安吉白茶茶多酚提取工艺的研究

[目的]研究安吉白茶茶多酚的提取工艺,为安吉白茶茶多酚的工业化生产提供理论指导。[方法]以安吉白茶为原料,以茶多酚得率为指标,通过单因素试验和正交试验,对离子沉淀法、醇提法、微波辅助提取法3种提取方法进行了比较。[结果]离子沉淀法在沉淀比为3∶20、沉淀pH为6、浸提时间为2.5 h、浸提温度为80℃的条件下茶多酚得率为20.8%;醇提法在浸提温度为80℃、料液比为1∶25、浸提时间为2 h、乙醇浓度为70%的条件下茶多酚得率为15.9%;微波辅助提取法在浸提温度为70℃、料液比为1∶25、微波时间为40 s、微波功率为80 W的条件下茶多酚得率为20.7%。[结论]微波辅助提取法是茶多酚工业化生产较理想的一种提取工艺。     

Polyphenol oxidase, tannase and proteolytic activity in relation to tannin concentration in the soil organic horizon under silver birch and Norway spruce

Our aim was to compare enzyme activities (tannase, polyphenol oxidase and protease) with concentrations of tannins and their ability to precipitate proteins in the litter layer and the humus layer under silver birch (Betula pendula Roth.) and Norway spruce (Picea abies L.). We also estimated the influence of these enzymes on protein-tannin complexes and the influence of tannins on proteolytic activity. The study site was a tree species experiment in Eno, middle-eastern Finland, having three replicated plots dominated by 42-year-old silver birch and Norway spruce. Our hypotheses were (1) tree species and soil layer have an influence on tannin concentrations and enzyme activities, (2) that tannin and protein concentrations in soil organic horizon are positively correlated with enzyme activities and (3) that the enzymes studied have the ability to degrade tannin-protein complexes and that tannins can inhibit proteolytic activity. Concentrations of total tannins and hydrolysable tannins, and tannase and proteolytic activities were higher in the humus layer than in the litter layer. In general the highest values of concentrations of total tannins and hydrolysable tannins and enzyme activities were obtained for the birch humus layer, but the concentrations of condensed tannins and proteins were highest in the litter layer and under spruce. A strong correlation between substrate concentration and enzyme activity was found between hydrolysable tannins and tannase activity. Polyphenol oxidase showed similar activities in both layers. To study the influence of enzymes on protein-tannin complex we synthesized such complexes using bovine serum albumin and either condensed tannins from silver birch and Norway spruce needles or a hydrolysable tannin, tannic acid. Studies with commercial enzymes and enzymes extracted from the soil showed some decrease in tannin concentration of the tannin-protein complex over time, but surprisingly, only a negligible decrease in protein concentration. Complexes of protein with condensed tannins were more recalcitrant than tannic acid-protein complexes. Tannins, depending on the concentration and chemical structure, tended to inhibit proteolytic activity. Our results indicate that protein-tannin complexes are relatively recalcitrant since the enzymes studied here do not effectively release protein from the complexes. Also proteolytic activity and the concentration of extractable proteins seem to be low in soil. However, tannin-degrading enzymes showed high activities.     

Valorization of three varieties of grape

In the present investigation, seed methanolic extracts of three Vitis vinifera (Muscat d’Italie, Syrah and Carignan) were assayed for their antioxidant activities. Results showed that there are strong variations in the contents of total phenols (440.97–121.94 mg GAE g⁻¹ DW), flavonoids (48.07–16.81 mg EC g⁻¹ DW) and tanins (37.15–14.9 mg EC g⁻¹ DW) from the studied seeds. The phenolic composition of these extracts was determined by RP–HPLC after acid hydrolysis. The main phenolic compound was quercetin with 27.2% in Muscat d’Italie, 48.8% in Syrah and 28.4% in Carignan. Besides, all seed extracts showed remarkable DPPH radical scavenging activity with IC₅₀ values ranged from 1.8 to 30 μg ml⁻¹. EC₅₀ values of reducing power activity ranged from 100 to 120 μg ml⁻¹. The high phenolic content and the considerable antioxidant activities of vitis seed extracts could potentially be considered as an expensive source of natural antioxidants.     

超声技术在植物多酚提取中的应用进展

为了促进超声技术在植物多酚提取领域的应用,本文总结了超声技术在植物多酚含量测定和提取中的应用进展,以及超声提取多酚工艺的优化方法。指出超声技术在在中药药材和中药制剂的多酚含量测定中,以及在提取总多酚、单宁、黄酮类化合物和多酚类单体的工艺中有广泛的应用。提出超声功率和频率、提取时间和温度、提取溶剂和料液比是影响多酚提取效率的主要因素,利用正交试验设计和响应曲面法能提高提取效率。认为超声技术适用于提取植物多酚,在植物多酚提取领域拥有广阔的应用前景。     

‘品丽珠’、‘西拉’和‘黑比诺’3个酿酒葡萄品种不同营养系果实品质比较分析

为有效发挥酿酒优良品种‘品丽珠’、‘西拉’和‘黑比诺’不同营养系的优点,为选育果实中酚类物质含量较高的营养系提供依据,分别以‘品丽珠’3个营养系、‘西拉’2个营养系和‘黑比诺’2个营养系成熟果实为材料,取样测定其单穗重、单粒重、可溶性固形物、可滴定酸含量、皮肉比(果皮与果肉质量比)、出汁率,示差比色法测定果皮中的总花色苷含量,比色法测定果皮、果肉和种子中的总酚、单宁、总类黄酮和原花色素含量。结果表明,‘品丽珠’、‘西拉’和‘黑比诺’果实品质存在品种差异,各营养系间也存在差异。‘黑比诺115’果皮和果肉中酚类物质含量较高,而‘黑比诺667’种子中较高;‘西拉100’果皮总花色苷、原花色素、果肉单宁和种子总类黄酮含量较高;‘品丽珠327’果皮总花色苷、果肉总酚和单宁、种子中原花色素含量较高,‘品丽珠c214’种子中总酚、单宁和总类黄酮含量较高,‘品丽珠409’果皮总类黄酮、原花色素和果肉中总类黄酮含量较高。     

茶多酚的应用

茶多酚是茶叶的特征成分之一,约占茶叶干物质总量的20%~30%。由于含有多个活性羟基,使其具有多种抗氧化、抗衰老、杀菌、预防心脑疾病等诸多保健功效,现已成为医药、食品、畜牧业等方面开发的热点,且已经开发出茶多酚含片、胶囊、减肥产品、美容产品等。茶多酚的抗氧化、杀菌、抗衰老等活性较强,因此能作为抗氧化剂在粮油食品、水产品、肉制品、方便食品等方面有较好的应用;而能起到抗菌消炎、减肥、降压等功效能在医药、美容等方面广泛应用;同时也能应用于化工、畜牧业等方面。     

毛细管电泳法测定槟榔多酚的组分

建立同时测定槟榔壳中6种酚类物质的高效毛细管电泳方法,研究分析不同浓度和不同pH值缓冲液对10种标准品(即:表儿茶素、儿茶素、柚皮素、芦丁、山奈素、阿魏酸、绿原酸、香豆酸、咖啡酸和没食子酸)的分离效果。结果显示,最佳电解缓冲液为0.1 mol/L、pH 9.0硼酸缓冲液,紫外检测波长为280 nm,分离电压为20 kV。该方法简便快速,能在20 min之内将10种酚类物质完全分离开,具有良好的精密度、回收率和线性关系。检测限范围为0.587 5～4.415 2μg/mL。     

山药总多酚的提取工艺优化

[目的]建立山药（Dioscorea opposita Thunb.）总多酚的提取工艺。[方法]以山药总多酚含量为考察指标,在单因素试验的基础上,经正交试验对山药总多酚的提取工艺条件进行优化。[结果]山药中总多酚提取的最佳试验条件：提取溶剂为50%丙酮水溶液,料液比为1∶15（W/V）,提取时间为80 min,提取温度为55℃,提取次数为2次。[结论]该研究可为山药多酚的深入研究与开发提供理论参考。     

桃金娘果实多酚抗氧化活性及乙酰胆碱酯酶抑制活性研究

为了探明桃金娘果实的多酚含量及其多酚的抗氧化活性和乙酰胆碱酯酶抑制活性,以为进一步开发利用奠定基础。以采自海南海口的桃金娘整果为实验材料,用95%体积分数的乙醇提取桃金娘多酚,采用福林酚法测定其总酚含量。对获得的桃金娘多酚进行DPPH、ABTS、羟基自由基清除率和乙酰胆碱酯酶抑制活性测定。结果表明,桃金娘的多酚含量较高,达2.45mg/g干物质,其对DPPH、ABTS和羟基自由基均具有显著的清除活性,并且其活性随着浓度的增加,清除能力也随之增强,其IC50分别为120.78、25.44、194.09μg/mL;桃金娘果实多酚对乙酰胆碱酯酶也显示出较强的抑制活性,IC50为15.07μg/mL,且随着浓度的增加,其抑制活性呈上升趋势。该实验显示桃金娘果实多酚不仅具有较好的抗氧化性还具有显著的乙酰胆碱酯酶抑制活性。     

In vitro antioxidant activity of ragweed (Ambrosia artemisiifolia L., Asteraceae) herb

The antioxidant activity in 70% aqueous acetone extracts of the herb of Ambrosia artemisiifolia L., Asteraceae was evaluated with regards to total polyphenol and flavonoid contents. Antioxidant activity has been assessed by two commonly used in vitro tests, based on determination of ferric-reducing antioxidant power (FRAP assay) and DPPH free radical scavenging ability (DPPH assay), against butylated hydroxytoluene (BHT), ascorbic acid and quercetin, which were used as positive control substances. The results of both antioxidant tests showed that the plant material expressed a considerable activity (DPPH IC₅₀ = 27.6 μg/ml; FRAP value = 2.37 mmol Fe²⁺/g), attributed to both flavonoid aglyca and resembling glycosides, as verified by dot-blot TLC analysis.