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云杉中含有大量的聚O-乙酰基葡糖甘露糖。部分葡糖甘露聚糖在机械制浆中溶出.同时由于白水系统的封闭循环.导致葡糖甘露聚糖不断积累。在机械制浆及抄纸中.葡糖甘露聚糖起着很多作用。在碱性过氧化氢漂白过程中.葡糖甘露聚糖通过脱乙酰基或吸附到机械浆纤维表面上的方式从水中脱除。这一吸附作用不仅可以改善得率. 相似文献
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离子色谱法测定苦瓜茶中的半乳糖、葡萄糖、甘露糖和果糖 总被引:2,自引:0,他引:2
建立了离子色谱法同时分离测定苦瓜茶中的半乳糖、葡萄糖、甘露糖和果糖的分析方法。用METROSEP CARB1(150mm×4.0mm)阴离子交换分离柱和脉冲安培检测器,对淋洗分离条件进行优化。选择了8mmol/L NaOH为淋洗液,淋洗液流速为1.0mL/min,总分析时间为25min。半乳糖、葡萄糖、甘露糖和果糖的检出限分别为0.105、0.126、0.152、0.587mg/L(进样体积20μL)。混标溶液连续8次进样,峰高的相对标准偏差为2.12%~5.43%,保留时间的相对标准偏差为2.06%~3.28%。样品测定的回收率为94.2%~99.8%。该方法具有样品前处理简单,灵敏度高,快速有效等优点。结果满意。为苦瓜茶中糖分的检测提供了一个简单有效的方法。 相似文献
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研究了壳聚糖对锌(Ⅱ)离子和铜(Ⅱ)离子的吸附动力学、吸附等温线及pH、壳聚糖脱乙酰度、温度等因素对壳聚糖吸附的影响。结果表明,壳聚糖对锌(Ⅱ)离子和铜(Ⅱ)离子的吸附行为符合Lang-muir模型,壳聚糖对锌(Ⅱ)离子和铜(Ⅱ)离子吸附规律均遵从单分子层吸附规律。温度、pH值和脱乙酰度对吸附量有显著影响,随温度的升高,壳聚糖对锌(Ⅱ)离子和铜(Ⅱ)离子吸附量增加;在pH2~6范围内,壳聚糖对锌(Ⅱ)离子和铜(Ⅱ)离子吸附随pH值的增大而增大;脱乙酰基程度高的吸附量较大。 相似文献
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以分离自植物乳杆菌异常发酵液的烈性噬菌体P2及其宿主Lactobacillus plantarum IMAU10120为研究对象,采用次级感染法筛选自发突变抗噬菌体菌株。对比突变株与野生株吸附特性,判断细胞生理状态对噬菌体吸附能力的影响。采用十二烷基硫酸钠、溶菌酶、蛋白酶K和三氯乙酸分别处理细胞壁,确定噬菌体P2的吸附位点。结果表明:成功筛选出1株抗噬菌体P2的植物乳杆菌突变株,且具有稳定的遗传耐受力。突变株与敏感株的吸附率均在97%以上,表明噬菌体吸附受体未发生改变。细胞生理状态对噬菌体吸附能力无显著差异。推断噬菌体P2的吸附受体可能与多糖-肽聚糖聚合物有关。 相似文献
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漂白工段阴离子垃圾的产生及解决方法 总被引:1,自引:0,他引:1
在废纸制浆过程中,阴离子垃圾主要来源于废纸浆木素的氧化降解断裂溶出、废纸中的油墨、胶粘物等,尤其来自制浆中的漂白工段和浮选工段。着重论述了漂白工段阴离子垃圾的产生途径及其危害,并结合生产实践阐明了减少阴离子垃圾的方法。 相似文献
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阴离子垃圾对新闻纸性能的影响及减轻影响的措施 总被引:8,自引:0,他引:8
本文论述了新闻纸纸料中阴离子垃圾的来源及对新闻纸性能的影响,以及减轻阴离子垃圾对新闻纸影响的措施,新闻纸纸料中的阴离了垃圾主要来源于机械浆的漂白,其主要成分可分为两大类,即溶解物质和胶体物质,这两类物质对新闻纸性能的影响不同,胶体物质对抗张强度影响最大,而溶解物质对耐破指数,松厚度及透气度影响最大,另外,不同纸料对相同成分的白水的敏感性不同,机械浆用过氧化氢漂白后,经济浆设备脱水或酸处理有效地降低阴离子垃圾。 相似文献
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Corn distillers dried grains with solubles (DDGS) has high feed value due to its nutritive contents. The ratio of wet distillers grains (WDG) and condensed distillers solubles (CDS) added during the production process determines the chemical composition of DDGS. Effect of changing this ratio on water sorption behaviour of DDGS, at different temperature, was studied. Five mathematical models were evaluated to explain the sorption behaviour of DDGS. Prediction of sorption isotherm from chemical composition using a four-component model was also investigated. DDGS followed a BET Type III isotherm with higher equilibrium moisture content at increasing relative humidity. Difference in the sorption isotherm curves of DDGS samples reduced as equilibrium relative humidity increased. Equilibrium moisture content of DDGS samples reduced with lowering of CDS quantity added during production process. Modified Halsey equation was found suitable for mathematically explaining the sorption behaviour of DDGS. Binding energy of water molecule with DDGS increased with lowering of CDS level. Sorption behaviour of DDGS can be predicted from the chemical composition of protein, sugar, minerals, starch, fibre and glycerol. Increase in CDS level increased the percent relative deviation of predicted values calculated using the modified four-component model and might be due to the interaction between the chemical compounds present in the samples. 相似文献
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对静态称重法测定的5个大米样品吸着等温线数据,分别采用Brunauer-Emmett-Teller(BET)、CAE、修正Chung-Pfost(MCPE)、修正Guggenhein-Anderson-de Boer(MGAB)、修正Henderson、修正Oswin及Strohman-Yoerger 7个方程进行拟合,MCPE被判定为大米最佳吸着等温线方程。以M=f(hr,t)形式表达的平均解吸等温线方程MCPE的3个参数C1、C2及C3各是492.539、39.846及0.176,在RH 70%下,对应的101、5、202、5、303、5℃条件下大米样品平均解吸值,分别是15.88%、15.49%、15.13%、14.80%、14.50%及14.21%。3个粳米(方正香米、东北普通米、松花江米)在25℃的安全水分是14.92%~15.39%,低于15.5%;2个籼米(泰国香米和江苏米)安全水分则是13.88%~14.43%,低于14.5%,与GB 1354—2009大米限量水分一致。大米吸着等热在含水率<20%干基条件下,随着米粒含水率增加而快速减少,在高于20%干基含水率则随含水率增加而缓慢减少。在含水率<22.5%干基条件下,较低温度下的大米吸附等热与解吸等热均高于较高温度;大米解吸等热高于吸附等热,但是随着含水率增加则差异减少。 相似文献
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为收集、保护和发掘西部牧区传统发酵乳制品中酵母菌资源,从新疆塔城地区牧区共采集8份牧民自制乳制品样品。采用细胞形态学、生理生化特性鉴定、5.8S rDNA序列同源性比对相结合的方法,对酵母菌进行了分离、纯化和鉴定,并考察了其耐高温、耐渗透压、耐乙醇等能力。结果表明,共分离出16株库德毕赤酵母菌(Pichia kudriavzevii)、6株戴尔有孢圆酵母(Torulaspora delbrueckii)、4株美极梅奇酵母菌(Metschnikowia pulcherrima)、2株马克思克鲁维酵母(Kluyveromyces marxianus)、2株酿酒酵母(Saccharomyces cerevisiae)、2株胶红酵母(Rhodotorula mucilaginosa)、2株乳酸克鲁维酵母(Kluyveromyces lactis)。库德毕赤酵母菌A2-1能够耐受42℃高温、2.4%高盐胁迫、50 g/100 g高糖胁迫以及12%酒精胁迫;马克思克鲁维酵母菌A2-13能够耐受42℃高温、2.4%高盐胁迫、50 g/100 g高糖胁迫以及16%酒精胁迫。可见,两株菌均能适应于工业开发需求。 相似文献
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Water Sorption Isotherms and Crispness of Fried Yam Chips in the Temperature Range from 293K to 313K
O.P. Sobukola O.U. Dairo T.T. Afe O.J. Coker 《International Journal of Food Properties》2013,16(3):561-575
Water sorption isotherms of fried yam chips were determined using a static gravimetric method with saturated salt solutions in the range of water activity between 0.22 and 0.85 at 293, 303 and 313K. Four sorption models namely GAB, Peleg, modified Mizrahi, and BET were fitted with the sorption data generated. The GAB model followed by Peleg and modified Mizrahi models were found to best represent the experimental data in the aw range of 0.22–0.85. However, the BET model was more applicable between aw range of 0.22–0.55. The adsorption isotherm of fried yam chips clearly showed the influence of temperature, decreasing the moisture content at a fixed water activity value with higher temperature. The net isosteric heats of sorption of water were estimated by applying the Clausius–clapeyron equation to the adsorption isotherms at different temperatures. The net isosteric heat of sorption was observed to be decreasing as moisture content increases. Samples stored in desiccators of 0.44 and 0.55 aw at 303 and 313K, respectively, were rated higher in terms of textural properties investigated. 相似文献
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