超高效液相-串联四极杆质谱联用法同时测定并比较甘草各部位中8种成分含量

建立同时检测甘草中8种成分:22-羟基-甘草次酸、3-epi-甘草次酸、甘草次酸、甘草酸、甘草苷、芒柄花黄素、异甘草酚、甘草香豆素的超高效液相色谱-串联四极杆质谱联用法。选用胆酸作为三萜成分的内标,相思子素2"-O-β-芹菜糖苷作为酚类化合物的内标。甘草样品经粉碎用甲醇(含内标液)超声提取,采用安捷伦ZORBAX RRHD C18柱(50 mm×2.1 mm,1.8μm),以甲醇-0.1%甲酸溶液为流动相,梯度洗脱,以电喷雾电离源,采用超高效液相-串联四极杆质谱联用动态多反应监测模式测定。结果表明,8种成分检出限均小于0.048 8μg/mL,定量限均小于0.195 2μg/mL,在0.048 8~12.500 0、0.048 8~12.500 0、0.012 2~12.500 0、0.048 8~50.000 0、0.048 8~50.000 0、0.012 2~12.500 0、0.012 2~15.000 0、0.195 2~12.500 0μg/mL范围内,22-羟基-甘草次酸、3-epi-甘草次酸、甘草次酸、甘草酸、甘草苷、芒柄花黄素、异甘草酚、甘草香豆素的峰面积与质量浓度呈良好线性关系,相关系数均大于0.99;方法回收率为97.2%~113.0%间;其日内及日间精密度实验的相对标准偏差分别为2.63%~4.47%及1.75%~3.72%。该方法灵敏度高、稳定性强、操作简便、快捷、准确,可用于甘草各部位及其相关食品质量控制。     

营养型调和油配方及甘草、诃子提取物复合抗氧化剂对其抗氧化作用的研究

目的研究甘草提取物(Glycyrrhiza uralensis extract,GUE)、诃子提取物(Terminalia chebula extract,TCE)复合抗氧化剂对营养型调和油氧化程度的影响。方法采用气质联用(gas chromatography-mass spectrometer,GC-MS)方法测定原料油中各类脂肪酸的含量,根据数学模型制备营养型调和油;然后采用Schaal烘箱法,评价复合抗氧化剂对营养型调和油的抗氧化作用,筛选出抗氧化作用较强的复合抗氧化剂。结果调和油的最佳配比花生油68.68%、葵花籽油19.23%、亚麻籽油12.08%。复合抗氧化剂对调和油的抗氧化作用顺序为:0.003%GUE+0.017%Vc0.005%TCE+0.015%Vc0.017%TCE+0.003%Ve0.017%GUE+0.003%Ve,0.003%GUE+0.017%Vc对调和油的抗氧化作用最强,它优于丁基羟基茴香醚(Butyl hydroxyl anisole,BHA),与2,6-二叔丁基-4-甲基苯酚(2,6-Di-tert-butyl-P-cresol,BHT)相当。结论对于含有多不饱和脂肪酸多的贮存的油脂,甘草与诃子提取物复合抗氧化剂具有代替人工合成抗氧化剂的潜能。     

重组羧肽酶原B突变体C383A的纯化与性质研究

目的纯化羧肽酶原B突变体C383A并研究其酶学性质。方法用DEAE-FF离子交换树脂纯化C383A,测定其动力学参数,温度对酶活性的影响、温度稳定性、最适pH以及pH稳定性等酶学性质,并与野生型比较。结果纯化后获得高纯度突变体C383A,与野生型相比,催化效率及稳定性均有提高,但与底物的亲和力降低,随着温度的上升催化速率的增长率低于野生型。结论将重组羧肽酶原B第383位Cys突变为Ala可对酶的性质产生影响,与野生型比较,C383A提高了酶的催化效率及温度和pH稳定性。     

大豆异黄酮生理活性的研究进展——(1)大豆异黄酮的代谢及雌激素特性

大豆尤其是大豆胚轴富含有益于人类健康的大豆异黄酮。人体内的两种专一肠道细菌能将大豆异黄酮中的大豆苷和染料木苷代谢为相应的糖苷配基大豆黄素和染料木黄酮。马雌酚是大豆黄素在肠内细菌作用下的代谢产物,具有比大豆异黄酮更高的生理活性,但是并非在所有摄取大豆异黄酮的健康成年人体内都能产生马雌酚,马雌酚的产生与体内是否存在某些特定的肠内菌丛有关。大豆蛋白能影响肠内菌丛的构成,进而提高大豆异黄酮的生物利用率。大豆异黄酮是一类选择性雌激素受体调节剂,具有雌激素和抗雌激素的双重活性,可安全有效地用于预防和治疗妇女更年期综合症。     

利用RIL群体分析小麦淀粉粘度性状与馒头品质的关系

利用重组自交系群体对淀粉粘度性状与馒头品质间的关系进行了全面分析。相关分析表明，峰值粘度、低谷粘度、最终粘度、反弹值、峰值时间均与馒头外观、结构、弹韧性、粘性、总分等5项指标呈显著正相关；回归分析结果表明，粘度性状与馒头品质间存在较强的线性关系，建立了馒头体积、比容、结构、弹韧性、粘性和总分与淀粉粘度性状的回归方程；通过通径分析明确了各粘度性状对馒头品质的直接效应和间接效应。     

Evaluation of heterologous α‐amylase production in two expression platforms dedicated for Yarrowia lipolytica: commercial Po1g–pYLSC (php4d) and custom‐made A18–pYLTEF (pTEF)

In view of the constantly increasing demand for cost‐effective, low‐energy and environmentally friendly industrial processes and household care products, enzyme production occupies an essential place in the field of biotechnology. Along with increasing demand for industrial and household care enzymes, the demand for heterologous expression platforms has also increased. Apart from the conventional hosts, e.g. Escherichia coli, Saccharomyces cerevisiae and Pichia pastoris, routinely used in heterologous protein expression, the non‐conventional ones have become more and more exploited in this field. Among the available yeast host systems, Yarrowia lipolytica appears to be an attractive alternative. The aim of this study was to compare efficiency of two Yarrowia‐based expression platforms, commercial Po1g–pYLSC and custom‐made A18‐pYLTEF, in expression of an insect‐derived, raw‐starch‐digesting α‐amylase, to select the ‘champion’ system for further studies on this valuable enzyme. Both expression platforms were compared with respect to copy number of the integrated expression cassette/transformed genome, and the recombinant strains performance (Po1g–pYLSC‐derived 4.29 strain, and A18‐pYLTEF‐derived B9 strain) during batch bioreactor cultures. Our results demonstrate that the average number of integration events into the recipient's genome was comparable for both expression systems under investigation, but with varying distribution of the multicopy integrants; and the number of the recombinant gene copies was highly correlated with the acquired amylolytic activity of the strains. Due to severe susceptibility of the recombinant AMY1 polypeptide to native proteases of the custom‐made expression system, the final yield of the enzyme was substantially lower when compared to the commercial Po1g–pYLSC (reaching a maximum level of 142.84 AU/l). Copyright © 2015 John Wiley & Sons, Ltd.     

Cloning and sequencing of the gene for apocytochrome b of the yeast Kluyveromyces lactis strains WM27 (NRRL Y-17066) and WM37 (NRRL Y-1140)

The apocytochrome b genes from two strains of the yeast Kluyveromyces lactis, have been isolated and sequenced. The coding sequences in strains WM27 (NRRL Y-17066) and WM37 (NRRL Y-1140) were identical but the upstream noncoding regions were slightly different. The sequences demonstrated the presence of a continuous open reading frame with no introns. The amino acid sequence, derived from the coding strand, showed 82% homology to the apocytochrome b of Saccharomyces cerevisiae strain D273-10B and only 58% homology to the protein from Schizosaccharomyces pombe strain 50. CUN and CGN codon families were absent from the K. lactis gene. Codon usage was very similar to that of other mitochondrial genomes with mostly U or A in the third position. There were two unusual features. All threonines were coded by ACA(U) and all arginines by AGA.     

厚皮香栲胶物理化学性质及鞣革性能的研究

厚皮香属热带野生山茶科植物,皮含鞣质高达25—30%,厚皮香鞣质属缩合类。厚皮香树在我国云南西双版纳的蓄积量最大,开发厚皮香鞣料制造栲胶有着实际的经济意义。本文采用对比研究的方法。对新品种厚皮香栲胶的物理化学性质及鞣革性能进行了研究,结果表明:1.厚皮香栲胶的渗透速度略慢于杨梅、荆树皮栲胶,而远比落叶松栲胶快。2.厚皮香栲胶鞣革的Ts大于85℃;鞣制系数大于60%,在对比试验中大于杨梅、落叶松栲胶,与荆树皮栲胶接近。3.厘皮香栲胶鞣革坚实。丰满、弹性好,得革率大,革色呈棕红。4.厚皮香栲陂在物理化学性质方面与荆树皮、杨梅锥胶比较接近。综合这些结果。可以认为厚皮香栲胶是一种比较优良的栲胶,值得开发和推广应用。     

雪菊化学成分分析、提取、鉴定及其生物活性研究进展

对目前国内外在雪菊（Coreopsis tinctoria）的有效化学成分分析、提取、鉴定及其生物活性等方面的研究进展进行综述,并提出一些建议,旨在为雪菊的深入研究和开发利用提供参考。     

Effect of Starter Culture and Packaging on the Chemical,Microbiological and Sensory Quality of Turkish Soudjouck (Sucuk)

Lactobacillus plantarum, Micrococcus aurantiacus, and Pediococcus pentosaceus in different combinations and amounts were used for the production of fermented soudjouck. The effects of starter cultures on total aerobic bacteria, and selected chemical properties of samples were determined. Additionally, the effects of starter culture and packaging on the sensory characteristics of final product were studied. It was found that nitrite and sugar content of samples decreased during ripening, while protein and fat content relatively increased with drying. Mesophilic aerobic bacteria counts increased in the first days of ripening and then decreased, similar trend was also observed for the counts of all three starter cultures. Sensory results showed that reducing amount of starter culture negatively affected and incorporation of glucano delta lactone (GDL) into formula along with starter culture had an adverse effect on the sensory properties. It was demonstrated that vacuum packaging improved the sensory properties; therefore, it should be preferred over normal packaging.     

芝麻香型白酒酿造功能霉菌及其与酵母的相互作用

通过对5株来自不同酿造环境的霉菌的生长速度、产酶、产酸以及产孢子能力的比较,筛选出具有生长迅速、产孢子和产酸较少以及较高的产酶能力的Aspergillus oryzae(XJ10)。将此菌株应用于芝麻香型白酒生产中,优化了霉菌与酵母的相互作用。固定酵母用曲量,霉菌麸曲用量从31 kg提高至125 kg,当霉菌麸曲用量为125 kg时,出酒率达到最高,为27.9%,同时,所产白酒的香气和口味品评分值最高。     

Study on the Pre-Treatment,Physical and Chemical Properties of Ramie Fibers Reinforced Poly (Lactic Acid) (PLA) Biocomposite

The comparative advantage of using vegetable fibers as reinforcement (fillers) attracted manufacturing industries over conventional composites. Natural fibers are purely green features that can easily decompose in a normal way to water and CO₂ when encountered with moisture during their disposal. In this research, the effect of pre-treatment and properties of ramie fibers reinforced polylactic acid (PLA) composite were studied. Before the composite preparation, ramie fibers were soaked in a solution of alkali (sodium hydroxide) and silane coupling agent to provide better compatibility between ramie fibers and PLA interface. Additionally, a design containing nine samples was conducted to study the effect of temperature, fiber volume ratio, molding pressure and time on composite fabrication. From the results, optimum processing parameters were identified based on the tensile, bending and impact strengths improvement from various tested samples. Furthermore, this study highlights the degradation process and properties of ramie fibers reinforced PLA composites by underground burial experimental procedures.     

酶法脱囊衣工艺优化及对甜橙囊胞品质的影响

以甜橙为原料,优化酶法脱囊衣工艺条件,在此基础上比较研究酶法与酸碱法脱囊衣对甜橙囊胞品质的影响。结果表明,酶法脱囊衣优化工艺参数为戊聚糖复合酶添加量0.35%、酶解温度50 ℃、酶解时间40 min。酸碱法脱囊衣后,囊胞汁液中VC、总酸、还原糖、总糖和香气成分的保存率分别为78.71%、56.01%、75.17%、79.45%、82.72%;酶法脱囊衣后,囊胞汁液中主要营养成分的保存率均可达96%以上,香气成分保存率也提高了15.46%。综合各项指标,酶法脱囊衣效果优于酸碱法。     

The HTL1 gene (YCR020W-b) of Saccharomyces cerevisiae is necessary for growth at 37 degrees C, and for the conservation of chromosome stability and fertility

A small 78 codon ORF, named HTL1 (Chen et al., unpublished results), situated between loci MAK31 and HSP30 on chromosome III of Saccharomyces cerevisiae, is required for growth at 37 degrees C. In this communication, we characterize the ORF and show that disruption of HTL1, besides preventing growth at 37 degrees C, causes genetic and/or epigenetic instability at 26 degrees C: ploidy increases in about 10% of cells grown from individual disruptants and a fraction of disruptant clones are predestined to a rapid and progressive loss of fertility during growth at 26 degrees C.     

Evaluation of Shelf Life of Superchilled Cod (Gadus morhua) Fillets and the Influence of Temperature Fluctuations During Storage on Microbial and Chemical Quality Indicators

Quality changes of aerobically packed cod fillets stored under superchilling and abusive temperature conditions were characterized by the growth of specific spoilage organisms (SSO) and the production of microbial metabolites measured by an electronic nose along with traditional sensory and chemical analysis (total volatile basic nitrogen [TVB‐N], pH). A new process based on quick contact freezing and cold air blasting was used to achieve superchilling of fillets before chilled (0.5 °C) or superchilled (‐1.5 °C) storage. Photobacterium phosphoreum dominated under temperature abusive conditions coinciding with high levels of TVB‐N and increased electronic nose responses indicating increased levels of alcohols and aldehydes at sensory rejection. Dominating growth of Pseudomonas spp. in 1 batch was associated with the origin, the catching method, and the cooling conditions during processing. The superchilling process followed by superchilled storage (‐1.5 °C) extended the sensory shelf life of the fillets for at least 3 d compared with traditional process, resulting in a total shelf life of 15 d. High content of TVB‐N was observed in superchilled fillets at sensory rejection. P. phosphoreum counts were lower under superchilling conditions (6.0 to 6.8 log colony‐forming units [CFU]/g), compared with the traditionally processed chilled fillets (7.2 log CFU/g). However, H₂S‐producing bacteria appeared to grow steadily under superchilling conditions reaching counts as high as 7.6 log CFU/g at sensory rejection.     

造纸废水负荷与温度和天气状况的关系探讨

为探讨温度和天气对造纸废水总化学需氧量(TCOD)的影响,比较了造纸废水TCOD在不同季节和天气状况下的变化情况,并且对大气温度和间歇式活性污泥法(SBR)入水温度的关系进行了分析。结果表明,大气温度和SBR入水温度存在相关性;随着入水温度增高,TCOD值也相对较高;大气温度波动较小时,阴天时的TCOD较晴天时的高。研究结果表明,造纸废水处理过程可以通过协同温度和曝气量更好地进行控制调节。     

Chemistry and Quality of Hibiscus (Hibiscus sabdariffa) for Developing the Natural-Product Industry in Senegal

ABSTRACT:  The objectives of this study were to assess and improve the quality of the hibiscus calyces from Senegal over 2 production seasons (2004 to 2005), to develop and adapt new procedures for the determination of hibiscus anthocyanins and analysis of the 2 major ones, delphinidin-3-sambubioside and cyanidin-3-sambubioside. The foreign matter, total ashes, and acid insoluble ashes showed that the calyces harvested in 2005 were produced following hygienic practices, while the color assessment of the calyces and analysis of hibiscus active principles also showed higher amounts of anthocyanins in 2005. A protocol to measure anthocyanins by pH-differential UV-Vis spectrophotometry was adapted to measure the hibiscus anthocyanins from a water extract. The spectrophotometric method for quantitation of total anthocyanins showed a close correlation ( r ²= 0.82) when compared with the HPLC method, suggesting the use of the colorimetric method in quality control programs as an affordable alternative method to assess anthocyanin content in hibiscus. New and raised standards for the cleanliness and active principle content in hibiscus are also proposed. This study demonstrated that the implementation of a quality control program and the application of agricultural good practices in the production and processing of hibiscus calyces can lead to higher quality natural plant products.     

~(60)C_o辐照预处理对苹果片脱水特性和品质的影响

进行了不同辐照剂量、热风温度、切片厚度对苹果脱水速率及品质的影响试验,结果表明:该三因子影响苹果片的脱水速率和外观质量。辐照剂量增加,热风温度增高,脱水速率高,VC含量和复水比下降。辐照剂量、热风温度、切片厚度三因素对脱水速率和干制品的外观质量、VC含量、复水比等四指标大都呈显著影响。     

Using the Essential Oil of Aloysia triphylla (L'Her.) Britton to Sedate Silver Catfish (Rhamdia quelen) during Transport Improved the Chemical and Sensory Qualities of the Fish during Storage in Ice

Exposure of silver catfish to 40 μL/L of the essential oil of Aloysia triphylla (AT) during in vivo transport delayed the onset and resolution of rigor mortis as well as the degradation of IMP into HxR compared to the control. The fish that were treated with 30 or 40 μL/L of AT received lower sensory demerit scores after 10 d of storage in ice compared to the control, and the fish that were treated with 40 μL/L of AT had a longer sensory shelf life than did the control. These results indicated that using AT as a sedative in the water in which the silver catfish were transported extended their freshness and increased their shelf life during refrigerated storage.     

CO_2超临界流体无污染制革技术研究超临界流体的基本原理及应用(I)

本文扼要介绍了ＣＯ２超临界流体的基本特性及相应的技术和装置，对其在制革工艺中应用的研究现状及前景进行了评述。