壳聚糖对银离子的吸附性能研究

壳聚糖（Chitosan,CTS）是自然界中储量仅次于纤维素的最丰富的天然高分子材料,其大分子链上含有较多的羟基、氨基等活性基团,已广泛用作各种载体材料.本文研究了壳聚糖对Ag＋的吸附性能,考察了不同条件下壳聚糖对Ag＋的吸附关系.pH值的提高和作用时间的延长均使吸附率增加,而较低温度下更有利于Ag＋的吸附,初始Ag＋浓度的高低对吸附量影响较大.     

壳聚糖醋酸盐的制备及其油脂吸附性能研究

采用半湿研磨法制备了壳聚糖醋酸盐(Ch-Ac),对其结构、理化性质进行了表征和测定。以食用油为吸附对象,探讨了搅拌速度、温度、介质pH等因素对Ch-Ac油脂吸附性能的影响,通过正交实验确定了Ch-Ac油脂吸附的最佳条件。实验结果表明:(1)Ch-Ac改善了壳聚糖的溶解性能而且具有较强的缓冲能力;(2)搅拌速度1000 r/min、温度25℃、介质pH=5的条件下,Ch-Ac的油脂吸附量(OBC)高达168.72 g/g,是壳聚糖OBC的10倍;(3)在pH=2～10的介质中,Ch-Ac的OBC均大于133.23 g/g,模拟人体胃肠pH环境连续变化,Ch-Ac的OBC为148.13 g/g。结果表明Ch-Ac的油脂吸附能力受介质pH影响较小。固体Ch-Ac制备方法简单、绿色环保,油脂吸附效率高,可在含油废水处理和降脂保健品等方面得到应用。     

壳聚糖对单宁酸的吸附性能研究

以活化后的壳聚糖为吸附剂,探究壳聚糖对水溶液中单宁酸的吸附性能。通过对实验过程中吸附动力学和吸附热力学的探究,采用粒内扩散模型、准一级动力学模型、准二级动力学模型对吸附动力学数据进行拟合处理,结果表明,壳聚糖吸附过程更符合准二级动力学模型(R²=0.996 5、R²=0.992 3);采用Langmuir等温吸附模型和Freundlich等温吸附模型对吸附热力学数据进行拟合,结果表明,壳聚糖吸附过程更符合Langmuir等温吸附模型(R²=0.995 9)。实验得出壳聚糖对水溶液中单宁酸的吸附属于单分子层的化学吸附。     

壳聚糖对银离子的吸附性能研究

壳聚糖(Chitosan,CTS)是自然界中储量仅次于纤维素的最丰富的天然高分子材料,其大分子链上含有较多的羟基、氨基等活性基团,已广泛用作各种载体材料.本文研究了壳聚糖对Ag+的吸附性能,考察了不同条件下壳聚糖对Ag+的吸附关系.pH值的提高和作用时间的延长均使吸附率增加,而较低温度下更有利于Ag+的吸附,初始Ag+浓度的高低对吸附量影响较大.     

壳聚糖对蔗糖溶液中单宁酸的吸附性能研究

目的:进行壳聚糖对蔗糖溶液中单宁酸的性能研究。方法:通过吸附动力学和吸附等温线的考察,将吸附动力学实验数据采用粒内扩散模型、准一级动力学模型和准二级动力学模型线性拟合,吸附等温线数据采用Langmuir模型和Freundlich模型线性拟合。结果:在单宁酸的初始浓度为100 mg/L和250 mg/L时,壳聚糖对蔗糖溶液中单宁酸的吸附动力学用准二级动力学模型的拟合效果最好(R²=0.9993和0.9957);壳聚糖对蔗糖溶液中单宁酸的吸附等温线用Langmuir模型拟合效果最好(R²=0.9977)。结论:该吸附属于单分子层的化学吸附,理论饱和吸附量为107.53 mg/g。     

壳聚糖对二甲酚橙的吸附

研究了壳聚糖对二甲酚橙的吸附性能．探讨了吸附时间、溶液初始质量浓度、吸附剂用量及溶液初始pH对二甲酚橙去除率的影响．结果表明：在pH为3及常温条件下，当壳聚糖用量为3g/L时对质量浓度为26．4mg/L的二甲酚橙去除率为90．1％     

壳聚糖对天冬酰胺的吸附性能研究

采用壳聚糖对水溶液中天冬酰胺的吸附性能进行初步研究。采用粒内扩散模型、准一级动力学模型和准二级动力学模型对壳聚糖吸附天冬酰胺的动力学数据进行拟合,并采用Langmuir等温方程和Freundlich等温方程对其吸附等温线数据进行结果拟合。试验表明,当天冬酰胺的初始浓度分别为50、100、150 mg/L时,壳聚糖对天冬酰胺的吸附过程均符合准二级动力学方程(R^2=0.985 7～0.993 2)。壳聚糖对天冬酰胺的吸附等温线符合Langmuir等温吸附模型(R^2=0.978 8),其饱和吸附量为87.72 mg/g。壳聚糖对天冬酰胺具有一定的吸附能力。     

壳聚糖对染料废水中酸性染料的吸附研究

研究生物功能材料壳聚糖对染料废水中酸性染料吸附情况,讨论各种条件如吸附时间、吸附剂浓度、染料浓度、溶液p H值等对吸附效果的影响。从实验结果中可知,当壳聚糖浓度为3g/L时,酸性黄A-K的去除效率基本可以达到98%,而吸附时间控制在60~80min是比较合适的。由于壳聚糖的特殊结构,在酸性条件下,壳聚糖对酸性黄A-K的吸附效果更佳;而当废水中染料浓度发生变化时,也应调整壳聚糖的浓度以达到较好的预处理效果。     

油脂脱色过程对游离脂肪酸影响研究

大豆油中所含游离脂肪酸（简称FFA）主要是亚油酸,亚油酸的两个双键之间含有一个活性很强的亚甲基,油脂脱色使用的脱色剂对该亚甲基参与的许多反应是天然的催化剂,本论文通过实验测定了脱色温度、时间、用量对FFA含量的影响.     

改性稻壳在菜籽油脱酸中的应用研究

以改性稻壳对菜籽油进行脱酸,研究脱酸条件;并且通过静态吸附实验研究改性稻壳对菜籽油中游离脂肪酸的吸附性能。研究结果表明,最佳脱酸条件为搅拌速度150 r/min、吸附时间120 min、改性稻壳的添加量2.25%、吸附温度45℃。在此条件下改性稻壳能够使菜籽油的酸值从3.78 mgKOH/g降至0.81 mgKOH/g;静态吸附试验结果表明,改性稻壳对初始酸价为5 mgKOH/g左右的原料油,具有较好的脱酸效果。     

Effect of free fatty acids on the flavour of frying oil

Lauric acid imparts soapy taste to edible oil and to fried bread in the concentration of less than 1 g·kg^-1, palmitic acid and stearic acid taste neutral in the concentration of up to 20 g·kg^-1, oleic acid is neutral in the same concentration range, while purified linoleic acid tastes slightly bitter, and the flavour of linolenic acid is bitter and rancid at the concentration of 1 g·kg^-1.     

The free fatty acids of palm kernel oil damaged by fungi

Examination of the free fatty acids and triglycerides of palm kernel oil decayed by fungi shows a significant fall in the level of lauric acid. Considerable differences in levels of free fatty acids are found, suggesting a wide variation in the ability of fungi to use these compounds.     

Effects of free fatty acids on the oxidative processes in purified olive oil

Several studies have investigated the interaction of free fatty acids with the oxidative phenomena involving oils during processing and storage. Nevertheless, the available information is insufficient and, in some cases, contradictory.The aim of this work was to throw light upon this matter, by evaluating – by means of different analytical approaches – the effect of adding increasing amounts of free fatty acids (0.25%, 0.5%, 1%, 3%) on the oxidative processes occurring in purified olive oil during oxidation at 60 °C.The results obtained showed that oxidized forms of triglycerides and polar oligopolymers of triglycerides increased during oxidation. Low amounts of added FFA caused a further increase of the levels of oxidized triglycerides and triglyceride oligopolymers – pointing out a pro-oxidant activity – while higher doses of added free fatty acids lead to lower amounts of oxidized forms of triglycerides respect to the purified oil. This could be due to an increase in peroxide decomposition exerted by free fatty acids when present in higher amounts.     

分子蒸馏富集甜杏仁油中多不饱和脂肪酸技术研究

研究影响分子蒸馏富集甜杏仁油中多不饱和脂肪酸的因素并确定最佳工艺参数。甜杏仁油经乙酯化后,通过单因素实验分析影响分子蒸馏效果的主要因素为蒸馏温度、刮板转速、进料速度和真空度,结合设备情况并应用响应面法中的Box-Behnken设计优化分子蒸馏参数,在60滴/min的进料速度下,经过优化得出最佳工艺参数为:蒸馏温度109℃,刮膜器转速350r/min,操作压力3Pa,在此条件下多不饱和脂肪酸的含量为93.883%。结果表明,分子蒸馏技术富集甜杏仁油中多不饱和脂肪酸是可行的。     

不同地域黄酒中酸类物质差异性研究

通过高效液相色谱、气相色谱法分别测定了全国不同地区的12种黄酒中的有机酸和游离脂肪酸含量,并以9种有机酸和5种游离脂肪酸为变量进行主成分分析。结果表明:黄酒有机酸中乳酸、乙酸和柠檬酸的含量最高,占总有机酸的80%以上;前4个主成分能代表12种样品中有机酸含量85.276%的信息,因子得分真实地反映了样品的产地、原料、工艺与有机酸的关联性。黄酒中游离脂肪酸种类丰富而且总量差异大,第一主成分、第二主成分累积贡献率达61.783%、83.822%,能够较好地代表原始数据所反映的信息,第一主成分包含C18∶0、C16∶0,第二主成分包含C14∶0、C18∶1,这4种物质对黄酒整体风味的作用可分为三种,即C18∶0和C16∶0、C14∶0、C18∶1。      

A chemometric approach for the quantification of free fatty acids in cottonseed oil by Fourier transform infrared spectroscopy

The aim of this study was to quantify free fatty acid in cottonseed oil (Gossypium) variety by a chemometric approach using Fourier transform infrared spectroscopy. Calibration standards were prepared by gravimetrical mixing of oleic acid (0.1–40 g/100 g) in neutralized cottonseed oil containing <0.1% free fatty acids. Fourier transform infrared technique coupled with partial least square and principle component regression models were used to develop calibrations in the specific absorption region of carbonyl between 1690–1727 cm^?1. On the basis of regression coefficient and evaluated free fatty acids results with comparison to titration method, partial least square was found to be more accurate than principle component regression calibration model. All the analyzed cottonseed oil varieties showed high content of free fatty acids in the range of 17.1–38.5%. The results of the present study indicated that Fourier transform infrared method in combination with partial least square or principle component regression could be used as a greener alternative to the standard titration method.     

从油脂加工控制反式脂肪酸

随着氢化油的大量使用,反式脂肪酸的危害逐渐显现。过量摄入反式脂肪酸会增加心血管疾病的危险性、诱导血栓形成,还能干扰脂肪酸代谢,影响青少年儿童的生长和智力发育。近年来,公众对反式脂肪酸的担忧越来越强。本文综述了反式脂肪酸的产生、来源及对人体的危害。反式脂肪酸有两个来源,天然存在和油脂加工过程中产生,其危害主要来自油脂氢化、精炼及煎炸过程产生的反式脂肪酸。因此,本文提出主要从以下3个方面控制反式脂肪酸:(1)寻找氢化油的替代品:酯交换油脂、酯化产品、油凝胶、棕榈油分提物等;(2)采用油脂提取新技术:水酶法提油、冷榨提油、超临界萃取提油等;(3)减少煎炸。旨在从源头把关,从根本上消除反式脂肪酸可能引起的健康隐患。     

Characterization of wax esters,free fatty alcohols and free fatty acids of crude wax from sunflower seed oil refineries

The sunflower seed wax (10–12%) from oil refineries was purified through two steps, namely, extraction using solvents and precipitation with chilled acetone. Fatty esters, free fatty alcohols and free fatty acids were separated by thin-layer chromatography (TLC). The fractions of fatty esters and free fatty alcohols were separated and identified by gas chromatography (GC) using a Dexil-300 column and OV-101 column, respectively, at temperatures from 150–290 °C and were further confirmed by Gas chromatography–mass spectrometry (GC–MS), using a capillary silica column SPB™-1 coated with polydimethyl siloxane. Among the long chain fatty esters (C₃₈–C₅₄), comprised of one unit of fatty alcohol and one unit of fatty acid through an ester linkage, the major esters were C₄₀–C_44, of which C₄₂ was predominant. These fatty esters, upon hydrolysis, followed by methylation and subsequent GC–MS analysis, showed the presence of C₁₆–C₃₀ fatty acids in the bound form, whereas methylation of native wax indicated the presence of C₁₈–C₃₀ fatty acids in the free form. Acetylation of hydrolysis product showed the presence of C₁₈–C₃₀ fatty alcohols in the bound form, where as acetylation of native wax indicated that the C₁₈–C₃₂ fatty alcohols were in the free form. n-Triacontanol (C₃₀), a plant growth regulator, was found in both free and bound forms.