The Viability of Lactobacillus rhamnosus GG and Lactobacillus acidophilus NCFM Following Double Encapsulation in Alginate and Maltodextrin

Lactobacillus rhamnosus GG (LGG) and Lactobacillus acidophilus NCFM (LNCFM) were encapsulated in alginate microgel particles (microbeads) by a novel dual aerosols method. The encapsulated probiotics in microbead gel matrix were further stabilized in maltodextrin solids by either spray or freeze-drying to form probiotic microcapsule powders. The free cells of probiotics were also sprayed and freeze-dried in maltodextrin only without microgel encapsulation. After rehydration of microgel-encapsulated powder, gel particles regained their shape. There was no difference in the loss of viability between encapsulated and unencapsulated probiotics during spray drying or freeze-drying. For LNCFM, spray-dried bacteria with or without gel encapsulation exhibited less death (3.03 and 3.07 log CFU/g reduction, respectively) than those of freeze-dried bacteria (4.36 and 4.89 log CFU/g reduction, respectively) after 6 months storage at 4 °C. The same trend was also observed in spray-dried LGG without gel encapsulation which showed 5.87 log CFU/g reduction in viability after 6 months at 4 °C; however, freeze-dried LGG without gel encapsulation exhibited a rapid reduction in viability of 5.91 log CFU/g within just 2 months. Gel-encapsulated LGG which was freeze-dried exhibited less death (3.32 log CFU/g reduction) after 6 months at 4 °C. This work shows that spray drying results in improved subsequent probiotic survivability compared to freeze-drying and that alginate gel encapsulation can improve the survivability following freeze-drying in a probiotic-dependent manner.     

Development of an Oriental-style dairy product coagulated by microcapsules containing probiotics and filtrates from fermented rice

The objectives of this study were to microencapsulate both probiotics and culture filtrates by spray drying to maintain enzyme activity and probiotic viability during storage. Thus, probiotics and culture filtrates from lao-chao were microencapsulated by spray drying with various outlet air temperatures, and the milk-clotting activity, survival of probiotics and physical properties of the microcapsules were determined. The end purpose was to create easy-to-use probiotic Kou Woan Loa cultures. In the near future, manufacturing probiotic Kou Woan Loa could be carried out by simply mixing milk with 5% microcapsules and waiting for 1 h for coagulation, which would be time saving and convenient. The present study has shown that microencapsulation of Lactobacillus acidophilus BCRC 14079, Bifidobacterium longum BCRC 14605 and culture filtrates from lao-chao by spray drying could provide a good protection for both milk-clotting enzymes and probiotics. The average of microcapsules size and density was 10 µm and 1.68 g/cm³, respectively. An increase in the microencapsulation efficiency of microcapsules and lower water activity was found when the outlet air temperature was raised. However, the survival of L. acidophilus and B. longum was reduced as the outlet air temperature increased. The numbers of probiotics were maintained above the recommended therapeutic minimum (10⁷ cfu/g) throughout storage.     

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.     

Survival of freeze-dried microcapsules of α-galactosidase producing probiotics in a soy bar matrix

Soy oligosaccharides, mainly α-galactosides, are prevalently present in soy protein products, and can result in unfavorable digestive effects when consumed. The aim of this research was to investigate the efficiency of α-galactoside reduction by probiotic bacterial hydrolysis and if such bacteria could be maintained in a high number in a soy protein product in a microencapsulated and freeze-dried form. The probiotic bacterium, Lactobacillus acidophilus LA-2, when induced by raffinose, exhibited a high level of α-galactosidase activity at 5.0 U/mg. To preserve probiotics with high viability, cells were microencapsulated and freeze-dried. Optimization of microencapsulation presented that a combination of κ-carrageenan and inulin at a proportion of 1.9:0.1 (w:w) as capsule wall materials, significantly retained the viability of the probiotics through freeze-drying (P ≤ 0.05). Scanning electron microscopic images confirmed that the morphology of the microcapsules was well preserved after freeze-drying. Upon incorporation into soy protein bars, the freeze-dried microcapsules of L. acidophilus LA-2 remained in high numbers throughout 14 weeks of storage at 4 °C. Results of this work with the support of other studies on microencapsulation benefits indicate a promising use of freeze-dried α-galactosidase positive microencapsulated probiotics in a soy food.     

Water activity in dry foods containing live probiotic bacteria should be carefully considered: a case study with Lactobacillus rhamnosus GG in flaxseed

This study evaluated the effect of water activity on the long-term storage stability of the probiotic Lactobacillus rhamnosus GG (LGG) in a dry food matrix. Viability of LGG was further studied in a crushed flaxseed matrix - a new possible product matrix to deliver probiotics - as well as in reference matrices as maltodextrin. Three different water activities (a(w)=0.11, 0.22 and 0.43) were used, and preparations were stored at room temperature for up to 14months. The viability of LGG was less dependent on the matrix used, but strongly dependent on the water activity. Viability in flaxseed was lost rapidly with a(w) 0.43: with a(w) 0.22 the reduction was 2.4 log(10) units and with a(w) 0.11 the reduction of viability was only 0.29 log(10) units during the entire storage time. Taken together, regulating water activity to a low value may offer possibilities for extending the shelf life of dry probiotic products.     

Effect of drying methods on the physical properties and microstructures of mango (Philippine ‘Carabao’ var.) powder

Mango powders were obtained at water content below 0.05 kg water/kg dry solids using Refractance Window® (RW) drying, freeze drying (FD), drum drying (DD), and spray drying (SD). The spray-dried powder was produced with the aid of maltodextrin (DE = 10). The chosen drying methods provided wide variations in residence time, from seconds (in SD) to over 30 h (in FD), and in product temperatures, from 20 °C (in FD) to 105 °C (in DD). The colors of RW-dried mango powder and reconstituted mango puree were comparable to the freeze-dried products, but were significantly different from drum-dried (darker), and spray-dried (lighter) counterparts. The bulk densities of drum and RW-dried mango powders were higher than freeze-dried and spray-dried powders. There were no significant differences (P ? 0.05) between RW and freeze-dried powders in terms of solubility and hygroscopicity. The glass transition temperature of RW-, freeze-, drum- and spray-dried mango powders were not significantly different (P ? 0.05). The dried powders exhibited amorphous structures as evidenced by the X-ray diffractograms. The microstructure of RW-dried mango powder was smooth and flaky with uniform thickness. Particles of freeze-dried mango powder were more porous compared to the other three products. Drum-dried material exhibited irregular morphology with sharp edges, while spray-dried mango powder had a spherical shape. The study concludes that RW drying can produce mango powder with quality comparable to that obtained via freeze drying, and better than the drum and spray-dried mango powders.     

乳清分离蛋白纤维和典型抗氧化剂对罗伊氏乳杆菌TMW 1.656在常温贮藏胁迫下存活的影响

为研究新型纳米材料乳清分离蛋白纤维（whey protein isolate fibrils,WPIF）和典型抗氧化剂对益生菌常温贮藏氧胁迫的保护影响,采用乳清分离蛋白（whey protein isolate,WPI）和WPIF为壁材,添加不同质量浓度的典型抗氧化剂表没食子酸儿茶素没食子酸酯（epigallocatechin gallate,EGCG）和谷胱甘肽（glutathione,GSH）,采用喷雾干燥法制备干态菌粉。结果表明,在常温贮藏期间,益生菌的贮藏稳定性按照WPIF≈WPI>WPI+0.5 mg/mL EGCG>WPI+0.5 mg/mL GSH>WPI+5.0 mg/mL EGCG>WPI+5.0 mg/mL GSH的顺序下降。WPIF保护菌体的效果与WPI相差不大,其原因可能是高温使得纤维发生分解和聚集,从而导致没有发挥纤维优越的效果;抗氧化剂EGCG和GSH在抑菌实验和贮藏实验中都显著加速了益生菌的死亡,且具有质量浓度依赖性,这可能与其本身的抗菌活性或氧化产物的细胞毒性有关。     

Microencapsulation of Lactobacillus rhamnosus GG by Transglutaminase Cross‐Linked Soy Protein Isolate to Improve Survival in Simulated Gastrointestinal Conditions and Yoghurt

Microencapsulation is an effective way to improve the survival of probiotics in simulated gastrointestinal (GI) conditions and yoghurt. In this study, microencapsulation of Lactobacillus rhamnosus GG (LGG) was prepared by first cross‐linking of soy protein isolate (SPI) using transglutaminase (TGase), followed by embedding the bacteria in cross‐linked SPI, and then freeze‐drying. The survival of microencapsulated LGG was evaluated in simulated GI conditions and yoghurt. The results showed that a high microencapsulation yield of 67.4% was obtained. The diameter of the microencapsulated LGG was in the range of 52.83 to 275.16 μm. Water activity did not differ between free and microencapsulated LGG after freeze‐drying. The survival of microencapsulated LGG under simulated gastric juice (pH 2.5 and 3.6), intestinal juice (0.3% and 2% bile salt) and storage at 4 °C were significantly higher than that of free cells. The survival of LGG in TGase cross‐linked SPI microcapsules was also improved to 14.5 ± 0.5% during storage in yoghurt. The microencapsulation of probiotics by TGase‐treated SPI can be a suitable alternative to polysaccharide gelation technologies.     

Tracking Amazonian cheese microbial diversity: Development of an original,sustainable, and robust starter by freeze drying/spray drying

Marajó cheese made with raw buffalo milk in the Amazon region of Brazil can be considered a good source of wild lactic acid bacteria strains with unexplored and promising characteristics. The aim of this study was to develop a potential probiotic starter culture for industrial applications using freeze drying and spray drying. A decrease in the survival rates of freeze-dried samples compared with spray-dried samples was noted. The spray-dried cultures remained approximately 10⁹ cfu·g⁻¹, whereas the freeze-dried samples showed 10⁷ cfu·g⁻¹ after 60 d of storage at 4°C. All of the spray-dried samples showed a greater ability to decrease the pH in 10% skim milk over 24 h compared with the freeze-dried samples. The spray-dried samples showed a greater resistance to acidic conditions and to the presence of bile salts. In addition, under heat stress conditions, reduction was under 2 log cycles in all samples. Although the survival rate was similar among the evaluated samples after drying, the technological performance for skim milk showed some differences. This study may direct further investigations into how to preserve lactic acid bacteria probiotics to produce spray-dried starters that have a high number of viable cells that can then be used for industrial applications in a cost-effective way.     

Process engineering parameters and type of n-octenylsuccinate-derivatised starch affect oxidative stability of microencapsulated long chain polyunsaturated fatty acids

Aim of the present study was to investigate the impact of the emulsifying carrier matrix constituent, n-octenylsuccinate-derivatised (OSA)-starch, and process conditions on physical characteristics and oxidative stability of microencapsulated fish oil. Furthermore, the effect of the drying medium, i.e. air or nitrogen, on lipid oxidation during spray-drying and subsequent storage was investigated. Particle characteristics and lipid oxidation of microencapsulated fish oil were both influenced by the type of OSA-starch and the drying conditions. The highest oxidative stability was observed for fish oil microencapsulated in OSA-starch with the lowest average molecular weight and glucose syrup spray-dried at a moderate temperature setting. Particle characteristics of the microcapsules were not attributable for differences in lipid oxidation during storage. In spray-dried carrier matrix particles, the particle size increased with increasing average molecular weight of the OSA-starch and was attributed to an increase in air inclusion. Thus differences in lipid oxidation of the microencapsulated fish oil were attributed to differences in air inclusion as affected by the type of OSA-starch. In terms of spray-drying under inert conditions and in the presence of air, lipid oxidation of microencapsulated fish oil was rather attributed to oxygen availability in the feed emulsion than in the drying gas.     

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。     

Survival of Microencapsulated Probiotic Bacteria after Processing and during Storage: A Review

The use of live probiotic bacteria as food supplement has become popular. Capability of probiotic bacteria to be kept at room temperature becomes necessary for customer's convenience and manufacturer's cost reduction. Hence, production of dried form of probiotic bacteria is important. Two common drying methods commonly used for microencapsulation are freeze drying and spray drying. In spite of their benefits, both methods have adverse effects on cell membrane integrity and protein structures resulting in decrease in bacterial viability. Microencapsulation of probiotic bacteria has been a promising technology to ensure bacterial stability during the drying process and to preserve their viability during storage without significantly losing their functional properties such acid tolerance, bile tolerance, surface hydrophobicity, and enzyme activities. Storage at room temperatures instead of freezing or low temperature storage is preferable for minimizing costs of handling, transportation, and storage. Concepts of water activity and glass transition become important in terms of determination of bacterial survival during the storage. The effectiveness of microencapsulation is also affected by microcapsule materials. Carbohydrate- and protein-based microencapsulants and their combination are discussed in terms of their protecting effect on probiotic bacteria during dehydration, during exposure to harsh gastrointestinal transit and small intestine transit and during storage.     

Probiotication of foods: A focus on microencapsulation tool

BackgroundWith almost thirty years of application in field of probiotics, microencapsulation is becoming an important technology for sustaining cell viability during food production, storage and consumption as well as for the development of new probiotic food carriers. Potentiality of microcapsules in protecting probiotics along human digestive tract seems to be well established. Instead, the inclusion of probiotics into foods, also in microencapsulated form, poses still many challenges for the retention of their viability, being food intrinsic and extrinsic factors crucial for this item.Scope and approachWe collect the relevant literature concerning the use of microencapsulation for the inclusion of probiotics in traditional food vehicles such as milk derivatives and in novel food carriers that were grouped in bakery, meat, fruit and vegetable. Furthermore we intent to highlight within different food categories the main factors that act in challenging probiotics viability and functionality. What we aim is to establish how microencapsulation is effectively promising in the research and development of innovative probiotic foods.Key findings and conclusionsDespite the relevant improvements toward the broadening of probiotic food products and categories, additional efforts have to be attempted. For this purpose, development of easy to use, stable and cheap probiotic microcapsules could be an important key for industrial spreading of microcapsules. Also the monitoring of cell stability along the entire food production including a real storage period as well as the assessment of encapsulated probiotic metabolism are some topics that require additional investigations.     

Survival of Brevibacterium linens (ATCC 9174) after Spray Drying, Freeze Drying, or Freezing

The objectives of this work were to: (1) contrast spray drying, freeze drying and freezing for large-scale preservation of B. linens, (2) determine the thermal resistance curves, and (3) measure the storage stability. When B. linens was freeze-dried and frozen in feed suspensions containing 3% (w/v) cell paste and 25% (w/w) total solids, survival was 100%. During spray drying, lethal thermal injury was the main cause of loss of viability. Accordingly, by extrapolation, 100% viability would be possible at an outlet-air temperature of 57°C. Spray-dried and freeze-dried cells were stable during storage at 4°C in the absence of oxygen and moisture.     

Spray Drying of Lactococcus lactis ssp. lactis C2 and Cellular Injury

Starter cultures were spray-dried at five outlet-air temperatures using four concentrations of cells in the feed solution. Powders made using the lowest outlet-air temperature and the highest cell concentration had the highest viability. Storage at 4°C for 3 mo caused a 34–86% loss of viability. Cellular injury resulted from dehydration, and exposure to high temperatures in the atomizer and during droplet drying. Lactic acid production was similar for frozen, freeze-dried and spray-dried cultures made from a single cell paste. The lag time before lactic acid production was apparently an inherent characteristic of each specific cell paste.     

Bifidobacterium Bb-12 microencapsulated by spray drying with whey: Survival under simulated gastrointestinal conditions,tolerance to NaCl,and viability during storage

Bifidobacterium Bb-12 was microencapsulated by spray drying with whey. This present work investigated the survival of these microcapsules under simulated gastrointestinal conditions, as well as their tolerance to NaCl and their viability during storage. The results showed a small decrease in the viability of microencapsulated Bifidobacterium at low pH. In relation to the exposure of Bifidobacterium to bile, microencapsulation with whey did not protect the probiotic cells; however, the viability of the microcapsules remained >6 log cfu/g, even after 24 h of incubation at the highest bile concentration analyzed. No growth was noted with either the free cells or the microencapsulated cells on MRS-LP with NaCl. The viability of the microcapsules stored at 4 °C remained high and constant for 12 weeks. When the microcapsules were added to a dairy dessert, the probiotic count remained above 7 log cfu/g for 6 weeks. Therefore, whey is a promising encapsulating agent for Bifidobacterium Bb-12.     

低乳糖益生菌乳粉制备研究

本实验以全脂牛奶为原料,探究低乳糖高益生菌乳粉的制备工艺,考察水解温度、pH、时间和乳糖酶添加量对水解率的影响.同时通过海藻酸钠-大豆分离蛋白复配壁材微胶囊包埋益生菌,各自制备完成后分别真空冷冻干燥低乳糖牛乳和益生菌微胶囊,干燥结束将低乳糖乳粉与益生菌微胶囊粉按质量比7:1的比例混合制得低乳糖益生菌乳粉.结果表明,牛乳...     

Role of glassy state on stabilities of freeze-dried probiotics

High viability of dried probiotics is of great importance for immediate recovery of activity in fermented foods and for health-promoting effects of nutraceuticals. The conventional process for the production of dried probiotics is freeze-drying. However, loss of viability occurs during the drying and storage of the dried powder. It is believed that achieving the "glassy state" is necessary for survival, and the glassy state should be retained during freezing, drying, and storage of cells. Insight into the role of glassy state has been largely adopted from studies conducted with proteins and foods. However, studies on the role of glassy state particularly with probiotic cells are on the increase, and both common and explicit findings have been reported. Current understanding of the role of the glassy state on viability of probiotics is not only valuable for the production of fermented foods and nutraceuticals but also for the development of nonfermented functional foods that use the dried powder as an adjunct. Therefore, the aim of this review is to bring together recent findings on the role of glassy state on survival of probiotics during each step of production and storage. The prevailing state of knowledge and recent finding are discussed. The major gaps of knowledge have been identified and the perspective of ongoing and future research is addressed.     

Lactose-free skim milk and prebiotics as carrier agents of Bifidobacterium BB-12 microencapsulation: physicochemical properties,survival during storage and in vitro gastrointestinal condition behaviour

Bifidobacterium BB-12 was microencapsulated by spray drying using lactose-free milk, lactose-free milk and inulin, and lactose-free milk and oligofructose, resulting in powders 1, 2 and 3, respectively. The highest encapsulation yield (88.01%) and the highest bifidobacteria viability during 120 days of storage were noted for spray-dried powder 2. Spray-dried powders 1 and 3 show a higher tendency to yellow colour. After being submitted to in vitro-simulated gastrointestinal conditions, the best probiotic survival rate result was found for spray-dried powder 3 (87.59%). Therefore, spray-dried powders containing prebiotics were the most appropriate combinations for microencapsulation of Bifidobacterium BB-12 and maintenance of cell viability during storage and gastrointestinal system, showing great potential to be used in lactose-free dairy products.     

Enhanced survival of spray-dried microencapsulated Lactobacillus rhamnosus GG in the presence of glucose

The survival of spray dried Lactobacillus rhamnosus GG (LGG) preparations encapsulated in whey protein isolate (WPI)-maltodextrin, WPI-maltodextrin-glucose, WPI-inulin, and WPI-inulin-glucose mixtures during storage at 25 °C (11%, 57% and 70% relative humidity, RH) was examined. The glass transition temperature of each encapsulant formulation was also assessed. RH was most important for maintaining viability over time; the inclusion of glucose improved viability, irrespective of when all formulations were in a glassy or rubbery state. When LGG microcapsule powders were stored at the same RH, the addition of glucose in the encapsulant formulation had a greater influence on survival of LGG during storage than the maintenance of a glassy state. Both the maintenance of a glassy state during storage and the incorporation of glucose in the encapsulant formulation were required for optimal survival of probiotic microcapsule powders prepared from fresh cultures.

Practical significance

The incorporation of glucose into the encapsulant formulation prior to spray drying of protein-carbohydrate based LGG formulations improves the survival of LGG during long term storage.