不同类型的碱对三氯蔗糖合成过程中氯代液中和效果的影响

蔗糖的DMF溶液与原酸酯在对甲苯磺酸的催化下生成蔗糖-4-乙酸酯和蔗糖-6-乙酸酯的混合物,在特丁胺作用下,将4-乙酸酯转换为6-乙酸酯,蔗糖-6-乙酸酯在DMF溶液中,由DMF和氯化亚砜制备的vilsmeier试剂作为氯化试剂生成的氯代液,分别用氢氧化钠的水溶液、氢氧化钾的水溶液、氨水、三乙胺进行后处理.通过中和后溶...     

蔗糖-6-乙酸酯氯化工艺的研究

三氯蔗糖是性能最为优良的高甜度甜味剂之一。蔗糖-6-乙酸酯的选择性氯化是合成三氯蔗糖的关键步骤。蔗糖酯化合成的蔗糖-6-乙酸酯,不经纯化,经适当处理直接进入氯化阶段,用氯化亚砜与DMF预先生成的Vilsmeier试剂对其进行氯化,该方法具有收率高、操作简便及后处理容易等特点。优化的工艺条件为反应温度115℃,SOCl2与蔗糖-6-乙酸酯的摩尔比10∶1,DMF(mL)与蔗糖-6-乙酸酯(g)之比12∶1及反应时间3h。对中间产物三氯蔗糖-6-乙酸酯,经熔点测定、IR及1H-NMR确认了结构。     

低温合成三氯蔗糖-6-苯甲酸酯及其工艺优化

以蔗糖-6-苯甲酸酯为原料,建立了一种低温氯代合成三氯蔗糖-6-苯甲酸酯的方法。探讨了氯代剂的用量、助溶剂的用量、反应温度、反应时间和溶剂的用量等因素对反应的影响。最终确定了最优条件为n(vilsmeier试剂):n(蔗糖-6-苯甲酸酯)=9∶1、反应温度为100℃、反应时间11h、V(DMF):m(蔗糖-6-苯甲酸酯)=2∶1(mL∶g)、V(DMF)∶V(DMAc)=5∶1。在此条件下,可在低温合成三氯蔗糖-6-苯甲酸酯,且三氯蔗糖-6-苯甲酸酯的得率达68%。     

催化蔗糖-6-乙酸酯合成的微生物筛选和培养条件优化

三氯蔗糖是目前最优秀的功能性甜味剂之一,其合成的关键步骤是蔗糖-6-乙酸酯的合成.从土壤中分离到一株能够在有机溶剂中催化合成蔗糖-6-乙酸酯的杆状细菌,命名为WZS01.对该菌株的培养基和培养条件进行了初步优化,在2.5％葡萄糖,1％蛋白胨,0.1％酵母粉培养基中,以聚氨酯泡沫作为菌体固定化基质,30℃培养18h.将吸附有菌体的聚氨酯泡沫干燥后作为催化剂,在2％底物浓度下,在二甲基甲酰胺/叔丁醇反应介质中催化18h,蔗糖-6-乙酸酯的摩尔产率达到83.3％,并通过红外和核磁确认了产物结构.     

工业生产三氯蔗糖-6-乙酸酯中Vilsmeier盐反应的研究

三氯蔗糖-6-乙酸酯作为工业上合成生产三氯蔗糖的直接原料,三氯蔗糖-6-乙酸酯收率对三氯蔗糖的成本有很大的影响。在合成三氯蔗糖-6-乙酸酯的过程中,氯化工艺尤为重要,氯化工艺的优劣直接关系到三氯蔗糖-6乙酯的收率和物料中焦油的含量。在氯化的过程中最重要的一步就是Vilsmeier盐生成的反应,通过对比对Vilsmeier盐反应的物料的投料顺序、滴加速率、反应体系温度的控制,确定Vilsmeier盐的最佳反应条件,从而使三氯蔗糖-6-乙酸酯的收率达到最佳,反应过程中对所有的物料进行高效液相色谱法分析,所测得结果与实际结晶相比较相接近。     

红外光谱和质谱法鉴定三氯蔗糖及其 合成中间体的结构

目的 研究验证三氯蔗糖及其合成中间体的结构表征。方法 用红外光谱仪扫描, 质谱仪进样分析蔗糖-6-乙酸酯、三氯蔗糖-6-乙酸酯和三氯蔗糖。结果 鉴定了三氯蔗糖及其合成中间体的主要官能团, 分子离子与碎片离子。结论 成功解析了三氯蔗糖及其合成中间体蔗糖-6-乙酸酯与三氯蔗糖-6-乙酸酯的分子结构。     

单酯化法合成高甜度甜味剂--三氯蔗糖的研究

本文研究了单酯化高甜度甜味剂－三氯蔗糖的合成。采用蔗糖与原乙酸三乙酯的反应保护蔗糖6－位羟基，亚硫酰氯／吡啶选择性氯化蔗糖6－乙酸酯制备三氯蔗糖。蔗糖6－乙酸酯的最佳氯化条件为：蔗糖6－乙酸酯浆状物20g，吡啶20ml，亚硫酰氯22－22ml，反应介质1，2－二氯乙浣，回流时间10-1h。其氯化产物采用甲醇－甲醇钠水解脱去6－位羟基得到三氯蔗糖。单酯化法较三苯甲基化法合成三氯蔗糖大大简化了操作过程，同时反应条件比较温和，也降低了对设备的要求。     

离子液体介质中脂肪酶催化合成蔗糖-6-乙酯工艺优化

分别以脂肪酶为催化剂、蔗糖和乙酸乙烯酯为原料、离子液体[Emim]PF6为反应介质,应用单因素实验和正交实验优化了蔗糖-6-乙酯合成的工艺条件。结果表明,蔗糖-6-乙酯最佳合成条件为:脂肪酶浓度60mg/m L、乙酸乙烯酯和蔗糖摩尔比6∶1、反应体系含水量2%(v/v)、反应温度45℃和反应时间15h,在此条件下,蔗糖-6-乙酯最终产率为89.86%。在最优条件下,脂肪酶重复利用5次,蔗糖-6-乙酯产率仍维持在初始产率50%以上,表现出了良好的稳定性。     

新型油脂--蔗糖豆油酸多酯的合成研究

用蔗糖和豆油酸甲酯合成了蔗糖豆油酸多酯，通过单因素及正交实验，得出合成蔗糖豆油酸多酯最佳合成条件为：豆油酸甲酯与蔗糖摩尔比为10：1。反应温度130℃，反应时间6h，此条件下反应产率达到92．9％。     

红外光谱和质谱法鉴定三氯蔗糖及其合成中间体的结构

目的研究验证三氯蔗糖及其合成中间体的结构表征。方法用红外光谱仪扫描,质谱仪进样分析蔗糖-6-乙酸酯、三氯蔗糖-6-乙酸酯和三氯蔗糖。结果鉴定了三氯蔗糖及其合成中间体的主要官能团,分子离子与碎片离子。结论成功解析了三氯蔗糖及其合成中间体蔗糖-6-乙酸酯与三氯蔗糖-6-乙酸酯的分子结构。     

发芽大豆酸奶的制备

以萌发至第4 天的发芽大豆和脱脂无糖乳粉为原料,制备发芽大豆酸奶。采用感官评价方法对产品风味进行评分,通过单因素试验确定发芽大豆与水的配比为1:4.5,以此配制豆芽浆;再以乳粉与水1:5.0 的配比制备乳液;正交试验确定最佳发酵条件：乳液在豆芽浆的质量分数60%、以100mL 豆芽乳计混合菌接种量为5mL、蔗糖添加量6g、发酵时间7h。最后对后熟时间对产品风味的影响进行实验,结果表明4℃条件下放置16h 以上风味最好。以本实验方法制备的发芽大豆酸奶具有滋味清香、凝固型酸奶固有的风味特征。     

固定化乳酸菌发酵草莓酸奶工艺研究

研究用海藻酸钠包埋乳酸菌发酵草莓酸奶工艺.研究结果表明固定化乳酸菌发酵草莓酸奶的最佳工艺条件为:海藻酸钠溶液浓度为1.5%,含菌种脱脂乳用量为6mL/100mL海藻酸钠溶液,胶珠的添加量为100mL海藻酸钠溶液/100 mL草莓奶液,胶珠直径为2 mm～3 mm,培养温度为40℃,白砂糖添加量为10%,草莓浆添加量15%.连续发酵结果表明固定化乳酸菌发酵草莓酸奶可连续使用10次.     

绿豆、红枣复合酸牛乳饮料的研制

以绿豆、红枣、酸奶为主要原料,研制绿豆、红枣复合酸牛乳饮料。以饮料感官指标为考察标准,通过单因素试验和正交试验确定饮料最佳工艺条件:绿豆汁和红枣汁的混合比例为6∶4(V/V),混合汁添加量为20mL/100mL,蔗糖添加量为10g/100mL,柠檬酸添加量为0.10g/100mL;稳定剂为CMC-Na、卡拉胶组成的复合稳定剂,添加量分别为0.3g/100mL和0.01g/100mL;单甘酯为乳化剂,添加量为0.05g/100mL。该产品营养全面,具有独特风味和较好的保健功能,有较高的推广价值。     

外源蔗糖对萝卜幼苗品质及代谢酶活性的影响

以“满堂红”品种的萝卜为材料,探究不同质量浓度的外源蔗糖喷洒处理对不同生长天数的萝卜幼苗营养品质（花青素、叶绿素、类胡萝卜素、总酚和芥子油苷等含量）及代谢酶（过氧化物酶（peroxidase,POD）和苯丙氨酸解氨酶（phenylalanine ammonialyase,PAL））活性的影响。结果表明：对于生长3、5 d和7 d的萝卜幼苗,0.4 g/100 mL和0.6 g/100 mL蔗糖处理均能够显著提高其花青素、叶绿素、类胡萝卜素、总酚、芥子油苷含量及POD、PAL活性（P＜0.05）,而0.2 g/100 mL蔗糖处理对其营养物质含量及抗氧化性的影响不显著（P＞0.05）;0.4 g/100 mL和0.6 g/100 mL蔗糖处理在改善其营养价值方面的差别不大。因此,在农业生产中,可采用质量浓度0.4 g/100 mL蔗糖喷洒处理萝卜幼苗来提高其营养价值。     

Formation of bromochlorodibenzo-p-dioxins and dibenzofurans from the high-temperature oxidation of a mixture of 2-chlorophenol and 2-bromophenol

The homogeneous, gas-phase oxidative thermal degradation of a 50:50 mixture of 2-bromophenol and 2-chlorophenol was studied in a 1 cm i.d., fused silica flow reactor at a concentration of 88 ppm, with a reaction time of 2.0 s, over a temperature range of 300 to 1000 degrees C. Observed products in order of decreasing yield included the following: dibenzo-p-dioxin (DD), 4-bromo-6-chlorodibenzofuran (4-B,6-CDF), phenol, 4,6-dibromodibenzofuran (4,6-DBDF), 2,6-dibromophenol, 4,6-dichlorodibenzofuran (4,6-DCDF), 2-bromo-4-chlorophenol, 2,4-dibromophenol, 2-chloro-4-bromophenol, 4-monobromodibenzofuran (4-MBDF), 4-monochlorodibenzofuran (4-MCDF), dibenzofuran (DF), 1-monobromodibenzo-p-dioxin (1-MBDD), 1-monochlorodibenzo-p-dioxin (1-MCDD), 2,4,6-tribromophenol, naphthalene, chloronaphthalene, bromonaphthalene, chlorobenzene, bromobenzene, and benzene. The results are compared and contrasted with previous results reported for the oxidations of pure 2-chlorophenol and 2-bromophenol as well as results for the pyrolysis of the mixture of 2-chlorophenol and 2-bromophenol. 4,6-DBDF and 4,6-DCDF were observed in higher yields than under pyrolytic conditions but considerably less than the yields observed for the individual oxidation of 2-chlorophenol and 2-bromophenol. The effect on chlorine and bromine on the concentration of hydroxyl radical is shown to control the dioxin-to-furan ratio.     

蒸煮温度和模拟液对复合膜中甲苯迁移及阻隔性能的影响

采用顶空气相色谱法研究不同蒸煮条件和模拟液种类对双向拉伸尼龙薄膜/流延聚丙烯薄膜耐蒸煮复合膜中残留甲苯迁移及阻隔性能的影响。结果表明,随着蒸煮温度升高和处理时间的延长,不同模拟液中甲苯的迁移率逐渐增大;其迁移率大小依次为：5 g/100 mL氯化钠＞0.2 g/100 mL谷氨酸钠＞10 g/100 mL蔗糖＞蒸馏水;高温蒸煮导致调味品模拟液处理复合膜的氧气透过量和水蒸气透过量上升;红外光谱、差示扫描量热仪和扫描电子显微镜分析结果表明,高温、蒸馏水和氯化钠处理会破坏膜的内部结构,使其结晶度下降,分子间作用力减弱、导致其结构松散、膜的表面凹凸不平、出现扭曲现象。     

Inulin blend as prebiotic and fat replacer in dairy desserts: optimization by response surface methodology

The purpose of this work was to optimize the formulation of a prebiotic dairy dessert with low fat content (<0.1 g/100 g) using a mixture of short- and long-chain inulin. Response surface methodology was applied to obtain the experimental design and data analysis. Nineteen formulations of dairy dessert were prepared, varying inulin concentration (3 to 9 g/100 g), sucrose concentration (4 to 16 g/100 g), and lemon flavor concentration (25 to 225 mg/kg). Sample acceptability evaluated by 100 consumers varied mainly in terms of inulin and sucrose concentrations and, to a lesser extent, of lemon flavor content. An interaction effect among inulin and sucrose concentration was also found. According to the model obtained, the formulation with 5.5 g/100 g inulin, 10 g/100 g sucrose and 60 mg/kg of lemon flavor was selected. Finally, this sample was compared sensorially with the regular fat content (2.8 g/100 g) sample previously optimized in terms of lemon flavor (146 mg/kg) and sucrose (11.4 g/100 g). No significant difference in acceptability was found between them but the low-fat sample with inulin possessed stronger lemon flavor and greater thickness and creaminess.     

TEXTURE IMPROVEMENT OF FRESH-PACK DILL PICKLES BY ADDITION OF LACTOSE AND SUCROSE

The influence of small amounts of lactose or sucrose on texture of fresh-pack dill pickles was evaluated by Instron texture profile analysis (TPA). Pickles were prepared with 0, 2, 4 and 6% by weight of either lactose or sucrose in a commerical brine. After equilibration of pickles with brine (30, 64 and 77 days), TPA values were obtained for brittleness, hardness, elasticity and total work of compression. Analysis of variance for the linear regression showed significant relationships between TPA values and sugar concentration. A minimum of 6% sugar is considered necessary for meaningful texture improvement. Sensory evaluation showed that sweetness may be detectable at the 4% and 6% sucrose levels. The presence of lactose was not objectionable at these levels.     

Formation of bromochlorodibenzo-p-dioxins and furans from the high-temperature pyrolysis of a 2-chlorophenol/2-bromophenol mixture

The homogeneous, gas-phase pyrolytic thermal degradation of a 50:50 mixture of 2-bromophenol and 2-chlorophenol was studied in a 1 cm i.d., fused silica flow reactor at a total concentration of 88 ppm, reaction time of 2.0 s, and temperatures from 300 to 1000 degrees C. Observed products included (in decreasing yield) naphthalene, dibenzo-p-dioxin (DD), phenol, dibenzofuran (DF), bromobenzene, chloronaphthalene, 4-bromo-6-chlorodibenzofuran (4-B,6-CDF), bromonaphthalene, benzene, 4,6-dichlorodibenzofuran (4,6-DCDF), chlorobenzene, 4-monobromodibenzofuran (4-MBDF), 4-monochlorodibenzofuran (4-MCDF), 1-mono-bromodibenzo-p-dioxin (1-MBDD), 2-chloro,4-bromophenol, 2,4-dibromophenol, and 2-bromo-4-chlorophenol. Unlike the case for the pyrolysis of pure 2-chlorophenol, 4,6-DCDF was observed, but the analogous 4,6-DBDF remained undetected similar to the individual results with 2-MBP. This indicates that the presence of bromine increases the concentration of chlorine atoms available for the formation of 4,6-DCDF. Due to bromine atoms acting as better leaving groups than chlorine atoms, the yield of DD was increased over that observed for the pyrolysis of 2-chlorophenol. The addition of bromine to a chlorinated hydrocarbon system results in an increase in the total yield of PCDD/Fs as well as PBDD/Fs and mixed PBCDD/Fs due to the ease of bromine elimination reactions as well as an increase of the chlorine atom concentration.