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该文采用傅里叶变换离子回旋共振质谱(FT-ICR-MS)、核磁共振氢谱(1H NMR)以及气相色谱-质谱(GC-MS)技术,对聚甘油脂肪酸酯的结构进行鉴定。样品溶解后进行FT-ICR-MS测定,根据精确分子离子数据,推测出聚甘油脂肪酸酯的基本结构以及甘油的聚合度,并采用1H NMR进行了验证。将聚甘油脂肪酸酯水解后,对脂肪酸部分进行甲酯化,经正庚烷萃取,由GC-MS测定,分析脂肪酸的组成。综合以上结果最终确定了聚甘油脂肪酸酯的结构。该研究为聚合物的结构鉴定提供了一种新的思路和方法。 相似文献
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脂肪酸丙烯醇酯的合成 总被引:4,自引:0,他引:4
用乙酸、丙酸、丁酸、戊酸、己酸分别与丙烯醇在加热下通过无水硫酸铜,进行反应,得到了乙酸丙烯酯、丙酸丙烯酯、丁酸丙烯酯、戊酸丙烯酯、己酸丙烯酯,其产率分别为60%,75%,74.2%,70%,72%. 相似文献
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建立了食品中脂肪酸单氯丙醇单酯与双酯含量的测定方法。称取0.1 g的油脂样品,加入内标后,转入氨基固相萃取柱,先以6.0 mL正己烷洗脱脂肪酸单氯丙醇双酯(MCPD双酯),再以6.0 mL正己烷-乙酸乙酯混合溶剂洗脱脂肪酸单氯丙醇单酯(MCPD单酯),分别收集洗脱液并浓缩至近干,残余物经甲醇钠水解和苯基硼酸(PBA)衍生后,供气相色谱/质谱(GC-MS)分析。MCPD单酯、MCPD双酯的检出限在83~142μg/kg(均以MCPD计)之间,线性范围为25~500μg/L(R2>0.9990)。以花生油和婴幼儿奶粉脂肪提取物为基质,在250~1000μg/kg范围内进行3种浓度水平的加标回收实验,MCPD单酯与双酯的回收率在86.5%~104.0%之间,相对标准偏差(RSD)为2.4%~13.2%(n=6)。此外,本方法成功应用于市售食用植物油和婴幼儿奶粉中MCPD单、双酯的污染调查。 相似文献
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蔗糖脂肪酸酯是一种无毒、安全、无刺激、无污染的非离子表面活性剂,它在食品、化妆品、洗涤剂及医药卫生用品方面有着广泛的用途。在其制备过程中,由于所用原料及反应条件不同,蔗糖酯中疏水基的链长分布及单、双酯的比例也不尽相同,因此,亲水-亲油平衡(HLB)值也各有差异。为了选择合乎要求的蔗糖脂肪酸酯,或在生产过程中对产品进行控制,测定其疏水基链长分布及单、双酯的比例就显得十分重要。 测定蔗糖酯亲水、疏水基组成的方法,一般采用预先皂化或氢化锂铝还原分解 相似文献
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聚羟基脂肪酸酯生物合成的研究进展 总被引:2,自引:0,他引:2
聚羟基脂肪酸酯 (PHA)是原核微生物在碳、氮营养失衡的情况下 ,作为碳源和能源贮存而合成的一类热塑性聚酯。它除了具有与化学合成高分子相似的性质外 ,还具有一般化学合成高分子没有的性质 ,如生物可降解性、生物相容性、压电性、光学活性等特殊性质 ,因而具有广阔的应用前景。国内外已对PHA进行了大量的研究。本文主要综述了近二、三年来国内外对PHA生物合成的研究进展 相似文献
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Abstract The rate constants for the reactive (kR) and unreactive (kQ) interaction of singlet molecular oxygen with three esters of polyunsaturated fatty acids (PUFA: cis-methyl oleate, MO; cis-methyl linoleate, MLA and cis-ethyl linolenate, ELN) are determined. The values of the ratio kQ/kR are 0.51, 0.26 and 0.20 for MO, MLA and ELN, respectively. This variation results principally from that of kR because the values of kQ are only slightly different (1.24 × 104M?1 s?1 for MO and ~1.0 × 104M?1 s?1 for MLA and ELN). It is shown that the rate constant kQ characterizes mainly an interaction with the unreactive part of the molecule rather than with the double bonds (solventlike quenching). Contrary to the already reported case of 1,5-polyenes for which kQ <<kR, the present results and those obtained from a number of literature data show that for PUFA and their esters, neither kR+ kQ nor kR are proportional to the total number of double bonds or of methylene groups adjacent to the double bonds. Instead, a linear correlation is observed by plotting kRvs the number of methylene groups adjacent to two double bonds. It is deduced that contrary to a common assumption, biallylic hydrogens have a reactivity higher than that of singly allylic hydrogens (reactivity ratio 1.19). The consequence of this result on the estimation of relative contributions of singlet oxygen and radical mechanisms to oxidation processes is discussed. Moreover, the whole of these results allows prediction of the values of kR and kQ for all unsaturated fatty acids (and their esters) of similar structure. 相似文献
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Three epoxy-, fifteen monohydroxy-, and three dihydroxyacids from lipids ofArtemisia leucodesSch. Seeds were identified using chemical, chromatographic, and spectral analyses. 相似文献
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根据热动力学的基础理论, 应用一级反应的无量纲参数法, 在20和30 ℃下测定了乙酸乙酯、丙酸乙酯和丁酸乙酯在乙醇-水混合溶剂中皂化反应速度常数, 并计算了它们的活化能, 结果在误差范围内与文献值相符合。还计算了这三个反应体系的活化自由能。本文讨论了反应物初始浓度和反应的速度常数与量热计冷却常数的关系。 相似文献
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多烯脂肪酸尿素包合富集的研究 总被引:10,自引:0,他引:10
近二十年生物化学,药理学,营养学的研究表明:多烯脂肪酸(PUFA)尤其是ω-3系列,具有特殊的生理功能。例如α-亚麻酸(α-Linolenic acid,ALA),EPA(Eicosapentaenoic aciod)具有降低血脂,预防心血管疾病发生的功效。而DHA(Docosahexaenoic acid)对大脑发育及视网膜的形成有着重要的促进作用^[1,2],自然界中,紫苏油中富含亚麻酸,鱼油中含有较多的EPA与DHA,将其富集提纯,可以提高产品的生理活性,成为目前保健品及医药开发的热点。 相似文献
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长链脂肪酸魔芋葡甘聚糖酯的制备及乳化性能研究 总被引:4,自引:0,他引:4
采用非均相酰化法制备了四个系列的长链脂肪酸魔芋葡甘聚糖酯(KGME).DTA图显示了葡甘聚糖酯的晶态结构变化,X 射线衍射分析表明了不同长度的酰链对葡甘聚糖酯晶态结构的影响.初步研究了葡甘聚糖酯在芳香烃及环烷烃两种水包油(O/W)乳液体系中其取代度与乳化力的关系.实验证明在水包油乳液体系中,取代度在某一范围的葡甘聚糖酯显示出较好的乳化能力,且在高盐浓度和酸性情况下,仍给出好的乳化作用.丁香油 水(O/W)乳液体系在室温下静置四个星期未发现破乳分离现象 相似文献
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在25°脂肪酸钠盐对正戊酸在水中溶度的影响是不规则的盐溶和盐析作用,其原因是排代出的新酸分布于正戊酸相和盐溶液相间[1]。黄子卿等[2]曾在25°研究脂肪酸盐(甲酸钠至戊酸钠)对正己酸在水中溶度的影响,除甲酸钠外,盐溶随盐的碳原子数目的增加而下降。Philip等[3]曾在25°测定苯甲酸在甲酸钠和乙酸钠水溶液中的溶度。在本文中,作者测定在25°苯甲酸在五种脂肪酸钠(甲酸钠至戊酸钠)水溶液中的溶度。 相似文献
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Abstract— The triplet state characteristics (spectrum, lifetime and quantum yield) for four dye sensi tisers [methylene blue (MB), erythrosin (ER), haematoporphyrin (HP) and riboflavin (RF)] were determined in methanol by laser flash photolysis and singlet oxygen yields (0.60 to 0.48) from time-resolved measurements of the 1270 nm near infrared emission. The reaction of singlet oxygen with four long chain unsaturated phenyl esters [oleate (18: 1), linoleate (18: 2), linolenate (18: 3) and arachidonate (20: 4)] was followed quantitatively using the singlet oxygen luminescence technique and also, after continuous420–700 nm irradiation, by HPLC and other analysis of the isomeric product monohydroperoxides. The overall quantum yield of photooxidation (∼10-2 ) was shown to be consistent with the observed singlet oxygen quenching constants(2–12 times 104 dm3 mol-1 s-1 ) for the four esters studied and the singlet oxygen lifetime in methanol (τ∼ 9 μs). The isomer product distribution was interpreted in terms of a dual singlet oxygen and radical mechanism, the radical contribution increasing with sensitiser in the order ER = MB < HP ≪ RF, but also showing some dependence on substrate unsaturation. Evidence is presented for singlet oxygen quenching by MB and RF ( kO = 1.6 and 6.0 times 107 dm3 mol-1 s-1 ) and for the accelerated photobleaching of the dye sensitisers in the presence of the unsaturated esters. 相似文献