富硒金针菇对自由基清除作用

采用现代分离技术从富硒金针菇中提取硒多糖和硒蛋白,采用苯酚- 硫酸法、ICP-MS 法和考马斯亮蓝染色法对硒多糖中多糖含量、硒含量及硒蛋白中蛋白和硒的含量进行测定;在Fenton 体系的最佳实验条件下,研究硒多糖和硒蛋白对羟自由基的清除作用。结果表明：硒多糖和硒蛋白清除羟自由基的效果比与之相同浓度的无机硒和相同浓度的多糖及蛋白都要明显;其中,硒多糖的最高清除率可达65.05%,而硒蛋白的最高清除率可达19.67%。     

富硒蛹虫草抗氧化作用研究

从富硒蛹虫草中提取硒多糖和硒蛋白。分别采用ICP-MS 法和苯酚硫酸法及考马斯亮蓝法对硒多糖和硒蛋白中硒、多糖及蛋白含量进行测定;在Fenton 体系中,以510nm 波长处的吸光度研究硒多糖和硒蛋白对羟自由基的清除作用。结果表明：硒多糖和硒蛋白清除羟自由基的效果强于相同浓度的无机硒、多糖及蛋白;其中,富硒蛹虫草硒多糖的对羟自由基最高清除率为38.02%,而硒蛋白的最高清除率可达75.00%。     

猪苓硒多糖连续合成工艺及抑菌性能研究

采用化学合成法,以猪苓多糖和亚硒酸钠为原料制备猪苓硒多糖.试验设计连续式合成工艺流程,并对硒多糖的连续式超声波辅助化学合成工艺条件进行研究;对所制备的硒多糖进行抑菌性能研究,并与猪苓多糖进行比较.结果表明,猪苓多糖、氯化钡、亚硒酸钠溶液浓度均为0.2 mg/mL,采用连续式合成猪苓硒多糖的最佳工艺条件为多糖进料流量30 mL/min,亚硒酸钠溶液与猪苓多糖溶液流量配比1∶1,反应温度70℃、反应釜内硝酸的浓度0.008 mL/mL,超声辅助合成频率为30 kHz,其合成率达26.5 mg/g;抑菌性能研究表明,猪苓硒多糖对大肠杆菌、金黄色葡萄球菌、啤酒酵母和黑曲霉均有抑制作用,且其抑菌能力明显优于猪苓多糖.     

枸杞多糖的硒化及其对人宫颈癌细胞的抑制作用

在硝酸催化作用下,利用亚硒酸钠对枸杞多糖进行分子修饰,合成硒化枸杞多糖,反应条件为硝酸体积分数0.5%,70℃反应10h,透析24h。采用体外抗肿瘤实验测定硒化枸杞多糖对人宫颈癌细胞生长的抑制作用。结果显示硒化枸杞多糖对人宫颈癌细胞具有一定的抑制作用,与未硒化的枸杞多糖相比有显著性差异,且呈一定的剂量依赖性。     

蜜环菌对硒的富集及多糖中硒的分布

采用不同的硒浓度对蜜环菌进行了补硒培养,研究了蜜环菌对硒的积累和存胞内外多糖中的分布.结果表明:菌丝体硒含量与多糖硒含量随着硒处理浓度的增加而增加,但硒积累量达到20mg/L后趋于稳定,胞内多糖的硒积累量达到10mg/L后趋于稳定,而胞外多糖硒积累量在硒处理浓度超过5mg/L后仍有增长趋势.     

枸杞硒多糖的合成及对人体肝癌HepG2细胞增殖的体外抑制作用评价

根据有机硒化合物的合成方法,本文以枸杞多糖和亚硒酸钠为原料,采用响应面法优化枸杞硒多糖的工艺条件。利用原子荧光、体外化学反应等分析技术测定了枸杞硒多糖中的硒含量,并用MTT法对枸杞硒多糖抑制人体肝癌细胞增殖的活性进行了初步评价。结果表明:制备枸杞硒多糖的最优条件是按照LBP为1 g计算,加入0.62 g Na₂SeO₃,用1% HNO₃充分溶解,再加入BaCl₂ 1 g,74 ℃反应9 h。在此条件下,枸杞硒多糖中的硒含量为648.65 μg/g。活性结果显示,枸杞多糖和枸杞硒多糖对HepG2细胞均有一定的抑制作用,所有枸杞硒多糖的抑制作用明显优于枸杞多糖,并且硒含量最高的Se-LBP₄组对肿瘤细胞HepG2的抑制效果最佳,抑制率为38.15%。枸杞硒多糖抑制HepG2增殖能力与其硒的含量呈正相关,有望作为食品、保健食品和医药的原料进一步开发。     

硒对蜜环菌的作用规律及其在多糖中的积累

采用不同硒浓度对蜜环菌进行了补硒培养,研究了硒对蜜环菌生长、蜜环菌多糖产率的影响以及蜜环菌对硒的积累。结果表明:浓度为10mg/L以下的硒能够促进蜜环菌的生长,超过该浓度之后,硒对蜜环菌的生长产生阻碍;在所设计的浓度范围内,硒能够促进蜜环菌胞内外多糖的合成和分泌。蜜环菌胞内外多糖中硒质量分数都随着硒处理浓度的增加而增加,但硒积累量变化趋势不尽相同。胞内多糖的硒积累量在硒处理浓度为10mg/L时后趋于稳定;胞外多糖硒积累量在硒处理浓度超过5mg/L后仍有增长趋势。     

硒多糖提取、结构和生物活性的研究进展

硒多糖是一种具备硒和多糖双重活性的化合物,是一种新型的膳食硒补充剂。近年来对硒多糖的结构和生物活性的研究越来越深入,但硒多糖的结构复杂,合成方法比较局限,缺乏系统性的归纳总结。该文主要对近年来硒多糖的提取及纯化、不同硒化方式下多糖的结构表征、硒与多糖的结合方式以及硒多糖在体内外的生物活性研究进行综述,旨在为硒多糖的深入研究与探索及其产品的开发与利用提供合理有价值的参考。     

款冬花硒多糖的制备及抗氧化性研究

本文对款冬花多糖(TFPs)进行硒化修饰工艺优化研究,并初步探讨了其抗氧化活性.研究采用亚硒酸钠硒化法,制备款冬花硒化多糖(STFPs);以多糖中硒含量为指标,采用响应面法对制备工艺条件进行优化;并进行STFPs清除DPPH·、O2-·和OH·的实验,研究其体外抗氧化活性.得到最佳硒化条件为:硒化试剂质量比(m(亚硒酸钠)∶m(款冬花多糖))=1.06∶1,反应温度70℃,时间11h,硝酸体积分数0.5％.此时STFPs中的平均硒含量为3.84mg/g,与TFPs相比,清除DPPH自由基的能力显著提高,对O2-,OH·的清除能力也有一定程度的提高.     

南瓜硒多糖的制备表征及活性分析

对南瓜多糖进行硒化修饰,并对南瓜硒多糖的体外抗氧化和抑制人乳腺癌细胞MDA-MB-231生长等活性进行研究。以提取、分离、纯化的南瓜多糖为前体物,用Na2SeO3硒化修饰制备南瓜硒多糖,并用紫外光谱、红外光谱、原子荧光光谱、热重分析对产物结构进行表征,采用邻苯三酚自氧化法、水杨酸法、四甲基偶氮唑蓝比色法测定其清除超氧阴离子自由基（O2－•）、羟自由基（•OH）的能力以及对人乳腺癌细胞MDA-MB-231生长的抑制作用。结果表明：制备产物结构中含有Se＝O键和Se-C键,即实现了南瓜多糖的硒化。南瓜硒多糖对O2 － ·、·OH的清除作用显著强于南瓜多糖,与样品量呈正相关;南瓜硒多糖对人乳腺癌细胞MDA-MB-231生长有抑制作用,比南瓜多糖具有更好的抑制效果。     

Separation of phospholipids from hen egg yolk by short packed silica gel column chromatography

Short packed silica gel column chromatography has been performed to optimize the production of phosphatidylethanolamine (PE) and phosphatidylcholine (PC) from hen egg yolk with very low or no toxic solvents. The effects of silica type, sample loading amount, dimension of the glass chromatotube, and mobile phase compositions were investigated and high separation efficiency was achieved: gradient elution as 200 mL ethanol followed by 300 mL 95% ethanol to fractionate PE and PC after neutral lipids (NL) removed by 120 mL ethyl acetate, 40 mm silica gel (54 to 74 μm) bed height of the chromatotube with 22 mm inner dia (ID), and 0.25 g sample loading amount. By this procedure, 3.69 g PE and 2.88 g PC per 100 g egg yolk lipids were obtained, respectively. The refined PE and PC were identified by high-performance liquid chromatography/ultraviolet detector (HPLC-UV) with purity over 96%. The fatty acids in egg yolk revealed that PE and PC characterized higher ratios of n- 6/n- 3 (PE, 7.41; PC, 8.99). 18:2 n- 6 of PC (15.21%) predominated over PE (10.29%), whereas the level of 20:4 n- 6 of PC (8.78%) was lower than PE (15.67%).     

红毛藻藻红蛋白的分离纯化及性质研究

从红毛藻(Bangiafusco-purpurea)中分离纯化得到纯度较高(A565/A280为5.0)的藻红蛋白(phycoerythrin,PE)。纯化过程包括:硫酸铵分级沉淀,阴离子交换柱层析,凝胶过滤柱层析。通过扫描藻红蛋白的紫外可见光谱,确定其为R-藻红蛋白。用SDS-PAGE及银染色法测定了组成R-藻红蛋白各亚基的相对分子量。并研究了pH值、温度、光照等理化因子对R-藻红蛋白稳定性的影响。     

草鱼头磷脂制备工艺优化及抗氧化性能分析

为了得到较高纯度的草鱼头磷脂并分析其抗氧化性能,采用乙醇溶液浸提冷冻干燥草鱼头粉末制备磷脂,正交试验确定其最优工艺后,利用薄层层析(TLC)分析比较草鱼头磷脂种类的组成及含量,利用气相色谱-质谱联用技术分析磷脂的脂肪酸组成,并进行体外抗氧化能力测定。结果表明:磷脂制备最优工艺方案为:乙醇浓度80%,料液比1:6 g/mL,提取温度65℃,提取时间3 h,在此条件下,得到草鱼头磷脂的纯度为84.20%±0.65%,提取率为3.03%±0.06%。草鱼头磷脂主要含有磷脂酰胆碱(PC)、磷脂酰乙醇胺(PE)、鞘磷脂(SM)、溶血磷脂酰胆碱(LPC)四种磷脂,其中PC的含量最高(60.00%±0.26%),其次为PE(20.00%±0.17%)。草鱼头磷脂脂肪酸组成以多不饱和脂肪酸(PUFA)为主(52.09%±0.59%),其中,C20:5n-3(EPA)和C22:6n-3(DHA)含量较高。体外抗氧化测定试验结果表明,草鱼头磷脂的羟自由基(·OH)清除能力和还原力能力都显著(P<0.05)优于对照的商品大豆磷脂。     

Effects of physicochemical factors and in vitro gastrointestinal digestion on antioxidant activity of R‐phycoerythrin from red algae Bangia fusco‐purpurea

R‐phycoerythrin (R‐PE) was purified from the red algae Bangia fusco‐purpurea after 35–50% ammonium sulphate fractionation followed by ion‐exchange column chromatography on DEAE‐Sepharose, resulting in a purity (A₅₆₅/A₂₈₀) ratio of 5.1. The circular dichroism spectroscopy results suggested that the structure of R‐PE is predominately helical. The antioxidant activity of R‐PE was studied and revealed changes in conformation and antioxidant activity at different temperatures and pH values. After in vitro‐simulated gastrointestinal (GI) digestion of R‐PE, the scavenging activity of ABTS radical (EC₅₀, 769.9 μg mL^?1), DPPH radical (EC₅₀, 421.9 μg mL^?1), hydroxyl radical (EC₅₀, 32.4 μg mL^?1) and reducing power (A₇₀₀ = 0.5, 625.8 μg mL^?1) were measured. Gel filtration chromatography analysis showed that the molecular weight distribution of the final GI digest that still contained high antioxidant activity was <3 kDa. Our present results indicate that digestion‐resistant antioxidant peptides of R‐PE may be obtained by in vitro GI proteinases degradation.     

Technical note: immunomagnetic procedure for positive selection of macrophages in ovine milk

A simple immunomagnetic procedure was developed to select macrophages from ovine milk by using a non-specific magnetic positive separation technique. Samples of ewe bulk milk were collected during early, mid, and late lactation; milk samples were centrifuged at 2,000 × g for 30 min at 4°C; the fatty fraction and supernatant were removed, and each pellet was dissolved in 500 μL of pH 7.4 phosphate buffered saline + 0.02% NaN₃. Cells were targeted for selection by using mouse-IgG anti-ovine macrophages. Several trials, testing 2 different fluorochrome-conjugated antibodies [i.e., mouse anti-human CD14:R-Phycoerythrin (RPE) (MCA1568PE, Serotec) and F(ab′)2 rabbit anti-mouse IgG:RPE (STAR12A, Serotec)] and 3 different labeling procedures, were performed to evaluate the purity of samples by flow cytometry. A morphological test was carried out by direct microscopic count in enriched fraction smears stained with May-Grünwald-Giemsa stain to confirm the presence of macrophages. The method described in the present technical note can be considered an innovative application to obtain a single-cell population of high purity selected from all the somatic cells in milk.     

Molecular species of phosphatidylethanolamine from continuous cultures of Saccharomyces pastorianus syn. carlsbergensis strains

Saccharomyces pastorianus syn. carlsbergensis strain 34/70 is well known to be the most used strain for lager beer production. The difference between this strain and very closely related strain 34/78 is the latter's greater flocculating character. This single physiological trait can cause technical difficulties in beer production. The aim of this study was to determine whether lipid analysis by a combination of thin layer chromatography (TLC) with electrospray ionization mass spectrometry (ESI-MS) could be used as a strain-typing technique in order to distinguish S. pastorianus syn. carlsbergensis strain 34/70 from strain 34/78. Both strains (34/70 and 34/78) were harvested after continuous culture under standard conditions. Polar lipids were then extracted from lyophilized cultures and analysed by TLC in order to separate phospholipid families. Phosphatidylethanolamine (PE) was extracted and investigated using ESI-MS, to gain further information on individual molecular species. Using TLC analysis, lipids were separated corresponding to standards for PE, phosphatidylcholine (PC), phosphatidylglycerol (PG), cardiolipin (CL), phosphatidylserine (PS), phosphatidylinositol (PI), phosphatidic acid (PA) and sphingomyelin (SM). ESI-MS of the PE band, separated by TLC, showed that electrospray mass spectra were highly reproducible for repeat cultures. Novel findings were that both brewing strains displayed major phospholipid peaks with m/z 714, PE (34 : 2) m/z 742, PE (36 : 2) and m/z 758, PE (37 : 1). However, strain 34/78 had additional peaks of m/z 700, PE (33 : 2) and m/z 728, PE (35 : 2). Strain 34/70 had an extra peak with m/z 686 PE (32 : 2). We conclude that combined TLC/ESI-MS can distinguish between S. pastorianus syn. carlsbergensis 34/70 and 34/78 and may be a useful typing technique for differentiation of closely related yeast strains. This novel approach may aid quality assurance and could be suitable for yeast collections and larger industrial companies.     

Physicochemical, nutritional, and antimicrobial properties of wine grape (cv. Merlot) pomace extract-based films

Abstract: Wine grape pomace (WGP) (cv. Merlot) extract‐based films were studied in terms of their physicochemical, mechanical, water barrier, nutritional, and antibacterial properties. Pomace extract (PE) was obtained by hot water extraction and had a total soluble solid of 3.6% and pH 3.65. Plant‐based polysaccharides, low methoxyl pectin (LMP, 0.75% w/w), sodium alginate (SA, 0.3% w/w), or Ticafilm^® (TF, 2% w/w), was added into PE for film formation, respectively. Elongation at break and tensile strength were 23% and 4.04 MPa for TF‐PE film, 25% and 1.12 MPa for SA‐PE film, and 9.89% and 1.56 MPa for LMP‐PE film. Water vapor permeability of LMP‐PE and SA‐PE films was 63 and 60 g mm m^?2 d^?1 kPa, respectively, lower than that of TF‐PE film (70 g mm m^?2 d^?1 kPa) (P < 0.05). LMP‐PE film had higher water solubility, indicated by the haze percentage of water after 24 h of film immersion (52.8%) than that of TF‐PE (25.7%) and SA‐PE (15.9%) films, and also had higher amount of released phenolics (96.6%) than that of TF‐PE (93.8%) and SA‐PE (80.5%) films. PE films showed antibacterial activity against both Escherichia coli and Listeria innocua, in which approximate 5‐log reductions in E. coli and 1.7‐ to 3.0‐log reductions in L. innocua were observed at the end of 24 h incubation test compared with control. This study demonstrated the possibility of utilizing WGP extracts as natural, antimicrobial, and antioxidant promoting film‐forming material for various food applications. Practical Application: WGP extract‐based edible films with the addition of a small amount of commercial polysaccharides showed attractive color and comparable mechanical and water barrier properties to other edible films. The films also demonstrated their potential antioxidant and antimicrobial functions. Hence, they may be used as colorful wraps or coatings for food, pharmaceutical, or other similar applications.     

龙葵果花色苷的分离与鉴定

采用硅胶柱层析技术分离制备龙葵果花色苷。分离得到的2 个花色苷馏分经紫外-可见光谱、高效液相色谱-电喷雾串联质谱（high performance liquid chromatography electrosprary ionization-mass spectrometry,HPLC-DADESI-MS/MS）进行结构鉴定,并结合酸水解分析糖苷种类。最终确定馏分Ⅰ为飞燕草素-3-琥珀酰阿拉伯糖苷,根据峰面积归一化法计算其纯度为94%;馏分Ⅱ为矢车菊素-3-半乳糖苷和矢车菊素-3-乙酰半乳糖苷,峰面积归一化法计算其纯度分别为45.67%和13.97%。     

鞣花酸和石榴皮多酚提取物抗氧化活性的比较

对鞣花酸提取物(EA)和石榴皮多酚提取物(PE)的抗氧化活性进行比较研究。通过HPLC法检测EA和PE中鞣花酸的含量,Folin-酚法检测PE中总多酚含量;采用H2O2处理HepG2细胞建立细胞氧化应激损伤模型,MTT法比较不同浓度的EA和PE对HepG2细胞氧化应激损伤的保护作用;采用DPPH法、·OH清除法检测PE和EA体外抗氧化作用。结果表明:与EA相比,PE中鞣花酸含量很低,但PE和EA均以剂量依赖的方式提高氧化损伤的HepG2细胞生存率,有显著的保护作用,且在同一的浓度下,PE的保护作用显著高于EA。PE和EA对DPPH法、·OH清除法的清除率均呈剂量依赖性增强。     

苦瓜果实中多糖的分离纯化及性质分析

以苦瓜果实为材料,经热水抽提、乙醇沉淀和Sevag 法去蛋白后获得了苦瓜果实粗多糖(MCP)。MCP 经DEAE- 纤维素柱离子交换柱层析分离得到4 个级分MCP-A、MCP-B、MCP-C 和MCP-D。MCP-A 经Superdex G-100 柱进一步纯化得到苦瓜果实多糖MCP-A1 组分。MCP-A1 经高效凝胶渗透色谱法(HPGPC)鉴定为均一组分,测定其平均分子量为93577D。经过对其理化性质鉴定表明,MCP-A1 不含蛋白质、核酸,含有糖醛酸,为非淀粉类多糖。红外光谱扫描结果表明,其具有典型的多糖吸收峰。