Optimisation of the microencapsulation conditions and physicochemical properties of enteric‐coated lactase microcapsules

Enteric double‐coated lactase microcapsules were developed, and the encapsulation conditions were optimised using response surface methodology. The optimum concentration of the enteric coating material was 4.85 g/100 mL, and the amount of core material was 1.85 mL. The particle size of the zein‐coated microcapsules was 2.868 μm, which was smaller than that of the other microcapsules. All microcapsules showed high zeta‐potential values between pH 6 and 8. The in vitro release rates of hydroxypropyl methyl cellulose phthalate (HPMCP)‐ and shellac‐coated microcapsules were superior to that of the zein‐coated microcapsules. Finally, the microcapsules were barely hydrolysed in simulated gastric fluid; however, almost all the microcapsules coated with HPMCP or shellac released their contents in simulated intestinal fluid within 2 h (93.23 and 97.27%, respectively).     

不同pH复合凝聚甜橙油微胶囊在热水中的释放

以明胶和阿拉伯胶为壁材,甜橙油为芯材,采用复合凝聚法制备球状多核微胶囊。研究了pH对复合凝聚微胶囊的形态、粒径、产率、载量及释放率的影响。结果表明:当pH由4.3降到3.7时,复合凝聚微胶囊具有球状多核的结构,粒径逐渐增加,但产率、载量变化不明显;在80℃热水中复合凝聚微胶囊逐渐溶胀,粒径变大,芯材通过扩散的方式缓慢地释放;pH4.3时,微胶囊在热水中的释放最为缓慢,60min仅释放6.0%。     

The competitive release kinetics and synergistic antibacterial characteristics of tea polyphenols/ε-poly-l-lysine hydrochloride core–shell microcapsules against Shewanella putrefaciens

To obtain the antibacterial agents with long-acting and slow-release properties, the microcapsules were prepared with tea polyphenols (TP), ε-poly-l -lysine hydrochloride (ε-PL) and TP/ε-PL as core materials. Meanwhile, the microcapsules were characterised, their release properties were measured, and their antimicrobial mechanisms against Shewanella putrefaciens were studied. At the initial release phase, TP and ε-PL are competitively released from the composite microcapsules. The release of TP and ε-PL is both fitted to the logistic model, indicating that the primary release mechanism is the disintegration and dissolution. The long-acting antibacterial properties of the microcapsules are better than those of the free antibacterial agent. The microcapsules can destroy the integrity of the cell membrane, and make the permeability improve. Also, the synthesis and expression of bacterial proteins are inhibited. Because of long-term antibacterial properties, the microcapsules have potential value for application in the preservation of food.     

Encapsulation and characterisation of grape seed proanthocyanidin extract using sodium alginate and different cellulose derivatives

Grape seed proanthocyanidin extract (GSPE) has health benefits. However, these phenolic compounds undergo degradation reactions and have undesirable sensorial characteristics. GSPE was encapsulated using sodium alginate (SA), SA-methyl cellulose (MC) and SA-hydroxypropyl methylcellulose (HPMC) for promoting controlled release, pH stability, temperature and storage period tolerance of GSPE. The microcapsules were characterised using scanning electron microscopy (SEM) and Fourier transform infra-red (FTIR) analysis. The SA-MC and SA-HPMC microcapsules appeared to have a more compact surface than SA-alone microcapsules. FTIR analysis indicated successful immobilisation of GSPE into the polymeric microcapsules. Moreover, the SA-MC and SA-HPMC microcapsules showed higher thermal stability. The microcapsules showed a relatively higher amount of released GSPE at a pH above six than at a lower pH. The SA-MC and SA-HPMC microcapsules could be used to retain more GSPE content in the gastric phase and to release it in the intestinal phase for possible absorption. Furthermore, after 28 days of storage at 25 °C, the GSPE retention rate of the microcapsules was still higher than 80%. GSPE encapsulated in SA-MC and SA-HPMC microcapsules results in lesser degradation and can be absorbed more effectively. This method has potential for the delivery of colon-specific materials while exhibiting a sustained-release characteristic.     

Temperature-Sensitive Microcapsules Containing Lactoferrin and Their Action Against Carnobacterium viridans on Bologna

ABSTRACT:  Lactoferrin (LF) was encapsulated in 2 types of emulsion to protect it from contact with agents like divalent cations, which interfere with its antimicrobial activity. First, paste-like microcapsules were prepared as water-in-oil (W₁/O) emulsions from mixtures of 20% w/v LF in distilled water, 20% w/v LF in 3% w/v sodium lactate or in 20 mM sodium bicarbonate, which were emulsified with an oil mixture of 22% butter fat plus 78% corn oil and 0.1% polyglycerol polyricinoleate. Second, freeze-dried double emulsion (W₁/O/W₂), powdered microcapsules were produced following emulsification of paste-like microcapsules in an external aqueous phase (W₂) consisting of a denatured whey protein isolate (WPI) solution. The release of LF from the W₁/O microcapsules was dependent on temperature and NaCl concentration. LF was not released from the W₁/O emulsion at <5.5 °C. Its release was greater from W₁/O microcapsules when suspended in 5% aqueous NaCl than in water at ≥10 °C, whereas LF release from freeze-dried microcapsules was not controlled by temperature change. Paste-like microcapsules were incorporated in edible WPI packaging film to test the antimicrobial activity of LF against a meat spoilage organism Carnobacterium viridans . The film was applied to the surface of bologna after its inoculation with the organism and stored under vacuum at 4 or 10 °C for 28 d. The growth of C. viridans was delayed at both temperatures and microencapsulated LF had greater antimicrobial activity than when unencapsulated. The temperature-sensitive property of the W₁/O microcapsules was reduced when they were incorporated into a WPI film.     

Inhibition of pork and fish oxidation by a novel plastic film coated with horseradish extract

An anti-oxidative plastic film coated with microcapsules containing volatile horseradish extract was developed. The oil-in-water-type microcapsule was produced by a modified orifice method to encapsulate the methanol extract of horseradish. The presence of naturally occurring antioxidants in the extract was confirmed by high performance liquid chromatography. Increasing the amount of chitosan during microcapsule formation increased the size of the microcapsules and decreased the rate of release of the horseradish extract, suggesting that the amount of extract released from the film can be modulated by the chitosan content of the microspheres. Covering pork and fish fillets with the anti-oxidative film delayed oxidative discoloration and rancidization. Collectively, these results showed that a horseradish-coated film containing natural antioxidants efficiently enhanced the stability of both pork and fish. This novel film may be a promising tool to prolong the shelf-life of meats.     

In-vitro evaluation of hydrocolloid–based encapsulated fish oil

The release behaviour of hydrocolloid-based encapsulated fish oil was carried out to understand its applicability as a controlled release delivery system. A casein-based Maillard reaction product (MRP), [caseinate–glucose-dried glucose syrup, MRP] and its corresponding non-MRP-based encapsulant materials were used to form stable emulsions with fish oil. The emulsion particle size distribution was found to be uniform with 90% of the particles below 1.3 μm. These oil/water emulsions were spray dried to obtain free-flowing fish oil microcapsules. All casein-based microcapsules had a free fat content of <1% and the encapsulation efficiencies were all >97%. A sequential in-vitro release protocol and a method for evaluation of the released oil in simulated gastric and intestinal fluids (SGF/SIF) were developed and tested in this study. A comparative analysis of release behaviour between caseinate and whey protein-based MRP and non-MRP-based encapsulant materials was also obtained. The amount of released oil after subjecting to the sequential in-vitro protocol was found to be <2% and 36% for caseinate and whey protein-based MRP microcapsules respectively.     

海藻酸钠薰衣草精油微胶囊的制备及其性能研究

为了提高薰衣草精油的稳定性并且能使精油能控时控释释放。本实验考察了不同浓度的Span 85对乳液质量的影响,同时考察了去稳定剂、海藻酸钠浓度、CaCl₂浓度、固化时间对薰衣草精油微胶囊制备效果的影响,进而得出适宜的薰衣草精油微胶囊制备条件,并对其性能进行了测定,同时研究了不同膜厚度和pH条件下薰衣草精油的释放情况。结果显示,分别加入乙醇、吐温20、乙醇加吐温20后微胶囊的膜厚度从20 μm增加至56 μm。释放结果表明,空白组在10 h内释放量达到了92%,乙醇组为80%,吐温20组为82%,但乙醇加吐温20组释放量仅为70%。此外还对微胶囊的载药量、包封率、粒径、形态等进行了考察,结果显示微胶囊的载药量在38.2%~57.2%之间,包封率在76.4%~92.8%之间,粒径处于45~84 μm之间。综上所述,所制备的微胶囊膜厚度可控、形态圆整均一,薰衣草精油的释放时间长短可通过调节膜的厚度及释放介质的pH来实现。     

Effects of different wall materials on stability and umami release of microcapsules of Maillard reaction products derived from Aloididae aloidi

Umami has a fast release in the long time high temperature cooking process. Microencapsulation technology can be used to control the release of aromas, and spray drying is the method most commonly used for preparing microcapsules. In this study, the Maillard reaction products from the enzymatic hydrolysate of the Aloididae aloidi were combined with chitosan (C); maltodextrin (M); chitosan and gum arabic (C + GA); M + GA; and C + M + GA via spray drying. Characterisation, flavour characteristics and umami release of microcapsules were analysed and determined. The results showed that the obtained microcapsules had the characteristics of low water content and high solubility, and had good embedding effect and thermal stability (especially M_{C + GA}). Scanning electron microscopy results showed that the addition of wall material increased the diameter of the particles. The microcapsules in M_C group and M_{C + GA} group showed the best apparent structure, which was round without pits or pores. In the controlled release study of umami, M_{C + GA} group showed the best sustained umami release, released 13.95%, 38.08% and 80% umami at 0.5, 4 and 32 min, respectively. In conclusion, adding C + GA as wall material of microcapsules had the best stability, flavour and taste sustained-release effect.     

Hydrolysis of Native Wheat and Corn Starch Granules by Glucoamylases from Aspergillus Niger and Rhizopus Niveus

The action of glucoamylase I and II (α-1,4-glucan glucohydrolase, E.C. 3.2.1.3) from Aspergillus niger and the glucoamylase from Rhizopus niveus on native wheat and corn starch granules was followed by using scanning electron microscopy (SEM) and by measuring the glucose released by enzymatic attack. Two distinct patterns of attack were observed. Glucoamylase I and the glucoamylase from R. niveus attacked the granule surface relatively uniformly, resulting in large disclike depressions. Glucoamylase II, while showing some disc-like depressions, produced small grooves (furrows) in the surface of the granule. Similar patterns were observed for both corn and wheat starch granules, except that attack by glucoamylase I and the glucoamylase from R. niveus on wheat starch granules also developed along the equatorial groove (not easily seen until the granules were exposed to enzyme solutions). Measuring glucose released indicated that hydrolysis by glucoamylase I and by the glucoamylase from R. niveus were nearly equal in extent and were about twice that by glucoamylase II.     

层层组装微胶囊的制备及其缓释性能

为研究聚电解质微胶囊对水溶性物质及染料的缓释作用,采用聚苯乙烯磺酸钠(PSS)调节碳酸钙(Ca CO3)微粒的生长,将聚丙烯胺盐酸盐(PAH)和PSS在其表面进行层层组装,用乙二胺四乙酸(EDTA)将Ca CO3微粒溶解去除,制得中空聚电解质微胶囊。将水溶性的罗丹明B包埋到微胶囊内部,研究组装层数、p H值大小、盐浓度对罗丹明B释放行为的影响。结果表明:层数越多,其囊壁越厚,渗透性越差,组装层数为7时,有最大的释放量;包埋罗丹明B的微胶囊在不同p H值条件下都能实现释放,且释放趋势相同,但酸性条件下的释放速度和释放量大于中性及碱性条件;盐浓度低于0.05 mol/L时,释放量和释放速度均得到很大提高,继续增加浓度,释放速率反而降低。     

白藜芦醇/紫胶钠盐微胶囊的响应面法优化及其释放性能

以碳酸钠改性制备的紫胶钠盐(SSC)用于包埋白藜芦醇(Res),优化喷雾干燥制备工艺,获得具有pH响应性的SSC/Res微胶囊,促进白藜芦醇的吸收与利用。以壁材与芯材之比(壁-芯比)、进口温度和进料流量为考察因素,Res的包埋率及载药量为指标,在单因素实验的基础上利用响应面设计优化了喷雾干燥法制备SSC/Res微胶囊的工艺,通过FT-IR、SEM、TG-DSC技术对SSC/Res微胶囊的性能进行表征,并研究其在模拟人体消化过程中的释放性能。结果表明:SSC/Res微胶囊的优化工艺为壁-芯比3:1(g/g),进口温度160℃,进料流量9.5 mL/min,此条件下Res的载药量为18.17%,与预测值一致。SSC/RES微胶囊为球体结构,表面光滑,热力学性质稳定,具有较好的pH响应性,能在模拟肠液中实现快速释放,累积释放速率为60%。     

热处理肌原纤维蛋白复凝聚法制备微胶囊及性能表征

探索罗非鱼（Oreochromis niloticus）中提取肌原纤维蛋白（MP）在热处理后（HMP）作为一种新型微胶囊的壳材料,在海藻酸钠（SA）和壳聚糖（CS）共存下,采用超声复凝聚法对玉米油进行微胶囊化,并对其性能进行表征。结果表明：当海藻酸钠含量2.5%,HMP含量3.0%,玉米油含量30%时,乳液粒径小而均匀,乳化稳定性高。壳聚糖含量为1.2%、海藻酸钠和壳聚糖质量比1:1、氯化钙浓度为5.0%时,通过超声复凝聚法得到的微胶囊平均粒径为88.74±2.60μm,包封率为82.59%±1.44%;微胶囊具有不规则形状和起伏的表面;红外光谱和X射线衍射结果表明,海藻酸钠与壳聚糖因静电结合作用,与HMP共同构成了微胶囊致密的外壳;DSC结果显示HMP微胶囊具有一定的热稳定性;HMP微胶囊显著降低了贮存过程中油脂的POV值与TBA值,有效延缓了玉米油的氧化速度;HMP微胶囊在整个模拟消化阶段的游离脂肪酸（FFA）释放量为92.67%,且在肠消化阶段释放更多的FFA,表明微胶囊化对芯材的释放起到了缓释作用。这项研究显示,HMP与海藻酸钠和壳聚糖复合后,是可以用于微胶囊制备及保护生物活性...     

喷雾干燥法制备可控释微胶囊及其释放性能研究

分别以VB1、ACE抑制肽和牛血清白蛋白为芯材,以聚丙烯酸树脂Ⅱ和乙基纤维素水分散体为壁材,按芯材/壁材比为1:10,喷雾干燥法制备微胶囊,并研究芯材在模拟胃肠液中的释放性能。分析结果表明,聚丙烯酸树脂Ⅱ微胶囊为表面光滑的圆球,乙基纤维素水分散体微胶囊表面有凹陷,芯材包埋率均大于98%。聚丙烯酸树脂Ⅱ微胶囊在模拟胃液中120 min芯材累计释放率小于10%,在模拟肠液中60 min则完全释放;乙基纤维素水分散体微胶囊在模拟胃肠液中芯材释放速率基本一致,120 min累计释放率达70%以上。以聚丙烯酸树脂Ⅱ为壁材的微胶囊可以实现在胃肠液中可控制释放芯材。     

牦牛酥油微胶囊的制备及特性分析

为提高传统牦牛酥油的贮藏稳定性和生物利用率，本实验以海藻酸钠、CaCl₂为复合壁材，以锐孔法制备牦牛酥油微胶囊。以包埋率为指标，通过单因素实验和正交试验确定最佳工艺参数，使用差式扫描量热仪（DSC）、热重分析（TGA）、傅里叶红外光谱（FTIR）、扫描电子显微镜（SEM）和激光粒度仪测定其理化性质，并研究微胶囊在胃肠液中的释放特性及贮藏稳定性。结果表明，当海藻酸钠浓度1.5%，CaCl₂浓度2.5%，芯壁质量比1.5:1，乳化温度50 ℃，固化时间30 min时，微胶囊包埋率最高为89.41%；含水量为5.25%、溶解度为57.22%、休止角为20.6°；平均粒径为929.773 μm，酥油在微胶囊化后热稳定性提高；释放实验表明，微胶囊在模拟胃液、肠液中释放率分别为11.52%、96.44%；贮藏实验表明，微胶囊货架期较牦牛酥油显著延长。     

响应面法优化苹果多酚微胶囊工艺

为确定苹果多酚微胶囊的最佳工艺,提高苹果多酚对不利环境的抗性及缓释能力,利用响应面法采用海藻酸钠、壳聚糖和氯化钙为壁材,以包埋率为响应值进行苹果多酚微胶囊工艺优化,并将优化后的微胶囊在模拟人工胃液、肠液中进行耐受性分析。结果显示,海藻酸钠浓度、氯化钙浓度、pH、芯壁比对苹果多酚包埋率均有显著影响。海藻酸钠浓度0.020 g/mL,氯化钙浓度0.040 g/mL,pH7.0,芯壁比2:1时,苹果多酚微胶囊的包埋率达到85.13%。微胶囊产品能减少苹果多酚在胃肠道中受到的破坏,在模拟胃液和肠液环境中得到了很好的释放,肠液中的最大释放率为83.00%。实验结果显示,该方法简单可行,有效提高了苹果多酚微胶囊的包埋率及缓释能力。     

Physicochemical and sensory properties of milk supplemented with lactase microcapsules coated with enteric coating materials

In this paper, we report the physicochemical and sensory properties of milk supplemented with a powder of microencapsulated lactase. The core material was lactase (β-galactosidase), the primary coating material was medium-chain triglyceride (MCT), and the secondary (enteric) coating material was either hydroxypropyl methylcellulose phthalate (HPMCP) or shellac, comparing both against market milk as a control. The physicochemical properties of both types of microcapsules were analyzed, including the particle size, zeta potential, and in vitro release behavior. To survey the stability of the microcapsules in milk during storage, we studied the residual lactose content and pH. Furthermore, to determine the properties of milk supplemented with the microcapsules, changes in color and sensory properties were evaluated during storage. The particle sizes (volume-weighted mean; D[4,3]) of the microcapsules coated with HPMCP or shellac were 2,836 and 7,834 nm, respectively, and the zeta potential of the capsules coated with shellac was higher than the zeta potential of those coated with HPMCP. The pH levels of milk supplemented with the lactase microcapsules were similar to those of the control (unsupplemented market milk); however, for milk supplemented with HPMCP-coated microcapsules, the pH was slightly lower. The core material, lactase, was released from the microcapsules during 12-d storage, and 18.82 and 35.09% of lactose was hydrolyzed in the samples for HPMCP- and shellac-coated microcapsules, respectively. The sensory characteristics of milk containing microcapsules coated with HPMCP did not show significant differences from the control, in terms of sweetness or off-taste, until 8 d of storage. However, shellac-coated microcapsules showed significant difference in sweetness and off-taste at d 8 and 6 of storage, respectively. The color of milk containing HPMCP-coated microcapsules did not show a significant difference during storage. However, that containing shellac-coated microcapsules was somewhat higher in color values than others. In particular, it showed significance from 0 to 4 d storage in L* and C* values. In conclusion, a powder of lactase microcapsules coated with HPMCP can be suitable as a supplement for milk.     

蜂胶醇提物微胶囊的制备及表征

微胶囊具有保护物质免受环境条件影响、掩盖异味和颜色、降低毒性、延长挥发性物质的储存时间,延缓或控制囊心物的释放等功能。本文采用复凝聚技术制备蜂胶醇提物(EEP)海藻酸钠-壳聚糖微胶囊,利用粒度分析仪、激光共聚焦显微镜、红外光谱仪和X射线衍射仪分析、体外释放试验和加速试验等表征微胶囊性状。研究结果表明,制备的EEP微胶囊形状为大小均匀球体,粒径大小为265±25 nm,包埋率和载药量分别达到72.80±3.8%和19.96±2.4%,海藻酸钠和壳聚糖反应形成微胶囊。模拟胃液和肠液条件下体外释放8 h,释放率46.60±0.80%;HPLC分析加速试验EEP微胶囊中7种物质含量变化为14.01%~39.68%,显著低于EEP中37.01%~77.45%。制得的EEP微胶囊粒径小、稳定性良好、释放率符合肠溶体系要求,对EEP中的活性物质具有一定的保护作用。     

壳聚糖-海藻酸钠微胶囊对葡萄多酚控制释放的研究

对壳聚糖-海藻酸钠包理法制备葡萄多酚微胶囊的工艺进行了研究，考察了微胶囊在模拟胃液和肠液环境中的控制释放效果。结果表明：壳聚糖浓度对微胶囊的包埋率影响最大；在pH6．0的条件下制备的微胶囊比pH5.0时制备的微胶囊对葡萄多酚具有更好的控释效果；被包埋物分子量越大，持续释放时间越长。     

Diffusion of jojoba oil microencapsulated and impregnated onto compressive garment through a pig skin

Scientific developments are in progress in order to create compressive fabric in the medical field. This study focused on the development of a compressive garment in polyamide designated for severe burns in terms of pressure and hydration release. The fabric was then enhanced by adding a moisturizing treatment. The improvement consisted of the impregnation of ethylcellulose microcapsules containing jojoba oil on the textile surface of compressive garment. The kinetic of release of this active ingredient from the microcapsules, as well as its diffusion through the skin, were assessed using the in vitro Franz diffusion cell system. The results showed a controlled release of jojoba oil over time. The amount of oil released during the experiments (168?h) and that which penetrated through the pig skin did not exceed 1% of the total amount of jojoba oil microencapsulated and impregnated on the surface of a compression garment. This study permitted to obtain a compressive garment which presents hydration properties.