母乳低聚糖对Caco-2肠上皮细胞屏障功能的影响

母乳低聚糖(HMOs)是母乳中的关键活性成分,具有调节肠道菌群,保护肠道屏障完整性和调节免疫等重要的生理功能。本研究构建Caco-2细胞肠上皮屏障及炎症损伤模型,用2’-岩藻糖基乳糖(2’-FL)、3’-唾液酸乳糖(3’-SL)和乳糖-N-新四糖(LNnT)3种分别代表中性岩藻糖基化、唾液酸化和中性非岩藻糖基化的HMO进行干预。通过测定细胞跨膜电阻值表征肠屏障完整性,采用酶联免疫吸附法测定炎症因子的分泌水平,以及实时荧光定量PCR技术分析紧密连接和炎症相关基因的表达水平,旨在探究HMO对肠屏障功能的保护作用及其调控机制。结果表明,与阴性对照组相比,3种HMO均能浓度依赖性地提高跨膜电阻值,降低IL-6和IL-8的基因表达水平和分泌量,其中10 mg/mL的3’-SL干预可使其降低至空白组水平;抑制IL-1β、TNF-α、COX-2和iNOS的基因表达,其中10 mg/mL的HMO干预组基因表达水平最低。在高质量浓度的HMO干预下Claudin-1、Claudin-3、ZO-1、ZO-2和Occludin的基因表达水平上调4倍,并抑制NF-κB信号通路的激活但该作用未表现出浓度依赖性。3种HMO在高质量浓度下(2.4 mg/mL和10 mg/mL)能发挥显著的肠屏障保护作用和抗炎活性,研究结果为HMO增强肠屏障功能和免疫调节功能的应用提供科学证据。     

Protective effect of isoquinoline alkaloid berberine on spontaneous inflammation in the spleen, liver and kidney of non-obese diabetic mice through downregulating gene expression ratios of pro-/anti-inflammatory and Th1/Th2 cytokines

This study investigated anti-inflammatory effects of berberine using non-obese diabetic (NOD) mice that spontaneously develop type 1 diabetes. The NOD mice were randomly divided into four groups, including control group (intragastric gavage with water), berberine low dose, berberine medium dose and berberine high dose groups, which were respectively administrated with 50, 150, and 500 mg berberine/kg BW through 14 weeks by consecutive tube feeding. Imprinting control region (ICR) mice were also selected as a species control group, to compare with NOD mice. Cytokine expression profiles in the spleen, liver and kidney were determined using enzyme-linked immunosorbent assay or real-time quantitative polymerase chain reaction assay. The results showed that berberine supplementation significantly (p < 0.05) decreased the expression ratios of pro-/anti-inflammatory and/or Th1/Th2 cytokines in the spleen, liver and kidney of NOD mice, suggesting that berberine supplementation alleviated spontaneous inflammation in the spleen, liver and kidney of NOD mice.     

乳及乳制品中的抗高血压活性肽

论述了乳及乳制品中的抗高血压活性肽的分离纯化、构性关系、对血管紧张素转换酶的抑制活性和抗高血压机理，以及其在体内的吸收特性。展望了乳源抗高血压肽的应用前景。     

Recycled paperboard with a barrier layer for food contact: set-off during stacking or reeling. Analytical method and preliminary results

The use of recycled paperboard for packaging dry foods is in the interest of sustainability of resources, but in most applications, the food must be protected against contamination, such as by a functional barrier on the internal surface of the paperboard box. After application, the paperboard is usually stacked or reeled before making boxes. During this period, the food-contact surface of the barrier layer is in contact with the outer side of the paperboard, which may result in set-off and subsequent contamination of food. A method is described for the determination of this path of migration, based on the taped format also used for the measurement of the barrier efficiency. Recycled paperboard containing the three surrogate substances n-heptadecane, 4-methyl benzophenone and dipropyl phthalate was taped to the food-contact side of the barrier layer. Pressure onto the test packs did not seem to be a relevant parameter. After periods of interest, a piece of the paperboard with the barrier layer was extracted and analysed for the surrogate substances. Another piece may be brought into contact with silicone paper to simulate the transfer to food. After 2 weeks at 60°C (simulating about 1 year at 25°C), set-off and the transfer to the silicone paper exceeded 1% for all barrier materials tested, but after 6 weeks at 40°C (around half a year at 25°C), set-off remained below 1% for all barrier layers except a multilayer with polyethylene on the food-contact surface. The preliminary conclusion is that set-off should be taken seriously, but may be kept low enough to provide sufficient protection of the packed food.     

Isolation and identification of some unknown substances in disposable nitrile-butadiene rubber gloves used for food handling

In Japan, disposable gloves made from nitrile-butadiene rubber (NBR) are frequently used in contact with foods. In a previous paper, we investigated substances migrating from various gloves made of polyvinyl chloride, polyethylene, natural rubber and NBR. Zinc di-n-butyldithiocarbamate (ZDBC), diethyldithiocarbamate (ZDEC) used as vulcanization accelerators, di(2-ethylhexyl)phthalate (DEHP) used as a plasticizer and many unknown compounds that migrated from NBR gloves into n-heptane were detected by GC/MS. In this paper, six unknown compounds were obtained from one kind of NBR glove by n-hexane extraction and each was isolated by silica gel chromatography. From the results of NMR and mass spectral analysis of the six unknown compounds, their structures are proposed as 1,4-dione-2,5-bis(1,1-dimethylpropyl)cyclohexadiene ( 1 ), 2-(1,1-dimethylethyl)-4-(1,1,3,3-tetra methylbutyl)phenol ( 2 ), 2,6-bis(1,1-dimethylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol ( 3 ), 2,4-bis(1,1,3,3-tetramethylbutyl)phenol ( 4 ), 2-(1,1-dimethylethyl)4,6-bis(1,1,3,3-tetramethylbutyl)phenol ( 5 ) and 2,4,6-tris(1,1,3,3-tetramethylbutyl)phenol ( 6 ). Compound 1 was observed in five of the seven kinds of NBR gloves, and compounds 2-4 and 6 , which are not listed in Chemical Abstract (CA), were present in four kinds of gloves.     

Bio-based coatings as potential barriers to chemical contaminants from recycled paper and board for food packaging

Partition and diffusion experiments were carried out with paper and board samples coated with different biopolymers. The aim was to evaluate the physicochemical behaviour and barrier properties of bio-coatings against migration of typical contaminants from recycled paper packaging. Focus was directed towards water-based, renewable biopolymers, such as modified starches (cationic starch and cationic waxy starch), plant and animal proteins (gluten and gelatine), poured onto paper with an automatic applicator. Additionally, a comparison with polyethylene-laminated paper was performed. Microstructural observations of the bio-coated paper allowed the characterisation of samples. From the partitioning studies, considerable differences in the adsorption behaviour of the selected contaminants between bio-coated or uncoated paper and air were highlighted. For both the polar and non-polar compounds considered (benzophenone and diisobutyl phthalate, respectively), the lowest values of partition coefficients were found when paper was bio-coated, making it evident that biopolymers acted as chemical/physical barriers towards these contaminants. These findings are discussed considering the characteristics of the tested biopolymers. Diffusion studies into the solid food simulant poly 2,6-diphenyl-p-phenylene oxide, also known as Tenax^®, confirmed that all the tested biopolymers slowed down migration. The Weibull kinetic model was fitted to the experimental data to compare migration from paper and bio-coated paper. Values found for β, an index determining the pattern of curvature, ranged from 1.1 to 1.7 for uncoated and polyethylene paper, whereas for bio-coated papers they ranged from 2.2 to 4.9, corresponding to the presence of an evident lag phase due to barrier properties of the tested bio-coatings.     

保健食品原料红景天的开发利用研究

红景天是一种珍稀药用植物．也是一种很有发展前途的新食品资源。阐述了红景天的生物学特性、有效成分、保健功能及毒性研究和保健饮料的开发研究等。并对红景天的进一步研览进行了展望。     

A^2/O+MBBR集成工艺处理印染废水

简要介绍印染废水的水质特点及改良传统活性污泥法(A2/O)+移动床生物膜反应(MBBR)工艺集成技术;重点介绍A2/O+MBBR工艺处理印染污水的运行效果。结果显示,在进水量20~60 L/h,溶解氧(DO)质量浓度1.5~4.5 mg/L,污泥回流比50%~90%,硝化液回流比250%~350%,好氧池污泥质量浓度(MLSS)2.0~3.5 g/L,好氧池悬浮填料装填比25%(体积比)的操作条件下连续稳定运行200天后,出水COD去除效果、氨氮去除效果、总磷去除效果、总氮去除效果远远优于《城镇污水处理厂污染物排放标准》的一级A标准。     

Hydrolysis of the toxic constituents (vicine and convicine) in fababean (Vicia faba L.) food preparations following treatment with β-glucosidase

Several experiments were carried out to determine whether the concentrations of vicine and convicine in fababean food preparations were reduced following heat and β-glucosidase treatment. Heating fababeans to relatively high temperatures was not effective in reducing the concentration of these glycosides. Treatment of cooked fababeans (fababean paste) with ground raw almond powder, which is a rich source of β-glucosidase (EC 3.2.1.21) activity, resulted in the hydrolysis of vicine and convicine. The degree of hydrolysis ranged from partial to complete and was dependent on the duration of the treatment period (1 to 24 h), the temperature at which treatment was carried out (1 to 30°C), the pH (6.4 to 4.6) as adjusted by the addition of lemon juice and the amount of ground almonds added to the fababean paste. For example, 88 to 89% of the glycosides were hydrolysed when 1 g of fababean paste was mixed with 0.1 g of almond powder and 0.1 ml of lemon juice and incubated at 30°C for 3 h. This study demonstrated that the concentration of vicine and convicine and their corresponding aglycones can be greatly reduced in fababean food preparations by enzymic hydrolysis.     

Occurrence of fumonisins B1 and B2 in Portuguese maize and maize-based foods intended for human consumption

Fumonisin B₁ (FB₁) and fumonisin B₂ (FB₂) are mycotoxins mainly produced by Fusarium verticillioides and Fusarium proliferatum, which are field pathogens of maize. A survey was conducted on the incidences of FB₁ and FB₂ in both maize and derived products purchased in Portugal. The analytical method involved extraction with methanol-water, clean-up by immunoaffinity column and derivatization with naphthalene-2,3-dicarboxaldehyde. Determination was carried out by high-performance liquid chromatography (HPLC) with spectrofluorimetric detection, with liquid chromatography/mass spectrometry (LC/MS) confirmation. The presence of FB₁ and FB₂ was determined in 67 samples of maize and maize-based foods, such as flour, semolina, starch, sweet maize, cornflakes and other breakfast cereals, and snacks collected in 2005. FBs were found in 15 samples at concentrations ranging from 113 to 2026 µg kg^-1. Two of the samples showed higher contamination levels than the limits established by the European Commission Regulation. None of the samples contained levels of fumonisins that would lead to an exposure exceeding the tolerable daily intake (TDI).     

Structure,Function, and Nutrition of Phytoferritin: A Newly Functional Factor for Iron Supplement

Ferritins are members of the superfamily of iron storage and detoxification proteins present in all living organisms and play important roles in controlling cellular iron homeostasis. In contrast to animal ferritin, relatively little information is available on the structure and function of phytoferritin. Phytoferritin is observed in plastids whereas animal ferritins are largely found in the cytoplasm of cell. Compared to animal ferritin, phytoferritin exhibits two major distinctive features in structure. First, phytoferritin contains a specific extension peptide (EP) at the N-terminal while animal ferritin lacks it. The EP is located on the exterior surface of protein, which recently has been found to act as a second ferroxidase center for iron-binding and oxidation, and regulate iron release during the germination and early growth of seedlings. Second, only H-type subunit has been identified in phytoferritin, which is usually a heteropolymer consisting of two different subunits, H-1 and H-2, sharing ～80% amino acid sequence identity. These two subunits in phytoferritin play a positively cooperative role in iron oxidative deposition in protein. Iron deficiency anemia (IDA) is the most common and widespread nutritional disorder in the world, so it is crucial to explore a safe and efficient functional factor for iron supplement. Fortunately, phytoferritin seems to be a suitable candidate. In legume seeds, more than 90% of iron is stored in the form of ferritin in amyloplasts. Recently, some studies at different levels have demonstrated that plant ferritin could be used as novel, utilizable, plant-based forms of iron for populations with a low iron status. This review focuses on recent progress in structure, function, and nutrition of phytoferritin.     

A novel 4-(2-pyridylazo) resorcinol functionalised magnetic nanosorbent for selective extraction of Cu(II) and Pb(II) ions from food and water samples

This paper describes a novel sorbent based on 4-(2-pyridylazo) resorcinol functionalised magnetic nanoparticles and its application for the extraction and pre-concentration of trace amounts of Cu(II) and Pb(II) ions. The nanosorbent was characterised by Fourier transform infrared spectroscopy, X-ray powder diffraction, thermal analysis, elemental analysis and scanning electron microscopy. The effects of various parameters such as pH, sorption time, sorbent dosage, elution time, volume and concentration of eluent were investigated. Following the sorption and elution of analytes, Cu(II) and Pb(II) ions were quantified by flame atomic absorption spectrometry. The limits of detection were 0.07 and 0.7 μg l^?1 for Cu(II) and Pb(II), respectively. The relative standard deviations of the method were less than 7%. The sorption capacity of this new sorbent were 92 and 78 mg g^?1 for Cu(II) and Pb(II), respectively. Finally this nanosorbent was applied to the rapid extraction of trace quantities of Cu(II) and Pb(II) ions in different real samples and satisfactory results were obtained.