络合滴定黑荆栲胶中单宁含量的新方法

利用单宁分子结构中酚羟基能与Ｐｂ＾２＋络合的原理，以Ｋ２ＣｒＯ４为指示剂，ＰＡＭ作终点增敏剂，用Ｐｂ＾２＋标准溶液络合滴定黑荆栲胶中单宁的新方法。该法比皮粉法快速、准确。     

猴头菌培养及提取工艺的研究

本文对猴头菌培养条件包括营养，温度，水份等以及提取工艺进行了研究。采取三级培养，固体发醇后提取浸膏，生产工艺简便。浸膏特征反应明显，且各种理化指标符合《中国药典》（１９９０）煎膏剂通则的要求。猴头菌Ｈｅｒｉｃｉｕｍ ｅｉｎａｃｅｕｓ近年来已有很多厂家利用菌丝体提取物，制成各种剂型的药物，用于治疗十二指肠溃疡病，胃窦炎，慢性胃炎，胃闷胀，胃痛等病，是一种治疗消化道疾病具有明显疗效的真菌药物。对此，我     

生姜提取液对牦牛肉保鲜效果的研究

以新鲜牦牛肉为原料,采用生姜提取液(鲜生姜汁∶蒸馏水=1∶5)喷淋处理,结合真空复合膜包装技术,研究在(3±1)℃条件下储藏21 d新鲜牦牛肉的感官品质、细菌总数、p H、挥发性盐基氮(TVBN)含量等指标的变化规律。结果表明,生姜提取液处理可保持牦牛肉较高的感官品质,降低水分损失率和菌落总数增长速度,储藏期间肉的p H处在鲜肉范围内,有效减缓了TVB-N含量的升高,明显延长了牦牛肉的储藏时间,具有较好的保鲜效果。     

Malting quality as affected by barley breeding (1944–1998) in Argentina

Eight malting cultivars of barley released from 1944 to 1998 in Argentina were sown in two growing seasons to evaluate the effect of breeding on malting quality. An adequate grain weight and screening percentage as in the older varieties were maintained in the recent releases. The grain protein concentration decreased in the modern cultivars together with a decreased in C-and an increased in B-hordein. These results were achieved without a clear trend through the time. Malt extract was increased by 0.054% per year in the period analysed and the most important contribution in the quality improvement was the introduction of Beka (known as a high quality cultivar released in Europe) in1966. There was not a clear trend in the breeding process to obtain more stability between years in the quality attributes, at least, in the characteristics analysed in the present study. Conversely, malt extract was less variable and this tendency was observed through the years of release of the cultivars. This revised version was published online in July 2006 with corrections to the Cover Date.     

蒸煮爆破处理过程中毛竹材加工剩余物主要化学成分的变化研究

采用硫酸水解法(aldito-acetate procedure)、X射线粉末衍射(XRD)、傅里叶变换红外光谱(FTIR)分析了蒸爆过程中毛竹材加工剩余物纤维聚集态结构及主要化学成分的变化.研究结果表明,(1)毛竹材加工剩余物经蒸爆处理,60%左右的半纤维素水解,木质素低分子化且裸露到纤维表面,易被80%乙醇及木质素溶剂提取,从而实现毛竹材加工剩余物主要组分的有效分离.(2)毛竹材加工剩余物经蒸爆处理,80%乙醇抽提物得率提高,综纤维素得率减少,木质素含量减少:葡萄糖相对含量增加,半纤维素降解明显.(3)210℃处理10 min和220℃处理10 min的蒸爆浆的化学组成变化几乎没有区别,但两者与200℃处理10 min差别较大,210℃处理10 min是毛竹材加工剩余物适宜的处理温度.(4)FTIR结果显示蒸爆处理后在1040～1060 cm-1区的吸收峰分裂为明显的2个峰表明半纤维素降解,1166 cm-1处的吸收强度明显减弱,表明C-O-C键有不同程度的断裂.X-身寸线衍射分析结果显示毛竹材加工剩余物蒸爆处理后纤维素相对结晶度增加.     

碳水化合物降解产物对酿酒酵母乙醇发酵的影响

研究了木质纤维原料预处理产生的主要碳水化合物降解产物对酿酒酵母乙醇发酵的影响,以及酿酒酵母对玉米秸秆酶水解液的乙醇发酵.碳水化合物降解产物对酿酒酵母NLH13乙醇发酵毒性依次为:甲酸>乙酸>糠醛>羟甲基糠醛,酿酒酵母NLH13乙醇发酵可耐受的甲酸和乙酸质量浓度分别为1和4 g/L,酿酒酵母NLHl3在2～10 g/L范...     

不同因素对乳突类圆线虫离体培养的影响

采用生物统计的正交试验设计方法，研究了Ｍ１９９、犊血清（ＣＢＳ）、鸡胚提取物（ＣＥＥ５０）、兔肝提取物（ＲＬＥ５０）、丙酮酸钠（ＳＰ）、水解酪蛋白（ＣＨ）和酵母提取物（ＹＥ）在离体培养中对乳突类圆线虫第三期幼虫存活和生长发育的影响。结果表明，只有ＣＢＳ和ＲＬＥ５０。对第三期幼虫的存活和生长发育起着显著的促进作用、在试验得出的最适含量组合的培养基内，幼虫生长发育最好，存活时间最长为３７ｄ。对Ｍ１９９、ＥＭＥＭ、Ｆ１２和ＲＰＭＩ１６４０这４种商品组织培养基进行了筛选试验；结果显示Ｍ１９９最佳，表明脂溶性维生素可能是乳突类圆线虫的离体培养所需营养之一。     

不同浸提条件对包膜控/缓释肥水中溶出率的影响

以几种不同包膜材料控／缓释肥为供试肥料,研究不同肥(养分)水比、浸提方式(连续浸提和更换浸提液)、温度和pH条件对控／缓释肥水中溶出率的影响。结果表明,浸提液中肥料浓度是影响养分释放的重要因素,加大肥水比、更换浸提液可以显著减小这种影响。升高温度,有机和无机材料包膜控／缓释肥水中溶出率均显著加快。肥料类型、肥水比对浸提液的pH都有显著影响,但在连续浸提和更换浸提液方式下,7d内浸提液的pH有着不同的变化趋势。控／缓释肥在pH.5的磷酸盐缓冲液中的溶出率显著高于在pH.7的磷酸盐缓冲液中的溶出率。因此,对于不同包膜材料控／缓释肥以一定pH值的微酸性缓冲溶液作为浸提剂,定期更换浸提液或采用动态流法,相同的氮(或磷、钾)水比,30℃左右的浸提条件是较为合理的。     

木质纤维素乙醇发酵研究中的关键点及解决方案

该文综述了近年来木质纤维素材料发酵生产乙醇的研究进展，提出了在木质纤维素原料发酵生产乙醇过程中的两大关键点，一是减少和消除原料预处理过程中抑制物及其有害影响；二是含木糖、葡萄糖、甘露糖、半乳糖等多种物质的混合物同时作为底物的乙醇发酵。在对已有研究结果比较和分析基础上，提出相应的解决方案。首先要采取综合的预处理过程，达到提高木质纤维素水解率的同时减少发酵抑制物；然后是提高发酵菌种对混合糖底物的利用能力和发酵生成乙醇的能力以及对抑制物的耐受性，以提高木质纤维素发酵生产乙醇的转化率。     

Effect of subcritical hydrophobicity in a sandy soil on water infiltration and mobile water content

Recent research shows that most soils are more or less water repellent. Already subcritical water repellency may cause incomplete soil wetting and preferential flow. Both processes potentially reduce the residence time of water and solutes in the vadose zone, resulting in an enhanced risk of groundwater contamination. The objective of the present paper is, therefore, to evaluate the impact of reduced soil wettability on the soil water infiltration rate and to investigate the tendency towards preferential flow with the analysis of the immobile water content in the infiltration zone. In november 2002, a field experiment was done in a coniferous forest, 30 km N of Hannover, Germany. Soil hydrophobicity was quantified by measuring the contact angles. The hydraulic conductivity of the podsolic sandy soil was measured depth‐dependent with a double‐ring tension infiltrometer in three soil horizons. To quantify possible preferential‐flow effects, a LiBr‐Tracer was added to the infiltrating water to evaluate the mobile water‐content fraction after infiltration. Additionally, infiltration rates of water were compared with infiltration rates of ethanol which were determined after water infiltration at the same locations. Results show that the actual water repellency of field‐moist soil was mainly subcritical (contact angle <90°). Water infiltration rates were reduced due to subcritical repellency by a factor of 3–170 compared with ethanol infiltration rates (exclusion of wetting effects). This spatially variable infiltration behavior was not clearly reflected neither by the small‐scale contact‐angle measurements nor by the analysis of the average immobile soil water content in the infiltration zone. We conclude that this specific infiltration behavior of water caused by small‐scale wettability effects may temporarily reduce the local connectivity of water‐flow pathways.