微胶囊化中性蛋白酶的技术研究

为了提高中性蛋白酶在干酪促熟中的应用效果,采用了海藻酸-钙和壳聚糖-海藻酸钠复合壁材微胶囊化中性蛋白酶.实验比较分析了两种壁材方法对微囊效果的影响,并最终对壳聚糖-海藻酸钠微胶囊制备过程中的主要因素如各系统的浓度、pH值、芯壁比等指标进行了研究,通过正交实验确定了酶微胶囊化的最优工艺参数.结果表明,壳聚糖-海藻酸钠复合壁材微胶囊化酶的包埋率、机械强度都明显高于海藻酸-钙法.确定了壳聚糖-海藻酸钠法微胶囊化中性蛋白酶的最佳工艺参数为:海藻酸钠溶液质量分数为3%,壳聚糖溶液为0.5%,氯化钙溶液为3%,壳聚糖溶液pH值为5.5,芯材与壁材比例为1:2.     

壳聚糖包裹柑橘精油微胶囊的制备工艺

以壳聚糖为壁材,研究壳聚糖包裹柑橘精油微胶囊的制备工艺。以乳化液稳定性为指标,选取乳化剂为单甘酯和Tween-60按质量比1∶1复合添加,优化得到壳聚糖包裹柑橘精油微胶囊制备的最佳工艺条件为乳化剂用量1.6%、壁芯质量比4∶1、搅拌速度500 r/min、包埋温度50℃。上述工艺条件下柑橘精油微胶囊的包埋率为92.0%。     

响应面法优化大鲵油微胶囊制备工艺

为了提高大鲵油的稳定性,采用喷雾干燥法制备大鲵油微胶囊。对壁材进行选择后,以包埋率为指标,研究壁材配比、壁芯材质量比、壁材添加量和乳化剂添加量对大鲵油微胶囊化的影响。通过单因素实验,利用响应面软件Box-Behnken设计模型确定大鲵油微胶囊化的最佳工艺条件。结果表明:大鲵油微胶囊化的最佳工艺条件为壁材配比(β-环状糊精与阿拉伯胶质量比)3.44∶1、壁芯材质量比5.37∶1、壁材添加量6.46%、乳化剂添加量2%(以壁材质量计)。在最佳工艺条件下,大鲵油微胶囊包埋率为88.06%。     

复凝聚法制备金枪鱼鱼油微胶囊的工艺优化

以鱼油微胶囊的外型和包封率为指标,考察了海藻酸钠质量分数、CaCO3质量分数、壳聚糖质量分数、乳化剂Span-80质量分数、芯壁比、壁材比、乳化速率对微胶囊制备效果的影响,通过正交设计得到了优化的工艺参数为:海藻酸钠质量分数1.5%、CaCO3质量分数8%、壳聚糖质量分数2.5%、乳化速率1000 r/min、乳化剂Span-80质量分数1%、芯壁比1∶4、壁材比1∶1,微胶囊包封率达到了90.73%±2.16%,微胶囊粒径为100μm左右,较均匀。     

红松仁油微胶囊化的乳化工艺研究

本文研究了红松仁油微胶囊化的乳化工艺,结果表明以CMC和麦芽糊精为壁材,单甘酯和蔗糖酯为乳化剂制备的微胶囊化红松仁油粉末油脂,在壁材含量为5%、壁材比(CMC与麦芽糊精的质量比)为13、乳化剂含量为0.3%、红松仁油与壁材的质量比0.25～0.5时,喷雾干燥的微胶囊化率在80%以上。     

肉桂醛微胶囊的制备工艺

研究了以阿拉伯树胶和麦芽糊精为壁材,喷雾干燥制备微胶囊化肉桂醛的工艺条件,探讨了壁材组成、乳化剂用量、固形物浓度,芯壁化,进风温度、进料速度、喷射压力等对微胶囊化效果的影响,经过正交试验,确定了最佳工艺条件。     

成品粮丁香精油微囊化防霉保鲜剂的研制

以丁香精油为芯材,β-环糊精和壳聚糖为壁材,采用包络结合法制备微胶囊,以正交优化的的方式确定制备微囊化的最佳环糊精浓度、壳聚糖浓度、乳化剂的浓度以及壁芯比,并对最佳配方的保鲜剂进行SEM表征、缓释效果测定以及防霉性的测定,结果表明:微囊化丁香精油的制备配方及工艺条件为:环糊精6.0%,壳聚糖1.0%,均相乳化剂吐温-80 0.2%,壁芯比4∶1;微囊化防霉保鲜剂的SEM图片显示粉末状微胶囊呈不定性状,保鲜剂呈缓慢释放的状态,并且具有防霉性。     

南瓜籽油的微胶囊化研究

采用喷雾干燥法将南瓜籽油进行微胶囊化,通过单因素和正交实验确定最佳的复合壁材配比、芯壁材配比及乳化剂的添加量,得到南瓜籽油微胶囊化的最佳工艺条件。结果表明,南瓜籽油微胶囊制备的最佳条件为阿拉伯胶与麦芽糊精的质量比为1:1、芯材与壁材的质量比为1:5、乳化剂的添加量为3.5%,此时南瓜籽油微胶囊的包埋率为81.05%。     

相变微胶囊的制备工艺

以石蜡为芯材,壳聚糖和海藻酸钠为壁材,采用乳化固化法制备相变微胶囊.探讨了影响相变微胶囊合成的主要因素,如乳化剂用量、乳化时间、搅拌速度,优化了工艺条件:乳化剂用量为15 mL/100 mL,乳化时间为60 min,搅拌速度为500 r/min.结果表明:按优化工艺条件制备的相变微胶囊颗粒较小、粒径分布窄、形态较规整、温度调节性能较好.     

单凝聚法芝麻油微胶囊制备工艺研究

为了提高芝麻油的稳定性和实用性,通过单凝聚法,以明胶为壁材,芝麻油为芯材,添加适量的乳化剂来制备微胶囊化芝麻油。以微胶囊成型效果和包埋率为指标,研究了壁材质量分数、芯壁比、乳化剂单甘脂浓度及操作温度对包埋效果的影响。在单因素试验的基础上,采用响应面法确定了单凝聚法制备芝麻油微胶囊的最佳工艺。实验结果表明:最佳工艺为明胶质量浓度4%,芯壁比1∶4,单甘脂浓度0.3%,操作温度60℃时,所得芝麻油微胶囊的包埋率最大为79.42%。     

Preparation of Acid‐Resistant Microcapsules with Shell‐Matrix Structure to Enhance Stability of Streptococcus Thermophilus IFFI 6038

Microencapsulation is an effective technology used to protect probiotics against harsh conditions. Extrusion is a commonly used microencapsulation method utilized to prepare probiotics microcapsules that is regarded as economical and simple to operate. This research aims to prepare acid‐resistant probiotic microcapsules with high viability after freeze‐drying and optimized storage stability. Streptococcus thermophilus IFFI 6038 (IFFI 6038) cells were mixed with trehalose and alginate to fabricate microcapsules using extrusion. These capsules were subsequently coated with chitosan to obtain chitosan‐trehalose‐alginate microcapsules with shell‐matrix structure. Chitosan‐alginate microcapsules (without trehalose) were also prepared using the same method. The characteristics of the microcapsules were observed by measuring the freeze‐dried viability, acid resistance, and long‐term storage stability of the cells. The viable count of IFFI 6038 in the chitosan‐trehalose‐alginate microcapsules was 8.34 ± 0.30 log CFU g^?1 after freeze‐drying (lyophilization), which was nearly 1 log units g^?1 greater than the chitosan‐alginate microcapsules. The viability of IFFI 6038 in the chitosan‐trehalose‐alginate microcapsules was 6.45 ± 0.09 log CFU g^?1 after 120 min of treatment in simulated gastric juices, while the chitosan‐alginate microcapsules only measured 4.82 ± 0.22 log CFU g^?1. The results of the long‐term storage stability assay indicated that the viability of IFFI 6038 in chitosan‐trehalose‐alginate microcapsules was higher than in chitosan‐alginate microcapsules after storage at 25 °C. Trehalose played an important role in the stability of IFFI 6038 during storage. The novel shell‐matrix chitosan‐trehalose‐alginate microcapsules showed optimal stability and acid resistance, demonstrating their potential as a delivery vehicle to transport probiotics.     

奇亚籽油微胶囊的制备及表征

为提高奇亚籽油的稳定性,对其进行微胶囊化。以包埋率为评价指标对冷冻干燥制备奇亚籽油微胶囊的工艺进行优化,利用激光粒度仪、扫描电镜、红外光谱仪和差示扫描量热仪(differential scanning calorimetry,DSC)等表征微胶囊性状。结果表明,微胶囊的最佳制备工艺为:壁材比(酪蛋白酸钠∶D-乳糖-水合物)1.1∶1(质量比)、固形物浓度31.32%、壁芯比2.34∶1(质量比),包埋率达到90.65%。所得微胶囊产品含有芯材、壁材的特征峰,表明形成奇亚籽油微胶囊的包埋结构。制得的奇亚籽油微胶囊呈不规则的几何形状和紧凑的结构,大小均匀,流动性较好,粉末表面光滑,黏度小,稳定性良好,可满足一般食品加工条件,为奇亚籽油微胶囊在食品工业中的应用提供参考。     

壳聚糖-海藻酸钠缓释制备红景天苷微囊

用壳聚糖 海藻酸钠微囊技术制备了一系列红景天苷微囊。试验结果表明 :海藻酸钠的浓度、壳聚糖的浓度及壳聚糖溶液的pH值对海藻酸钠 壳聚糖微囊的包埋率、载药量及缓释性能有影响 ,海藻酸钠和壳聚糖微囊能作为红景天苷活性成分的载体。     

复凝聚法鼠李糖乳杆菌微胶囊工艺优化及储藏稳定性

为提高鼠李糖乳杆菌在贮藏过程中的稳定性,以明胶、阿拉伯胶为壁材,采用复凝聚法制备鼠李糖乳杆菌微胶囊。研究以湿态微胶囊的包埋率为指标,考察pH、壁材浓度、转速和菌添加量对复凝聚法微胶囊制备的影响,在单因素试验的基础上进行正交试验,优化最佳工艺。将最优条件下的湿微胶囊进行喷雾干燥和真空冷冻干燥,并在不同水分活度和不同温度条件下研究了喷雾干燥和真空冷冻干燥鼠李糖乳杆菌微胶囊的储藏稳定性。结果表明,pH 3.75、壁材浓度1.5%、转速200 r/min、菌添加量109 CFU,此条件下制备的鼠李糖乳杆菌微胶囊包埋率最高,为93.21%;复凝聚法制备的鼠李糖乳杆菌湿微胶囊干燥后,每克真空冷冻干燥微胶囊的活菌数比喷雾干燥微胶囊高1.9个对数值;储藏时水分活度越低,温度越低,鼠李糖乳杆菌微胶囊的储藏性越好;与喷雾干燥微胶囊相比,储藏时真空冷冻干燥微胶囊在高水分活度下较稳定,且在不同水分活度、不同温度条件下的活性均高于喷雾干燥微胶囊。因此复凝聚法制备的鼠李糖乳杆菌微胶囊真空冷冻干燥后能更好的保护鼠李糖乳杆菌,延长其储藏期。     

An Improved Method of Microencapsulation of Probiotic Bacteria for Their Stability in Acidic and Bile Conditions during Storage

ABSTRACT: The purpose of this study was to develop a method for applying an extra coating of palm oil and poly‐L‐lysine (POPL) to alginate (ALG) microcapsules to enhance the survival of probiotic bacteria. Eight strains of probiotic bacteria including Lactobacillus rhamnosus, Bifidobacterium longum, L. salivarius, L. plantarum, L. acidophilus, L. paracasei, B. lactis type Bl‐O4, and B. lactis type Bi‐07 were encapsulated using alginate alone or alginate with POPL. Electron microscopy was used to measure the size of the microcapsules and to determine their surface texture. To assess if the addition of POPL improved the viability of probiotic bacteria in acidic conditions, both ALG and POPL microcapsules were inoculated into pH 2.0 MRS broths and their viability was assessed over a 2‐h incubation period. Two bile salts including oxgall bile salt and taurocholic acid were used to test the bile tolerance of probiotic bacteria entrapped in ALG and POPL microcapsules. To assess the porosity and the ability of the microcapsule to hold small molecules in an aqueous environment a water‐soluble fluorescent dye, 6‐carboxyflourescin (6 FAM), was encapsulated and its release was monitored using a UV spectrophotometer. The results indicated that coating the microcapsules with POPL increased the overall size of the capsules by an average of 3 μm ± 0.67. However, microcapsules with added POPL had a much smoother surface texture when examined under an electron microscope. The results also indicated that the addition of POPL to microcapsules improved the average viability of probiotic bacteria by > 1 log CFU/mL when compared to ALG microcapsules at 2 h of exposure to acidic conditions. However, similar plate counts were observed between ALG and POPL microcapsules when exposed to bile salts. This suggests that an extra coating of POPL could be readily broken down by bile salts that are commonly found in the lower gastrointestinal tract (GIT). Upon testing the porosity of the microcapsules, findings suggest that POPL microcapsules were less porous and hold 52.2% more fluorescent dye over a 6‐wk storage period.     

不同搅拌速度下的复合凝聚桔油微胶囊在制备过程中的形态变化

研究不同搅拌速率下的明胶-阿拉伯胶复合凝聚橘油微胶囊在制备过程中的形态变化以及载量对释放性质的影响。结果表明：在复合凝聚阶段,当搅拌速率由200r/min 增加到600r/min时,微胶囊具有球状多核的结构,粒径逐渐减小;当搅拌速率不超过400r/min 时,微胶囊在凝胶化和固化阶段仍保持球状多核结构,而高速搅拌其形态会变得不规则。搅拌速率增加,微胶囊的载量提高,高载量和小粒径使微胶囊的释放速率增加。制备具有良好缓释性能的复合凝聚球状多核微胶囊的最佳搅拌速率是400r/min。     

Microencapsulated Lactobacillus rhamnosus GG powders: relationship of powder physical properties to probiotic survival during storage

Freeze-dried commercial Lactobacillus rhamnosus GG (LGG) were encapsulated in an emulsion-based formulation stabilized by whey protein and resistant starch and either spray-dried or freeze-dried to produce probiotic microcapsules. There was no difference in loss of probiotics viability after spray drying or freeze drying. Particle size, morphology, moisture sorption, and water mobility of the powder microcapsules were examined. Particle size analysis and scanning electron microscopy showed that spray-dried LGG microcapsules (SDMC) were small spherical particles, whereas freeze-dried LGG microcapsules (FDMC) were larger nonspherical particles. Moisture sorption isotherms obtained using dynamic vapor sorption showed a slightly higher water uptake in spray-dried microcapsules. The effect of water mobility, as measured by nuclear magnetic resonance (NMR) spectroscopy, at various water activities (a(w) 0.32, 0.57, and 0.70) and probiotic viability during storage at 25 °C was also examined. Increasing the relative humidity of the environment at which the samples were stored caused an increase in water mobility and the rate of loss in viability. The viability data during storage indicated that SDMC had better storage stability compared to FDMC. Although more water was adsorbed for spray-dried than freeze-dried microcapsules, water mobility was similar for corresponding storage conditions because there was a stronger water-binding energy for spray-dried microcapsule. This possibly accounted for the improved survival of probiotics in spray-dried microcapsules.     

丁香精油微胶囊工艺优化及其对冰温猪肉保鲜效果的影响

为克服丁香精油在保鲜应用中易挥发、难溶于水的缺点,采用复凝聚法制备丁香精油微胶囊,以包埋率为评价指标,采用Box-Behnken中心组合试验和响应面分析法优化包埋工艺,并将丁香精油微胶囊应用于冰温猪肉的保鲜。结果表明,所得回归模型具有高度显著性(p<0.0001),方程对试验拟合较好,在CaCl₂浓度12 g/L,壁芯比7:1 (m/m),复合壁材比(海藻酸钠-壳聚糖)0.8:1 (m/m),包埋时间47 min的条件下,制得的丁香精油微胶囊包埋率最高为84.20%,与预测包埋率相对误差小于5%;用该条件制备的丁香精油微胶囊处理冷却猪肉,冰温下对照组猪肉可保鲜9 d,空芯组可保鲜21 d,精油组可保鲜27 d,表明丁香精油微胶囊可显著延长冰温猪肉的保鲜期(p<0.05)。     

利用纳米SiO2模板制备壳聚糖季铵盐/海藻酸钠自组装微胶囊的研究

分别以壳聚糖季铵盐和海藻酸钠为阳离子组分和阴离子组分,采用高分子聚电解质的层层自组装(LBL)技术在纳米二氧化硅微球(SiO2)模板上构建自组装多层膜,获得了核/壳结构微胶囊。结果显示这种微胶囊的平均粒径为396.4 nm,平均每个单分子沉积层的厚度约为2.5 nm。通过罗丹明B对自组装微胶囊的囊壁材料进行修饰,在荧光显微镜下观察到微胶囊分布均匀,且发出明亮的红色荧光。进而,通过稀氢氟酸溶液去除SiO2核模板,成功获得了壳聚糖季铵盐/海藻酸盐空心微胶囊。这种空心微胶囊作为一种新型的包载活性物质的载体将有望在功能纸、药物控制释放和酶的固定化等领域发挥重要的作用。     

自修复双层微胶囊的制备及其在玄武岩织物上的应用

为提高玄武岩织物的抗折性能,首先用原位聚合法制备单层微胶囊,囊壁为三聚氰胺-尿素-甲醛共聚物(MUF),囊芯为环氧树脂;然后将固化剂二氨基二苯砜吸附在单层微胶囊表面,以MUF再次包覆制成双层微胶囊;最后将双层微胶囊涂覆到玄武岩织物表面。测试了微胶囊的微观形貌和化学结构,分析了微胶囊自修复玄武岩织物的自修复性能。结果表明:制备的微胶囊结构致密、表面光滑;当玄武岩纤维受到破坏时,微胶囊破裂流出修复剂和固化剂通过聚合反应生成网络大分子修复裂纹;修复7 d后玄武岩织物的最大断裂强力和折皱回复性能可基本恢复,延伸性能有很大改善,抗折性能得到有效提高。