不同来源脂肪酶催化餐厨废油水解实验研究

研究不同来源的脂肪酶催化餐厨废油水解反应制备脂肪酸,通过单因素实验考察了酶用量对酶解率的影响,在此基础上采用正交实验对水解工艺参数酶用量、水解温度、油水比和水解时间进行优化。结果表明:猪胰脂肪酶L3621和假丝酵母脂肪酶LS20在适宜条件下均可实现餐厨废油的高效酶催化水解;L3621最佳水解条件为酶用量700 U/g、水解温度45℃、油水比1∶1.2、水解时间36 h,在此条件下酶解率达94.30%;LS20最佳水解条件为酶用量600 U/g、水解温度40℃、油水比1∶1、水解时间36 h,在此条件下酶解率达96.84%。     

棕榈油的酸催化水解工艺研究

以棕榈油为原料进行常压酸催化水解工艺研究。考察了反应时间、反应温度、催化剂用量、油水质量比及乳化剂用量对棕榈油水解反应的影响,得出棕榈油一次酸催化水解的最佳反应条件:反应时间7 h,反应温度100℃,催化剂浓硫酸用量7.5%,油水质量比1∶1,乳化剂磺酸用量0.5%;在最佳反应条件下棕榈油水解产物酸值(KOH)为192.77 mg/g,水解率达到91.96%。并研究出一套循环水解的工艺流程,实现油脂水解产物的循环利用,提高了水相中甘油的含量。     

餐厨废油环氧化的初步研究

以餐厨废油为反应物,研究了原料配比、反应温度、时间、催化剂用量等因素对餐厨废油环氧化效果的影响,结果表明:当原料配比为餐厨废油∶乙酸∶双氧水∶催化剂=1∶0.2∶1.13∶0.002 7(质量百分比)、反应温度80℃、反应时间5 h时,餐厨废油的环氧化值达到最大;通过红外光谱(FTIR)和热重(TG)分析表明:在1 005 cm–1左右出现了较强的C–O–C环氧化基团,1 600 cm–1左右的C=C双键吸收峰明显减弱,说明餐厨废油发生了很好的环氧化作用;且环氧化后的热解温度与餐厨废油相比提早了200℃,热解时间和速率也有相应的降低,说明餐厨废油中氧含量的比例有一定的提高。     

豆渣制取草酸工艺研究

以豆渣为原料制取二水合草酸,研究了硫酸质量分数、干豆渣浸泡时间、硝酸用量、反应时间、反应温度及催化剂五氧化二矾-三氯化铁(质量比1∶1)用量对草酸收率的影响,并对产品进行了质量测定。结果表明,豆渣制取草酸的最佳工艺条件为:硫酸质量分数70%,干豆渣浸泡时间3 h,硝酸、干豆渣、催化剂质量比2. 1∶1∶0. 002,反应时间5～6 h,反应温度65～70℃。在最佳工艺条件下,采用母液套用的方法连续操作9批物料,二水合草酸收率平均可达76. 5%,纯度99. 5%。产品经红外光谱确定为草酸,熔点101. 5℃,铁盐和硫酸盐含量分别为0. 002%和0. 04%,850℃灼烧残渣为0. 07%。     

超声波强化油脂皂化水解制备亚油酸工艺优化及脲包法富集研究

研究了超声波强化条件下制备亚油酸的最佳工艺及脲包法富集效果的影响因素。在单因素试验基础上,采用正交试验分析了皂化时间、超声波功率、加碱量和皂化温度条件对制备效果的影响。结果表明:亚油酸的最佳制备工艺条件是皂化时间25 min、超声波功率140 W、加碱量95 mL、皂化温度80℃,在此工艺条件下进行验证实验,与正交试验模型结果理论值基本一致。脲包法富集亚油酸的最佳条件是尿素与油脂用量比为3∶1(g/g)、溶剂(95%乙醇)与油脂液料比16∶1(mL/g)、富集温度5℃、富集时间20 h,在此条件下进行富集效果验证实验,滤液中亚油酸的碘值172.8,得率70.32%。     

废皮屑水解胶原改性皮革加脂剂

采用环氧化菜籽油为原料,经废皮屑水解胶原改性制备皮革加脂剂.通过研究水解胶原用量、催化剂用量、三乙醇胺用量及反应时间和反应温度等条件对加脂剂加脂效果的影响,确定最佳条件为:胶原用量为环氧化油脂质量的10%;催化剂用量为环氧化油脂质量的3.0%左右;反应温度为55℃;反应时间控制在7.0～9.0 h之间;促进剂三乙醇胺用量为环氧化油脂质量的0.5%～1.5%.     

综合指标评价鉴别餐厨废油脂的研究

通过测定各类食用植物油和餐厨废油脂的特征指标和品质指标,对其特征指标(折光指数、碘值和短链饱和脂肪酸)进行差异性分析,进行餐厨废油脂的初步鉴别;采用主成分分析法(Principal components analysis,PCA)以酸价、过氧化值、极性组分、金属元素含量和反式脂肪酸含量为主要品质指标对各类油脂进行分析,从5个影响油脂品质的指标中提取3个主成分构建数学评价模型,通过各类油脂的主成分得分鉴别餐厨废油脂。研究表明,餐厨废油脂的特征指标与各类食用植物油存在显著性差异;利用评价模型计算出各类油脂在各主成分的得分,3个餐厨废油脂样品的主成分综合得分比普通食用植物油高,油脂总体品质恶劣,表明综合指标评价鉴别餐厨废油脂是可行的。     

脂肪酶强化水解餐厨油脂促进厌氧消化

采用批次实验研究了脂肪酶预处理对餐厨油脂水解及其对厌氧消化性能的影响。首先考察了酶用量、水油比、pH和温度等因素对餐厨油脂水解的影响,进而通过响应面分析确定了其最佳预处理条件;最后基于预处理条件下的餐厨废水(含油脂)的厌氧消化实验,分析了预处理对餐厨废水厌氧消化的重要影响。结果表明:餐厨油脂的最佳预处理条件为:酶用量质量分数1.15%、水油质量比0.9、pH 8.0、温度42.5℃,水解率预测值为86.6%,重复实验水解率为(88.1±2.2)%,与预测值较为接近,表明该响应面模型能够很好地预测上述4个反应条件对水解的影响。对实际餐厨废水进行脂肪酶预处理和厌氧消化研究发现,加酶组的累积甲烷产量为572.12mL/g·COD,较餐厨废水组(368.86 mL/g·COD)和含油废水组(499.47 mL/g·COD)分别提高了55.10%和14.56%,表明餐厨废水中的脂肪具有较大的产甲烷潜力,脂肪酶预处理能显著提高油脂的产甲烷效率。对不同预处理条件下厌氧反应过程的pH、挥发性脂肪酸(VFAs)及脱氢酶活性进行了对比分析,发现酶促预处理对系统pH的影响较小;其对VFAs及脱氢酶活性的影响主要体现在厌氧消化前期,表现为对VFA及脱氢酶活性的显著提高,说明预水解能够保证产甲烷过程的底物供给并提高产甲烷效率。     

食用植物油与餐厨废油脂中三酰甘油氧化聚合物含量的研究

为了探寻餐厨废油脂的标志性氧化产物,采用正相硅胶柱制备色谱预分离油脂中极性物,联用高效体积排阻色谱方法测定三酰甘油氧化聚合物(oxidized triacylglycerol polymers,TGP),统计分析了12种常见品种44个新鲜食用植物油样品和具代表性的三大类61个来源不同、精炼程度各异的餐厨废油脂样品的TGP含量,显示食用植物油中TGP平均质量分数为(0.68±0.37)%,精炼餐厨废油脂中平均质量分数为(6.10±3.44)%,二者TGP含量具极显著差异(P<0.01)。结果表明TGP可望成为鉴别源于餐厨废弃食用油的二次油的指标。     

固体酸碱催化餐饮废油脂制备生物柴油

采用固体酸、碱催化餐饮废油脂制备生物柴油.首先用煅烧后的(NH4>)2>SO4>/Al2>O3>催化甲醇和餐饮废油脂中的游离脂肪酸进行预酯化反应,然后再用煅烧后的Na2CO3/Al2O3催化甲醇和餐饮废油脂中的甘油三酯进行酯交换反应.结果表明,经预酯化的餐饮废油脂在以正己烷为溶剂、溶剂用量为1.5 mL/g(oil)、醇油摩尔比为15:1、反应温度为50℃、反应时间为4 h和催化剂用量为8%的最佳工艺条件下进行酯交换反应.反应转酯率为96.85%.     

酶法合成生物表面活性剂

总结了外源酶催化法和整胞微生物代谢法合成生物表面活性剂的特点,并将外源酶催化法对整胞微生物代谢法及传统化学合成法的优势进行了比较.详细介绍了单甘酯、糖酯、(溶血)磷脂、纯异头烷基糖苷和氨基酸型表面活性剂等生物表面活性剂的酶催化合成方法及其研究进展;展望了酶工程的进步、化学 酶催化技术进展、外源多酶联合催化技术的开发与应用、酶膜反应器和其它连续酶反应器的开发,以及反应 分离耦合技术在酶催化过程中的应用将给酶法合成生物表面活性剂带来的机遇.     

Single step green process for the preparation of antimicrobial nanotextiles by wet chemical and sonochemical methods

Abstract

In this work, the green synthesis of silver nanoparticles (AgNPs) was carried out by using Zanthoxylum rhesta plant’s fruit extract for the first time. The green synthesis and in situ deposition of AgNPs on cellulose fibers in cotton was carried out by wet and sonochemical methods. The AgNPs and AgNPs-deposited cotton fabrics were fully characterized. The crystallite size of particles obtained by both methods was around 37?nm and the hydrodynamic diameters were in the range of 69 to 184?nm and 75 to 111?nm. The scanning electron microscopy (SEM) images showed uniform deposition of the nanoparticles on cotton fabrics. The AgNPs-deposited cotton fabrics showed excellent antibacterial activities against gram positive and gram negative bacteria namely, Escherichia coli (E-coli), Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus subtilis. This work presents a significant advancement in the preparation of antimicrobial nanotextiles by a smart combination of green synthesis and in situ deposition approach.     

两性聚丙烯酰胺纸用增干强剂的合成及其应用

以丙烯酰胺、丙烯腈、丙烯酸和促进剂MPA为原料合成两性聚丙烯酰胺纸用增干强制，并讨论了各反应条件对产品性能的影响。同时对产品进行了抄纸应用试验。     

高含量水性脂肪族聚氨酯皮革涂饰剂的合成及应用

以 IPDI、四氢呋喃聚醚、1 ,4-丁二醇、二羟甲基丙酸、丙酮和三乙胺为原料合成了高含量水性脂肪族聚氨酯皮革涂饰剂乳液。探讨了影响这一乳液稳定性的因素。结果表明 ,这一乳液分散粒径要适中 ,以确保它的贮存稳定性 ,在中和乳化时 ,要增加剪切作用的强度 ,以尽量减少乳液的静态粘度。这一皮革涂饰剂可用于各类皮革涂饰中 ,效果良好。     

盐酸帕洛诺司琼的合成

目的合成盐酸帕洛诺司琼。方法以1,2,3,4-四氢-1-萘甲酸为起始原料,经拆分、胺化、还原、关环、成盐制得盐酸帕洛诺司琼。结果目标化合物经核磁共振氢谱、质谱、红外及元素分析等确证其化学结构,总收率9.4%。结论本工艺操作简便,成本较低,反应条件温和,产品质量易控制。     

Milking time and risk of over-milking can be decreased with early teat cup removal based on udder quarter milk flow without loss in milk yield

Increasing the milk flow rate at which milking is terminated can shorten milking time and increase milking efficiency. The effects on milk yield and composition have not been fully investigated when the take-off is set at the udder quarter level and independent of feeding during milking. The objective of this study was to investigate the effect of 3 take-off levels at the udder quarter level (0.06, 0.3, and 0.48 kg/min) applied with or without feeding during milking on milking time, milk yield, the degree of udder emptying, milk composition, and free fatty acids. In this study, 30 cows were allocated into 6 groups, balanced by lactation number, lactation stage, and milk yield, and subjected to a 3 × 2 factorial arrangement of treatments using a Latin square design. Treatments were applied for 1 wk each. This study demonstrated milking time could be reduced by applying up to a take-off level of 0.48 kg/min on udder quarter level without losing milk yield or compromising milk composition or udder health.     

Carvone: Why and how should one bother to produce this terpene

d-Carvone or (4S)-(+)-carvone has a caraway/dill odour and is the main constituent of caraway (Carum carvi) and dill (Anethum graveolens) seed oils whilst l-Carvone or (4R)-(−)-carvone has a sweet spearmint odour and is the main constituent of spearmint (Mentha spicata). Carvone is produced by both extraction and purification of essential oils from caraway, dill and spearmint seeds and by chemical and biotechnological synthesis.     

The production of intrinsically labeled milk protein provides a functional tool for human nutrition research

Oral or intravenous administration of labeled, free amino acids does not allow the direct assessment of protein digestion and absorption kinetics following dietary protein intake. Consequently, dietary protein sources with labeled amino acids incorporated within the protein are required. The aim of this study was to produce milk proteins intrinsically labeled with l-[1-¹³C]phenylalanine that would allow the assessment of protein digestion and absorption kinetics and the subsequent muscle protein synthetic response to dietary protein intake in vivo in humans. Two Holstein cows (body weight of 726 ± 38 kg) were continuously infused with l-[1-¹³C]phenylalanine at 402 μmol/min for 44 to 48 h, during and after which plasma samples and milk were collected. After milk protein separation, casein was used in a subsequent human proof-of-principle experiment. Two healthy males (aged 61 ± 1 yr; body mass index of 22.4 ± 0.1 kg/m²) ingested 35 g of casein highly enriched with [1-¹³C] phenylalanine. Plasma samples were collected at regular intervals, and skeletal muscle biopsies were collected before and 6 h after casein ingestion. In the initial experiment, a total of 5.83 kg of l-[1-¹³C]phenylalanine-enriched milk protein (casein enrichment was 29.4 molar percent excess) was collected during stable isotope infusion in the cows. In the proof-of-principle study, ingestion of 35 g of intrinsically labeled casein resulted in peak plasma l-[1-¹³C]phenylalanine enrichments within 90 min after protein ingestion (9.75 ± 1.47 molar percent excess). Skeletal muscle protein synthesis rates calculated over the entire 6-h period averaged 0.058 ± 0.012%/h. The production of intrinsically labeled milk protein is feasible and provides dietary protein that can be used to investigate protein digestion and absorption and the subsequent muscle protein synthetic response in vivo in humans.     

水性聚氨酯的合成与性能研究(I) 聚氨酯组成对其性能的影响

由聚酯多元醇、IPDI、DMPA等以不同配方合成了水性聚氨酯乳液 ,并对其性能进行了研究。结果发现 :DMPA含量、NCO/ OH比值均影响水性聚氨酯的黏度、粒径和力学性能等     

喷墨印花中的图像修补技术

阐述了图像修补技术在喷墨印花中的心用，分析了基于纹理合成和非纹理合成的图像修补技术的基本算法以及基本理论，并且把两种基本算法通过实验进行对比。