魔芋膳食纤维对油脂体外消化特性的影响

向油脂乳液中加入一定量魔芋膳食纤维，采用pH-stat法模拟油脂体外消化过程，考察魔芋膳食纤维对乳液在胃肠道中消化特性的影响，并研究乳液消化前后有效粒径、粒径分布、Zeta电位和微观结构的变化。结果表明，魔芋膳食纤维对乳液消化特性和消化前后理化性质产生显著性影响。随着纤维含量增加，乳液初始消化速率和最终消化程度均减小，含0.5%(质量分数)魔芋膳食纤维的乳液经胰脂肪酶消化120 min后脂肪酸释放率仅为14.84%;乳液粒径在体外消化的不同阶段逐渐增大，且同一消化阶段随纤维添加量增加而增大；肠消化后Zeta电位绝对值均大于40 mV,脂滴不稳定，发生聚集。脂肪乳液中脂质的最终消化率随体系中纤维添加量的增加而降低，该研究结果对胃肠道中脂质消化的控制及低热量功能食品的开发具有重要意义。     

OPO结构脂在模拟婴儿胃肠道消化环境中脂肪酸的释放特性

为研究OPO（1,3-二油酸2-棕榈酸甘油三酯）结构脂在模拟婴儿胃肠道消化环境中脂肪酸释放特性,根据母乳脂肪酸组成特点,制备了OPO结构脂（O组）。以婴儿配方粉中常用植物油混合物（Z组）作对比,测定脂肪酸组成及Sn-2位脂肪酸分布情况,分析消化过程中脂肪酸释放率、粒径和zeta电位的变化,并测定了消化产物中游离脂肪酸和甘油单酯的组成。研究结果表明：相同处理条件下,O组粒径集中分布在波长198 nm处,Z组大多分布在波长229 nm处,粒径分布的不同反映在初始消化阶段脂肪酸释放率存在明显差异（P<0.05）。胃液模拟30 min后,O组脂肪酸释放率为12.83%,Z组为8.92%。经体外胃肠道消化后测得O组脂肪酸的最终释放率为62.67%,而Z组仅为51.83%。结论：O组和Z组Sn-2位脂肪酸的分布存在差异（P<0.05）,薄层色谱法验证了O组Sn-2位棕榈酸的含量较高且与母乳更接近。在模拟体外消化时表现出更高的脂肪酸释放率。消化产物甲酯化后经气-质谱分析,O组消化后产物中游离不饱和脂肪酸和棕榈酸甘油单酯含量均高于Z组。将本试验获得的OPO油脂和混合植物油脂在体外的消化脂肪酸释放特性进行比较,可得出如下结论：OPO结构脂经消化后,其脂肪酸更有利于婴儿消化吸收利用。     

鳙鱼和三文鱼头汤中不同粒径胶粒的抗氧化活性

鱼头汤在熬煮过程中会自组装形成不同粒径大小的胶粒。该研究选取熬煮时间为150 min的鳙鱼和三文鱼头汤,采用马尔文激光粒度分析仪测定其经粗滤、离心、微滤和超滤处理后胶粒的粒径分布,利用6种化学法研究不同粒径大小的鳙鱼和三文鱼头汤胶粒的体外抗氧化能力。结果表明,经过一系列不同的处理,汤中胶粒的平均粒径显著减小(P <0. 05)。鳙鱼和三文鱼头汤胶粒的DPPH·清除能力和O_2~-·清除能力接近(P>0. 05),鳙鱼头汤胶粒的Fe~(2+)螯合能力和ABTS~+·清除能力大于三文鱼头汤(P <0. 05),但都表现为粗滤>离心>微滤>超滤,三文鱼头汤胶粒的·OH清除能力和总还原能力大于鳙鱼头汤(P <0. 05)。不同粒径大小的鳙鱼和三文鱼头汤胶粒均具有抗氧化活性,且粒径较大时抗氧化活性更好,为鱼头汤的精深加工与应用提供了理论依据。     

均质压力对亚麻籽油体乳液稳定性及体外消化的影响

本实验以亚麻籽油体为研究对象,通过对其进行均质处理,得到了稳定的富含α-亚麻酸的亚麻籽油体乳液,为居民在日常膳食中提高-3不饱和脂肪酸摄入量提供了新的途径。在保持均质时间相同的条件下(3 min),对亚麻籽油体进行不同均质压力(40、80、120 MPa)与均质次数(1～3次)处理,考察均质处理对亚麻籽油体乳液的性质、环境稳定性(pH、离子强度、热、氧化稳定性)、储藏稳定性和消化特性的影响。结果表明,FOB在120 MPa下均质处理3次,电位绝对值增加,粒径显著减小(P<0.05)。均质处理后的亚麻籽油体乳液在50～90℃下热处理30 min,粒径、电位稳定,且表现出更好的氧化稳定性和储藏稳定性(P<0.05)。均质处理亚麻籽油体并不影响其对pH4～5和离子强度不稳定(P>0.05)。消化结果表明,均质处理后的亚麻籽油体乳液具有更快的脂肪酸释放速率(FFA)。综上,均质处理显著了减小亚麻籽油体乳液的粒径,增强了亚麻籽油体的储藏稳定性和氧化稳定性,且加快了脂肪酸释放速率。     

钙盐和蛋白质配比对1,3-二油酸-2-棕榈酸甘油酯乳液体外消化的影响

利用体外模拟胃肠消化系统,考察酪蛋白和乳清蛋白的不同比例和矿物质含量及两者相互作用对1,3-二油酸-2-棕榈酸甘油酯（1,3-dioleoyl-2-palmitoylglycerol,OPO）消化的影响,并对体外消化后的脂肪酸释放率、粒度分布和脂肪酸组成进行测定。结果表明,胃消化阶段,相同乳化剂配比,OPO型乳液脂质生物利用率随CaCl2浓度增加而增加;且在20 mmol/L CaCl2浓度下,不同蛋白质配比（乳清蛋白-酪蛋白）,乳液体外消化过程中游离脂肪酸（free fatty acid,FFA）释放率大小顺序为：10∶0＞6∶4＞0∶10。体外模拟脂质消化前后平均粒径分析结果显示,在不同CaCl2浓度影响下,胃肠消化后乳液平均粒径大于新鲜乳液;随Ca2＋浓度增加,新鲜乳液d（0.1）、d（0.5）、d（0.9）值均增加,且在加胃肠消化液后,平均粒径显著增大。在肠消化阶段,3 组乳液在不同CaCl2浓度下,FFA释放速率及程度均随CaCl2浓度增加而增加。胃肠消化后的产物FFA和单甘酯组成分析表明：乳液消化后,FFA和单甘酯主要由棕榈酸和油酸组成。除此之外,本实验还考察了不同钙盐对OPO乳液脂质消化的影响,结果表明溶解度高的钙盐加速脂质水解,有利于脂肪酸的释放即在肠消化阶段FFA释放速率和程度次序为：柠檬酸钙＞氯化钙＞乳酸钙＞碳酸钙。     

超声及高压均质制备的β-胡萝卜素纳米乳液的消化规律

通过体外模拟消化,研究超声及高压均质制备的β-胡萝卜素纳米乳液的消化规律。结果表明:胃模拟消化过程中,两种方式制备的β-胡萝卜素纳米乳液的平均粒径均显著增大(P0.05),这与乳液界面吸附的部分大豆蛋白被胃蛋白酶酶解有关,且两种纳米乳液均发生了絮凝现象;小肠模拟消化过程中,两种纳米乳液的平均粒径和浊度皆降低,且ζ电位呈负增加;经胃肠消化后,两种纳米乳液的游离脂肪酸释放率显著高于单纯的β-胡萝卜素溶于油相,且均大于100%,说明磷脂酰胆碱与油相在肠消化过程中均发生了消化。比较β-胡萝卜素的生物可利用度得知,超声处理制备的纳米乳液营养素的生物利用率较高。研究结果为超声及高压均质处理用于制备β-胡萝卜素纳米乳液提供参考。     

消化工艺参数对氢氧化钙粒径的影响

研究了消化反应中各工艺参数对消化后氢氧化钙及苛化后碳酸钙粒径的影响。实验结果表明,消化工艺参数对消化反应生成的氢氧化钙的粒径有不同程度的影响,影响程度高低顺序依次为消化水温度、生石灰固含量、搅拌转速;当搅拌转速350 r/min、消化水温度90℃、生石灰固含量10%时,消化反应后所得氢氧化钙的粒径最小。随生石灰粒径减小,其消化速率明显提高,且最终温度和消化转化率也随之提高。氢氧化钙粒径逐渐减小的同时,苛化后碳酸钙粒径也逐渐减小,粒径分布逐渐变窄,苛化率提高,且苛化后碳酸钙平均粒径大于氢氧化钙平均粒径。     

脂质体在婴儿体外胃肠道消化的膜结构稳定性

建立体外模拟婴儿胃肠道消化体系(成人为对照),研究脂质体在胃部的氧化应激效应和在小肠环境的脂解动力学。结果表明:脂质体消化后平均粒径明显减小、Zeta电位负电性增加;脂质体经胃部消化磷脂膜氧化程度(硫代巴比妥酸值)明显提高;在小肠消化过程中不断释放游离脂肪酸,且婴儿胃肠道环境水解率(38%)明显低于成人(80%),释放过程符合伪一级方程;傅里叶变换红外光谱研究发现,磷脂特征官能团(C=O、P=O、—CH_2)峰值发生改变,脂质体在婴儿胃肠道环境膜结构破坏程度低于成人。研究结果为脂质体运载营养素应用于婴儿配方食品提供了理论指导。     

茶多酚纳米脂质体悬浮液的制备与性质研究

用乙醇注入法制备了茶多酚纳米脂质体悬浮液,考察了超声与高压均质2种后处理方式对脂质体包封率与粒径的影响。结果发现:2种后处理方式对包封率的影响差别不大,但经高压均质处理制备得到的脂质体粒径较小。对乙醇注入-高压均质后处理制备的茶多酚纳米脂质体悬浮液的性质研究表明:其平均粒径为91.4nm,多分散指数为0.114;在pH 7.0、离子强度为0.05 mol/L的磷酸盐缓冲液(PBS)中的释放动力学特性基本符合一级动力学模型;随着贮藏时间的延长或贮藏温度的升高,体系的稳定性下降。     

枯草芽孢杆菌对大豆蛋白-磷脂复合乳液在体外消化中稳定性的影响

为探讨枯草芽孢杆菌在消化过程中对大豆蛋白-磷脂复合乳液稳定性的影响。本试验设计胃肠消化模型,通过对加菌与不加菌的O/W型和W/O型乳液的乳化活性指数（Emulsifying activity index,EAI）、乳化稳定指数（Emulsification stability index,ESI）、浊度、粒径、Zeta电位检测和显微观察,考察乳液是否出现分离、絮凝、聚集上浮等现象。结果表明,在胃消化阶段,O/W型和W/O型乳液EAI、ESI、粒径、电位都明显减小,显微观察显示液滴密度减小,体积增大;加入枯草芽孢杆菌的乳液与不加菌乳液相比,各指标减小的幅度更大。在小肠消化阶段,O/W型和W/O型乳液EAI和ESI整体呈上升趋势,而粒径和电位则明显下降,另外,两者的显微观察显示液滴密度减小,体积也减小。与不加菌的相比,加入枯草芽孢杆菌后乳液EAI、ESI、粒径显著降低,电位显著升高（P<0.05）。综合上述结果,枯草芽孢杆菌促进了大豆蛋白-磷脂复合乳液在消化过程中的破乳现象。     

Fabrication,characterization and lipase digestibility of food-grade nanoemulsions

The behavior of nanoemulsion-based delivery systems within the gastrointestinal tract determines their functional performance. In this study, the influence of particle radius (30–85 nm) on the in vitro digestion of nanoemulsions containing non-ionic surfactant stabilized lipid (corn oil) droplets was examined using simulated small intestine conditions. Nanoemulsions were prepared by a combination of high-pressure homogenization and solvent (hexane) displacement. Lipid droplets with different sizes were prepared by varying the oil-to-solvent ratio in the disperse phase prior to homogenization. The fraction of free fatty acids (FFA) released from emulsified triacylglycerols (TG) during digestion was measured by an in vitro model (pH-Stat titration). Nanoemulsions exhibited a lag-period before any FFA were released, which was explained by inhibition of lipase adsorption to the oil–water interface by free surfactant. After the lag-period, the digestion rate increased with decreasing oil droplet diameter (increasing specific surface area). The total amount of FFA released from the emulsions increased from 61% to 71% as the mean droplet radius decreased from 86 nm to 30 nm. The incomplete digestion of the emulsified lipids could be explained by inhibition of lipase activity by the release of fatty acids and/or by interactions between lipase and surfactants molecules.     

The simulated in vitro infant gastrointestinal digestion of droplets covered with milk fat globule membrane polar lipids concentrate

Milk fat globule membrane polar lipids (MPL) are increasingly used as the surface-active components for emulsions in many infant food products. However, the precise effect of the emulsifier MPL on the digestion of lipids during gastrointestinal digestion has not been elucidated. This study investigated the lipid digestion of droplets covered with MPL with different sizes in a simulated in vitro infant gastrointestinal digestion assay. The well-used surface-active component casein was used as a control. Four types of emulsions were formulated: small and large droplets covered with MPL concentrate (MPL-S and MPL-L, with volumetric means of 0.35 ± 0.01 and 4.04 ± 0.01 μm, respectively), and small and large droplets covered with casein (CN-S and CN-L, with volumetric means of 0.44 ± 0.01 and 4.09 ± 0.03 μm, respectively). The emulsions were subjected to in vitro gastrointestinal digestion using a semidynamic model mimicking infant digestion. Through the determination of particle size evolution, zeta-potential, and microstructure of emulsions, the lipid droplets covered with MPL were found to be more stable than that of the CN-S and CN-L during gastrointestinal digestion. Moreover, although CN-S and CN-L showed a higher initial lipolysis rate at the beginning of gastric digestion, droplets covered by MPL exhibited a significantly higher amount of free fatty acid release during later digestion. The amount of free fatty acid release of the emulsions in both gastric and intestinal digestion could be generally classified as MPL-S ≥ MPL-L > CN-S > CN-L. Our study highlights the crucial role of MPL in the efficient digestion of emulsions and brings new insight for the design of infant food products.     

鳙鱼不同部位的成分分析及营养评价

以鳙鱼为研究对象,对鳙鱼不同部位（头、背、腹、尾）的基本成分、蛋白组成、氨基酸组成、胶原蛋白含量和脂肪酸组成进行测定分析,并对其营养价值进行综合评定。结果表明：不同部位（头、背、腹、尾）的粗蛋白含量略有差异,分别为18.32%、18.04%、17.37%和17.62%;其中盐溶性蛋白和水溶性蛋白含量较高,分别为8.36%、8.43%、8.42%、8.37%和4.88%、4.78%、4.75%、4.73%;不同部位均含有较高含量的胶原蛋白,其中尾部含量最高,达9.54 mg/g,背及腹部相对较低;鳙鱼各部位蛋白质中氨基酸组成无显著差异,必需氨基酸含量较高,均达到40%以上,第一限制氨基酸为蛋氨酸+胱氨酸,第二限制氨基酸为缬氨酸;鳙鱼背肉含有丰富的矿物元素,其中钙含量最高,达1 195.36 mg/kg;鳙鱼腹部脂肪中不饱和脂肪酸的相对百分含量为69.77%,其中多不饱和脂肪酸为28.80%。     

小麦胚芽贮藏期内脂质水解酸败机理解析

以小麦胚芽为研究对象,构建脂质水解酸败的模拟体系以及原位体系,解析小麦胚芽贮藏期内脂质水解酸败的机理。结果表明:光照、氧气和脂肪氧合酶未对小麦胚芽模拟体系中的游离脂肪酸含量产生明显影响,而脂肪酶则显著提升游离脂肪酸生成量;此外,游离脂肪酸生成量随水分活度增加而增加,于水分活度为0.75时达峰值,且小麦胚芽内部结合水和不易流动水含量也呈显著增加趋势,水分以及脂质流动性增加;小麦胚芽原位体系中游离脂肪酸含量随贮藏时间延长而逐渐增加,磷脂酰胆碱含量恰相反,且小麦胚芽脂质体膜遭到破坏,游离出的甘油三酯聚集形成油滴。由此可见,小麦胚芽脂质水解酸败模式主要表现为其脂质体膜中的磷脂酰胆碱降解而释放甘油三酯,而后甘油三酯经由脂肪酶催化水解生成大量的游离脂肪酸,从而产生水解酸败现象。     

盐质量分数对鱼头汤熬煮过程中微纳米颗粒形成的影响

目的：探究盐质量分数对金枪鱼头汤熬煮过程中微纳米颗粒（micro/nano particles,MNPs）形成的影响。方法：在优化的鱼水质量比1∶8、油煎时间40 s、油煎温度120 ℃、熬煮时间150 min条件下熬煮鱼头汤,探究不同的加盐质量分数（0.3%、0.4%、0.5%、0.6%、0.7%）对熬煮鱼头汤中营养物质迁移的影响;利用纳米粒度电位仪分析盐质量分数对鱼头汤熬煮过程中MNPs形成的影响;通过光学显微镜和激光共聚焦显微镜结合分子荧光标记研究盐质量分数对熬煮鱼头汤中MNPs形态变化及其各组分之间相互作用的影响。结果表明,在加盐质量分数为0.5%的条件下,汤中营养物质的溶出量达到最大。纳米粒度电位仪分析结果显示,不同盐质量分数对MNPs的平均粒径、聚合物分散性指数和Zeta-电位有显著影响（P＜0.05）。当加盐质量分数为0.5%时,MNPs的尺寸最小。加盐能促进汤中MNPs的形成,当盐质量分数为0.5%时,汤中形成了具有稳定双分子层、平均粒径为（519.10±3.11）nm的MNPs。激光共聚焦显微镜观察结果显示,Cl－渗透进入MNPs的中心并与甘油三酯结合,Na＋则与分布在MNPs外围的电负性多糖结合并抵消其负电荷。在适宜盐质量分数下,熬煮的金枪鱼头汤中营养物质的迁移量达到最大,熬汤过程由甘油三酯、磷脂、蛋白质和糖基化分子（糖脂和糖蛋白）自组装形成的MNPs稳定性也达到最大,营养物质在汤中的稳定性增加。     

Nanoliposomal encapsulation of chia oil for sustained delivery of α-linolenic acid

Chia oil is a popular source of ω-3 fatty acids, typically α-linolenic acid. This study reports the encapsulation of chia oil in nanoliposome to protect ω-3 fatty acids and to obtain a sustained release of chia oil during digestion. Nanoliposomal encapsulation was carried out using solvent evaporation, followed by sonication. The encapsulation process was conducted using different lipid contents, with different concentrations of soy phosphatidylcholine (S), Tween 80 (T) and volumes of the aqueous phase. The maximum encapsulation efficiency was found to be 88.31%, and the average particle size was 49.25 nm; a moderate repulsion among the particles was observed. Differential scanning calorimetry study revealed enhanced thermal stability of chia oil in nanoliposomes. A negligible release (3.39%) of encapsulated chia oil was observed in the simulated gastric fluid, and a 74.72% sustained release was recorded in the simulated intestinal fluid. This formulation can be a suitable supplement of ω-3 fatty acids for food and therapeutic applications.     

Control of lipase digestibility of emulsified lipids by encapsulation within calcium alginate beads

Structured delivery systems, fabricated from natural lipids and polymers, are finding increasing use to improve the oral bioavailability of poorly water-soluble drugs and nutraceuticals, as well as to control the release of lipophilic bioactive molecules within the human gastrointestinal tract. This study focused on the development of filled hydrogel particles to control the digestion and release of encapsulated lipids. These filled hydrogel particles were fabricated by trapping sub-micron lipid droplets within calcium alginate beads. These particles remained intact when the pH was varied from 1 to 7, but exhibited some shrinkage at pH 1 and 2. The free fatty acids released from the filled hydrogel particles after addition of pancreatic lipase were monitored using a pH-stat in vitro digestion model. Encapsulation of lipid droplets within calcium alginate beads (d = 2.4 mm) reduced the free fatty acids released from around 100% to less than 12% after 120 min. The rate and extent of lipid digestion increased with decreasing bead size (from 3.4 to 0.8 mm), decreasing degree of cross-linking (i.e., lower calcium or alginate concentrations), and decreasing triglyceride molecular weight (i.e., tributyrin > MCT ≈ corn oil). These results have important implications for the design of delivery systems to protect and release lipophilic bioactive components within the human body, as well as to modulate satiety/satiation by controlling the rate of lipid digestibility.     

Zein/tannic acid complex nanoparticles‐stabilised emulsion as a novel delivery system for controlled release of curcumin

The present work was aimed to evaluate the potential of the gel‐like Pickering emulsions (50%, v/v, oil) stabilised by zein/tannic acid (TA) complex colloidal particles (ZTPE) as a new encapsulation system of lipophilic ingredients. Compared with sodium caseinate‐stabilised emulsions (SCE) and bulk oil, the better protective effects of ZTPE on the chemical stability of curcumin were observed when they suffered from UV light, and the lipid oxidation rate remarkably reduced in ZTPE. Also, the zein particle layers loaded with TA around the oil droplets can provide protection against harsh gastric environment, facilitating to slow down the release of free fatty acids (FFA) and curcumin during in vitro simulated digestion. These findings show that ZTPE have a good potential to act as an efficient encapsulating agent to protect functional ingredients from degradation and control their release during digestion, which can further improve the bioavailability of bioactive ingredients.