLC pattern of polyphenols. At normal water supply, the tolerant genotype was distinguished by a higher content of all polyphenol types, higher proline, carotenoids and AR capacity and lower MDA level compared with the sensitive genotype. In plants subjected to water deficit, a decline of all polyphenol compounds, carotenoids and AR capacity was observed. However, this response was less pronounced in the tolerant than in the sensitive genotype, i.e. despite the stress conditions imposed, the tolerant plants maintained a more effective defence system. The data are corroborated by the weaker structural membrane damage in the drought-exposed tolerant vs. sensitive genotype, according to the MDA test. Hence, diverse chemical types are involved in the non-enzymatic ROS-scavenging system of cotton plants and can be related to the drought tolerance of this important crop.     

发酵型冬虫夏草菌茶的制备工艺研究

以绿茶为主要原料,配伍麦麸组成固体培养基,接种冬虫夏草菌进行固体发酵培养,加工冬虫夏草菌茶。结果显示,冬虫夏草菌在茶叶为主料添加麦麸的培养基上长势良好,通过L9（34）正交试验,以菌茶粗多糖含量为指标,筛选出培养基最优配方为茶叶60 g、麦麸30 g、碳酸钙0.4 g、蔗糖1.2 g。在料水比为5∶3（w·v-1）培养基上,接种12%（mL·g-1）冬虫夏草液体菌种,24℃培养12 d,55℃烘干,粉碎包装。成品菌茶汤为酒红色,香气清淡,无絮状物沉淀,pH值7.28,菌茶粗多糖含量为7.566%,茶多酚含量为1.488%。     

黑茶发酵优势菌对茶多酚的生物转化研究

利用从茯砖茶中分离出的冠突散囊菌和从普洱茶中分离出的黑曲霉、根霉分别接种于以茶多酚作为唯一碳源的培养基中,进行单一菌株发酵,对发酵过程茶多酚类化合物的变化规律进行分析.结果表明,发酵期内,随着发酵时间延长,各发酵液的茶多酚总量显著降低,冠突散囊菌、黑曲霉、根霉发酵液中多酚分别降低38.9％、85.5％和92.1％;黄酮类总量在黑曲霉、根霉的作用下先下降后上升,冠突散囊菌则波动上升;各处理儿茶素总量均显著下降,其中酯型儿茶素含量直线下降,非酯型儿茶素和没食子酸的含量均先增加后减少.在黑曲霉、根霉作用下,茶黄素、茶红素含量显著减少,茶褐素含量增加.冠突散囊菌发酵液中茶黄素含量减少,茶红素含量增加,茶褐素含量基本不变.基于不同优势菌对茶多酚的转化在质和量上均有差异,有必要对其转化产物进行深入研究.     

橄榄多酚类物质研究进展

橄榄是中国传统的药用植物,其中多酚类物质是橄榄重要的功效成分之一。目前,橄榄多酚类物质研究较为 广泛,常用的提取方法包括温浸法、超声波辅助提取法、微波辅助提取法、超声与微波协同辅助提取法等,分离纯化 后采用液相色谱或液质联用技术鉴定多酚类物质的种类和成分,并对其抗氧化、抗病毒、抗菌消炎、抗癌抑癌、解酒 护肝和提高机体免疫等方面的药理活性进行验证。此外,橄榄多酚类物质合成和代谢分子机理也已经被初步阐释。基 于上述研究报道,本文进一步对橄榄多酚类物质后续研究方向和产业化开发利用前景进行展望。