发酵小麦制酒精残渣中寡肽的抗氧化及免疫活性

研究从发酵小麦制酒精残渣中提取分离出的寡肽抗氧化和免疫活性。将112 只4 周龄雌性健康昆明小鼠随机分成14 组,基础对照组和实验1～6组饲喂正常基础料的同时分别灌胃生理盐水、低、中、高3 个剂量的寡肽（五肽和七肽）,高脂对照组和实验7～12组饲喂高脂料的同时分别灌胃生理盐水、低、中、高3 个剂量的寡肽（五肽和七肽）,连续灌胃28 d后,测定基础对照组和实验1～6组血清中丙二醛（malondialdehyde,MDA）含量,肝匀浆中MDA含量、超氧化物歧化酶（superoxide dismutase,SOD）、过氧化氢酶（catalase,CAT）和谷胱甘肽过氧化物酶（glutathione peroxidase,GSH-Px）活性,脾脏中淋巴T细胞CD3＋、CD4＋和CD8＋数量,测定基础对照组、高脂对照组和实验7～12组十二指肠、空肠和回肠中MDA含量、SOD、CAT、GSH-Px活性。结果显示,与高脂对照组相比,灌胃寡肽后,血清、肝脏和肠道中MDA含量显著下降（P＜0.05）,SOD、CAT、GSH-Px活性显著升高（P＜0.05）,CD4＋/CD8＋显著升高（P＜0.05）。结果表明寡肽均具有体内抗氧化能力和免疫活性,而且能够清除高脂饮食带来的氧化损伤。     

In vitro accessibility of β‐carotene from cooked Sri Lankan green leafy vegetables and their estimated contribution to vitamin A requirement

Vitamin A deficiency is an important issue for public health in Sri Lanka, where pro‐vitamin A carotenoids from green leafy vegetables provide most of the dietary vitamin A. The objective of this study was to analyse the β‐carotene content of seven types of green leafy vegetables and calculate the contribution of one traditionally cooked portion to the recommended daily allowance (RDA) of retinol. The total amount and in vitro accessibility of β‐carotene were determined using HPLC. The in vitro method simulates the conditions in the human intestinal tract. The all‐trans‐β‐carotene content in the fresh blanched vegetables ranged from 149 µg g^?1 dry weight (DW) in leaves of Alternanthera sessilis (mukunuwanna) to 565 µg g^?1 DW in Amaranthus caudatus (thampala). One portion (100 g) of green leaves cooked without fat (coconut) only contributed from 140 to 180 µg mg^?1 of the recommended daily allowance. A. sessilis, Centella asiatica (gotukola), Spinacea oleracea (nivithi) and A. caudatus, cooked with coconut fat contributed 140–680 µg mg^?1. However, stir‐fried or ‘malluma’ preparations (with coconut products) of Sesbania grandiflora (kathurumurunga) and Manihot esculenta (manioc) may provide more than 1.59–4.37 times the RDA of retinol. These results show that not only the choice of green leaves used but also the addition of fat while cooking is of great importance. Copyright © 2005 Society of Chemical Industry     

电子自旋共振法和分光光度法测定酿酒葡萄籽原花青素抗氧化活性

利用电子自旋共振技术(ESR)对酿酒葡萄籽原花青素4个不同提取样品(GSP0、GSP1、GSP2、GSP3)抗氧化特性进行研究,并采用分光光度法进行对比分析。结果表明:电子自旋共振法和分光光度法均测得,GSP3样品对DPPH自由基清除能力最强;反应30min,质量浓度小于40mg/L时,样品质量浓度与清除率呈正相关,质量浓度大于40mg/L时,清除率趋于稳定。ESR测得的原花青素的清除率普遍高于分光光度法:反应30min,ESR测得不同质量浓度的GSP0的清除率最低为35.99%,最高为99%,而分光光度法测得分别为7.06%、78%;ESR测得的GSP3清除率最低为52.45%、最高值为99%,分光光度法测得的清除率分别是29%、95%。     

Effects of UV-C Light Processing on Some Quality Characteristics of Grape Juices

White and red grape juices (GJs) were subjected to ultraviolet C (UV-C) light as a non-thermal preservation technology using a coiled tube UV-C reactor with nine lamps. The effects of UV-C light on microbial (total aerobic count and yeast and mould count) and some chemical quality characteristics (total phenolics, antioxidant capacity, anthocyanin and polymeric colour, etc.) of white and red GJs were investigated. The results were compared with control (untreated) and heat-treated juice samples. Single-pass UV-C treatment (12.6 J/mL) of white and red GJs resulted in 3.51 and 3.59 log reductions in total aerobic count and, 2.71 and 2.89 log reductions in yeast and mould counts, respectively. The microbial loads of both GJs were completely eliminated after two passes through the reactor (25.2 J/mL). After UV-C and heat treatments, there were no significant changes in antioxidant capacity, total phenolics, titratable acidity, soluble solids and pH of white and red GJs (P?>?0.05). The losses in monomeric anthocyanins were 6.1% and 8.7% after UV-C treatment of 12.6 and 25.2 J/mL doses, respectively. However, anthocyanin level of red GJ was significantly affected by the heat treatment with an 11.8% loss (P?<?0.05). The percent polymeric colour of the red GJ with heat treatment was significantly higher compared to the colour with the UV-C treatment.     

不同采后处理对冷藏‘南丰蜜桔’角质层形态结构及化学组成的影响

角质层是采后果实的质量调控器,不同采后贮藏条件可以改变其形态结构及化学组成。热激（heat shock,HT）和壳聚糖（chitosan,CS）处理已被证实能有效延缓果实衰老。本文以‘南丰蜜桔’为实验对象,采用扫描电子显微镜（scanning electron microscopy,SEM）和气相色谱-质谱联用仪（gas chromatography-mass spectrometry,GC-MS）,研究不同采后保鲜方式（热激、壳聚糖、热激联合壳聚糖处理）对冷藏75 d期间‘南丰蜜桔’角质层形态结构及化学组成的影响。结果表明:‘南丰蜜桔’外蜡晶体呈不规则血小板状,热激导致外蜡重分布形成更光滑的表皮外观;外蜡和内蜡分别检出38种和50种组分,其主要成分均为烷烃、酸类、酯类、萜类,角质单体共检出7种成分,主要为酸类;十六烷酸是蜡质和角质最主要的组分。外蜡含量整体上无明显的变化规律,而内蜡呈先减后增的趋势,冷藏45 d时3种保鲜方式均能有效延缓外蜡和内蜡含量的降低,其中热激效果最为显著。冷藏期间角质单体含量持续下降,3种保鲜方式均能明显抑制其含量的降低,其中,以热激处理的效果最为明显。热激处理可通过改变外蜡晶体的结构,以及调节角质层的成分代谢来保持‘南丰蜜桔’的贮藏品质,这为其开发采后贮藏保鲜策略提供了科学依据。     

Screening method for ecotoxicological hazard assessment of 42 pharmaceuticals considering human metabolism and excretory routes

We assessed the ecotoxicological hazard potential of 42 pharmaceuticals from 22 therapeutic groups, including metabolites formed in humans. We treated each parent drug and its metabolites as a mixture of similarly acting compounds. If physicochemical or effect literature data were missing, we estimated these with quantitative structure-activity relationships (QSAR). Additionally, we estimated micropollutant removal efficiency of urine source separation using pharmaceutical information. On average, 50% of a parent drug was metabolized, and 70% was excreted with urine, albeit with large variations among drugs. Metabolism reduced the toxic potential of all but eight drugs. The subsequently modeled risk quotient was mostly below the threshold of one. However, ibuprofen and its metabolites in a mixture could pose an ecotoxicologal risk; and possibly also acetylsalicylic acid, bezafibrate, carbamazepine, diclofenac, fenofibrate, and paracetamol. Lipophilicity and sale quantities of parent drugs alone were insufficient to estimate their ecotoxicological risk. Urine separation could decrease the ecotoxicological risk of some, but not all drugs. The estimated risk quotients were equal in urine and feces, again with large variations among compounds. Because of scientific limitations of the model and inconsistent literature data the results are somewhat uncertain. However, this new approach allows first tier screening of single drugs, thus supporting decision-making.     

Methyl-nitrocatechols: atmospheric tracer compounds for biomass burning secondary organic aerosols

Detailed chemical analysis of wintertime PM?? collected at a rural village site in Germany showed the presence of a series of compounds that correlated very well with levoglucosan, a known biomass burning tracer compound. Nitrated aromatic compounds with molecular formula C?H?NO? (M(w) 169) correlated particularly well with levoglucosan, indicating that they originated from biomass burning as well. These compounds were identified as a series of methyl-nitrocatechol isomers (4-methyl-5-nitrocatechol, 3-methyl-5-nitrocatechol, and 3-methyl-6-nitrocatechol) based on the comparison of their chromatographic and mass spectrometric behaviors to those from reference compounds.Aerosol chamber experiments suggest that m-cresol, which is emitted from biomass burning at significant levels, is a precursor for the detected methyl-nitrocatechols. The total concentrations of these compounds in the wintertime PM??were as high as 29 ng m?3, indicating the secondary organic aerosol (SOA) originating from the oxidation of biomass burning VOCs contributed non-negligible amounts to the regional organic aerosol loading.