Microencapsulation of Lactobacillus plantarum ATCC 8014 through spray drying and using dairy whey as wall materials

Water-soluble microencapsulation using gum Arabic and skim milk enhances viability and efficacy of Pediococcus acidilactici probiotic strains for application in broiler chickens

OBJECTIVE

This study aimed to develop and evaluate the effectiveness of a water-soluble microencapsulation method for probiotic strains using gum Arabic (GA) and skim milk (SKM) over a three-month storage period following processing.

METHODS

Four strains of Pediococcus acidilactici (BYF26, BYF20, BF9, and BF14) that were typical lactic acid bacteria (LAB) isolated from the chicken gut were mixed with different ratios of GA and SKM as coating agents before spray drying at an inlet temperature 140°C. After processing, the survivability and probiotic qualities of the strains were assessed from two weeks to three months of storage at varied temperatures, and de-encapsulation was performed to confirm the soluble properties. Finally, the antibacterial activity of the probiotics was assessed under simulated gastrointestinal conditions.

RESULTS

As shown by scanning electron microscopy, spray-drying produced a spherical, white-yellow powder. The encapsulation efficacy (percent) was greatest for a coating containing a combination of 30% gum Arabic: 30% skim milk (w/v) (GA:SKM30) compared to lower concentrations of the two ingredients (p<0.05). Coating with GA:SKM30 (w/v) significantly enhanced (p<0.05) BYF26 survival under simulated gastrointestinal conditions (pH 2.5 to 3) and maintained higher survival rates compared to non-encapsulated cells under an artificial intestinal juices condition of pH 6. De-encapsulation tests indicated that the encapsulated powder dissolved in water while keeping viable cell counts within the effective range of 106 for 6 hours. In addition, following three months storage at 4°C, microencapsulation of BYF26 in GA:SKM30 maintained both the number of viable cells (p<0.05) and the preparation's antibacterial efficacy against pathogenic bacteria, specifically strains of Salmonella.

CONCLUSION

Our prototype water-soluble probiotic microencapsulation GA:SKM30 effectively maintains LAB characteristics and survival rates, demonstrating its potential for use in preserving probiotic strains that can be used in chickens and potentially in other livestock.

Selenized lactic acid bacteria microencapsulated by spray drying: A promising strategy for beef cattle feed supplementation

This study aimed to assess the technical feasibility of incorporating selenized Lactobacillus spp. microencapsulated via spray drying into cattle feed. Gum Arabic and maltodextrin were used as encapsulating agents. The encapsulation process was carried out with a drying air flow rate of 1.75 m3/min, inlet air temperature of 90°C, and outlet air temperature of 75°C. The viability of the encapsulated microorganisms and the technological characteristics of the obtained microparticles were evaluated. Microorganisms were incorporated into beef cattle feed to supplement their diet with up to 0.3 mg of Se per kilogram of feed. The encapsulated particles, consisting of a 50/50 ratio of gum Arabic/maltodextrin at a 1:20 proportion of selenized biomass to encapsulant mixture, exhibited superior technical viability for application in beef cattle feed. Supplemented feeds displayed suitable moisture, water activity, and hygroscopicity values, ensuring the preservation of viable microorganisms for up to 5 months of storage, with an approximate count of 4.5 log CFU/g. Therefore, supplementing beef cattle feed with selenized and microencapsulated lactic acid bacteria represents a viable technological alternative, contributing to increased animal protein productivity through proper nutrition.

Viability of Free and Alginate-Carrageenan Gum Coated Lactobacillus acidophilus and Lacticaseibacillus casei in Functional Cottage Cheese

The survivability of encapsulated and nonencapsulated probiotics consisting of Lactobacillus acidophilus and Lacticaseibacillus casei and the nutritional, physicochemical, and sensorial features of cottage cheese were investigated under refrigeration storage at 4 °C for 28 days. Microbeads of L. acidophilus and L. casei were developed using 2% sodium alginate, 1.5% sodium alginate and 0.5% carrageenan, and 1% sodium alginate and 1% carrageenan using an encapsulation technique to assess the probiotic viability in cottage cheese under different gastrointestinal conditions (SGF (simulated gastric juice), SIF (simulated intestinal fluid)), and bile salt) and storage conditions. Scanning electron microscopy (SEM) elucidated the stable structure of microbeads, Fourier transform infrared spectroscopy (FTIR) confirmed the presence probiotics in the microcapsules, and X-ray diffraction (XRD) demonstrated the amorphous state of microbeads. Furthermore, the highest encapsulation efficiency was observed for alginate 1% and carrageenan 1% microbeads (T3), i.e., 95%. Likewise, viability was recorded in T3 against SGF, SIF, and bile salt solution, i.e., 8.5, 8.8, and 8.9 log CFU/g at 80 min of exposure, compared to the control. The results of pH showed a significant (p < 0.05) decline that ultimately increased the titratable acidity. Nutritional analysis of cottage cheese revealed the highest levels of ash, protein, and total solids in T3, exhibiting mean values of 3.2, 22, and 43.2 g/100 g, respectively, after 28 days of storage. The sensory evaluation of cottage cheese demonstrated better color, flavor, and textural attributes in T3. Conclusively, synergistic addition of L. acidophilus and L. casei encapsulated with alginate-carrageenan gums was found to be more effective in improving the viability of probiotics in cottage cheese than noncapsulated cells while carrying better magnitudes of ash and protein, lower acidity, and pleasant taste.

Development of a microencapsulated probiotic delivery system with whey, xanthan, and pectin

Pediococcus pentosaceus is a lactic acid bacterium that has probiotic potential proven by studies. However, its viability can be affected by adverse conditions such as storage, heat stress, and even gastrointestinal passage. Thus, the aim of the present study was to microencapsulate and characterize microcapsules obtained by spray drying and produced only with whey powder (W) or whey powder combined with pectin (WP) or xanthan (WX) in the protection of P. pentosaceus P107. In the storage test at temperatures of - 20 °C and 4 °C, the most viable microcapsule was WP (whey powder and pectin), although WX (whey powder and xanthan) presented better stability at 25 °C. In addition, WX did not show stability to ensure probiotic potential (< 6 Log CFU mL-1) for 110 days and the microcapsule W (whey powder) maintained probiotic viability at the three temperatures (- 20 °C, 4 °C, and 25 °C) for 180 days. In the exposition to simulated gastrointestinal juice, the WX microcapsule showed the best results in all tested conditions, presenting high cellular viability. For the thermal resistance test, WP microcapsule was shown to be efficient in the protection of P. pentosaceus P107 cells. The Fourier transform infrared spectroscopy (FTIR) results showed that there was no chemical interaction between microcapsules of whey powder combined with xanthan or pectin. The three microcapsules produced were able to protect the cell viability of the microorganism, as well as the drying parameters were adequate for the microcapsules produced in this study.

Microencapsulation and Application of Probiotic Bacteria Lactiplantibacillus plantarum 299v Strain

Microencapsulation is an up-and-coming technology for maintaining the viability of probiotics. However, the effect of core-to-wall ratios and ratios of polysaccharides on the protection of the Lactiplantibacillus plantarum 299v strain has not been deeply discussed. Lyophilization of the Lp. plantarum 299v strain was conducted, and different core-to-wall ratios and ratios of maltodextrin (MD) and resistant starch (RS) were applied. Results demonstrated that the content of MD and RS had an influence on the yield and bulk density in both core-to-wall ratios (1:1 and 1:1.5). In addition, samples coated with a core-to-wall ratio of 1:1.5 had significantly higher viability than those coated with a core-to-wall ratio of 1:1. Moreover, samples coated with core-to-wall ratios of 1:1 and MD:RS 1:1, as well as core-to-wall ratios of 1:1.5 and MD:RS 3:1, had the highest cell number after simulated gastric fluid and simulated intestinal fluid testing, respectively. Furthermore, the optimal formulation for the application of microencapsulated Lp. plantarum 299v in apple juice (serving as a functional beverage) is listed as follows: core-to-wall ratios of 1:1 and MD:RS 1:1, with the fortification method, and stored at 4 °C. After 11 weeks of storage, the cell count was 8.28 log (CFU/mL). This study provided a strategy for Lp. plantarum 299v to achieve high viability in long-term storage and provides an application in functional apple beverages.

Microencapsulation of Yarrowia lipolytica: cell viability and application in vitro ruminant diets

Microencapsulation is an alternative to increase the survival capacity of microorganisms, including Yarrowia lipolytica, a widely studied yeast that produces high-value metabolites, such as lipids, aromatic compounds, biomass, lipases, and organic acids. Thus, the present study sought to investigate the effectiveness of different wall materials and the influence of the addition of salts on the microencapsulation of Y. lipolytica, evaluating yield, relationship with cell stability, ability to survive during storage, and in vitro application of ruminant diets. The spray drying process was performed via atomization, testing 11 different compositions using maltodextrin (MD), modified starch (MS) and whey protein concentrate (WPC), Y. lipolytica (Y. lipo) cells, tripolyphosphate (TPP), and sodium erythorbate (SE). The data show a reduction in the water activity value in all treatments. The highest encapsulation yield was found in treatments using MD + TPP + Y. lipo (84.0%) and WPC + TPP + Y. lipo (81.6%). Microencapsulated particles showed a survival rate ranging from 71.61 to 99.83% after 24 h. The treatments WPC + Y. lipo, WPC + SE + Y. lipo, WPC + TPP + Y. lipo, and MD + SE + Y. lipo remained stable for up to 105 days under storage conditions. The treatment WPC + SE + Y. lipo (microencapsulated yeast) was applied in the diet of ruminants due to the greater stability of cell survival. The comparison between the WPC + SE + Y. lipo treatment, wall materials, and the non-microencapsulated yeast showed that the microencapsulated yeast obtained a higher soluble fraction, degradability potential, and release of nutrients.

Stability and Survivability of Alginate Gum-Coated Lactobacillus rhamnosus GG in Simulated Gastrointestinal Conditions and Probiotic Juice Development

Survivability of probiotics is severely affected by harsh gastrointestinal conditions. In the present study, microbeads of Lactobacillus rhamnosus GG were formulated using alginate (1.5% w/v) and combination of alginate (1.5% w/v) with xanthan gum (0.5% w/v) through an emulsion technique to improve bacterial viability in low pH orange juice and in gastrointestinal conditions. The microbeads were tested for encapsulation efficiency, survivability in bile salt, SGF (simulated gastric juice), SIF (simulated intestinal fluid), and storage stability. Probiotic orange juice was formulated and tested for physicochemical parameters (pH, titratable acidity, and total sugars) and sensorial properties during storage. Gum-coated alginate microbeads (T3) showed higher encapsulation efficiency, i.e., 95.2% compared to alginate microbeads (T2), i.e., 86.85%. Similarly, T3 showed the highest resistance against bile salt (8.50 log CFU/g), SGF (7.95 log CFU/g), and SIF (8.0 log CFU/g) during 80 min exposure compared to T2 and free cells. The viability of gum-coated alginate beads (T3) remained above 107 CFU/g in gastrointestinal conditions and at the end of 21 days storage (8.3 log CFU/mL). All physicochemical parameters of probiotic juice were significantly ( $p\le 0.05$ ) decreased with respect to storage except acidity. In addition, minimal changes in physicochemical parameters were observed in T3 compared to other treatments. Treatment had no significant impact on the sensory characteristics of juice, but storage had a significant effect ( $p\le 0.05$ ) on the sensory characteristics of juice. The alginate gum microbeads improve the survivability of probiotics for targeted delivery. Hence, encapsulated probiotics can be used for functional beverage development to take advantage of their therapeutic benefits.

Spray Drying Encapsulation of Pediococcus acidilactici at Different Inlet Air Temperatures and Wall Material Ratios

Pediococcus acidilactici has gained research and commercial interest due to its outstanding probiotic properties, yet its survival during storage and consumption requires improvement. This study aims to enhance P. acidilactici survival using spray drying encapsulation. Different inlet air temperatures (120 °C, 150 °C, and 170 °C) and whey protein isolate (WPI):gum arabic (GA) ratios (1:1, 3:1, 1:3) were tested. Cell viability was significantly (p < 0.05) affected by the inlet temperature but not the WPI:GA ratio. Increasing the inlet temperature to 170 °C significantly decreased P. acidilactici viability by 1.36 log cycles, from 8.61 log CFU/g to 7.25 log CFU/g. The inlet temperature of 150 °C resulted in a powder yield (63.12%) higher than at 120 °C (58.97%), as well as significantly (p < 0.05) lower moisture content (5.71%) and water activity (aw 0.21). Viable cell counts in all encapsulated P. acidilactici were maintained at 5.24−6.75 log CFU/g after gastrointestinal tract (GIT) simulation, with WPI:GA of 3:1 and inlet temperature 150 °C having the smallest log reduction (0.3 log cycles). All samples containing different WPI:GA ratios maintained sufficient viability (>7 log CFU/g) during the first three weeks of storage at 25 °C. These results could provide insights for further developing P. acidilactici as commercial probiotic products.

Microencapsulation for Food Applications: A Review

Food products contain various active ingredients, such as flavors, nutrients, unsaturated fatty acids, color, probiotics, etc., that require protection during food processing and storage to preserve their quality and shelf life. This review provides an overview of standard microencapsulation technologies, processes, materials, industrial examples, reasons for market success, a summary of recent applications, and the challenges in the food industry, categorized by active food ingredients: flavors, polyunsaturated fatty acids, probiotics, antioxidants, colors, vitamins, and others. We also provide a comprehensive analysis of the advantages and disadvantages of the most common microencapsulation technologies in the food industry such as spray drying, coacervation, extrusion, and spray cooling. This review ends with future perspectives on microencapsulation for food applications.

Survival of Microencapsulated Lactococcus lactis Subsp. lactis R7 Applied in Different Food Matrices

Survival of Lactococcus lactis subsp. lactis R7, microencapsulated with whey and inulin, was analyzed when added to blueberry juice, milk, and cream. For 28 days, cell viability was evaluated for storage (4 °C), simulated gastrointestinal tract (GIT), and thermal resistance. All matrices demonstrated high cell concentration when submitted to GIT (11.74 and 12 log CFU mL^-1), except for the blueberry juice. The thermal resistance analysis proved the need for microencapsulation, regardless of the food matrix. The results indicate that L. lactis R7 microcapsules have potential for application in different matrices and development of new probiotic products by thermal processing.

Totipotency of Daucus carota L. Somatic Cells Microencapsulated Using Spray Drying Technology

The carrot is considered a model system in plant cell culture. Spray drying represents a widely used technology to preserve microorganisms, such as bacteria and yeasts. In germplasm conservation, the most used methods are freeze drying and cryopreservation. Therefore, the aim of this work was to evaluate the effect of spray drying on the viability and totipotency of somatic carrot cells. Leaf, root and stem explants were evaluated to induce callus with 2 mg/L of 2,4-dichlorophenoxyacetic acid (2,4-D). Calli obtained from the stem were cultivated in a liquid medium with 1 mg/L of 2,4-D. Cell suspensions were spray dried with maltodextrin-gum Arabic and maltodextrin-xanthan gum mixtures, two outlet air temperatures (50 and 60 °C) and 120 °C inlet air temperature. Results showed that carrot cells were viable after spray drying, and this viability remained for six months at 8 °C. The totipotency of the microencapsulated cells was proven. Cells that were not spray dried regenerated 24.6 plantlets, while the spray dried cells regenerated 19 plantlets for each gram of rehydrated powder. Thus, spray drying allowed researchers to obtain viable and totipotent cells. This work is the first manuscript that reported the spray drying of plant somatic cells.

Utilization of diverse protein sources for the development of protein-based nanostructures as bioactive carrier systems: A review of recent research findings (2010-2021)

Consumer awareness of the relationship between health and nutrition has caused a substantial increase in the demand for nutraceuticals and functional foods containing bioactive compounds (BACs) with potential health benefits. However, the direct incorporation of many BACs into commercial food and beverage products is challenging because of their poor matrix compatibility, chemical instability, low bioavailability, or adverse impact on food quality. Advanced encapsulation technologies are therefore being employed to overcome these problems. In this article, we focus on the utilization of plant and animal derived proteins to fabricate micro and nano-particles that can be used for the oral delivery of BACs such as omega-3 oils, vitamins and nutraceuticals. This review comprehensively discusses different methods being implemented for fabrications of protein-based delivery vehicles, types of proteins used, and their compatibility for the purpose. Finally, some of the challenges and limitations of different protein matrices for encapsulation of BACs are deliberated upon. Various approaches have been developed for the fabrication of protein-based microparticles and nanoparticles, including injection-gelation, controlled denaturation, and antisolvent precipitation methods. These methods can be used to construct particle-based delivery systems with different compositions, sizes, surface hydrophobicity, and electrical characteristics, thereby enabling them to be used in a wide range of applications.

Microencapsulation of Lactobacillus rhamnosus ATCC 7469 by spray drying using maltodextrin, whey protein concentrate and trehalose

This study aimed to microencapsulate Lactobacillus rhamnosus (L. rhamnosus) ATCC 7469 with whey protein concentrate (WPC), maltodextrin and trehalose by spray drying and to assess the impact of microencapsulation on cell viability and the properties of the dried powders. Spray-drying conditions, including inlet air temperature, air flow rate and feed pump, were fixed as independent variables, while probiotic survival, moisture content, water activity and effective yield were established as dependent variables. The survival of encapsulated L. rhamnosus by spray drying was optimized with response surface methodology, and the stability of the powder was assessed. The optimum spray-drying conditions were an inlet air temperature, air flow rate and feed pump rate of 169 °C, 33 m³·h^-1 and 16 mL·min^-1, respectively, survival of 70%, air aspiration of 84% and outlet air temperature of 52 °C, achieving an overall desirability of 0.96. The physicochemical and structural characteristics of the produced powder were acceptable for application with regard to residual water content, hygroscopicity, water activity, and particle size. The results indicated that a protein-trehalose-maltodextrin mixture is a good wall material to encapsulate L. rhamnosus, showing important thermal protection during the drying process and increasing survival. However, a decrease in this capacity is observed at an air outlet temperature of approximately 101 °C. The possible effects of the wall materials and the drying conditions on survival are also discussed.

Spray drying encapsulation of bioactive compounds within protein-based carriers; different options and applications

Spray-drying is known as a common and economical technique for the encapsulation of various nutrients and bioactive compounds. However, shear and thermal tensions during atomization and dehydration, as well as physicochemical instability during storage, result in a loss of these compounds. As a solution, bioactives are stabilized into different carriers, among which proteins and peptides are of particular importance due to their functional properties, surface activity, and film/shell formability around particles. Given the importance of stabilization of bioactive compounds during spray drying, this paper focuses on the role of composition and type of carriers, as well as the characteristics and efficiency of various protein-based carriers in the encapsulation and maintaining of physicochemical, structural, and functional properties, along with biological activity of bioactive compounds (e.g., oleoresins, sterols, polyphenols, anthocyanins, carotenoids, probiotics, and peptides), and nutrients (e.g., vitamins, fatty acids and minerals) alone or in combination with other biopolymers.

Spray-drying microencapsulation using whey protein isolate and nano-crystalline starch for enhancing the survivability and stability of Lactobacillus reuteri TF-7

Decrease of survivability and stability is a major problem affecting probiotic functional food. Thus, in this study, Lactobacillus reuteri TF-7 producing bile salt hydrolase was microencapsulated in whey protein isolate (WPI) or whey protein isolate combined with nano-crystalline starch (WPI-NCS) using the spray-drying technique to enhance the survivability and stability of probiotics under various adverse conditions. Spherical microcapsules were generated with this microencapsulation technique. In addition, the survival of L. reuteri TF-7 loaded in WPI-NCS microcapsules was significantly higher than WPI microcapsules and free cells after exposure to heat, pH, and simulated gastrointestinal conditions. During long-term storage at 4, 25, and 35 °C, WPI-NCS microcapsules could retain both survival and biological activity. These findings suggest that microcapsules fabricated from WPI-NCS provide the most robust efficiency for enhancing the survivability and stability of probiotics, in which their great potentials appropriate to develop as the cholesterol-lowering probiotic supplements.

Effective microencapsulation of Enterococcus faecium in biopolymeric matrices using spray drying

The objective of this work was to evaluate the potential of whey protein concentrate (WPC), native agave fructans (NAF), and their mixture (WPC-NAF, 1:1 w/w) as wall materials and evaluate the physicochemical properties and stability of encapsulated Enterococcus faecium during the spray drying, storage, and passage through the simulated gastrointestinal tests. The encapsulated microorganisms with WPC-NAF by spray drying showed greater viability (9.26 log CFU/g) and a higher microencapsulation yield (88.43%). They also had a smaller reduction in the cell count (0.61 log cycles), while the microcapsules produced with NAF had the greatest reduction in viability during the simulated gastrointestinal tests. Similarly, probiotics encapsulated with WPC-NAF revealed a higher survival rate (> 8 log CFU/g) when stored at a water activity of 0.328. The thermal analysis showed that the addition of NAF to the WPC produced a slight shift in the Tg towards temperatures higher than that shown by NAF. Therefore, this study provides evidence that the spray drying process was appropriate to encapsulate the probiotic strain Enterococcus faecium and that the mixture WPC-NAF protected it from adverse drying conditions and improved the viability of Enterococcus faecium during storage and simulated gastrointestinal tests, demonstrating that the combination of NAF and WPC as encapsulating material is adequate in the production of more stable microcapsules with potential application in various foods.Key Points• E. faecium was successfully encapsulated in WPC and NAF.• WPC-NAF offered protection to E. faecium in the gastrointestinal tests and during storage.• Aw around 0.328 positively influenced the viability of the microorganism during storage. Graphical abstract.

Spray drying and storage of probiotic-enriched almond milk: probiotic survival and physicochemical properties

BACKGROUND

The combination of the nutritional profile of almond milk with the benefits of probiotic bacteria is an interesting development to meet the demand for sustainable and health-promoting food. Almond milk inoculated with probiotic Lactobacillus plantarum (ATCC8014) was spray dried and the almond, its milk, and powders were characterized physicochemically. Samples were characterized in terms of bacterial survival before and after atomization. Bacterial viability and total fatty acid changes were studied during 8 months' storage at 4 and 22 °C.

RESULTS

Results showed adequate physicochemical properties and an optimal bacterial survival rate, maintaining almost the same values before and after the spray-drying operation. A decrease was observed in the cell viability for samples stored at 4 °C. However, the cell count was maintained above the minimum level suggested (10⁷ living cells) to allow potential probiotic functionality for 8 months. On the other hand, the count cell of powders stored at 22 °C was below the minimum level required after 6 months. The fatty acids profile was not significantly (P > 0.05) affected by storage time and temperature.

CONCLUSION

A new almond-based-product with probiotics was developed to meet consumer demands. Almond nutrients were recovered from almond milk powder and were found to be a good source of K and high in Mg and in monounsaturated fat. The viability of bacteria was assured during 8 months of storage at 4 °C and up to 6 months for samples stored at 22 °C. © 2020 Society of Chemical Industry.

Encapsulation of Lactobacillus spp. using bovine and buffalo cheese whey and their application in orange juice

The aim of this study was to evaluate and compare the efficiency of bovine (CW) and buffalo cheese whey (BCW) as encapsulating agents for the spray-drying (SD) of endogenous Lactobacillus pentosus ML 82 and the reference strain Lactobacillus plantarum ATCC 8014. Their protective features were also tested for resistance to storage (90 days, 25 °C), simulated gastrointestinal tract (GIT) conditions, and for their application in orange juice. Survival rates after SD were approximately 95% in all samples tested, meaning both CW and BCW performed satisfactorily. After 90 days of storage, both species remained above 7 log Colony Forming Units (CFU)/g. However, CW generally enabled higher bacterial viability throughout this period. CW microcapsule characteristics were also more stable, which is indicated by the fact that BCW had higher moist content. Under GIT conditions, encapsulated lactobacilli had higher survival rates than free cells regardless of encapsulating agent. Even so, results indicate that CW and BCW perform better under gastric conditions than intestinal conditions. Regarding their use in orange juice, coating materials were probably dissolved due to low pH, and both free and encapsulated bacteria had similar survival rates. Overall, CW and BCW are suitable encapsulating agents for lactic acid bacteria, as they provided protection during storage and against harmful GIT conditions.

Co-Microencapsulation of Anthocyanins from Black Currant Extract and Lactic Acid Bacteria in Biopolymeric Matrices

Anthocyanins from black currant extract and lactic acid bacteria were co-microencapsulated using a gastro-intestinal-resistant biocomposite of whey protein isolate, inulin, and chitosan, with an encapsulation efficiency of 95.46% ± 1.30% and 87.38% ± 0.48%, respectively. The applied freeze-drying allowed a dark purple stable powder to be obtained, with a satisfactory content of phytochemicals and 11 log colony forming units (CFU)/g dry weight of powder (DW). Confocal laser microscopy displayed a complex system, with several large formations and smaller aggregates inside, consisting of biologically active compounds, lactic acid bacteria cells, and biopolymers. The powder showed good storage stability, with no significant changes in phytochemicals and viable cells over 3 months. An antioxidant activity of 63.64 ± 0.75 mMol Trolox/g DW and an inhibitory effect on α-amylase and α-glucosidase of 87.10% ± 2.08% and 36.96% ± 3.98%, respectively, highlighted the potential biological activities of the co-microencapsulated powder. Significantly, the in vitro digestibility profile showed remarkable protection in the gastric environment, with controlled release in the intestinal simulated environment. The powder was tested by addition into a complex food matrix (yogurt), and the results showed satisfactory stability of biologically active compounds when stored for 21 d at 4 °C. The obtained results confirm the important role of microencapsulation in ensuring a high degree of protection, thus allowing new approaches in developing food ingredients and nutraceuticals, with enhanced functionalities.

In-vitro GIT Tolerance of Microencapsulated Bifidobacterium bifidum ATCC 35914 Using Polysaccharide-Protein Matrix

Longevity of probiotic is the main concern for getting maximum benefits when added in food product. Bifidobacterium, a probiotic, tends to lose its viability during gastrointestinal track (GIT) transit and storage of food. Their viability can be enhanced through microencapsulation technology. In this study, Bifidobacterium bifidum (B. bifidum) ATCC 35914 was encapsulated by using two experimental plans. In the first plan, chitosan (CH) at 0.6, 0.8, and 1.0% and sodium alginate (SA) at 4, 5, and 6% were used. Based on encapsulation efficiency, 6% sodium alginate and 0.8% chitosan were selected for single coating of the bacteria, and the resulting micro beads were double coated with different concentrations (5, 7.5, and 10%) of whey protein concentrate (WPC) in the second plan. Encapsulation efficiency and GIT tolerance were determined by incubating the micro beads in simulated gastrointestinal juices (SIJ) at variable pH and exposure times, and their release (liberation of bacterial cells) profile was also observed in SIJ. The microencapsulated bacterial cells showed significantly (P < 0.01) higher viability as compared to the unencapsulated (free) cells during GIT assay. The double-coated micro beads SA 6%-WPC 5% and CH 0.8%-WPC 5% were proven to have the higher survival at pH 3.0 after 90 min of incubation time and at pH 7.0 after 3-h exposure in comparison to free cells in simulated conditions of the stomach and intestine, respectively. Moreover, double coating with whey protein concentrate played a significant role in the targeted (10^6-9 CFU/mL) delivery under simulated intestinal conditions.

Development of Whey Protein Concentrate-Pectin-Alginate Based Delivery System to Improve Survival of B. longum BL-05 in Simulated Gastrointestinal Conditions

Bifidobacterium longum BL-05 encapsulated beads were developed by using whey protein concentrate (WPC) and pectin (PE) as encapsulating material through extrusion/ionic gelation technique with the objective to improve survival of probiotics in harsh gastrointestinal conditions. B. longum BL-05 was grown in MRS (de man rogosa and sharpe) broth, centrifuged and mixed with polymeric gel solution. Bead formulations E₄ (2.5% WPC + 1.5% PE) and E₅ (2% PE) showed the highest value for encapsulation efficiency, size, and textural properties (hardness, cohesiveness, springiness) due to increasing PE concentration. The survivability and viability of free and encapsulated B. longum BL-05 was assessed through their resistance to simulated gastric juice (SGJ), tolerance to bile salt, release profile in simulated intestinal fluid (SIF), and storage stability during 28 days at 4 °C. The microencapsulation provided protection to B. longum BL-05 and encapsulated cells were exhibited significant (p < 0.05) resistance to SGJ and SIF as compared to free cells. Bead formulations E₃ (5.0% WPC + 1.0% PE) and E₄ (2.5% WPC + 1.5% PE) exhibited more resistance to SGJ (at pH 2 for 2 h) and at 2% bile salt solution but comparatively slow release as compared to other bead formulations. Free cells lost their viability when stored at 4 °C after 28 days but microencapsulated cells demonstrated promising results during storage and viable cell count was > 10⁷ CFU/g. This study revealed that extrusion using WPC and PE as encapsulating material could be considered as one of the novel technologies for protection and effective delivery of probiotics.

Whey Protein Concentrate, Pullulan, and Trehalose as Thermal Protective Agents for Increasing Viability of Lactobacillus plantarum Starter by Spray Drying

It is necessary to add protective agents for protecting the probiotic viability in the preparation process of probiotics starter. In this study, we used whey protein concentrate (WPC), pullulan, trehalose, and sodium glutamate as the protective agent and optimized the proportion of protective agent and spray-drying parameters to achieve the best protective effect on Lactobacillus plantarum. Moreover, the viable counts of L. plantarum in starter stored at different temperatures (-20°C, 4°C, and 25°C) for 360 days were determined. According to response surface method (RSM), the optimal proportion of protective agent was 24.6 g/L WPC, 18.8 g/L pullulan, 16.7 g/L trehalose and 39.3 g/L sodium glutamate. The optimum spray-drying parameters were the ratio of bacteria to protective agents 3:1 (v: v), the feed flow rate 240 mL/h, and the inlet air temperature 115°C through orthogonal test. Based on the above results, the viable counts of L. plantarum was 12.22±0.27 Log CFU/g and the survival rate arrived at 85.12%. The viable counts of L. plantarum stored at -20°C was more than 1010 CFU/g after 200 days.

The Combined Usage of β-Cyclodextrin and Milk Proteins in Microencapsulation of Bifidobacterium bifidum BB-12

The present study aimed to determine the effects of combined usage of β-cyclodextrin with whey protein isolate and sodium caseinate on the microencapsulation of Bifidobacterium bifidum-BB12 by spray drying.From the results, the highest count of B. bifidum was provided by whey protein isolate as 8.62 log CFU/g. The increasing concentration of β-cyclodextrin considerably increases gastric and intestinal resistance to B. bifidum cells. In the gastric and intestinal test, the highest protection was determined in whey protein isolate substituted with 10% β-cyclodextrin with reduction rates of 0.98 and 3.30%, respectively. Moreover, free cells did not survive in the same gastric conditions. The lowest hygroscopicity was determined in whey protein isolate as 8.57%. It must be noted that increasing β-cyclodextrin concentration in carrier material combination led to an increase in hygroscopicity of microcapsules. In general, substitution with β-cyclodextrin increased the particle size of microparticles, and microcapsules produced with whey protein isolate had a smaller size than that of sodium caseinate.

Effect on Viability of Microencapsulated Lactobacillus rhamnosus with the Whey Protein-pullulan Gels in Simulated Gastrointestinal Conditions and Properties of Gels

Lactobacillus rhamnosus GG (LGG) has low resistance to low pH and bile salt in the gastrointestinal juice. In this study, the gel made from whey protein concentrate (WPC) and pullulan (PUL) was used as the wall material to prepare the microencapsulation for LGG protection. The gelation process was optimized and the properties of gel were also determined. The results showed the optimal gel was made from 10% WPC and 8.0% PUL at pH 7.5, which could get the best protective effect; the viable counts of LGG were 6.61 Log CFU/g after exposure to simulated gastric juice (SGJ) and 9.40 Log CFU/g to simulated intestinal juice (SIJ) for 4 h. Sodium dodecyl sulphite polyacrylamide gel electrophoresis (SDS-PAGE) confirmed that the WPC-PUL gel had low solubility in SGJ, but dissolved well in SIJ, which suggested that the gel can protect LGG under SGJ condition and release probiotics in the SIJ. Moreover, when the gel has highest hardness and water-holding capacity, the viable counts of LGG were not the best, suggesting the relationship between the protection and the properties of the gel was non-linear.

Microencapsulation of an indigenous isolate of Bacillus thuringiensis by spray drying

In this study, microencapsulation by spray drying was performed to protect spores and crystals of an indigenous isolate of Bacillus thuringiensis Se13 from environmental stress. The effects of wall material, inlet temperature, and outlet temperature on microencapsulation of Bt-Se13 were investigated using Taguchi's orthogonal array. The most suitable wall material determined as maltodextrin DE10. The optimum inlet and outlet temperatures of spray drier were determined as 160 °C and 70 °C, respectively. The number of viable spores, mean particle size, wetting time, percentage of suspensibility and moisture content of the product produced under optimum conditions were determined as 8.1 × 10¹¹ cfu g^-1, 13.462 µm, 25.22 s, 77.66% and 7.29%, respectively. As a result of efficiency studies on Spodoptera exigua in the laboratory conditions, the LC₅₀ was determined as 1.6 × 10⁴ cfu mL^-1. Microencapsulated Bt-Se13 based bio-pesticide may be registered for the control of S. exigua and can be tested against other lepidopterans which share the same environment.

Soy extract and maltodextrin as microencapsulating agents for Lactobacillus acidophilus: a model approach

The present study aimed to optimise the microencapsulation of Lactobacillus acidophilus La-05 by spray drying, using soy extract and maltodextrin as encapsulants. Air inlet temperature, maltodextrin/soy extract ratio and feed flow rate were investigated through Central Composite Rotational Design (CCRD). Probiotic viability increased with increasing the proportion of soy extract. Temperature and feed flow rate had a negative effect. Particle diameter ranged from 4.97 to 8.82 μm, water activity from 0.25 to 0.52 and moisture from 2.30 to 7.01 g.100g-1 Particles produced following the optimised conditions (air temperature of 87 °C, maltodextrin/soy extract ratio of 2:3 w.w-1, feed flow rate of 0.54 L.h-1) reached Encapsulation yield (EY) of 83%. Thermogravimetry and FTIR analysis suggested that microcapsules could protect L. acidophilus cells against dehydration and heating. During storage, microencapsulated probiotic had high cell viability (reductions ranged between 0.12 and 1.72 log cycles). Soy extract/maltodextrin presented well-encapsulating properties of Lactobacillus acidophilus La-05.

Suitability of kefir powder production using spray drying

Spray drying was applied for the production of kefir powder. The survival of microorganisms after drying, storage and simulated gastrointestinal (GI) conditions was investigated. Kefir was obtained by fermentation of milk and whey permeate, and was dehydrated directly (traditional kefir) or using different carriers (skim milk, whey permeate and maltodextrin). Low survival (5.5 log and <2 log CFU/g for lactic acid bacteria and yeast respectively) of microorganisms was achieved when kefir was dehydrated without thermoprotectants (carriers). In contrast, survival of the microorganisms was significantly improved in the presence of different carriers. When skim milk (SM) was used as the carrier medium, lactic acid bacteria (LAB) survival was above 9 log CFU/g. In contrast, viability of yeast was dramatically reduced after spray drying in these conditions. When whey permeate was used as the carrier medium, LAB survival was 8 log CFU/g and yeast survival was above 4 log CFU/g. LAB in the kefir powder survived better the simulated GI conditions when spray drying was conducted in SM. LAB in kefir powder sample dehydrated in SM and SM plus maltodextrin remained stable for at least 60 days at 4 °C. Our results demonstrated that spray drying of kefir is a suitable approach to obtain a concentrated kefir-derived product.

Modeling the Combined Effects of Temperature, pH, and Sodium Chloride and Sodium Lactate Concentrations on the Growth Rate of Lactobacillus plantarum ATCC 8014

Nowadays, microorganisms with probiotic or antimicrobial properties are receiving major attention as alternative resources for food preservation. Lactic acid bacteria are able to synthetize compounds with antimicrobial activity against pathogenic and spoilage flora. Among them, Lactobacillus plantarum ATCC 8014 has exhibited this capacity, and further studies reveal that the microorganism is able to produce bacteriocins. An assessment of the growth of L. plantarum ATCC 8014 at different conditions becomes crucial to predict its development in foods. A response surface model of the growth rate of L. plantarum was built in this study as a function of temperature (4, 7, 10, 13, and 16°C), pH (5.5, 6.0, 6.5, 7.0, and 7.5), and sodium chloride (0, 1.5, 3.0, 4.5, and 6.0%) and sodium lactate (0, 1, 2, 3, and 4%) concentrations. All the factors were statistically significant at a confidence level of 90%  (p<0.10). When temperature and pH increased, there was a corresponding increase in the growth rate, while a negative relationship was observed between NaCl and Na-lactate concentrations and the growth parameter. A mathematical validation was carried out with additional conditions, demonstrating an excellent performance of the model. The developed model could be useful for designing foods with L. plantarum ATCC 8014 added as a probiotic.