酪蛋白-葡萄糖-PGG纳米复合物的制备及其延缓线虫衰老能力的研究

本文采用凝胶电泳、红外光谱和荧光光谱研究酪蛋白与葡萄糖美拉德接枝物的相互作用方式,接着用溶剂蒸发法制备酪蛋白-葡萄糖-PGG(1,2,3,4,6-O-五没食子酰葡萄糖)纳米复合物,以期提高PGG的水溶性及延缓秀丽隐杆线虫衰老能力。结果表明,生成的接枝物分子量大于116 ku。糖末端的羰基与蛋白的氨基以化学共价键相连,酪蛋白中引入的糖分子具有D-吡喃葡萄糖环结构。PGG与酪蛋白或酪蛋白-葡萄糖作用力主要为疏水力。PGG与酪蛋白-葡萄糖接枝共聚物在疏水力诱导下协同组装得到酪蛋白-葡萄糖-PGG纳米复合物,纳米粒子包埋率为62.27%,粒径为265 nm。该纳米粒子外观呈淡黄色。当浓度为10 mg/m L时,该纳米粒子在水中溶解度较好。酪蛋白-葡萄糖-PGG纳米复合物组线虫平均寿命比PGG组延长了13.00%,因此酪蛋白-葡萄糖接枝共聚物的包埋能有效增强PGG的延缓线虫衰老能力。     

几种微胶囊包裹方法对葡萄籽原花青素包裹效果的对比研究

以喷雾干燥法研究了β-环糊精,多孔淀粉-明胶,麦芽糊精-大豆分离蛋白三种壁材的包裹方法对葡萄籽原花青素的包裹效果。结果表明,β-环糊精不适于包裹原花青素;多孔淀粉-明胶包埋原花青素时,以进风口温度200℃,出风口温度60℃的处理得到的包埋率最高,为98,34%;麦芽糊精-大豆分离蛋白也是一种良好的壁材,几乎可以全部包埋原花青素。当进风口温度190℃,出风口温度55℃,进料流量40mL/min时包埋率可达80%以上。     

直链糊精-共轭亚油酸复合物的制备及理化性质分析

本文以蜡质玉米淀粉脱支得到的直链糊精为包合载体,共轭亚油酸(CLA)为客体分子,水-乙醇法制备直链糊精-CLA复合物。复合物的形成通过扫描电镜、X-射线衍射仪和DSC进行验证,并对复合物水溶液的粒径分布、储存稳定性、溶解度及复合物氧化稳定性等性质进行研究。结果表明:直链糊精与共轭亚油酸形成的复合物呈块状结构,表面光滑,是典型的V型结构,峰值温度为83℃;复合物在水溶液中的粒径可达到纳米级,但储存稳定性差,复合物水溶液经超声波处理后,复合物粒径进一步降低,且溶液的稳定性提高;室温下复合物的溶解度为62.64%,并随着温度的升高而增大,当温度为90℃时,其溶解度可达91.05%;与直链糊精形成复合物后,共轭亚油酸的氧化稳定性得到提高。这说明使用直链糊精对共轭亚油酸进行包埋,是一种有效的提高共轭亚油酸溶解度和化学稳定性的方法。     

响应面法优化花青素/Fe3O4纳米复合物的制备工艺及其体外消化研究

为了提高花青素的生物利用率，本研究采用共沉淀的方法制备花青素/Fe₃O₄纳米复合物。利用响应面法(Response Surface Method,RSM)优化花青素/Fe₃O₄纳米复合物的合成，并对花青素/Fe₃O₄纳米复合物进行粒径分析、Zeta电位测定、扫描电子显微镜、傅里叶变换红外光谱分析以及体外模拟消化实验。结果表明花青素/Fe₃O₄纳米复合物的最佳制备条件为花青素与Fe₃O₄的质量比为1:46，反应时间为19.6 h，反应温度为47℃，此工艺条件下花青素的包封率为87.51%。该纳米复合物粒径分布集中在100～1200 nm，且分布均匀，Zeta电位为-48.15 mV。通过扫描电子显微镜观察到花青素与Fe₃O₄纳米粒子间形成了表面光滑的球状颗粒。花青素/Fe₃O₄纳米复合...     

微波场中大米蛋白-糊精接枝反应的工艺研究

采用微波加热技术对大米蛋白与麦芽糊精进行接枝改性,通过接枝物回收率和溶解度的测定,对其工艺进行优化。以溶解度为响应值,在微波功率200～500W、大米蛋白-麦芽糊精质量配比为1:5的条件下,采用响应面法对其工艺进行优化,最佳工艺条件为:累计加热时间9.90min、反应温度79.73℃、反应pH11.18,此时大米蛋白溶解度从7.95%提高至35.82%。     

小麦醇溶蛋白自组装纳米粒子负载白藜芦醇的性质研究

小麦醇溶蛋白是谷朊粉的主要成分之一,用小麦醇溶蛋白包埋白藜芦醇以达到稳定白藜芦醇的目的。用反溶剂法制得其自组装纳米粒子,对乙醇浓度、蛋白浓度、分散液pH、分散液盐浓度等因素对纳米粒子的粒径以及Zeta电位的影响做出了探究。发现在乙醇浓度为65%,蛋白质浓度4%,分散液pH为4.5,分散液盐浓度为0.00 mol/L时,得到理想的纳米粒子,其粒径约为(185.1±8.5)nm,Zeta电位为(19.36±1.03)m V。而后在最佳条件下用小麦醇溶蛋白纳米粒子负载白藜芦醇,发现该复合物在芯壁比为1∶40时包埋率最高,此时粒径(166.7±3.7)nm,Zeta电位(15.68±0.74)m V,包埋率为55.0%,载药率为1.5%。小麦醇溶蛋白纳米粒子可以用来稳定白藜芦醇。     

不同壁材选择对姜油树脂微胶囊化的影响

测定麦芽糊精(DE=7)与大豆蛋白、麦芽糊精(DE=14)与大豆蛋白、麦芽糊精与明胶、麦芽糊精与酪蛋白等不同壁材组合的黏度及壁材不同配比时包埋率和溶解性,研究不同壁材对姜油树脂微胶囊化的影响。结果表明,在不同的壁材组合中,在大豆蛋白与麦芽糊精比例一定的情况下,高DE值的麦芽糊精与大豆蛋白混合壁材的水溶液黏度值较小,且当麦芽糊精:大豆蛋白为2∶1时,得到的微胶囊产品具有较高的包埋率和溶解性。     

紫玉米芯花青素的超声波辅助提取及喷雾干燥的工艺优化

以紫玉米芯为原料,利用响应面实验优化花青素的超声波辅助提取工艺,并将获得的花青素冻干粉添加麦芽糊精,后经喷雾干燥制成花青素粉。响应面实验结果表明,最佳提取条件为:料液比为1∶13(g/m L)、提取温度为41℃、水浴提取时间为31 min、超声提取时间为20 min,在此条件下,得到花青素提取量为(4.623±0.021)mg/g,提取率为94.8%。花青素提取液添加麦芽糊精,经喷雾干燥工艺制成花青素粉,在进风温度为150℃、花青素冻干粉与麦芽糊精质量比为1∶1、固形物浓度为15%时,得到的花青素粉包埋率为86.7%,水分含量为4.8%。本实验得到了紫玉米芯花青素超声辅助提取和花青素粉制备的最佳工艺条件,为紫玉米芯的开发利用提供了参考依据。     

果胶与莲原花青素复合物理化性质及体外抑菌活性研究

目的:提高原花青素稳定性及抑菌活性。方法:以芒果为原料,采用酸法(pH为2.5的柠檬酸)提取果胶,果胶的分子量分布采用凝胶渗透色谱法测定,中性糖组成采用气相色谱-质谱联用仪分析,通过红外光谱分析确定其特征官能团、酯化度及半乳糖醛酸含量采用滴定法测定;随后将果胶和原花青素复合物按物理方法复合,并分别采用差示扫描量热法(Differential scanning calorimetry,DSC)、等温滴定量热法(Isothermal titration calorimetry,ITC)、流变学特性分析、纳米粒度电位分析仪、扫描电子显微镜(Scanning electron microscope,SEM)等方法,比较了果胶与复配物的热稳定性、流变特性、溶液粒径和Zeta电位、微观形态等理化特性。在此基础上进一步分析了原花青素、原花青素-果胶复合物对4株金黄色葡萄球菌的抑制率。结果:所提取的芒果果胶包含2个级分,Mw分别为2.6724×104和2.2525×105;中性糖组成为鼠李糖:岩藻糖:阿拉伯糖:木糖:甘露糖:半乳糖的摩尔比为1.226:0.087:1:0.025:006:0.091;酯化度为91.09%±2.23%,半乳糖醛酸含量为82.32%±0.51%;复合物的玻璃化转变温度比原果胶降低;在同一质量浓度下复合物表观黏度低于果胶;复合物溶液的粒径显著减小,Zeta电位绝对值增大;通过SEM观察,果胶-原花青素复合物的表面比果胶更光滑平整;果胶与原花青素相互作用是以氢键驱动为主的自发放热反应。果胶-原花青素复合物对4株高于原花青素,且对金黄色葡萄球菌ATCC27217的抑制效果最佳,其IC₅₀为0.006 mg/mL。结论:芒果果胶是一个高酯化度的酸性杂多糖,当与原花青素复合后,使原花青素的热稳定性显著提高,Zeta电位绝对值明显增大,溶液粒度大大降低,而且更加均匀,二者相互作用主要为氢键驱动的放热反应。复合物对4株金黄色葡萄球菌的抑制效果明显高于原花青素。     

β-胡萝卜素/酪蛋白纳米复合物的形成及β-CE的生物利用率

β-胡萝卜素(β-CE)具有多种生物活性,但是不稳定,容易降解,利用酪蛋白(CN)对β-胡萝卜素进行自组装能够对其起到保护作用,从而提高β-胡萝卜素在食品工业中的利用价值。本文以β-CE/CN形成纳米复合物为背景,研究了其形成的影响因素、粒径分布以及β-CE的生物利用率。结果表明,β-CE/CN纳米复合物的形成受温度与β-CE/CN质量比的影响较大,β-胡萝卜素经酪蛋白自组装后,其水溶解性提高。经体外消化实验,β-CE/CN纳米复合物经胰蛋白酶和胃蛋白酶酶解后,酶解产物经SDS-PAGE分析,酪蛋白随着酶解时间的延长其水解程度增加,因此β-CE从纳米复合物中更易释放出来,其生物利用率提高。     

Analysis of tannins in seeds and skins of Shiraz grapes throughout berry development

The flavan-3-ol and proanthocyanidin composition of both seeds and skin of Vitis vinifera L. cv. Shiraz grapes was determined by reversed-phase HPLC after acetone extraction and acid-catalysis in the presence of excess phloroglucinol. Samples were taken at weekly intervals from fruit-set until commercial harvest. The main period of proanthocyanidin accumulation in grape seeds occurred immediately after fruit-set with maximum levels observed around veraison. Over two seasons there was variation in both the timing and content of proanthocyanidins in seeds. In skin, proanthocyanidin accumulation occurred from fruit set until 1–2 weeks after veraison. Proanthocyanidin subunit composition was different in seeds and skin and changed during berry development but the mean degree of polymerisation of the tannin polymers in skins was higher than in the seeds at all stages of berry development. Proanthocyanidin levels in both seeds and skin decreased between veraison and harvest. Additional proanthocyanidin subunits were released when the residues remaining after acetone extraction were subjected to direct acid-catalysis in the presence of phloroglucinol. In the seeds, these accounted for much of the post-veraison decrease, but not in grape skin. At harvest, 75% of extractable berry proanthocyanidin was in the seeds. Accumulation of proanthocyanidins in the seeds appears to be independent of that in the skins, but in both tissues synthesis occurs early in berry development and maximum levels are reached around veraison.     

壁材对香草兰精油微胶囊物性与释放特性的影响

本实验分别以β-环糊精（β-cyclodextrin,β-CD）、β-CD＋麦芽糊精（maltodextrin,MD）、辛烯基琥珀酸淀粉钠（octenylsuccinate starch sodium,OSS）、酪蛋白为壁材,以香草兰精油为芯材,采用喷雾干燥制备具有缓释性的微胶囊。以产率、包埋率、溶解性、缓释性、乳化液稳定性等为评定指标,对比分析4?种壁材的包埋效果。结果表明：以OSS为壁材的香草兰精油微胶囊（VO-OSS）产率最高,为84.17%,包埋率为78.04%,溶解度和乳状液稳定性分别为96.31%和97.82%,具有良好的冲调性、溶解性和乳化性。MD与β-CD复配壁材的香草兰精油微胶囊（VO-MD）产率和包埋率最低,分别为71.37%和61.18%。在粒径方面,VO-OSS粒径最小,为190?nm。扫描电子显微镜观察结果显示,VO-OSS表面结构光滑、呈球状。VO-OSS在60?℃贮存10?d后,香兰素的保留率为54.62%,表明缓释性高于其他3?种微胶囊。综合所有指标,对比其他3?种微胶囊产品,OSS是制备香草兰精油微胶囊的最佳壁材。     

杜仲籽油冻干脂质体的制备及表征

为增加杜仲籽油的水溶性和稳定性,提高其生物利用度,将杜仲籽油制成冻干脂质体。采用乙醇注入-超声法制备杜仲籽油脂质体悬浮液并进行冻干处理,以冻干后样品外观、再分散性及复溶后包埋率为指标优化其冻干工艺条件,分析杜仲籽油冻干脂质体的微观形态、粒径、Zeta电位与储藏稳定性,利用差示扫描量热仪(DSC)、X射线衍射仪(XRD)分析冻干保护剂在脂质体中的存在状态。结果表明:杜仲籽油冻干脂质体制备的最佳冻干工艺条件为预冻温度-50℃、预冻时间12 h、干燥时间36 h、冻干保护剂为甘露醇、甘露醇与大豆卵磷脂质量比8∶1。在最佳冻干条件下,杜仲籽油冻干脂质体为白色球状,复溶后包埋率为(72.52±1.95)%,粒径为(389.67±4.81) nm,PDI为0.255±0.013,Zeta电位为(-22.62±1.66) mV,储藏稳定性较好。     

不同壁材对β胡萝卜素微胶囊性质的影响

探究不同壁材(明胶、阿拉伯胶、麦芽糊精)对其通过相同工艺所形成的β胡萝卜素微胶囊性质影响。对β胡萝卜素微胶囊的包埋率、溶解性、颜色强度、壁材与芯材之间新生成的官能团、ζ电位、粒径、高温稳定性进行评估。结果表明:壁材对包埋率、壁材与芯材之间新生成的官能团、粒径、高温稳定性无显著性影响。结构上带有共轭体系的阿拉伯胶有着更亮的颜色强度,作为蛋白的明胶由于氢键的存在导致其所形成的微胶囊溶解度更低。壁材对微胶囊的水溶液的ζ电位有着显著性影响。同时,X衍射证明不同壁材在形成的微胶囊过程当中均无晶体的形成,但是壁材的成膜性严重影响着微胶囊表面的光滑性。研究结果表明壁材较大地影响着β胡萝卜素微胶囊的理化性质,因此壁材选择需更加慎重。     

中链脂肪酸脂质体的制备及其特性评价

采用薄膜蒸发-超声法制备中链脂肪酸脂质体,考察单因素制备工艺对包封率的影响以及所得脂质体的外观形态、粒径、Zeta电位和稳定性。结果表明,中链脂肪酸脂质体的最佳工艺条件为:磷脂与胆固醇之比为3:1,中链脂肪酸与总脂材比为1:10,表面活性剂(吐温-80)与膜材之比为3:10,制备温度为35℃。最佳工艺条件下产物包封率可达82.9%,平均粒径为240.420.3nm,Zeta电位为-52.273.2mV,4℃下放置90d质量稳定。     

Spray-dried conjugated linoleic acid encapsulated with Maillard reaction products of whey proteins and maltodextrin

Encapsulation performance of Maillard reaction products (MRPs) produced by whey proteins and maltodextrin were examined for microencapsulation of conjugated linoleic acid (CLA) using spray-drying. CLA was encapsulated using 3 different wall materials containing a single constituent such as whey protein concentrate (WPC), whey protein isolate (WPI), and maltodextrin (MD), and 4 different MRPs. For the development of MRPs, ratios of WPC to MD were 1:2 and 1:3, whereas those of WPI to MD were 1:5 and 1:10. CLA and wall material were mixed and homogenized, and then spraydried. The physical properties of encapsulated CLA powders were characterized by particle size and morphology, ζ-potential, flowability, solubility, and dispersibility. The CLA powders coated with WPI-based MRPs have better encapsulation efficiency, water solubility, and smaller particle size than those coated with WPI, WPC, or MD alone. These encapsulated CLA powders have a number of possible utilities as ingredients in a variety of foods.     

Separation and characterisation of proanthocyanidins in Virginia type peanut skins by LC-MS

Proanthocyanidins were extracted from peanut skins, an agricultural waste product of Virginia. Proanthocyanidin composition of single solvent and multistep extraction procedures of peanut skins were compared by HPLC-UV-vis absorbance. The multistep extraction procedure yielded more proanthocyanidin peaks and larger peak areas. Thus this extraction procedure was chosen for subsequent fractionation. Fractionation was performed by size exclusion (Toyopearl HW-40S) and normal phase (NP) (porous silica) high performance liquid chromatography (HPLC) before reversed phase (RP) electrospray ionisation liquid chromatography-mass spectrometry analysis (ESI-LC-MSⁿ). Proanthocyanidin separation on the NP column was better overall, compared to size exclusion chromatography, and thus was chosen for characterisation by MS. Peanut skin procyanidins were found to separate in order of increasing molecular weight on the NP column. The ESI-MS generated positive and negative molecular-type ions and their dissociation product ions were used to identify specific proanthocyanidins and procyanidins. New proanthocyanidin dimeric and trimeric species were identified. These species consisted of one or two (epi)catechin units bound to luteolin or kaempferol. Monomers through nonamers of flavan-3-ols were identified by retention time and their multistep (MSⁿ) dissociation pathway. Hexamers were identified as both singly and doubly charged negative ions, [M−zH]^z−, z = 1 or 2. Species of greater than pentamers were tentatively identified due to their low ionisation efficiency and significant overlap of species both chromatographically and in the MS spectra.     

葡萄籽低聚原花青素化学成分及抗氧化研究

对葡萄籽低聚原花青素中的原花青素B2进行了分离纯化,并将葡萄籽低聚原花青素(opc’s)、原花青素B2对比白藜芦醇、红酒提取物、苹果多酚、VC、VE和水溶性V(ETrolox)的抗氧化活性进行了研究。结果表明,原花青素B2和opc’s对DPPH自由基和羟自由基都具有较好的清除活性。对DPPH自由基的清除作用与VE相当,其IC50分别为1.20μg/mL和1.39μg/mL,明显强于VC和Trolox;原花青素B2和opc’s对羟自由基的抑制率明显高于VC、VE和Trolox。opc’s经过层析分离纯化后得到的原花青素B2清除DPPH自由基的效果有所提高,但对于羟自由基的清除活性提高不明显。     

Effect of Polymerization on Antioxidant and Xanthine Oxidase Inhibitory Potential of Sea Buckthorn (H. rhamnoides) Proanthocyanidins

Abstract: Inhibitory potential of sea buckthorn (Hippophae rhamnoides L) seed proanthocyanidins against oxidative stress and xanthine oxidase activity was evaluated. Composition of antioxidant proanthocyanidins was profiled by analyzing the cleavage products obtained by the acid catalyzed hydrolysis in the presence of phloroglucinol. Catechin, epicatechin, gallocatechin, and epigallocatechin were found as the extension and terminal subunits of proanthocyanidins with an average degree of polymerization (ADP) of 14.7. Seed proanthocyanidins showed considerably high antioxidant and xanthine oxidase inhibitory potentials. Antioxidant and xanthine oxidase inhibitory capacity evaluation of proanthocyanidin fractions with varying ADP showed that proanthocyanidins with lower molecular size were more effective as superoxide anion (ADP ≤ 4.2) and hydroxyl radical (ADP ≤ 5.9) scavengers and xanthine oxidase (ADP ≤ 3.1) inhibitors. ADP of the studied proanthocyanidin fractions did not show significant influence on their DPPH and ABTS radical scavenging and ferric reduction capacities.     

苦丁皂苷D的分离纯化及其纳米粒的制备表征

目的:为了提高苦丁皂苷D的水溶性。方法:采用常压柱层析法、半制备高效液相色谱法等手段从苦丁茶冬青中分离纯化皂苷,获得化合物苦丁皂苷D（Kudinoside D）。以聚谷氨酸（γ-PGA）和L-苯丙氨酸乙酯（L-PAE）为原料,分别采用沉淀法、透析法制备苦丁皂苷 D纳米粒,利用透射电镜和动态纳米粒度仪对纳米粒理化性质进行表征,利用透析法考察其体外释药特性。结果:与沉淀法相比,透析法制备的苦丁皂苷 D纳米粒的包封率和载药量分别提高了1.5、4.5倍,包封率达65.46%,载药量达13.24%。苦丁皂苷 D纳米粒呈规则球形,平均粒径为（75±25）nm,Zeta电势为33.7。结论:体外释药实验表明苦丁皂苷 D纳米粒可提高药物的水溶性,具有良好的体外缓释效果。