磷酸处理后苦卤脱镁母液蒸发析盐规律研究

针对制盐苦卤利用氨法制取MS(OH)2的脱镁母液,加入磷酸并固液分离后的澄清液,实验研究了其蒸发析盐规律.研究证明,蒸发过程中NaCl和NH4Cl为主要析出盐类,其最终析出率分别为66.31%和33.41%,在研究的蒸发水量范围内,蒸发过程中有少量光卤石析出.     

海水淡化浓盐水等温蒸发过程硫酸钙析出规律研究

海水淡化在获得淡水的同时副产大量浓盐水,浓盐水的盐度、温度等均高于自然海水,如在渤海湾内直接大量排放浓盐水势必会对周围海洋环境造成污染,为此实现浓海水资源的综合利用势在必行.研究浓海水不同温度下等温蒸发过程硫酸钙的析出规律可以为浓海水综合利用提供理论依据.室内试验研究表明:不同温度下等温蒸发时硫酸钙析出点稍有变化,30℃等温蒸发硫酸钙析出点为密度1.108 8 g/cm3,此时水分蒸发率为58.4%,溶液硫酸钙质量分数5.4g/kg;50℃等温蒸发硫酸钙析出点为密度1.1094g/cm3,此时水分蒸发率为60.1%,溶液硫酸钙质量分数5.6 g/kg;75℃等温蒸发硫酸钙析出点为密度1.1000g/cm3,此时水分蒸发率为60.3%,溶液硫酸钙质量分数5.8 g/1000 g;100℃等温蒸发硫酸钙析出点为密度1.0680g/cm3,此时水分蒸发率为53.4%,溶液硫酸钙质量分数4.4g/1000g.     

淡化后浓海水蒸发浓缩析盐规律研究

以海水淡化后浓海水为原料完成蒸发浓缩析盐规律研究,实验结果表明: 浓海水蒸发浓缩硫酸钙的析出点为12.21 °Be'(d=1.091 3g/cm3);氯化钠析出点为25.78 °Be'(d=1.216 0 g/cm3),浓海水蒸发浓缩过程组成变化规律与海水浓缩过程组成变化规律完全一致.浓海水日晒制盐是完全可行的.     

卤水制纯碱反应第一阶段反应动力学研究

卤水制备纯碱分两步进行,第一步用卤水、碳酸氢铵反应得到碳酸氢钠微溶析出和氯化铵溶液,过滤.第二步将碳酸氢钠煅烧得纯碱.在搅拌速度1000r/min,15℃～35℃,配料摩尔比(NH4HCO3/NaCl)为1.0,卤水的初始浓度280g/L～330g/L的条件下,通过实验研究了第一步反应的过程动力学,结果表明该反应受化学反应控制,为二级反应,其动力学模型为:1/CA0(1-X)=7.44×10-2C0.2568A0exp(-6.43×103/RT)×t.     

鸭肉在盐腌过程中嫩度和超微结构变化的研究

通过对鸭肉盐腌处理过程中嫩度及相关指标变化的研究,阐明了在此过程中嫩度变化的机制.取新鲜的番鸭腿肉,分别在20 g/L、40 g/L、60 g/L和80 g/L NaCl溶液中进行腌制,测定剪切力值、结缔组织热变性温度,并在透射电镜下观察肌原纤维的结构的变化.试验结果表明,随着盐浓度的增加,剪切力值呈现出降低的趋势,热变性点的数量减少,并且变性的温度发生了变化.超微结构观察表明,新鲜鸭肉在用NaCl溶液进行腌制,将对肌原纤维的崩解起到促进作用,肌节长度变化不大,其中20～40 g/L NaCl溶液的作用尤为明显,在此浓度下有助于改善鸭肉的嫩度.     

除硫后制盐母液浓缩结晶析出光卤石的研究

针对海盐场排出的制盐母液,采用机械冷冻法和氯化钙沉淀法将溶液中的硫酸根降低到10 g/L以下得到除硫母液,在不兑入老卤的情况下将除硫母液进行不同蒸发终止沸点下的浓缩,然后将蒸发浓缩后的清液冷却结晶析出光卤石。根据光卤石中的氯化钾含量计算在不同蒸发终止沸点和相同冷却结晶温度下氯化钾的析出率,从而找到除硫母液的蒸发终止沸点与浓缩清液冷却结晶时氯化钾的析出率关系。     

真空制盐错流转料自动控制在我厂应用

我厂是以有钡黄卤与岩卤兑卤为原料的真空制盐厂家,由于原料卤水中含有MgCl_2和CaCl_2,故在制盐过程中,随着NaCl的析出,料液中的MgCl_2和CaCl_2的含量就逐渐增高。当料液浓度达到30°Be′时,NaCl已析出80％,而CaCl_2的含量竟高达200g/1以上,同时料液粘度增大,沸点上升增高,有效温差下降,罐内蒸发强度也下降。若再耗用能量蒸发浓缩,在经济上是得不偿失,无再蒸发之必要,必须将母液排掉,这一过程我们称为“排旦”。     

海水循环冷却系统排放水浓缩规律及制盐研究

文章研究了海水循环冷却系统排放浓海水在室内自然蒸发过程中,CaSO4、NaCl的析出规律、主要离子的浓度变化规律以及日晒盐的化学组成和毒性.试验结果表明:海水循环冷却系统排放浓海水的CaSO4析出点为13.89°Be′,NaCl析出点为25.76°Be′,此时CaSO4的析出率为90.32％;实验制得的日晒盐化学组成符合制盐业一级品标准,并属实际无毒.因此,利用海水循环冷却系统排放浓海水制盐切实可行.     

海洋红酵母Rhodotorula sp.06产类胡萝卜素的研究

对海洋红酵母Rhodotorula sp.06产类胡萝卜素的最优条件进行研究,比较不同碳源、氮源、NaCl、装液量、培养时间对菌体生物量和色素形成的影响,通过正交实验确定最佳摇瓶发酵条件组合。结果表明,海洋红酵母的最佳摇瓶发酵条件为:蔗糖15g/L、蛋白胨20g/L、NaCl20g/L、NH4Cl7.5g/L、24℃、装液量80/250mL、发酵时间72h。在此最优条件下,其生物量、类胡萝卜素含量和产量分别为10.27g/L、296.11μg/g、3.04mg/L。     

干酪乳杆菌05—21在酸、胆盐和渗透压胁迫条件下的同源抗性和交叉抗性反应研究

对干酪乳杆菌在干酪生产和人体胃肠道环境中主要面临的酸、胆盐和渗透压3种胁迫条件下的同源抗性和交叉抗性进行研究.首先确定酸、胆盐、NaCl胁迫的亚致死水平和致死水平分别为pH值为5.0和pH值为3.5,质量浓度为0.5 g/L和3 g/L,20 g/L和180 g/L.同源抗性实验表明,酸诱导2h存活率可提高23倍,胆盐诱导提高25倍,NaCl诱导提高75倍.交叉抗性实验表明,酸诱导后茵体在胆盐、NaCl中存活率分别提高20倍和11倍:而NaCl诱导后茵体在胆盐中存活率提高250倍,但却不能诱导茵体的抗酸能力.稳定期茵体具有比对数期菌体更强的抗胁迫能力.实验结果为优化干酪生产工艺,提高干酪乳杆菌在胃肠道中的存活率提供了理论基础.     

表面活性剂对C.I.活性蓝221的增溶作用

分别以NaCl、AEO9、AEO3、JFC、AES和L-64为添加剂,研究了它们对C.I.活性蓝221在25 ℃水中的溶解度的影响。实验结果表明,NaCl的加入会大幅降低染料的溶解度;而五种表面活性剂对染料都有增溶作用,增溶效果依次为：JFC（L-64）>AEO9>AEO3>AES。当JFC或L-64用量为80 g/L时,可使C.I.活性蓝221的溶解度由空白时的100 g/L提高至190 g/L。以JFC,L-64,AEO9为混合助溶剂时,当溶液中含有15 g/L JFC, 20 g/L L-64和5 g/L AEO9时,C.I.活性蓝221的溶解度可以提升至200 g/L,染料溶液稳定时间达20 h以上。     

漂洗过程中锌离子对鲢鱼鱼糜凝胶特性的影响

以鲢鱼鱼糜为研究对象,通过测定凝胶强度、持水性、蒸煮损失率、色度、质构特性、水分分布状态、微观结构和蛋白质分子质量分布指标,分析了漂洗过程中锌离子对鲢鱼鱼糜凝胶特性的影响。结果表明,用含有锌离子的漂洗液漂洗较用清水漂洗和质量分数0.15%Na Cl漂洗对鲢鱼鱼糜凝胶性能有较大改善,其中,当锌离子浓度为6μmol/L时,鲢鱼鱼糜凝胶的凹陷距离、凝胶强度和咀嚼度均处于最大值(8.47 mm、2 325.90 g·mm、2 752.12 g·mm);破断力为274.74 g,较清水漂洗提高了14.95%;该浓度条件下凝胶对水的束缚能力增强,持水性达到最大值(83.13%),并且蒸煮损失率和横向弛豫时间T23为最小值(分别为9.39%、45.47 ms);白度得到提升。在锌离子的作用下,肌球蛋白重链通过交联作用形成较大聚集体,且凝胶微观结构均匀致密。     

黄水基质微生物发酵合成γ-聚谷氨酸培养基及条件优化

以白酒酿造副产物黄水为基质,微生物发酵生产γ-PGA,以期为黄水的综合利用寻求一条新途径的同时,实现黄水的高值化利用。本文以黄水作为微生物发酵用基质,通过检测发酵液中γ-PGA浓度、发酵液粘度、残留谷氨酸及葡萄糖浓度,利用单因素及响应曲面设计试验优化黄水微生物发酵合成γ-PGA的培养基及条件,结果显示:pH为7.0、稀释8倍的黄水作为溶剂时,玉米糖化液浓度75 g/L（按可溶性固形物含量计）,牛肉粉浓度70 g/L,谷氨酸钠浓度45 g/L,NaCl浓度12 g/L,K₂HPO₄浓度7 g/L,接种量1%,装液量25 mL/250 mL,37 ℃发酵72 h,γ-PGA产量达14.510 g/L。由此可见,黄水基质微生物发酵合成γ-PGA是可行的。     

产胶原酶的琥珀葡萄球菌分离鉴定及其培养优化研究

针对胶原蛋白难消化利用的现状,自烟台近海分离筛选产胶原蛋白降解酶的微生物,获得高产菌株SM12,并经形态观察、生理生化试验和16S rDNA鉴定,确定菌株SM12为琥珀葡萄球菌（Staphylococcus succinus）。通过单因素试验确定最佳培养基成分及发酵条件为20 g/L葡萄糖,15 g/L牛肉膏,20 g/L NaCl,10 g/L明胶,初始pH 7.5,培养温度37 ℃,接种量7.5%（V/V）,装液量100 mL/500 mL。在此最佳条件下,筛选的菌株SM12在发酵24 h后获得最大胶原酶活力185.32 U/mL,具备在水产加工下脚料高值化加工领域的应用潜力。     

Prediction of Lactose Crystals Present in Supersaturated Lactose and Whey Solutions by Measuring the Water Activity

Linear models based on water activity measurement were developed to predict the crystalline fraction of lactose present in the supersaturated crystal-solution mixture of lactose and whey. By this method, it was possible to measure the crystalline fraction in the mixture even if the sample is opaque or coloured, which would be difficult to measure by the conventional refractometric method. To calculate the fraction of lactose crystallized, the differential water activity of the crystallized mixture and non-crystalline supersaturated solution needs to be determined. For the pure lactose, the predictive linear equation was Δ?L = 1874.4 Δ?a_w, whereas for whey it was Δ?L = 1155.2 Δ a_w, where Δ L is the amount of α-lactose monohydrate crystals (g 100g^?1 water) that is in the crystallized solution, and Δ a_w is the differential water activity after and prior to crystallization. Other equations such as Raoult's. Norrish, and Money-Born were also tested to predict the water activity of supersaturated solutions of lactose or whey.     

万寿菊干花中叶黄素的实验室制备

用正己烷萃取万寿菊干花粉末多遍至萃取液无色,合并过滤萃取液。负压旋转蒸发浓缩萃取液至其中总类胡萝卜素含量为5%(W/V)。向浓缩液中加入等体积的10%(W/V)氢氧化钾乙醇溶液,在室温条件下,充氮,搅拌,皂化12h。用乙醚和2%(W/V)的氯化钠水溶液液-液萃取皂化反应产物。用氯化钠溶液多次洗涤乙醚相至氯化钠洗液的pH为7。收集乙醚相,负压旋转蒸发除去其中的乙醚,并进一步负压加热干燥除去水分至恒重。测定产物的总类胡萝卜素含量及类胡萝卜素组成。收集色谱图上叶黄素组分的质谱图作为对其定性的依据。     

东方伊萨酵母生物转化法制备胞二磷胆碱

以5'-胞苷酸和磷酸胆碱钙为底物,利用东方伊萨酵母生物转化生成胞二磷胆碱,并对转化条件进行优化,得到最优的转化条件(胞苷酸17.5g/L,磷酸胆碱钙12.5g/L,磷酸氢二钾12.5g/L,硫酸镁3.0g/L,硫酸锰0.6g/L,葡萄糖50g/L,甲苯30mL/L,酵母泥375g/L,转化液pH8.0),胞二磷胆碱产量可达10g/L以上,最高可达11.592g/L。对转化液去细胞、去蛋白质,717离子交换树脂吸附胞二磷胆碱,以0.05mol/LNaCl洗脱,可以得到纯度在98%以上的胞二磷胆碱。     

大豆植酸分离方法对测定结果的影响

探讨了大豆植酸的浸提、离心和离子交换条件对其测定结果的影响。大豆经磨粉、过筛后 ,用 0 3 5mol/LHCl 0 7mol/LNa2 SO4溶液能充分提取出大豆的植酸 ;沸水浴后40 0 0r/min离心 10min可除去蛋白质 ;阴离子交换时 ,依次用 15mL蒸馏水、15mL 0 0 5mol/LNaCl淋洗 ,而后用 2 0mL 0 7mol/LNaCl以 1 0mL/min的速度洗脱 ,洗脱液的植酸加标回收率达到 98%以上 ;4个大豆样品中植酸测定结果的相对标准偏差分别为 1 2 3 %、4 0 5 %、1 5 3 %和 1 83 %。     

Antimicrobial effect of electrolyzed oxidizing water against Escherichia coli O157:H7 and Listeria monocytogenes on fresh strawberries (Fragaria x ananassa)

ABSTRACT:  Antibacterial activity of electrolyzed oxidizing (EO) water prepared from 0.05% or 0.10% (w/v) sodium chloride (NaCl) solutions against indigenous bacteria associated with fresh strawberries ( Fragaria × ananassa ) was evaluated. The efficacy of EO water and sodium hypochlorite (NaOCl) solution in eliminating and controlling the growth of Listeria monocytogenes and Escherichia coli O157:H7 inoculated onto strawberries stored at 4 ± 1 °C up to 15 d was investigated at exposure time of 1, 5, or 10 min. Posttreatment neutralization of fruit surfaces was also determined. More than 2 log₁₀ CFU/g reductions of aerobic mesophiles were obtained in fruits washed for 10 or 15 min in EO water prepared from 0.10% (w/v) NaCl solution. Bactericidal activity of the disinfectants against L. monocytogenes and E. coli O157:H7 was not affected by posttreatment neutralization, and increasing exposure time did not significantly increase the antibacterial efficacy against both pathogens. While washing fruit surfaces with distilled water resulted in 1.90 and 1.27 log₁₀ CFU/mL of rinse fluid reduction of L. monocytogenes and E. coli O157:H7, respectively, ≥ 2.60 log₁₀ CFU/mL of rinse fluid reduction of L. monocytogenes and up to 2.35 and 3.12 log₁₀ CFU/mL of rinse fluid reduction of E. coli O157:H7 were observed on fruit surfaces washed with EO water and NaOCl solution, respectively. Listeria monocytogenes and E. coli O157:H7 populations decreased over storage regardless of prior treatment. However, EO water and aqueous NaOCl did not show higher antimicrobial potential than water treatment during refrigeration storage.     

Determination of residual avoparcin in chicken muscle by HPLC with ultraviolet and amperometric detection

An analytical method was developed for determination of residual avoparcin in chicken muscle by measuring alpha- and beta-avoparcin, major components of the pharmaceutical preparation avoparcin, using HPLC with UV and amperometric detectors. The analytical HPLC was run on a Cosmosil 5C18-AR column (4.6 mm x 25 cm) with a gradient formed from A: 2.5% acetic acid, 0.01 mol/L sodium heptane sulfonic acid-acetonitrile (88.5:11.5) (pH 4.0) and B: 2.5% acetic acid-acetonitrile (10:90), using UV and amperometric detection (AMD) with glassy-carbon electrode (+900 mV). Avoparcin was extracted from chicken muscle by homogenization with methanol-0.2 mol/L sulfuric acid (6:4) followed by centrifugation after pH adjustment to 4 with 1 mol/L sodium hydroxide. The supernatant was evaporated to dryness, and the residue was dissolved in water. The aqueous layer was adjusted to pH 4 by adding 1 mol/L sodium hydroxide. Then it was purified on a Sep-Pak tC18 plus ENV cartridge. The cartridge was washed with water, and retained substances were eluted with 50% methanol. The eluate was evaporated to dryness under reduced pressure. The residue was dissolved in water and determined by HPLC. Recoveries of avoparcin spiked in chicken muscle were 73.1-88.1% at levels of 2-10 micrograms/g. The detection limits were 0.5 microgram/g (UV) and 0.2 microgram/g (AMD).