碱解小麦麦麸制备阿魏酸的工艺条件研究

研究以小麦麸皮为原料碱解制备阿魏酸的工艺条件.用淀粉酶和蛋白酶酶解除去麦麸中的淀粉和蛋白质,氢氧化钠碱解制得阿魏酸,并以阿魏酸量为考察指标通过正交试验确定碱解麦麸制备阿魏酸的最佳工艺条件.试验结果表明:酶解50 g麦麸,两种酶的最佳用量分别为:耐高温α-淀粉酶0.45 g,中性蛋白酶0.5 g;碱解麦麸制备阿魏酸的最佳工艺条件:氢氧化钠浓度1%,碱解温度85℃,碱解时间4 h;在此条件下水解50 g麦麸可获得406.2 mg阿魏酸.此工艺条件可用于小麦麦麸制备阿魏酸.     

利用麦麸制备阿魏酸条件研究

该文研究以麦麸为原料制备阿魏酸技术路线。首先采用淀粉酶和蛋白酶除去麦麸中部分淀粉 和蛋白质,然后通过正交实验确定碱解麦麸制备阿魏酸最佳工艺条件:氢氧化钠浓度0.5％,水解温度 60℃,水解时间6 h,添加0.03％亚硫酸钠;并采用HPLC检测阿魏酸。     

碱解麦麸制备阿魏酸的研究

将麦麸脱脂、去蛋白质后采用正交实验,确定了碱解麦麸释放阿魏酸的最佳工艺为:氢氧化钠浓度0.5%,提取温度85℃,提取时间6h。提取液中添加100mg/L的亚硫酸钠能增加释放出的阿魏酸的保留率,并可通过增加碱浓度而缩短提取时间。碱降解后剩余的残渣较之原麦麸更易被盐酸和黑曲霉分泌的多糖水解酶降解,显示残渣可作为制备低聚糖的基料。     

小麦麸皮阿魏酸的制备

本文以小麦麸皮为原料,采用碱法和酶法制备阿魏酸,通过正交试验确定出制备阿魏酸的最佳工艺参数,碱液浸提法阿魏酸最高释放量为3.08mg/g麦麸,最优组合是碱液浓度为1%,温度为80℃,提取时间为4h,麸皮粒度为80目;酶法提取的最高释放量为3.35mg/g麦麸,最优组合是料液比1∶20,混合酶浓度1%,混合酶作用时间3h。另外,碱处理后的反应液颜色为深棕色,褐变较为严重;混合酶处理后反应液颜色较浅。酶法提取效果较佳。     

碱法提取麸皮中阿魏酸的工艺条件研究

以小麦麸皮为原料,利用α-淀粉酶和碱性蛋白酶去除麸皮中的淀粉和蛋白质,用氢氧化钠溶液水解小麦麸皮制备阿魏酸,以阿魏酸提取量为指标通过正交实验确定最佳工艺条件。结果表明:去除50 g麦麸中的淀粉和蛋白质时,α-淀粉酶的最佳用量为3 mL,碱性蛋白酶的最佳用量为0.3 g;碱解麸皮制备阿魏酸的最佳工艺条件为:氢氧化钠质量分数为1%,料液比为1:15,碱解时间2 h,碱解温度80℃。在此条件下,阿魏酸的最佳提取量为2.47 mg/g。     

米糠蛋白提取工艺条件的优化

以米糠为原料,分别采用碱法和酶法对米糠蛋白进行提取。在提取过程中,以蛋白提取率为指标,确定料液比、酶用量、时间和温度对米糠蛋白提取率的影响,通过正交试验确定最佳提取工艺。结果表明：碱法最佳提取工艺为料液比1:10(g/mL)、提取时间2.5h、提取温度45℃,米糠蛋白提取率可达57.8%。酶法最佳提取工艺为酶用量2%(E/S)、酶解时间2.5h、酶解温度50℃,米糠蛋白提取率可达38.4%。     

小麦麸皮阿魏酸的制备

本文以小麦麸皮为原料，采用碱法和酶法制备阿魏酸，通过正交试验确定出制备阿魏酸的最佳工艺参数，碱液浸提法阿魏酸最高释放量为3.08mg／g麦麸，最优组合是碱液浓度为1％，温度为80℃，提取时间为4h，麸皮粒度为80目；酶法提取的最高释放量为3、35mg／g麦麸，最优组合是料液比1：20．混合酶浓度1％。混合酶作用时间3h。另外，碱处理后的反应液颜色为深棕色，褐变较为严重；混合酶处理后反应液颜色较浅。酶法提取效果较佳。     

高温蒸煮麦麸提取阿魏酸低聚糖的研究

本文采用高温蒸煮法处理麦麸,提取麦麸中的阿魏酸低聚糖.在试验中,主要研究了不同处理时间、不同处理温度对阿魏酸得率的影响.结果表明:当温度为170℃,保温时间为10min,阿魏酸低聚糖提取量最高,可达1.153×10-5 mol/g麦麸.     

纤维素酶法提取辣椒碱的工艺研究

研究了纤维素酶(16568U/g)提取辣椒中辣椒碱的工艺.研究发现:酶解液初始pH值5.2,酶量为7 mg/g,酶解时间3 h,酶解温度40 ℃为酶解最适条件.通过酶解处理后的辣椒碱产量为3.096 mg/g,比传统的乙醇提取法提高了约16 %,而且该法提取辣椒碱时间短、温度要求低、操作简单.     

超声波辅助酶法提取玉米皮阿魏酸的工艺优化及抗氧化研究

采用响应面法优化超声波辅助木聚糖酶联合提取玉米皮中阿魏酸工艺,建立阿魏酸得率与超声温度、超声时间、酶添加量、酶解时间四因素的数学模型,确定玉米皮阿魏酸的最适提取工艺参数;以清除自由基能力评价玉米皮阿魏酸的抗氧化活性。结果表明:玉米皮阿魏酸提取的最佳工艺条件为超声温度33℃、超声时间80 min、酶添加量0.83%、酶解时间65 min、酶解温度50℃,阿魏酸得率为3.47 mg/g。在此优化条件下,玉米皮阿魏酸对DPPH自由基、羟自由基及超氧阴离子自由基均具有较强清除作用,半数抑制浓度分别为0.552、0.282和0.111 mg/m L。     

竞争中寻求差异差异中寻求认同如何提升珠宝首饰品牌竞争力

伴随着珠宝首饰业的迅猛发展，行业竞争不断激烈，首饰业中的批发，加盟连锁，加工等业务均不同程度地在发生转变，企业中传统的“商标”意识逐渐向“品牌”意识转型已成为市场发展的规律。     

Bifidobacterium species isolated from animal feces and from beef and pork meat

Bifidobacteria were isolated from 122 of 145 samples of animal feces (from cattle, swine, sheep, goats, horses, rabbits, chickens, geese, and pigeons) from farms in France and Austria and from 92 of 955 production and processing chain samples of beef and pork (obtained at slaughter, cutting, and retail). Bacterial strains were identified to species by phenotypic numerical classification based on API 50CH and ID 32A tests and DNA-DNA hybridization. Bifidobacterium pseudolongum was present in 81% (99 of 122 samples) of all Bifidobacterium-positive fecal samples and predominated in samples from all animal species except those from swine from Austria. In these Austrian swine samples, the majority of strains were identified as Bifidobacterium thermophilum (78%), followed by B. pseudolongum (48%). The distribution of B. thermophilum and B. pseudolongum differed significantly between Austrian swine and cattle samples such as those collected along beef and pork production and processing chains. Bifidobacterium animalis was isolated from swine feces, and Bifidobacterium ruminantium was isolated from cow dung. Six fecal isolates (from cattle, swine, rabbits, goats, and horses) were identified as belonging to Bifidobacterium species of predominantly human origin: B. adolescentis, B. bifidum, and B. catenulatum. Only one other species, Bifidobacterium choerinum, was detected with low frequency in a pork processing chain. B. pseudolongum subsp. pseudolongum was predominant in pig feces, whereas B. pseudolongum subsp. globosum was predominant in feces from other animal species. Four strains closely related to both subspecies (58 to 61% DNA reassociation) formed a distinct genomic group. PCR techniques, which are more rapid and sensitive than culture-based methods, could be used to detect directly B. pseudolongum and B. thermophilum as indicators of fecal contamination along the meat processing chain.     

Purification and characterization of X-prolyl-dipeptidyl-aminopeptidase from Lactobacillus lactis and from Streptococcus thermophilus

X-Prolyl-dipeptidyl-aminopeptidase recently was found in several lactic acid bacteria. This article describes the purification of the enzymes from Lactobacillus lactis and Streptococcus thermophilus and compares their characteristics. Enzymes from both strains are serine-peptidases. They both have a molecular weight of about 165,000 daltons, an isoelectric point near 4.5, and are constituted of two subunits. The pH optimum of the enzyme isolated from L. lactis is 7.0, whereas the enzyme from S. thermophilus possesses a broad pH optimum between 6.5 and 8.2 with glycyl-L-prolyl-aminomethylcoumarin as substrate. Below pH 5, both enzymes are unstable; however, that from S. thermophilus is more rapidly denatured. The enzyme from S. thermophilus is more sensitive to heat than the corresponding enzyme from L. lactis. Enzymes from the both strains have different specificities towards various substrates and are differently effected by metals, chelators, and other inhibitors. The importance of this enzyme for the metabolism of lactic acid bacteria is discussed.     

Malnutrition and dietary protein: evidence from China and from international comparisons

Malnutrition, as measured by anthropometric status, is a powerful risk factor for illness and elevated death rates throughout life. Understanding the relative importance of disease, dietary quantity, and dietary quality in causing malnutrition is therefore of major importance in the design of public policy. This paper contributes to the understanding of the relative importance of quantity and quality of diet by utilizing aggregate data to complement previously reported individual-level studies. Three compilations of anthropometric data--one involving subjects from 13 provinces in China, another involving subjects from 64 counties in China, and a third involving 41 populations in 40 countries--are used to examine the relative importance for human growth of inadequacies of dietary energy and protein. The analysis involves regressing average adult heights and weights against estimates of average energy and protein availability (by province, county, or country) and per capita incomes. We use protein availability in part as a marker for overall quality of the diet, while recognizing that protein is far from perfectly correlated with dietary fat or micronutrient availability. The paper discusses issues of both data quality and statistical methodology, and points to relevant resulting caveats to our conclusions. Subject to these limitations, all three analyses suggest that, at the levels of dietary intake in these populations, lower protein intake is related to growth failure whereas lower levels of energy availability are not. The protein effect appears stronger for males than for females.     

Isolation and Properties of Starch from Wild Yam from Zimbabwe

Wild Yam (Dioscorea dumetorum) was collected during the wet as well as dry season in the bush of Zimbabwe. Starch from its tubers was isolated in behavioral conditions and properties were determined such as size of granules, content of water, amylose, phosphorus, proteins and lipids, characteristics of gelation of its gels and thermal properties (TG, DTG, DTA).     

Prevalence and antibiotic-resistance of Salmonella isolated from beef sampled from the slaughterhouse and from retailers in Dakar (Senegal)

A study was made of Salmonella contamination in beef sampled from a slaughterhouse and from retailers in Dakar, Senegal. The serotypes as well as antibiotic-resistance patterns of the Salmonella isolates were determined. A total of 435 meat samples (236 from the slaughterhouse, 199 from retailers) were tested. Among them, 275 (63%) were positive for Salmonella, 43% (101/236) from the slaughterhouse and 87% (174/199) from the retailers. Furthermore, 97% of the investigated retailers had at least one beef sample contaminated by Salmonella. The 286 Salmonella isolates were divided into 51 serotypes. The most prevalent serotypes were Salmonella bredeney (25%), S. muenster (8%), S. waycross (7%), S. corvallis (4%) and S. kentucky (4%). About 62% of the isolates were resistant to nitrofurans. Resistance rates were lower to streptomycin (22%), sulfamethoxazole (15%), spectinomycin (1%), chloramphenicol (1%), and tetracycline (0,4%) while low-level resistance to quinolones was detected. About 16% of the Salmonella strains were multiresistant to two or more antibiotic families. Finally, ten resistance profiles have been identified. This study shows the huge spread of Salmonella in the beef production chain in Dakar, Senegal. Finally, this study provides the very first data about Salmonella prevalence in sub-saharian Africa.     

由杏仁壳及其他农产品废弃物制备生物纺织纤维

绿色产品是否存在其他价值?能否将废弃物转化为具有额外价值的原材料?来自大学实验室和工业公司的研究者们正尝试采用木屑、杏仁壳或其他农产品废弃物作为原料制备纺织品。Ecolastane项目主要致力于研究可再生产业用纺织纤维的生产。     

从信用和规则做起

何谓信用，辞海解释为：信用就是诚实、不欺、遵守诺言。信用就是一种信守承诺的责任感，是对自己行为后果负责的道德感，说白了就是不蒙人，守规矩，说话算数，表里如一。信用作为一种文化传统和理念，是人类不断发展而修炼出来的一种美德，也是一种待人处事的经验积累。因为不管你身在何方，不管你处在什么年代，只有讲信用、守规矩，你才能得到别人的接纳和尊重，才能很容易与别人交流，也才能找到忠诚的朋友，更重要的是你可以通过诚信和努力到达理想的彼岸。俗话说，没有规矩，就不能成方圆。做任何事情包括做游戏都要有规则。守纪律，…     

Rheological properties of mustard mucilage isolated from raw and from processed mustard

Mucilage of yellow mustard (Sinapis alba L.) exhibits completely different rheological behaviour, depending on where it has been extracted from. Whereas mucilage isolated from intact mustard seeds or from separated brans acts like many hydrocolloids (e.g. increasing viscosity significantly at low concentrations) these and related properties (i. e. shear thinning behaviour) are lost, once mustard seeds are processed. Mucilage extracted from processed mustard only raises viscosity slightly. Although the supernatant of processed mustard consists of 3-5% mucilage (dry matter), it exhibits Newtonian flow. Changes of rheological properties of mustard mucilage were attributed to a change of molecular shape from an extended to a globular state due to processing. Chemical analysis has shown a significant raise of nitrogen content of mucilage after processing and during storage, indicating some chemical reaction taking place, possibly involving proteins.     

Antiradical and functional properties of subcritical water extracts from edible mushrooms and from commercial counterparts

This study deals with the antioxidant and functional potential of subcritical water extracts from edible mushrooms, in comparison to commercial products. Pleurotus citrinopileatus extracts showed the highest phenolic content and antioxidant properties. Similar results were determined in commercial extracts of Coriolus versicolor. The highest growth inhibition in selected human carcinogenic cells was identified for the P. citrinopileatus extract obtained during heating up to 160 °C. Rheological studies confirmed that glucan-based hydrogels prepared with mushroom extracts exhibited enhanced viscoelastic properties compared to those formulated with commercial products. The extracts providing the strongest gels were obtained from Pleurotus eryngii, followed by Hericium erinaceus and Pleurotus citrinopileatus. No water syneresis for the proposed hydrogels was observed. The formulated hydrogels could be interesting for their application in the food sector.