嗜酸乳杆菌喷雾干燥技术的研究

研究利用喷雾干燥法对嗜酸乳杆菌进行微胶囊化处理，以微胶囊产品细菌存活率作为主要考察目标，设计了四因素三水平的正交试验。通过正交试验分析，得出微胶囊细菌存活率优化工艺条件为：进风温度140℃；进料速度14．58ml／min；主要壁材阿拉伯胶与麦芽糊精的配比为1：10；壁材浓度为20％。微胶囊内细菌的存活率可达63％，活菌数达到108cfu／ml数量级。并对微胶囊进行了表征。     

半胱氨酸盐酸盐-乙基纤维素微胶囊的制备研究

选用半胱氨酸盐酸盐作为芯材,乙基纤维素作为壁材,采用有机溶剂蒸发技术制备微胶囊。通过单因素实验和正交分析得到最佳实验条件:壁材浓度为1%,海藻酸钠保护液浓度为0.5%,乙酸乙酯做溶剂,油水相比为5∶1,搅拌速度为1000 r/min,时间为2 h时得到的微胶囊的包埋率最高,粒径最小,分布最均匀。     

单细胞AA油喷雾干燥微胶囊化壁材包埋性能的研究

采用喷雾干燥法微胶囊化单细胞AA油,探讨几种壁材的包埋性能.实验结果表明,常用的几种水溶性壁材中变性淀粉具有最高的包埋效率,但是其微胶囊化的AA油氧化稳定性很差,氧化稳定性较高的是乳蛋白;复合壁材中添加玉米糖浆对单细胞AA油的微胶囊包埋效果和氧化稳定性都是极为有利的,无论在干燥状态还是在溶液中其氧化稳定性都是最高的.微胶囊的表面形态观测发现,除了阿拉伯胶的微胶囊表面多呈凹陷、皱缩现象外,其它壁材的微胶囊基本为光滑圆球形;复合壁材AW01微胶囊表面未观测到明显的裂纹,而其它均发现明显裂纹或裂缝.     

耐高温微胶囊化食用香精的研究

以明胶、阿拉伯胶为壁材,通过复合凝聚法可制备易于过滤的球状多核微胶囊。最佳的制囊工艺条件为：壁材浓度为1％,芯材：壁材（质量比）=2：1,明胶：阿拉伯胶（质量比）=1：1,pH值为4．0,甲醛：明胶（质量比）=1：1。     

茶油微胶囊的制备及其缓释性能研究

为提高茶油的存储稳定性，以乳清分离蛋白(WPI)与阿拉伯胶(GA)为复合壁材，转谷氨酰胺酶为固化剂，采用复凝聚法制备茶油微胶囊。首先，以凝聚率为指标，通过单因素实验确定最佳的壁材复凝聚参数；随后，以微胶囊形貌和包埋率为指标，通过单因素实验和响应面实验确定最佳的茶油微胶囊制备条件：壁材质量分数2.0% 、壁材组分WPI与GA的质量比1:1、芯壁质量比0.84:1、复凝聚pH=4.3、复凝聚温度40 ℃和搅拌速度500 r/min，此时包埋率达89.67%。红外光谱、扫描电镜、粒度分布、休止角、POV值和热重分析结果表明，茶油微胶囊结构完整、粒径均一且具有良好的流动性、分散性、热稳定性和抗氧化性。体外缓释数据表明，茶油微胶囊在模拟胃液和肠液中的缓释机理均符合Ritger-Peppas缓释模型，符合人体消化吸收特性。茶油微胶囊化保护茶油的有效成分，扩展其使用范围，提高其消化吸收效果。     

丹参酮的微胶囊化

将丹参酮溶解于肉豆蔻酸异丙酯后，采用明胶／阿拉伯胶为壁材，使用复合凝聚法对其进行了微胶囊化，研究了多种反应条件对丹参酮／肉豆蔻酸异丙酯微胶囊化的影响。结果发现，壁材和芯材的组成比例对微胶囊的包埋率有较大的影响；搅拌速度的增加会使微胶囊的粒度变小；表面活性剂的加入会使微胶囊的粒度分布变窄。在合适的条件下，制备得到的微胶囊产品包埋率可达80％以上，平均体积粒度可达几十微米。     

溶剂蒸发法制备高效氯氟氰菊酯微胶囊及其性能表征

针对高效氯氟氰菊酯使用过程中对人体皮肤的刺激性以及对水生生物的高毒性,以乙基纤维素为壁材,二氯甲烷为溶剂,通过设计L9（34）正交试验,采用溶剂蒸发法制备高效氯氟氰菊酯微胶囊,同时对微胶囊的理化性质和缓释特性进行表征。根据微胶囊平均粒径和未包封率的综合评分确定最佳制备工艺为：25%二氯甲烷,0.75%乙基纤维素,2%乳化剂,剪切8 min。扫描电子显微镜观察发现,所制微胶囊具有粒径大小均匀,表面光滑等特性;红外光谱图表明,高效氯氟氰菊酯被乙基纤维素包埋;释放特性曲线也表明微胶囊具有较好的缓释性能。该工艺操作简单,制备周期短,成囊性好,可为农药微胶囊的制备提供有效途径。     

乙基纤维素微胶囊红磷的制备及性能表征

目前微胶囊红磷大多采用原位聚合法制备，工艺较为复杂，使用的囊壳原料可能对环境造成危害。为解决这一问题，本文以可降解材料乙基纤维素（EC）为壁材，无水乙醇为壁材溶剂，蒸馏水为壁材非溶剂，采用相分离法制备微胶囊红磷，并利用FTIR、SEM及XPS表征微胶囊红磷的形态及包覆效果，同时对样品的热稳定性、吸湿性及感度进行测定，以此确定最佳工艺条件。实验结果表明：经EC包覆后的红磷样品表面粗糙，包覆率随乙基纤维素添加量的增多而升高，最高可达94.8%；EC囊壳能有效提高红磷的热稳定性及安定性，降低吸湿率。在保证红磷正常使用不受影响的前提下，取0.6g乙基纤维素、2g红磷为最佳工艺条件，包覆率达93.2%；制备的微胶囊红磷样品热稳定性提高，着火点升高至310℃；10d后吸湿率降低至6.8%，较普通红磷降低约16.8%；微胶囊红磷摩擦感度降至34%，较未处理红磷降低52%。采用相分离法在常温、中性条件下制备EC包覆微胶囊红磷，工艺简便，材料绿色环保，制备的微胶囊红磷样品具有良好的使用性能。     

明胶/阿拉伯胶复合凝聚法制备DCOIT微胶囊

以羟乙基纤维素(HEC)为乳化剂、明胶和阿拉伯胶为壁材、4,5-二氯-2-正辛基-4-异噻唑啉-3-酮(DCOIT)芯材、甲醛为固化剂、冰醋酸(HAc)和氢氧化钠(NaOH)为pH值调节剂,采用复合凝聚法制备了DCOIT微胶囊。通过单因素试验法探讨了壁材浓度、壁芯比、反应时间、pH值、搅拌速率和乳化剂类型等对微胶囊的粒径、稳定性和包埋率等影响。结果表明:当w(壁材)=3%、壁芯比=m(壳层单体)/m(核层单体)=3、反应时间为2 h、pH≤4.5和搅拌速率为1 000 r/min时,相应DCOIT微胶囊的性能相对最佳。     

喷雾干燥法制备革兰氏阴性菌微胶囊生物相容性研究

根据细菌的生长情况,考察了阿拉伯胶、β-环糊精、麦芽糊精3种壁材及其混合对细菌活性影响,并进一步确定主要的胶囊材料的浓度。实验结果表明,该新微胶囊体系具有好的生物相容性,且进一步考察了该体系壁材的成膜性。     

Effect of Selected Additives on Microencapsulation of Anthocyanin by Spray Drying

Microencapsulation of anthocyanin pigment present in Garcinia indica Choisy was carried out with maltodextrin of various dextrose equivalents (DE 06, 19, 21, and 33) and other additives such as gum acacia and tricalcium phosphate to enhance the stability of the pigment. The microencapsulated pigment containing 5.0% maltodextrin DE 21, 0.25% gum acacia, and 0.25% tricalcium phosphate was found to have lowest hygroscopic moisture content (4.38%), highest antioxidant activity (69.90%), and highest anthocyanin content (485 mg/100 g). The glass transition temperature was 44.59°C. The sorption isotherms for microencapsulated powder showed that the samples were stable up to water activity less than 0.43. The scanning electron microscope structures depicted that the particle size ranged from 5 to 50 μm with smooth spheres. Storage at 4°C increased the half-life twofold compared to that of the spray-dried product kept at ambient temperature (25°C).     

Helping to choose operating parameters for a coating fluid bed process

The feasibility of solid particles coating in a fluid bed with a Wurster tube is studied for several types of particles and aqueous coating solutions. The model products are wheat semolina, beads of glass, alumina, resin polystyrene, plastic PMMA, with a size range between 125 and 1250 μm and densities between 500 and 2500 kg m⁻³. The chosen coatings are representative of those used for the food products, such as maltodextrin, acacia gum, and sodium chloride in aqueous solution.

The air flow rate suitable for a regular circulation of particles in the reactor is determined for each particle type. For each coating solution, the flow rate leading to agglomeration is considered as the maximal limit flow rate to use for coating. Then comparative coating experiments were realized.

For a similar initial load of particles, the same mass of coating was atomized (13.5 g min⁻¹) at 50 °C. The mass of coating deposit on particle surface is increased linearly during an atomization sequence lasting 33 min. For example, for every 100 g of alumina particles, the rates are 0.48, 0.51, and 0.53 g min⁻¹ for sodium chloride, maltodextrin, and acacia gum, respectively. We then obtain a coating efficiency between 87% and 98%.

In the specific case of sodium chloride on glass beads, the deposit of crystallized salt was linear during 10 min then stopped. Addition of acacia gum (50%) to the NaCl coating solution leads again to a linear deposit over 65 min.     

Microencapsulation of extra‐virgin olive oil by spray‐drying: Influence of wall material and olive quality

Encapsulation is a process by which small particles of core products are packaged within a wall material to form microcapsules. One common technique to produce encapsulated products is spray‐drying which involves the conversion of liquid oils in the form of an emulsion into dry powders. Emulsification conditions, wall components, and spray‐drying parameters have been optimized for the microencapsulation of different extra‐virgin olive oils. To achieve this goal, the influences of emulsion conditions have been evaluated for different wall components such as proteins (sodium caseinate and gelatin), hydrocolloids (Arabic gum), and hydrolyzed starches (starch, lactose, and maltodextrin). In addition, for each of the tested conditions the ratio of wall solid‐to‐oil and spray‐drying parameters were as well optimized. The microencapsulation effectiveness was determined based on process yield and the ratio between free and encapsulated oil (microencapsulation efficiency). Highest encapsulation yields were achieved when gelatin, Arabic gum and maltodextrin and sodium caseinate and maltodextrin were used as encapsulation agents and the ratio of wall solid‐to‐oil was 1:4 and 1:2, respectively. Under these conditions, 53% of oil was encapsulated. The influence of olive oil quality in the microencapsulation process was evaluated in terms of fatty acids profile alteration after the microencapsulation process.     

共轭亚油酸微胶囊化中壁材优化的研究

以大豆分离蛋白(SPI)、麦芽糊精(MD)为主要壁材,研究了以喷雾干燥法对共轭亚油酸(CLA)微胶囊化时其复合壁材的优化及其方法。利用界面膜成膜理论分析了各组分配比对微胶囊化效果的影响,进而指导最优条件的选择。结果表明,SPI与MD质量比为1∶4,壁材中玉米糖浆质量分数为38.5%,固形物质量分数在16.7%,CLA添加量以微胶囊质量分数计约为16%时,微胶囊化产率(MEY)和效率(MEE)分别达到了98%和85%;加入明胶可进一步提高微胶囊产品的含油量而微胶囊化效果基本不变。     

Microencapsulation of Cinnamon Oleoresin by Spray Drying Using Different Wall Materials

Microencapsulation of spice oleoresin is a proven technology to provide protection against degradation of sensitive components present therein. The present work reports on the microencapsulation of cinnamon oleoresin by spray drying using binary and ternary blends of gum arabic, maltodextrin, and modified starch as wall materials. The microcapsules were evaluated for the content and stability of volatiles, entrapped and total cinnamaldehyde content for six weeks. A 4:1:1 blend of gum arabic:maltodextrin:modified starch offered a protection, better than gum arabic as seen from the t_1/2; i.e., time required for a constituent to reduce to 50% of its initial value.     

Microencapsulation of Cinnamon Oleoresin by Spray Drying Using Different Wall Materials

Microencapsulation of spice oleoresin is a proven technology to provide protection against degradation of sensitive components present therein. The present work reports on the microencapsulation of cinnamon oleoresin by spray drying using binary and ternary blends of gum arabic, maltodextrin, and modified starch as wall materials. The microcapsules were evaluated for the content and stability of volatiles, entrapped and total cinnamaldehyde content for six weeks. A 4:1:1 blend of gum arabic:maltodextrin:modified starch offered a protection, better than gum arabic as seen from the t_1/2; i.e., time required for a constituent to reduce to 50% of its initial value.     

Optimization of Freeze Drying Conditions for Purified Pectinase from Mango (Mangifera indica cv. Chokanan) Peel

Response surface methodology (RSM) along with central composite design (CCD) was applied to optimize the freeze drying conditions for purified pectinase from mango (Mangifera indica cv. Chokanan) peel. The effect of pectinase content (-2.66, 62.66 mg/mL), Arabic gum (-1.21, 10.21%, w/v), and maltodextrin (0.73, 7.26%, w/v) as independent variables on activity, yield, and storage stability of freeze-dried enzyme was evaluated. Storage stability of pectinase was investigated after one week at 4 °C and yield percentage of the enzyme after encapsulation was also determined. The independent variables had the most significant (p < 0.05) effect on pectinase activity and yield of the enzyme. It was observed that the interaction effect of Arabic gum and maltodextrin improved the enzymatic properties of freeze-dried pectinase. The optimal conditions for freeze-dried pectinase from mango peel were obtained using 30 mg/mL of pectinase content, 4.5 (%, w/v) of Arabic gum, and 4 (%, w/v) of maltodextrin. Under these conditions, the maximum activity (11.12 U/mL), yield (86.4%) and storage stability (84.2%) of encapsulated pectinase were achieved.     

Microencapsulation of Essential Oil from Fruits of Pterodon emarginatus Using Gum Arabic and Maltodextrin as Wall Materials: Composition and Stability

The present investigation reports the microencapsulation of the essential oil from the fruits of Pterodon emarginatus by spray drying using gum arabic and maltodextrin. X-ray diffraction studies established that the essential oil was entrapped within the microcapsules rather than being adsorbed onto the surface. The morphology of the microcapsules was analyzed by scanning electron microscopy (SEM). The particle size (Sauter [3,2]) and particle size distribution of microcapsules were also determined. The microcapsules were evaluated for the content and stability of both volatiles and the major component, β-caryophyllene, for 45 days. A 1:3:3.6 blend of essential oil: gum arabic: maltodextrin offered the best protection, with 98.63% of the essential oil being retained and the same proportion of β-caryophyllene being entrapped. The obtained results showed that the microcapsules might have potential applications in the protection of essential oil from fruits of P. emarginatus and contribute to the development of an herbal medicine.     

Spray drying microencapsulation of Lippia sidoides extracts in carbohydrate blends

The microencapsulation of Lippia sidoides extracts in blends of carbohydrates was investigated. The extraction conditions were determined through a 2² factorial design. The effects of the plant:solvent ratio (A – 7.5:100 and 15:100 m/m) and the extraction time (B – 30 and 90 min) on thymol content of extractive solutions were evaluated, using a 2:1 (v/v) of ethanol:water at a temperature of 50 °C, as a solvent system. The selected extract was subjected to spray drying. Blends of maltodextrin and gum arabic at different proportions (4:1; 3:2; 2:3; 0:1) (m/m) were used as encapsulating material. The protective effects of the maltodextrin and gum arabic blends were evaluated by determination of the thymol retention in the dried product, which ranged from 70.2 to 84.2% (related to the content in the extractive solution). An increase in the gum arabic to maltodextrin (DE10) ratio has positive effect on thymol retention. L. sidoides extracts and spray-dried products showed antifungal activity against tested fungal strains (Candida albicans – ATCC 64548, Candida glabrata – ATCC 90030, Candida krusei – ATCC 6258, and Candida parapsilosis – ATCC 22019), evidencing their potential as a natural antifungal agent for medicinal, food, and cosmeceutical purposes.     

Spray Drying of Elderberry (Sambucus nigra L.) Juice to Maintain Its Phenolic Content

Spray drying was studied with Elderberry (Sambucus nigra L.) juice using a Buchi B-290 spray dryer. Different inlet temperatures ranging from 70°C to 120°C and two feed flow rates of 180 ml/hr and 300 ml/hr were considered for the experiment. The operating parameters were optimized in terms of total phenolic content retention, color, and powder recovery. The inlet temperature of 80°C with feed flow rate of 180 ml/hr gave high phenolic content retention with good color but lower recovery of the dried powder, i.e., less than 50%. To increase the recovery percentage during the drying process, the elderberry juice was spray dried with five different wall materials, i.e., soya milk powder, soya protein powder, isolated soya protein, gum acacia, and maltodextrin. Wall materials were evaluated in terms of total phenolic content retention, color of the powder, and mass recovery percentage. The gum acacia and maltodextrin gave better results and high recovery percentage, i.e., more than 70%. The best three combinations were stored under three different storage conditions in three different packagings to monitor the stability of the phenolic content and color of the powder.