Effect of Various Encapsulating Materials on the Stability of Probiotic Bacteria

ABSTRACT:  Ten probiotic bacteria, including Lactobacillus rhamnosus , Bifidobacterium longum , L. salivarius , L. plantarum , L. acidophilus , L. paracasei , B. lactis type Bl-04, B. lactis type Bi-07, HOWARU L. rhamnosus , and HOWARU B. bifidum , were encapsulated in various coating materials, namely alginate, guar gum, xanthan gum, locust bean gum, and carrageenan gum. The various encapsulated probiotic bacteria were studied for their acid and bile tolerance. Free probiotic organisms were used as a control. The acid tolerance of probiotic organisms was tested at pH 2 over a 2-h incubation period. Bile tolerance was tested with taurocholic acid over an 8-h incubation period. The permeability of the capsules was also examined using a water-soluble dye, 6-carboxyflourescin (6-CF). The permeability was monitored by measuring the amount of 6-CF released from the capsules during a 2-w storage period. Results indicated that probiotic bacteria encapsulated in alginate, xanthan gum, and carrageenan gum survived better ( P < 0.05) than free probiotic bacteria, under acidic conditions. When free probiotic bacteria were exposed to taurocholic acid, viability was reduced by 6.36 log CFU/mL, whereas only 3.63, 3.27, and 4.12 log CFU/mL was lost in probiotic organisms encapsulated in alginate, xanthan gum, and carrageenan gum, respectively. All encapsulating materials tested released small amounts of 6-CF; however, alginate and xanthan gum retained 22.1% and 18.6% more fluorescent dye than guar gum. In general, microcapsules made of alginate, xanthan gum, and carrageenan gum greatly improved the survival of probiotic bacteria when exposed to acidic conditions and bile salts.     

Optimization of Incorporated Prebiotics as Coating Materials for Probiotic Microencapsulation

ABSTRACT: The purpose of this research was to improve probiotic microencapsulation using prebiotics and modern optimization techniques to determine optimal processing conditions, performance, and survival rates. Prebiotics (fructooligosaccharides or isomaltooligosaccharides), growth promoter (peptide), and sodium algi-nate were incorporated as coating materials to microencapsulate 4 probiotics ( Lactobacillus acidophilus, Lacto-bacillus casei, Bifidobacterium bifidum , and Bifidobacterium longum ). The proportion of the prebiotics, peptide, and sodium alginate was optimized using response surface methodology (RSM) to 1st construct a surface model, with sequential quadratic programming (SQP) subsequently adopted to optimize the model and evaluate the survival of microencapsulated probiotics under simulated gastric fluid test. Optimization results indicated that 1% sodium alginate mixed with 1% peptide and 3% fructooligosaccharides as coating materials would produce the highest survival in terms of probiotic count. The verification experiment yielded a result close to the predicted values, with no significant difference ( P > 0.05). The storage results also demonstrated that addition of prebiotics in the walls of probiotic microcapsules provided improved protection for the active organisms. These probiotic counts remained at 10⁶ to 10⁷ colony-forming units (CFU)/g for microcapsules stored for 1 mo and then treated in simulated gastric fluid test and bile salt test.     

Effect of Homogenization Techniques on Reducing the Size of Microcapsules and the Survival of Probiotic Bacteria Therein

ABSTRACT:  This study investigated 2 different homogenization techniques for reducing the size of calcium alginate beads during the microencapsulation process of 8 probiotic bacteria strains, namely,  Lactobacillus rhamnosus ,  L. salivarius ,  L. plantarum ,  L. acidophilus ,  L. paracasei, Bifidobacterium longum ,  B. lactis  type Bi-04, and  B. lactis  type Bi-07. Two different homogenization techniques were used, namely, ultra-turrax benchtop homogenizer and Microfluidics™ microfluidizer. Various settings on the homogenization equipment were studied such as the number of passes, speed (rpm), duration (min), and pressure (psi). The traditional mixing method using a magnetic stirrer was used as a control. The size of microcapsules resulting from the homogenization technique, and the various settings were measured using a light microscope and a stage micrometer. The smallest capsules measuring (31.2 μm) were created with the microfluidizer using 26 passes at 1200 psi for 40 min. The greatest loss in viability of 3.21 log CFU/mL was observed when using the ultra-turrax benchtop homogenizer with a speed of 1300 rpm for 5 min. Overall, both homogenization techniques reduced capsule sizes; however, homogenization settings at high rpm also greatly reduced the viability of probiotic organisms.     

益生菌山药饮料发酵工艺优化及其冷藏稳定性

本研究以山药粉为原料,益生菌Lactobacillus plantarum P-8和Bifidobacterium lactis V9为发酵剂,对发酵工艺进行优化,以得到一种兼具山药营养价值与益生菌益生特性的益生菌山药饮料。通过单因素实验研究发酵时间、接种量、发酵温度对饮料中活菌数、滴定酸度以及pH的影响,在此基础上结合响应面分析获得发酵益生菌山药饮料最优发酵工艺参数,即接种量为 2×10⁶ CFU/mL、发酵时间为19.1 h、发酵温度为37 ℃。在此条件下饮料活菌数为4.3×10⁸ CFU/mL,滴定酸度为105.3 °T。对饮料在4 ℃下贮藏28 d,贮藏期内饮料活菌数稳定维持在10⁸ CFU/mL,饮料组织状态良好、风味及口感稳定。     

微胶囊壁材辛烯基琥珀酸酯化淀粉的界面性质和乳化稳定性

本文使用两种辛烯基琥珀酸酯化淀粉HI-CAP100和N-LOK为壁材制备微胶囊化薄荷油并研究了这两种壁材的界面性质和乳化稳定性。研究结果表明，HI-CAP100不仅能有效地降低油，水界面的界面张力，而且能在油，水界面上形成具有良好粘弹性且界面粘度较高的界面膜，由其制备的乳状液具有很高的乳化稳定性。由HI-CAP100为壁材制备的高载量（40％，W/W）的微胶囊化薄荷油产品的微胶囊化产率、效率均超过95％，经30℃贮存6个月，其保留率仍高达95．3％，显示出微胶囊化薄荷油具有良好的贮存稳定性。     

不同储备条件对储备棕榈油氧化稳定性的影响

针对高温高湿的珠三角地区储备的24度精炼棕榈油,以及常规储备精炼棕榈油出现的问题,重点探究了不同储备条件下金属离子和温度两个因素对棕榈油氧化稳定性的影响。试验结果表明,储备油罐若未作食品级内防腐处理,储备期间油罐内壁氧化产生的金属离子会对棕榈油产生明显的促氧化作用,棕榈油氧化速度明显加快,过氧化值快速升高,酸值有变化但不明显;等同质量的棕榈油,在夏季高温期入库储藏要比冬季低温期入库储藏更容易氧化变质。     

酪蛋白水解产物对含益生菌酸奶中益生菌数量的影响

文研究了牛奶蛋白水解产物对发酵牛奶中益生菌生长的促进作用,并对在两周的贮存期内活性益生菌菌数的稳定性进行了比较研究。实验以益生菌菌株-嗜酸乳杆菌作为研究用菌种。利用novo型碱性蛋白酶水解酪蛋白获得水解度分别为4.7%、7.1%、8.8%、10.1%、12.6%的酪蛋白水解产物,研究以0.5、1、2和4g/L四个添加水平加入发酵酸奶中,分析其对益生菌生长情况的影响。结果证明,酪蛋白水解产物的添加普遍促进了嗜酸乳杆菌在酸奶中的生长。随着添加量的增加,嗜酸乳杆菌在发酵牛奶中的稳定性得到了同步提高。但综合分析,水解度为8.8%的水解产物,添加量为2g/L时,可使益生菌的生长活性和稳定性状态最佳。研究结果证实,选择优化的酪蛋白水解产物对发酵牛奶中益生菌的生长及维持其生存能力均会产生积极地促进作用,也对发酵乳行业生产符合国际标准的益生菌产品具有重要的理论和实践的价值。     

海藻酸钠和乳清蛋白作为益生菌包埋壁材的比较

利用海藻酸钠和乳清蛋白分别制备包埋有两歧双歧杆菌的微胶囊,测定了不同微胶囊的粒径、包埋效率、缓冲能力和外观形态,同时还考察了不同微胶囊对两歧双歧杆菌保护效果的影响。结果表明：乳清蛋白微胶囊的粒径和包埋效率均要高于海藻酸钠微胶囊,分别为202.5 μm,87.8%和118.3 μm,48.1%;虽然在高胆盐环境中两种微胶囊对两歧双歧杆菌的保护效果没有显著差别,但在低酸环境、模拟胃液和常温贮藏期中,相比于海藻酸钠微胶囊,乳清蛋白微胶囊将两歧双歧杆菌的存活量分别提高了大约5、2、0.5（lg（CFU/mL））。乳清蛋白微胶囊在pH值偏中性的环境中具有较高的缓冲能力;在外观形态上,由高浓度乳清蛋白溶液制备而来的微胶囊具有较好的呈球性和致密度,这些可能是乳清蛋白微胶囊具有较高保护效果的原因。     

Survival of Lactic Acid Bacteria and Their Lactases under Acidic Conditions

Effects of sonication, survival, and β-galactosidase activity of four lactic cultures were investigated in pH 1.5-3.5 range. Lactobacillus delbruekii subsp. bulgaricus and Streptococcus thermophilus exhibited the highest β-galactosidase activity in skim milk and broth systems, respectively. The β-galactosidases from L. delbruekii subsp. bulgaricus, S. thermophilus, and L. acidophilus showed optimum activity in the neutral pH range and 55°C. Viable count of all four cultures decreased most rapidly at pH 1.5, but L. acidophilus and L. delbruekii subsp. bulgaricus survived better than the other organisms. The decrease of enzyme activity of unsonicated cultures with pH was slight, especially at pH 3.5. However, acidification of sonicated cultures to pH 3.5 or lower resulted in rapid and permanent loss of enzyme activity.     

Microencapsulation of Bifidobacterium bifidum F‐35 in Whey Protein‐Based Microcapsules by Transglutaminase‐Induced Gelation

Abstract: Bifidobacterium bifidum F‐35 was microencapsulated into whey protein microcapsules (WPMs) by a transglutaminase (TGase)‐induced method after optimization of gelation conditions. The performance of these WPMs was compared with that produced by a spray drying method (WPMs‐A). WPMs produced by the TGase‐induced gelation method (WPMs‐B) had larger and denser structures in morphological examinations. Native gel and SDS‐PAGE analyses showed that most of the polymerization observed in WPMs‐B was due to stable covalent crosslinks catalyzed by TGase. The degradation properties of these WPMs were investigated in simulated gastric juice (SGJ) with or without pepsin. In the presence of pepsin, WPMs‐A degraded more quickly than did WPMs‐B. Finally, survival rates of the microencapsulated cells in both WPMs were significantly better than that of free cells and varied with the microencapsulation method. However, WPMs‐B produced by TGase‐induced gelation could provide better protection for microencapsulated cells in low pH conditions and during 1 mo of storage at 4 °C or at ambient temperature.     

Growth Medium for Culturing Probiotic Bacteria for Applications in Vegetarian Food Products

Vegetarian probiotic foods by definition, must be free from all animal-derived ingredients. This not only includes the product ingredients but the probiotic inoculum as well. Probiotic starter cultures are traditionally grown and stored in media containing milk or meat-derived ingredients. The presence of these ingredients makes the probiotic cell concentrates unsuitable for use in vegetarian products and thus creates the need for a growth medium free from animal-derived ingredients. This study investigated the growth of two strains of Lactobacillus acidophilus (MJLA1 and La-5), L. paracasei ssp. paracasei (LCSH1 and 01) and Bifidobacterium lactis (BDBB2 and Bb-12) in five media. Growth parameters such as maximum cell concentrations, lag phase and growth rate, were calculated using the growth curves generated by DModel, Institute of Food Research, U.K. Results showed that several media were suitable, with results comparable or better than the commonly used laboratory media MRS and RCM. Media containing 25 g/L soy peptone, yeast extract and glucose monohydrate gave the most desirable results with the strains examined.     

婴儿配方食品调和油微胶囊化的研究

依据母乳脂肪中主要脂肪酸含量,通过气相色谱和建立多元方程来调配调和油,并用喷雾干燥法对调和油微胶囊化进行研究,探索了工艺条件,找出了最佳工艺参数。     

玉米黄色素的微胶囊化和稳定性研究

以超临界CO2流体萃取的玉米黄色素为芯材,辛烯基琥珀酸淀粉酯和β-环糊精为壁材,通过乳化、均质、喷雾干燥等工艺,制备了微胶囊玉米黄色素,并对产品的稳定性进行研究.结果表明,玉米黄色素微胶囊化最佳工艺条件为:辛烯基琥珀酸淀粉酯和β-环糊精比值为1:1、固形物含量为20%、芯壁比为1:10,产品包埋率达88.6%.玉米黄色素对光、热、pH和金属离子的稳定性明显增强.     

微胶囊技术在益生菌CICC 6075冰淇淋中的应用

为探究微胶囊技术在冰淇淋生产中的可行性,本研究以乳蛋白为壁材,应用乳化法制备嗜酸乳杆菌CICC 6075微胶囊。以未加菌的冰淇淋(冰淇淋A组)为空白对照,探讨了微胶囊(冰淇淋C组)及裸菌(冰淇淋B组)的添加对冰淇淋理化性质、感官性状等指标的影响。结果表明,添加CICC 6075裸菌及微胶囊均未对冰淇淋的性质产生明显影响。但在冰淇淋的加工及贮藏过程中,微胶囊由于致密的结构可对菌体提供良好的保护,因而明显提高了CICC 6075的活菌数。搅拌凝冻使冰淇淋B中的CICC 6075活菌数下降(1.20±0.08)lg CFU/g,而冰淇淋C中仅下降(0.09±0.07)lg CFU/g;在-18 ℃的条件下贮藏150 d,冰淇淋B中的活菌数降至(5.54±0.03)lg CFU/g,低于益生菌发挥健康功效的最低阈值;而冰淇淋C中仅下降了(0.60±0.08)lg CFU/g,最终活菌数高达(8.09±0.03)lg CFU/g。此外,在消化特性检验中发现,150 d的低温贮藏,使冰淇淋B中CICC 6075的耐胃酸性和对小肠上皮细胞的粘附性均明显下降(6.16%±0.04%,16.76%±0.05%),明显高于冰淇淋C的下降率(1.92%±0.07%,4.47%±0.09%)。综上,微胶囊技术可以明显提升益生菌对不良环境(如低温、胃液)的抗性,因而可以在保证冰淇淋良好品质特性的同时,提升其功能活性,具有一定的应用前景。

     

Microencapsulation of Oils: A Comprehensive Review of Benefits,Techniques, and Applications

Microencapsulation is a process of building a functional barrier between the core and wall material to avoid chemical and physical reactions and to maintain the biological, functional, and physicochemical properties of core materials. Microencapsulation of marine, vegetable, and essential oils has been conducted and commercialized by employing different methods including emulsification, spray‐drying, coaxial electrospray system, freeze‐drying, coacervation, in situ polymerization, melt‐extrusion, supercritical fluid technology, and fluidized‐bed‐coating. Spray‐drying and coacervation are the most commonly used techniques for the microencapsulation of oils. The choice of an appropriate microencapsulation technique and wall material depends upon the end use of the product and the processing conditions involved. Microencapsulation has the ability to enhance the oxidative stability, thermostability, shelf‐life, and biological activity of oils. In addition, it can also be helpful in controlling the volatility and release properties of essential oils. Microencapsulated marine, vegetable, and essential oils have found broad applications in various fields. This review describes the recognized benefits and functional properties of various oils, microencapsulation techniques, and application of encapsulated oils in various food, pharmaceutical, and even textile products. Moreover, this review may provide information to researchers working in the field of food, pharmacy, agronomy, engineering, and nutrition who are interested in microencapsulation of oils.     

游离与微胶囊化益生菌对酸奶感官性质的影响

对游离益生菌与微胶囊化益生菌（嗜酸乳杆菌和双歧杆菌）的存活率、pH、胞外多糖的产生进行了比较,且对添加这两种形式的益生菌酸奶,在贮存7周后的感官性质进行了评定。结果表明,微胶囊有助于提高益生菌在酸奶中存活率,且添加游离或包埋益生菌的酸奶在贮存期间,其外观、色泽、风味及酸度并无显著变化,但酸奶的质地（光滑程度）变化显著。     

松子制取松子油及其微胶囊化的研究

通过浸出法制取松子油，并进一步测定其理化性质，用气相色谱法分析松子的油的主要脂肪酸组成，表明其含有高度的不饱和脂肪酸，精炼后的松子油进行微胶囊化。     

百里香精油的微胶囊制备及其缓释性能

以啤酒废酵母为壁材包埋制备百里香精油微胶囊,分别考察精油酵母比、包埋温度、包埋时间对精油微胶囊效果的影响。百里香精油最佳包埋条件为精油酵母比为2:1、包埋温度60℃、包埋时间10h。百里香精油包埋率为86.71%;100℃加热30h,精油微胶囊挥发率仅有15.8%。缓释实验结果表明:微胶囊能够降低油脂氧化和香味释放速度,延长精油的使用寿命。     

Microencapsulation of Squid Oil with Hydrophilic Macromolecules for Oxidative and Thermal Stabilization

The oxidative and thermal stabilities of unencapsulated and encapsulated squid oils were compared by polyene ratio, DSC-FTIR and pressure DSC. Wall material containing gelatin, caseinate and maltodextrin provided optima1 protection against oxidation. Stability was improved when lecithin and Avicel were part of the wall material. The synergistic effects of lecithin with naturally occurring α-tocopherol and the compact structures of microcapsules enhanced stability. Stability of squid oil microcapsules decreased when α-tocopherdl was removed by alumina chromatography. Both DSC-FTIR and pressure DSC were suitable for evaluating oxidative and thermal stability of encapsulated oil products.     

植物源益生乳酸菌的筛选及其特性

为筛选具有益生特性的植物源乳酸菌,以传统发酵蔬菜中分离的1 000 株乳酸菌为出发菌株,进行了耐酸性、耐胆盐能力、抑菌性、体外抗氧化能力、药敏性、溶血性和氨基酸脱羧酶活性等特性研究,并对筛选菌株进行了16S rDNA 鉴定。经pH 3.0 MRS培养得乳酸菌82 株,再经pH 2.5 MRS培养得乳酸菌49 株;49 株菌经0.3%胆盐测试,均具有耐胆盐能力;根据镜检形态结合发酵植物源的不同从中挑选19 株乳酸菌进行药敏性、溶血性、抑菌性、氨基酸脱羧酶活性和1,1-二苯基-2-三硝基苯肼自由基清除实验。结果表明,19 株菌对所选20 种抗生素多数表现敏感,其中4 株菌对20 种抗生素都较敏感;19 株菌对供试致病菌都有不同程度抑制能力且都无溶血性;经氨基酸脱羧酶活性试剂盒结合聚合酶链式反应扩增检测表明,19 株菌无产生物胺的潜在威胁;有5 株菌体外抗氧化能力高于40%。可见19 株菌均具有益生菌的基本特性。经16S rDNA鉴定,7 株为发酵乳杆菌、6 株为植物乳杆菌,嫩江杆菌、戊糖片球菌、利莫西杆菌、戊糖乳杆菌、屎肠球菌、短乳杆菌分别各1 株。