高顺式β-胡萝卜素及纳米结构脂质载体的制备

发布时间：2018-09-09 13:07

【摘要】：现有研究表明,9-顺-β-胡萝卜素具有比全反式异构体更强的生理活性。一般食物原料中多含有全反式β-胡萝卜素,只有盐生杜氏藻中9-顺式β-胡萝卜素的占比可以达到40%左右,但盐生杜氏藻价格昂贵,不利于大规模生产应用。因此,寻求一种以全反式β-胡萝卜素为原料,高效制备高顺式异构体含量、特别是高9-顺-β-胡萝卜素含量的异构化方法非常必要。另外,由于自身结构的限制,β-胡萝卜素几乎不溶于水、稳定性较差且生物利用度不高,作者尝试通过制备β-胡萝卜素-纳米结构脂质载体(β-C-NLC),有效克服β-胡萝卜素的使用缺陷,以方便其在水基食品中的应用。高9-顺占比β-胡萝卜素产品制备方法研究。以化学合成法生产的β-胡萝卜素(全反式占比达96%,9-顺式占比仅为0.15%)为原料,采用常规溶剂回流法做初步异构化处理,利用液相-离子阱质谱联用仪(HPLC-APCI-MS)对异构化处理后的产物进行测定,发现其主要成分为15-顺式、13-顺式、9,13-双顺式、全反式和9-顺式等五种β-胡萝卜素异构体,证实该测定方法有效。在对比常规溶剂回流、高温短时溶剂回流、碘掺杂二氧化钛纳米催化剂配合溶剂回流等异构化工艺的基础上,对碘掺杂二氧化钛纳米催化剂配合溶剂回流工艺进行单因素及正交试验,优选出制备高9-顺占比β-胡萝卜素异构体的最优条件为:β-胡萝卜素溶解在乙酸乙酯中,底物浓度1 mg/m L,体系温度75°C,时间105 min,催化剂用量1.1 mg/mg(基于β-胡萝卜素),此时,9-顺式β-胡萝卜素异构体相对含量达到25.31%,总顺式异构体的相对含量为47.41%。反应过程中β-胡萝卜素的降解率为12.6%。该制备方法适用于高9-顺式β-胡萝卜素的制备,且工艺简单,成本较低。关于储藏条件对异构化产品稳定性影响的研究结果表明:在避光避氧低温并添加适量的抗氧化剂的条件下储藏,可大大减少异构化产品的氧化降解,提高其稳定性。β-胡萝卜素-纳米结构脂质载体制备工艺研究。通过高压均质法制备β-胡萝卜素-纳米结构脂质载体并确定了最佳制备条件:经加热的油相(分子蒸馏单甘酯和中长链甘油酯)与水相(吐温80作为表面活性剂)混合,混合物在16000 rpm下剪切处理2 min,再在500 bar压力下均质3次,总脂质浓度为9%(w/v),表面活性剂浓度为1.4%(w/v),固液脂比例为3:1(w/w)。在该条件下,β-C-NLC中β-胡萝卜素的包封率达到95.64%,纳米结构脂质载体体系中β-胡萝卜素的含量达到2.9 mg/g,其平均粒径为191 nm,多分散指数(PDI)约为0.2,载体体系具有良好的分散稳定性。透射电镜结果表明载体呈球形。探究了贮藏条件对β-C-NLC稳定性的影响。结果表明在避光避氧,贮藏温度为4°C且p H为3.5-7.5的条件下贮藏时,其粒径变化小,分散体系稳定性好,β-胡萝卜素的降解率低,β-C-NLC的稳定性得到一定程度的提高。
[Abstract]:The present studies have shown that 9-cis-尾-carotene has stronger physiological activity than all-trans isomers. Most of the food raw materials contain all-trans 尾 -carotene, only 9- cis-beta-carotene can reach about 40% in the halophytic Dunaliella, but the price of Dunaliella salina is expensive, which is not conducive to large-scale production and application. Therefore, it is necessary to find an efficient isomerization method using all-trans 尾 -carotene as raw material to prepare high cis isomer content, especially 9cis 尾 -carotene content. In addition, because of the restriction of its own structure, 尾 -carotene is almost insoluble in water, and its stability is poor and its bioavailability is not high. The authors try to overcome the defects of 尾 -carotene by preparing 尾 -carotene-nano-structure lipid carrier (尾 -C-NLC). In order to facilitate its application in water-based food. Study on preparation method of 尾-carotene with high 9-cis ratio. Using 尾 -carotene produced by chemical synthesis (all-trans ratio of Prida 96- 9- cis is only 0.15%) as raw material, conventional solvent reflux method was used for preliminary isomerization treatment. Five 尾 -carotene isomers were determined by liquid-ion trap mass spectrometry (HPLC-APCI-MS) after isomerization. It was found that the main components of the isomerization products were 15-cis-13-cis 13-cis, all-trans and 9- cis-isomers. It was proved that this method is effective for the determination of 尾 -carotene isomers. On the basis of comparing the isomerization processes such as conventional solvent reflux, high temperature and short time solvent reflux, iodine doped titanium dioxide nanocatalyst and solvent reflux, etc. A single factor and orthogonal experiment was carried out for the preparation of 尾 -carotene isomers with high 9-cis-ratio 尾 -carotene by using iodine doped titanium dioxide nano-catalyst and solvent reflux process. The optimum conditions were as follows: 尾 -carotene dissolved in ethyl acetate, and the optimum conditions were as follows: 尾 -carotene was dissolved in ethyl acetate, and 尾 -carotene was dissolved in ethyl acetate. The substrate concentration was 1 mg/m / L, the system temperature was 75 掳C, and the catalyst dosage of 105 min, was 1.1 mg/mg (based on 尾 -carotene). The relative content of 尾 -carotene isomer reached 25.31 and the relative content of total cis-isomer was 47.41%. The degradation rate of 尾-carotene was 12. 6% during the reaction. The method is suitable for the preparation of high 9-cis 尾 -carotene, and the process is simple and the cost is low. The study on the effect of storage conditions on the stability of isomerized products shows that the oxidative degradation of isomerized products can be greatly reduced when stored under the condition of avoiding light and avoiding oxygen and adding appropriate amount of antioxidants. The preparation process of 尾-carotene-nano structure lipid carrier was studied. The 尾 -carotene nanostructure lipid carrier was prepared by high pressure homogenization method and the optimum preparation conditions were determined: the mixture of heated oil phase (molecular distillation monoglyceride and medium-long chain glycerol ester) and water phase (Tween 80 as surfactant). The mixture was shearing at 16000 rpm for 2 min, and then homogenized for 3 times under 500 bar pressure. The total lipid concentration was 9% (w / v), surfactant concentration was 1.4% (w / v) and solid-liquid / lipid ratio was 3:1 (w / w). Under these conditions, the encapsulation efficiency of 尾 -carotene in 尾 -C-NLC was 95.64, and the content of 尾 -carotene in nano-structured lipid carrier system was 2.9 mg/g,. The average particle size of 尾 -carotene in the carrier system was nm, and the polydispersity index (PDI) was about 0.2. The carrier system had good dispersion stability. Transmission electron microscopy showed that the support was spherical. The effect of storage conditions on the stability of 尾-C-NLC was investigated. The results showed that when the storage temperature was 4 掳C and pH was 3.5-7.5, the particle size changed little, the dispersion system was stable, the degradation rate of 尾 -carotene was low, and the stability of 尾 -C-NLC was improved to some extent.
【学位授予单位】：江南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TS201.2;TB383.1

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