卷烟中多酚类物质的分析

为考察卷烟中的多酚与其质量的关系,采用反相高效液相色谱法测定了17种烤烟型卷烟和6种混合型卷烟中6种多酚的含量。结果表明:①在所分析的国产烤烟型卷烟中,无论是多酚物质的总量还是主要多酚物质的含量均有随着卷烟档次和其内在质量的升高而增加的趋势;②烤烟型卷烟样品中的多酚含量高于混合型卷烟样品;③4种国产混合型卷烟的多酚含量高于2种进口混合型卷烟;④在分析的所有卷烟样品中,都是新绿原酸、绿原酸和芸香苷为主要多酚,其中绿原酸含量约占总多酚量的60%左右。结论是,多酚含量与烤烟型卷烟的内在质量、卷烟类型和国产与进口混合型卷烟可能有一定的关系,仅新绿原酸、绿原酸和芸香苷甚至仅一种绿原酸含量的变化就基本上可以反映出卷烟中多酚总量的变化趋势。     

红豆中多酚类物质的提取及其含量测定的研究

本文研究了红豆中多酚类物质的提取工艺，并采用比色法对其含量进行了测定。结果表明，采用大孔吸附树脂层析法提取红豆多酚，效果较为理想。比色法测定其含量，方法简单、快速，结果准确。     

多酚的食物来源及生物有效性

介绍了食品中存在的多种多酚的性质及其含量;分析了农业生产、工业化生产对多酚含量的影响以及综述了目前在多酚的生物有效性方面的研究进展。     

过氧化物酶在蔗汁澄清工艺中除酚脱色的研究

本文研究了pH值、温度、H2O2用量及辣根过氧化物酶(HRP)用量等因素对辣根过氧化物酶催化H2O2氧化多元酚类的影响,并分别用HRP处理亚硫酸法糖厂的混合汁、清汁、糖浆,考察其对糖汁的除酚脱色效果。试验结果表明,HRP催化H2O2氧化处理糖汁具有明显的除酚脱色作用。     

松多酚类活性物质抗氧化构效关系与作用机制研究进展

研究表明,心脑血管疾病、癌症、衰老、炎症反应等多种疾病的发生都与活性氧自由基造成的氧化损伤有密切关系。因此,高效、低毒、易得的优良天然抗氧化剂的开发一直是近年研究的热点。松多酚是松科植物树皮及种子壳中富含的多酚类化合物,具有良好的抗氧化活性,是一种高效的自由基清除剂,在现代医药保健行业中日益得到重视。对松多酚的组分及结构分析、抗氧化活性构效关系及其作用机制研究进展作一综述。     

UV-B-induced changes of volatile metabolites and phenolic compounds in blueberries (Vaccinium corymbosum L.)

There are many reports on the potential consequences of UV-B radiation on plants, but there is a rather limited understanding of the effect on secondary plant metabolites, e.g. phenolic compounds and volatiles, at all. The popularity of highbush blueberries (Vaccinium corymbosum L.) is mainly due to its unique flavour and its high content of bioactive compounds, i.e. phenolic compounds. However, information on UV-B elicitor mediated changes on secondary plant metabolites on blueberries is scanty. In the present study, blueberry fruits were harvested and exposed to UV-B radiation with different dosage and adaptation times. With regard to volatile secondary metabolites, C₆-aldehydes, terpenes and ketones, an increase of the relative peak area was observed after both UV-B treatments (0.075 and 0.15 Wh/m² = low [L] and high [H] dosage, respectively). Furthermore, there was a strong influence of the adaptation time. Increasing relative peak areas were determined already after a short adaptation time (2 h) at both, low and high UV-B dosages, but after 24 h adaptation time relative peak areas decreased significantly. However, alcoholic compounds, as degradation products of aldehydes, showed opposite results. In contrast, the non-volatile phenolic compounds revealed a continuously increase with UV-B intensity.     

Antioxidant and Anti-Inflammatory Properties of Lower-Polymerized Polyphenols in Oolong Tea

This study investigated the antioxidant and anti-inflammatory properties of the fractionated tea extract, a lower-polymerized polyphenol-rich extract ultrafiltrated from oolong tea. The amounts of total polyphenols, flavonoids and condensed tannin were enriched in fractionated tea extract compared to oolong tea. Furthermore, fractionated tea extract was a stronger scavenger of nitric oxide and 2,2-diphenyl-1-picryhydrazyl radicals than oolong tea. When lipopolysaccharide-treated RAW264.7 macrophages were co-incubated with both tea extracts (500 μg/mL) or (-)-epigallocatechin gallate (100 μg/mL) for 16 h, all samples (oolong tea, fractionated tea extract, and (-)-epigallocatechin gallate) suppressed nitric oxide production by 60, 48, and 46%, respectively, and the suppression was due to nitric oxide-scavenging. However, only fractionated tea extract lowered the proportion of phospholipid arachidonic acid and type II-cyclooxygenase expression, thereby decreasing PGE₂ synthesis by 29%. In conclusion, fractionated tea extract was rich in potent antioxidant substances capable of inhibiting the production of pro-inflammatory mediators.     

超临界萃取技术及其在啤酒花浸膏生产上的应用

随着科学技术的发展,超临界流体萃取技术以其独特的优势越来越受到人们的关注。对超临界流体萃取技的发展概况、原理、应用以及未来发展做了简单介绍,并着重叙述了其在啤酒花浸膏的生产过程中的应用。     

Polyphenols of chickpea and blackgram as affected by domestic processing and cooking methods

The effects of soaking, cooking, autoclaving and sprouting on the polyphenol contents of eight cultivars of chickpea (Cicer arietinum) and four of blackgram (Vigna mungo) were studied. All the treatments reduced the polyphenols of the legume seeds, but to a varying extent. Sprouting and autoclaving had the most pronounced effect; ordinary cooking and soaking were relatively less effective.     

制丝过程中多酚等成分及相关酶活性的变化

为探索制丝过程烟草中多酚等化合物含量及相关酶活性的变化规律,分析了制丝过程中6个关键生产工序前后烟草中多酚、淀粉、总糖、还原糖、总烟碱、总氮以及多酚氧化酶和总淀粉酶活性的变化。结果表明,在制丝过程的6个关键工序中,多酚、淀粉、总糖、总烟碱和总氮均持续降低;多酚氧化酶和淀粉酶经第1次润叶后及贮片后持续降低;还原糖除在贮片后略有增加外,其它工序均降低。     

咖啡浆果总多酚美白机制初探

考察咖啡浆果总多酚对体外培养的人黑素细胞A375增殖、凋亡、酪氨酸酶活性及黑素合成的影响。采用大孔吸附树脂AB-8分离富集咖啡浆果中的总多酚;体外培养黑素细胞,采用四甲基偶氮唑蓝（MTT）法测定总多酚对细胞增殖的影响,流式细胞仪测定其凋亡细胞,酶学方法测定其对酪氨酸酶活性的影响,比色法测定黑素含量变化情况。咖啡浆果总多酚在一定剂量下能明显抑制黑素细胞增殖且促进其凋亡,抑制酪氨酸酶活性,并显著降低A375细胞黑素的合成。结果表明,咖啡浆果总多酚可抑制黑素细胞增殖,促进其凋亡,降低酪氨酸酶活性,最终减少黑素合成,这可能是其具有美白作用的机制之一。     

Stability of Apple Polyphenols as a Function of Temperature and pH

The effect of heat treatment on apple polyphenols was investigated at six different temperatures over three different lengths of time. Apple polyphenols, after heat treatment, maintained similar concentrations in solution compared to the control (at room temperature). The effect of pH on apple polyphenols was investigated at 11 different pH levels and at 2 different temperatures. The pH-optimum for apple polyphenols proved to be 5.0. Two apple polyphenol concentrations, three vitamin C concentrations, two sugar concentrations, and two different temperatures were chosen to investigate the effect of apple polyphenols on vitamin C. Apple polyphenols showed good stability and can be used in many types of food products.     

超声波提取杏鲍菇多酚工艺的响应面法分析

在单因素试验的基础上,利用响应面法优化超声提取杏鲍菇多酚的工艺条件,根据中心组合设计原理采用三因素三水平响应面分析法,依据回归分析确定最优提取工艺条件为:液料比49.98 mL/g,超声功率458.01W,提取时间50.41 min,杏鲍菇多酚的提取得率达1.11718％.     

Digestion and bioavailability of bioactive phytochemicals

There are many scientific reports on determination of the content and biological activity of compounds found in food. However, these analyses are not sufficient to determine their effect on the human body. During digestion of food ingredients, many changes can modify their structure and this may affect their absorption and bioactivity. Many phenolic aglycones are hydrophilic and can be absorbed through biological membranes by diffusion. However, most polyphenols occur in the glycosidic form, which undoubtedly affects their absorption in the intestine. Oligopeptides are also absorbable via secondary active transport but based on the hydrogen ion gradient or with transporter PepT1. The bioavailability of phytochemicals is determined by their molecular weight or chemical structure and the food matrix. Accordingly, the aim of this work was to present the novel scientific reports related to the influence the many factors on digestibility, bioaccessibility and activity of selected bioactive compounds of plant origin.     

Identification of the Polyphenols in Barley and Beer by HPLC/MS and HPLC/Electrochemical Detection

Barley polyphenols were isolated using acetone/water (70/30) followed by Sephadex LH-20 chromatography. HPLC/Electrospray mass spectrometry showed the presence of proanthocyanidin dimers, trimers, tetramers, and pentamers. HPLC/electrochemical detection was used to survey the contents of these compounds in a range of barley varieties. Principal components analysis showed that the naked barley varieties Morrell, and to a lesser extent Namoi, were different from the other barley varieties. Beer polyphenol extracts were prepared using Sephadex LH-20 chromatography. A large number of proanthocyanidin dimers and trimers could be detected using HPLC/MS. HPLC/electrochemical detection was used to survey a range of beer types. Compounds detected included catechin, epicatechin, gallocatechin, epigallocatechin, a number of proanthocyanidin dimers and trimers, and a number of phenolic acids. The peaks removed by PVPP have been determined. Principal components analysis was used to identify those compounds which distinguished the beer types. The first principal component was due to prodelphinidin B3, catechin, gallocatechin and two unidentified compounds which were removed by PVPP and the second principal component was due to phenolic acids. Efforts to identify the compounds removed by PVPP have commenced.     

茉莉花茶中茶多酚的提取分离纯化及其抗氧化性能研究

本实验采用溶剂法浸提茉莉花茶中茶多酚,研究发现,相对最优的工艺条件为:温度70℃,乙醇溶液浓度60%,提取次数1次,提取时间60min。在此浸提工艺下提取到茶多酚粗提物后用石油醚、氯仿和乙酸乙酯萃取,得乙酸乙酯相过聚酰胺柱分离纯化,将得到的不同洗脱组分过高效液相色谱检测发现:30%乙醇洗脱组分含表儿茶素没食子酸酯(ECG)最高,60%乙醇洗脱组分中含有表没食子儿茶素没食子酸酯(EGCG),95%乙醇洗脱组分主要是儿茶素没食子酸酯(CG)。继而对不同组分进行抗氧化活性研究得出:60%洗脱组分对油脂的抗氧化活性最高;30%洗脱组分与60%洗脱组分对DPPH自由基50%清除率的浓度分别为0.1723mg/ml、0.1693mg/ml。     

Interactions between phytochemicals from fruits and vegetables: Effects on bioactivities and bioavailability

The combinations of two or more phytochemicals bring about changes in the ultimate biological effects and/or the bioavailability of each component. A number of mixtures of pure bioactive compounds or phytochemical-containing plant extracts provide synergy with regard to antioxidant status, anti-inflammation, anti-cancer and chemoprevention of several oxidative stress and metabolic disorders in vitro. The biological activities of food phytochemicals depend upon their bioaccessibility and bioavailability which can be affected by the presence of other food components including other bioactive constituents. The interactions between phytochemicals during intestinal absorption could result in changes in the bioavailability of the compounds, which in turn affects the intensity of their bioactivities. This paper provides an overview of combined biological effects of phytochemical mixtures derived from fruits and vegetables with a focus on anti-oxidative, anti-inflammatory and anti-carcinogenic activities. The bioavailability impairment or enhancement caused by the co-consumption of dietary phytochemicals is also discussed. Finally, research gaps for future studies on phytochemical interactions are identified.     

Polyphenols and antioxidant capacity of Phaseolus vulgaris stored under extreme conditions and processed

Phaseolus vulgaris is a foodstuff that not only supplies nutrients, but also bioactive compounds with antioxidant capacity; however, bad post-harvest storage or processing can diminish the antioxidant capacity. In this work, the effect of storage under extreme conditions, of thermal processing and of fermentation on the content of phenolic compounds and their antioxidant capacity (AA) in beans of just harvested P. vulgaris were evaluated. Combination of temperatures of 30 and 50 °C and relative humidity of 11% and 80% for 150 days were evaluated. Extreme storage conditions drastically decreased the AA, demonstrating that post-harvest storage at low temperature and humidity preserves the antioxidant capacity of the beans. Regarding processing, cooking decreased the scavenging effect and the AA by 63.5% and 56.8%, while fermentation decreased them by only 14% and 22%, respectively. It was concluded that the loss of antioxidant capacity due to heating is less in fermented beans.     

Polyphenols content and antioxidant capacity of eggplant pulp

The influence of organic and conventional farming practices on the phenolic content in eggplant samples belonging to two cultivars, Blackbell (American eggplant) and Millionaire (Japanese eggplant) grown under similar environmental conditions was evaluated. Phytochemical investigation of the eggplant extracts showed that N-caffeoylputrescine, 5-caffeoylquinic acid, and 3-acetyl-5-caffeoylquinic acid made up the bulk of total eggplant phenolics. In addition, this is the first report on identification of trace quantities of three additional flavonols, namely, quercetin-3-glucoside, quercetin-3-rhamnoside, and myricetin-3-galactoside in freeze-dried eggplant pulp. The phenolic content of the conventionally grown Blackbell variety was marginally higher or equal to those grown organically. However, the phenolic content of the Millionaire organic variety was much greater than the conventionally grown samples. Eggplant extract inhibition of cupric-ion mediated oxidation of low-density lipoproteins was highly correlated with the content of 5-caffeolquinic acid (R² = 0.9124), the most abundant phenolic acid identified.     

Ruminal degradability and lysine bioavailability of soybean meals and effects on performance of dairy cows

Evaluations of 4 soybean meal (SBM) products were conducted in 3 experiments. The 4 products were 1) solvent SBM (SSBM), 2) SSBM treated with 0.05% baker's yeast and toasted at 100°C (YSBM), 3) expeller SBM (ESBM), and 4) lignosulfonate-treated SBM (LSBM). Multiparous Holstein cows (n = 32; 152 ± 63 d in milk; body weight = 708 ± 77 kg; producing 41 ± 7 kg/d of milk at the beginning of the study) were used in a 4 × 4 Latin square design with 28-d periods to investigate cow responsiveness to supplemental ruminally undegradable protein (RUP) from the SBM products. Dietary treatments were formulated by substituting all of the SSBM and part of the ground corn with YSBM, ESBM, or LSBM to yield isonitrogenous diets. Diets were formulated to provide adequate ruminally degradable protein, but deficient RUP and metabolizable protein supplies. No differences among dietary treatments were observed for dry matter intake, body weight gain, milk and component yields, or efficiency of milk production. The lack of response to changes in SBM source was likely due to an adequate RUP and metabolizable protein supply by all the diets. In situ ruminal degradations of YSBM and LSBM were slower than those of SSBM or ESBM; thus, RUP contents of YSBM and LSBM were greater than those of SSBM or ESBM. The RUP of all SBM products had similar small intestinal digestibility. Available Lys contents, estimated chemically or by using a chick growth assay, were less for YSBM and LSBM than for SSBM or ESBM, suggesting deleterious effects of processing on Lys availability in YSBM and LSBM.