Brown Macroalgae (Phaeophyceae): A Valuable Reservoir of Antimicrobial Compounds on Northern Coast of Spain

The search for new sources of antimicrobial compounds has become an urgent need, due to the threat that the spread of bacterial resistance represents for global health and food safety. Brown macroalgae have been proposed as a great reservoir in the search for novel antimicrobial compounds. In this study, mid-polarity extracts were performed with a selection of 20 brown macroalgae species from northern Spain. The total polyphenol, carbohydrate and protein contents were quantified by spectrophotometry. The volatile organic compounds (VOCs) of whole macroalgae were also studied as a biomarker of their metabolic state in the representative species of the tested families by gas chromatography-mass spectrometry (GC-MS). The antimicrobial potential of the extracts was assessed by a disk diffusion assay against 20 target bacteria and further determinations of the minimum inhibitory (MIC) and minimum bactericidal concentrations (MBC) were performed by a microdilution assay for the active extracts. Ericaria selaginoides, Bifurcaria bifurcata and Dictyota dichotoma showed an antimicrobial effect against six Gram-positive strains: Bacillus cereus, Bacillus subtilis, Geobacillus stearothermophilus, Listeria monocytogenes, Staphylococcus aureus and Staphylococcus haemolyticus. The phenolic content was generally higher in the extracts that showed antimicrobial activity, followed by carbohydrates and low contents of proteins. The results obtained in this study reveal the potential of brown macroalgae as a promising alternative source of antimicrobial compounds as functional ingredients for the application in industrial fields.     

我国热带海水大型珍珠贝类的珍珠养殖技术现状及对策建议

为改善马氏珠母贝 (Pinctada martensii) 外套膜组织和细胞体外培养的效果,探究了添加不同浓度的天然提取物茶多酚对外套膜组织和细胞培养液的优化效果。结果显示,当茶多酚的添加量为0.5%~2.0% (体积分数) 时,马氏珠母贝外套膜细胞的生物活性显著高于对照组 (P<0.05);当添加量为1.0%时,相对细胞生物活性最高。5组完全培养液 (0%、0.5%、1.0%、1.5%、2.0%组) 均能较好地促进细胞的生长增殖,且细胞的生长曲线均呈“S”型;当培养液中茶多酚的添加量为1.0%时,外套膜细胞增殖效果最优。研究表明,马氏珠母贝外套膜组织和细胞在最适培养液中均能大量增殖游离细胞,且正常分泌珍珠质,其中培养液中的钙离子 (Ca²⁺) 浓度随着组织和细胞增殖过程呈先减后增的趋势,但始终低于初始浓度。研究结果进一步优化了马氏珠母贝外套膜组织和细胞培养液,为推动马氏珠母贝无核珍珠的培育提供了理论基础。

     

茶多酚对固始鸡生产性能和脂类代谢的影响

为了研究茶多酚对固始鸡生产性能和脂类代谢的影响,选取1日龄固始鸡90只,随机分为3组,1组为对照组,饲喂基础日粮,2、3组为试验组,分别在基础日粮中添加质量分数为0.025%和0.050%的茶多酚。于21日龄、42日龄时测定血清中脂类指标,于42日龄时测定腹脂率、肝脂率和生产性能。结果显示:0.025%、0.050%的茶多酚能降低试鸡血液中总胆固醇、甘油三酯和低密度脂蛋白胆固醇的含量,明显增加血液中高密度脂蛋白胆固醇含量,降低鸡的腹脂率和肝脂率,试验期试鸡的生产性能未受到任何影响。上述结果表明,饲料中添加茶多酚有利于改善固始鸡的脂类代谢。     

加工模式对烟叶梗丝多酚类及其烟气挥发酚化合物的影响

为低害梗丝加工工艺设计参数的优化选择提供参考,采用流化床、滚筒和气流干燥3种加工模式处理梗丝卷制卷烟,分别测定梗丝中多酚化合物含量及卷烟烟气挥发酚的释放量。结果表明:不同产地梗丝中的3种主要多酚类物质含量存在差异,河南产地梗丝中的绿原酸和莨菪亭含量最高,分别为12.79~14.05mg/g和6.43~5.50mg/g,云南产地梗丝中的芸香苷含量最高,为1.60~1.86mg/g;不同加工模式下,梗丝多酚类物质含量及其烟气挥发酚释放量有差异,其中,滚筒流化床气流干燥;主流烟气挥发酚释放量与其梗丝多酚类化合物具有相关性,相关系数为-0.639~0.913。采用气流干燥模式更有利于降低烟叶多酚类化合物及其烟气挥发酚物质含量。     

不同窖藏时间丹溪红曲酒活性成分及抗氧化评价

为探究不同窖藏时间（3、5、8、15和20年）丹溪红曲酒的活性成分及抗氧化能力,参照GB/T 13662—2018《黄酒》的方法对酒精度、总酸、pH、总糖和非糖固形物含量进行测定,采用3,5-二硝基水杨酸比色法对还原糖进行测定,采用福林酚法对总多酚和总黄酮含量进行测定,利用1,1-二苯基-2-苦肼基（DPPH）自由基清除能力和氧自由基吸收能力（ORAC）评价红曲酒的体外抗氧化能力,并且运用高效液相色谱（HPLC）法测定红曲酒中洛伐他汀的含量。结果表明：1）总糖含量随着窖藏时间的增加先降低后升高,窖藏20年的红曲酒总糖和还原糖的质量浓度最高,分别为46.92和22.35g/L;非糖固形物的含量随着窖藏时间的增加先升高后降低,窖藏8年的红曲酒非糖固形物的质量浓度最高,为33.95g/L;2）总多酚及总黄酮含量随着窖藏时间的增加先小幅升高后降低,窖藏5年的红曲酒总多酚及总黄酮质量浓度最高,分别为6.49和4.23mg/mL;3）各窖藏时间红曲酒均具有较强的抗氧化能力,其中窖藏3年的红曲酒对DPPH自由基的清除能力最强,8年红曲酒具有最高的ORAC值;4）各窖藏时间红曲酒中洛伐他汀含量较为稳定...     

管道补口热收缩带粘接质量的超声检测方法

为解决管道补口热收缩带剥离强度人工抽检效率低、人为因素影响大的问题,通过超声波理论分析以及对不同粘接强度管道补口试件的试验分析,以及采用超声检测技术对管道补口热收缩带的粘接质量进行无损检测,实现剥离强度的定性及半定量评价,确定了能够明显反映管道补口热收缩带剥离强度的超声波特征参数。研究表明：超声波信号平均功率和低频能量两个参量与热收缩带剥离强度呈反比,可用于剥离强度的全面、快速检测。基于这两个参数指标,采用超声波反射法对补口样品的测试结果与补口样品手动机械拉伸测试结果一致,验证了参数选择的有效性。超声波特征参数可为建立补口热收缩带粘接质量的超声无损检测方法提供参考依据。     

氟对茶叶品质成分代谢的的影响

通过盆栽试验研究氟了对茶树新梢生长和品质成分含量的影响。适量增加土壤氟水平能提高新梢产量,但在高氟水平下新梢产量明显下降。茶多酚、咖啡碱及儿茶素(EGCG等)的含量随土壤氟水平的增加而逐渐降低,高氟水平下新梢的游离氨基酸含量也显著下降,苯丙氨酸解氨酶(PAL)、谷氨酸合成酶(GOGAT)的活性也随土壤和茶树氟浓度的增加而下降,说明氟可能抑制茶树儿茶素的合成代谢和氮素代谢。上述结果表明,氟对茶树生长和品质成分的影响与氟水平有关,虽然低浓度氟对茶树生长有一定的促进作用,但高浓度氟抑制茶树生长和茶多酚、氨基酸等品质成分的代谢。     

Analysis of polyphenols in cereals may be improved performing acidic hydrolysis: A study in wheat flour and wheat bran and cereals of the diet

Most analytical studies on polyphenols in cereals refer to compounds determined in aqueous-organic extracts and alkali hydrolysates, but an appreciable amount of polyphenols bound to cell wall constituents may remain insoluble in the residues of extraction and alkali hydrolysis. The main objective of this work was to determine if sulphuric acid hydrolysis may release significant amounts of polyphenols to be considered for analytical and nutritional studies. HPLC/MS analyses of polyphenols were performed in methanol–acetone extracts, alkali and sulphuric acid hydrolysates of wheat flour, bran and a pool of cereals of the diet. The amount of polyphenols found in the acidic hydrolysates (200–1600 mg/100 g) was higher than in alkali hydrolysates (0.2–372 mg/100 g). Lower amount of polyphenols were found in the methanol–acetone extracts (44–160 mg/100 g). Hydroxybenzoic, caffeic, cinammic, ferulic and protocatechuic acids were the main constituents of the hydrolysates. The contribution of cereals to the intake of dietary polyphenols in Spain was estimated around 360 mg/person/day (65 mg of extractable and 295 mg nonextractable polyphenols).     

茶多酚片治疗慢性肾小球肾炎的临床观察

按照多中心临床试验的原则评价了茶多酚片治疗慢性肾小球肾炎（肺肾气虚症）的有效性和安全性,采用多中心、分层区组随机、双盲双模拟、阳性药物（肾炎四味片）平行对照,观察病例240例,治疗组和对照组各120例,观察周期为8周。治疗8周后,茶多酚片组的疾病疗效、证候疗效、尿蛋白疗效和尿红蛋白疗效的愈显率分别为：35.0%、38.5%、49.6%和59.7%;同时有效率分别为：71.8%、86.1%、80.0%和72.6%,与对照组（肾炎四味片）组间比较均无统计学差异。实验过程中均未见不良反应及严重不良事件发生,茶多酚片组与肾炎四味片组受试者均评价为安全性1级。结果表明,茶多酚片是治疗慢性肾小球肾炎（肺肾气虚症）安全有效的药物,其疗效不低于肾炎四味片。     

近10年我国茶多酚发明专利的统计报告

本文对近10年来我国公开的茶多酚发明专利数量和分类进行了统计分析,并将其与茶的发明专利、茶叶产量的变化相结合,进行数据比较,结果表明,茶多酚在生活需要方面的发明专利在整个发明专利中一直处于主导地位,占年茶多酚专利数量65%;茶多酚应用于保健食品是目前发明专利中的一个重点,茶的发明专利数与茶叶总产量的增长趋势基本相符。说明茶多酚的研究与茶叶生产相互推动。