Impact of Milk Protein Type on the Viability and Storage Stability of Microencapsulated Lactobacillus acidophilus NCIMB 701748 Using Spray Drying

Stability and expression of K-ras mimotopes in freeze-dried recombinant Lactococcus lactis NZ3900-fermented milk powder during storage in vacuum packaging

AIMS

This study aims to evaluate the storage stability of the freeze-dried recombinant Lactococcus lactis NZ3900-fermented milk powder expressing K-ras (Kristen rat sarcoma viral oncogene homolog) mimotopes targeting colorectal cancer in vacuum packaging.

METHODS AND RESULTS

The freeze-dried L. lactis-fermented milk powder stored in 4-ply retortable polypropylene (RCPP)-polyamide (PA)-aluminium (AL)-polyethylene terephthalate (PET) and aluminium polyethylene (ALPE) was evaluated throughout 49 days of accelerated storage (38°C and 90% relative humidity). The fermented milk powder stored in 4-ply packaging remained above 6 log10 CFU g-1 viability, displayed lower moisture content (6.1%), higher flowability (43° angle of repose), water solubility (62%), and survivability of L. lactis after simulated gastric and intestinal digestion (>82%) than ALPE packaging after 42 days of accelerated storage. K-ras mimotope expression was detected intracellularly and extracellularly in the freeze-dried L. lactis-fermented milk powder upon storage.

CONCLUSIONS

This suggests that fermented milk powder is a suitable food carrier for this live oral vaccine.

Innovative Insights for Establishing a Synbiotic Relationship with Bacillus coagulans: Viability, Bioactivity, and In Vitro-Simulated Gastrointestinal Digestion

This study investigates the use of encapsulating agents for establishing a synbiotic relationship with Bacillus coagulans (TISTR 1447). Various ratios of wall materials, such as skim milk powder, maltodextrin, and cellulose acetate phthalate (represented as SMC1, SMC3, SMC5, and SMC7), were examined. In all formulations, 5% inulin was included as a prebiotic. The research assessed their impact on cell viability and bioactive properties during both the spray-drying process and in vitro gastrointestinal digestion. The results demonstrate that these encapsulating agents efficiently protect B. coagulans spores during the spray-drying process, resulting in spore viability exceeding 6 log CFU/g. Notably, SMC5 and SMC7 displayed the highest spore viability values. Moreover, SMC5 showcased the most notable antioxidant activity, encompassing DPPH, hydroxy radical, and superoxide radical scavenging, as well as significant antidiabetic effects via the inhibition of α-amylase and α-glucosidase. Furthermore, during the simulated gastrointestinal digestion, both SMC5 and SMC7 exhibited a slight reduction in spore viability over the 6 h simulation. Consequently, SMC5 was identified as the optimal condition for synbiotic production, offering protection to B. coagulans spores during microencapsulation and gastrointestinal digestion while maintaining bioactive properties post-encapsulation. Synbiotic microcapsules containing SMC5 showcased a remarkable positive impact, suggesting its potential as an advanced food delivery system and a functional ingredient for various food products.

Encapsulation of Bifidobacterium animalis subsp. lactis Through Emulsification Coupled with External Gelation for the Development of Synbiotic Systems

Aim of this work was the development of integrated and complex encapsulating systems that will provide more efficient protection to the probiotic strain Bifidobacterium animalis subsp. lactis (BB-12) in comparison to the conventional plain alginate beads. Within the scope of this study, the encapsulation of BB-12 through emulsification followed by external gelation was performed. For this purpose, a variety of alginate-based blends, composed of conventional and novel materials, were used. The results demonstrated that alginate beads incorporating 1% carrageenan or 2% nanocrystalline cellulose provided great protection to the viability of the probiotic bacteria during refrigerated storage (survival rates of 50.3% and 51.1%, respectively), as well as in vitro simulation of the gastrointestinal tract (survival rates of 38.7 and 42.0%, respectively). The incorporation of glycerol into the formulation of the beads improved the protective efficiency of the beads to the BB-12 cells during frozen storage, increasing significantly their viability compared to the plain alginate beads. Beads made of milk, alginate 1%, glucose 5%, and inulin 2% provided the best results in all cases. The microstructure of beads was assessed through SEM analysis and showed absence of free bacteria on the surface of the produced beads. Consequently, the encapsulation of BB-12 through emulsification in a complex encapsulating system was proved successful and effective.

Optimization of spray dried yogurt and its application to prepare functional cookies

Introduction

Spray-dried yogurt powder (SDYP) has shelf stability and other functional properties that improve solubility and facilitate the use, processing, packaging, and transportation of other food derivatives, such as bread and pastries on a large scale. The present research was conducted to develop SDYP and further its utilization to prepare functional cookies.

Methods

Yogurt was spray-dried by employing different outlet air temperatures (OAT) (65°C, 70°C & 75°C) and inlet air temperature (IAT) (150°C, 155°C & 160°C). Spray drying shows that increasing the temperature increases nutritional loss, whereas S. thermophilus culture shows resistance to the intensive heat approaches. On the other hand L. delbrueckii subsp. Bulgaricus culture was found to be significantly affected. A total of 4 treatments, including one control for the functional cookies development.

Results and discussion

A directly proportional relation was investigated between the increasing concentration of SDYP and baking characteristics and cookie's mineral and protein profile. Bioactive parameters like antioxidant activity of 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and total phenolic content (TPC) were also affected significantly. The sensory profile shows an incline towards T0 (0% SDYP) to T3 (10% SDYP) in all attributes but starts to decline when the concentration of SDYP reaches 15%. This study suggests that by employing a certain combination of temperatures (OAT: 60°C IAT: 150°C); maximum survival of inoculated culture can be achieved, and this powder can be utilized in the development of functional cookies with enhanced sensory as well as biochemical characteristics significantly (P< 0.05).

Membrane Emulsification as an Emerging Method for Lacticaseibacillus rhamnosus GG® Encapsulation

Techniques capable of producing small-sized probiotic microcapsules with high encapsulation yields are of industrial and scientific interest. In this study, an innovative membrane emulsification system was investigated in the production of microcapsules containing Lacticaseibacillus rhamnosus GG® (Lr), sodium alginate (ALG), and whey protein (WPI), rice protein (RPC), or pea protein (PPC) as encapsulating agents. The microcapsules were characterized by particle size distribution, optical microscopy, encapsulation yield, morphology, water activity, hygroscopicity, thermal properties, Fourier-transform infrared spectroscopy (FTIR), and probiotic survival during in vitro simulation of gastrointestinal conditions. The innovative encapsulation technique resulted in microcapsules with diameters varying between 18 and 29 μm, and encapsulation yields > 93%. Combining alginate and whey, rice, or pea protein improved encapsulation efficiency and thermal properties. The encapsulation provided resistance to gastrointestinal fluids, resulting in high probiotic viability at the end of the intestinal phase (> 7.18 log CFU g-1). The proposed encapsulation technology represents an attractive alternative to developing probiotic microcapsules for future food applications.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s11947-023-03099-w.

Prevention of Fungal Contamination in Semi-Hard Cheeses by Whey–Gelatin Film Incorporated with Levilactobacillus brevis SJC120

Cheese whey fermented by lactic acid bacteria (LAB) was used to develop an edible film with antifungal properties. Five LAB strains isolated from artisanal cheeses were screened for antifungal activity and incorporated into a whey–gelatin film. Of the strains tested, Levilactobacillus brevis SJC120 showed the strongest activity against five filamentous fungi isolated from cheese and cheese-making environment, at both 10 °C and 20 °C. The cell-free supernatant from L. brevis inhibited fungal growth by more than 80%. Incorporation of bacterial cells into the film did not alter the moisture content, water vapor permeability, or mechanical and optical properties. The whey–gelatin film was also able to maintain the viability of L. brevis cells at 107 log CFU/g after 30 days at 10 °C. In cheeses wrapped with L. brevis film, the size of fungal colonies decreased by 55% to 76%. Furthermore, no significant differences (p > 0.05) were observed in cheese proteolysis or in the moisture, fat, and protein content of the cheese wrapped with films. The results showed that whey–gelatin film with L. brevis SJC120 can reduce the contamination of cheese with filamentous fungi and could be used as an alternative to conventional cheese preservation and packaging.

The Effect of Decreased Ca++/Mg++ ATPase Activity on Lactobacillus delbrueckii subsp. bulgaricus sp1.1 Survival during Spray Drying

Compared with the commonly used technique of freeze-drying, spray drying has lower energy costs. However, spray drying also has a fatal disadvantage: a lower survival rate. In this study, the survival of bacteria in a spray-drying tower decreased as the water content was reduced. The water content of 21.10% was the critical point for spray drying Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus) sp1.1 based on sampling in the tower. Based on the relationship between the moisture content of spray drying and the survival rate, the water content of 21.10% was also the critical point for the change in the survival rate during spray drying. Proteomic analysis was used to investigate the reasons for L. bulgaricus sp1.1 inactivation during and after spray drying. Gene Ontology (GO) enrichment revealed that differentially expressed proteins were mainly associated with the cell membrane and transport. In particular, proteins related to metal ion transport included those involved in the transport of potassium, calcium and magnesium ions. The protein-protein interaction (PPI) network revealed that Ca⁺⁺/Mg⁺⁺ adenosine triphosphatase (ATPase) may be a key protein. Ca⁺⁺/Mg⁺⁺ ATPase activity decreased substantially during spray drying (p < 0.05). Supplementation with Ca⁺⁺ and Mg⁺⁺ significantly increased the expression of ATPase-related genes and enzyme activity (p < 0.05). The Ca⁺⁺/Mg⁺⁺ ATPase activity of L. bulgaricus sp1.1 was enhanced by increasing the intracellular Ca⁺⁺ or Mg⁺⁺ concentration, thus increasing the survival of spray-dried LAB. Bacterial survival rates were increased to 43.06% with the addition of Ca⁺⁺ and to 42.64% with the addition of Mg⁺⁺, respectively. Ca⁺⁺/Mg⁺⁺ ATPase may be the key to the damage observed in spray-dried bacteria. Furthermore, the addition of Ca⁺⁺ or Mg⁺⁺ also reduced bacterial injury during spray drying by enhancing the activity of Ca⁺⁺/Mg⁺⁺ ATPase.

Improvement of functional properties of cow's milk peptides through partial proteins hydrolysis

Allergy by cow's milk proteins is among the major food allergies and could be reduced by the partial hydrolysis of these proteins by proteases, without significantly affecting its physicochemical properties. In addition, the peptides generated through enzymatic hydrolysis of the cow's milk can present prebiotic and bioactive properties. In this work, the cow's milk proteins were submitted to a controlled hydrolysis by Novo-Pro D® and the influence of the degree of hydrolysis (DH) on peptide size distribution was evaluated, as well as the prebiotic and antimicrobial properties of milk hydrolysates. It was shown that for DH-10%, all the peptides have sizes lower than 12 kDa which is the size of the most allergenic proteins, without apparent changes in the milk, as long as heating of the hydrolysate is avoided. The protein hydrolysis promoted a great improvement in the milk functional properties. In addition, the obtained milk peptides presented great prebiotic activities, as indicated by the significant improvement of the growth of prebiotic L. acidophilus and L. reuteri and by the production of bacteriocins indicated by the inhibition halos in the growth of a pathogenic microorganism.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05533-x.

Citrate effect on the swelling behaviour and stability of casein microparticles

Casein microparticles obtained from casein micelles by volume exclusion of added pectin and subsequent film drying remain stable in the acidic and neutral pH range, but swell strongly in the basic range. Calcium significantly impacts on the stability and water-binding behavior of phosphorylated caseins and the aggregates and gels formed from them. For a future effective and controlled use as a carrier for bioactive substances, e.g. via the gastrointestinal tract, we therefore investigated how the addition of the calcium chelating agent citrate affects the swelling and stability of the microparticles. Citrate concentrations of 2 mM and above cause a stronger swelling of the microparticles at pH 8, while above 4 mM the second characteristic swelling step starts earlier and thus can also be investigated within the observation time of 120 min. All swelling kinetics can be simulated using seven parameters of a dynamic model, which reproduces the individual swelling steps via volume inflows and outflows into a reservoir. While the rate coefficient for swelling step 1 increases linearly with citrate concentration, no such dependence could be found for swelling step 2. The more citrate is used, the faster the microparticles decompose in turbidity experiments after the addition of sodium dodecyl sulfate, which can be related to a weakening of the hydrophobic interactions.

Reevaluating a non-conventional procedure to microencapsulate beneficial lactobacilli: assessments on yield and bacterial viability under simulated technological and physiological conditions

BACKGROUND

Maintaining viability of beneficial microorganisms applied to foods still constitutes an industrial challenge. Many microencapsulation methodologies have been studied to protect probiotic microorganisms and ensure their resistance from manufacturing through to consumption. However, in many Latin-American countries such as Argentina there are still no marketed food products containing microencapsulated beneficial bacteria. The objectives of this work were: (i) to obtain microcapsules containing Lactobacillus fermentum L23 and L. rhamnosus L60 in a milk protein matrix; and (ii) to evaluate the viability of microencapsulated lactobacilli exposed to long-term refrigerated storage, mid-high temperatures and simulated gastrointestinal conditions.

RESULTS

The method of emulsification/rennet-catalyzed gelation of milk proteins used in this study led to high encapsulation yields for both strains (98.2-99%). Microencapsulated lactobacilli remained viable for 120 days at 4 °C, while free lactobacilli gradually lost their viability under the same conditions. Microencapsulation increased the resistance of lactobacilli to mid-high temperatures, since they showed survival rates of 95-99.3% at 50 °C, and of 72.5-74.4% at 65 °C. Under simulated gastric conditions, the microencapsulated lactobacilli counts were higher than 8.5 log CFU mL^-1 and showed survival rates between 96.61% and 97.74%. Furthermore, in the presence of bile (0.5-2% w/v) the survival of microencapsulated strains was higher than 96%.

CONCLUSION

The microencapsulation process together with the matrix of milk proteins used in this study protected beneficial Lactobacillus strains against these first simulated technological and physiological conditions. These findings suggest that this microencapsulation method could contribute to secure optimal amounts of living lactobacilli cells able to reach the intestine. © 2021 Society of Chemical Industry.

Production, Processing, and Protection of Microalgal n-3 PUFA-Rich Oil

Microalgae have been increasingly considered as a sustainable “biofactory” with huge potentials to fill up the current and future shortages of food and nutrition. They have become an economically and technologically viable solution to produce a great diversity of high-value bioactive compounds, including n-3 polyunsaturated fatty acids (PUFA). The n-3 PUFA, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), possess an array of biological activities and positively affect a number of diseases, including cardiovascular and neurodegenerative disorders. As such, the global market of n-3 PUFA has been increasing at a fast pace in the past two decades. Nowadays, the supply of n-3 PUFA is facing serious challenges as a result of global warming and maximal/over marine fisheries catches. Although increasing rapidly in recent years, aquaculture as an alternative source of n-3 PUFA appears insufficient to meet the fast increase in consumption and market demand. Therefore, the cultivation of microalgae stands out as a potential solution to meet the shortages of the n-3 PUFA market and provides unique fatty acids for the special groups of the population. This review focuses on the biosynthesis pathways and recombinant engineering approaches that can be used to enhance the production of n-3 PUFA, the impact of environmental conditions in heterotrophic cultivation on n-3 PUFA production, and the technologies that have been applied in the food industry to extract and purify oil in microalgae and protect n-3 PUFA from oxidation.

The Impact of Date Syrup on the Physicochemical, Microbiological, and Sensory Properties, and Antioxidant Activity of Bio-Fermented Camel Milk

Fermented camel milk is rich in nutrients and vitamins necessary for the health of humans and has therapeutic properties. Date palm camel milk has been reported to be beneficial for preventing and treating various diseases in Arab countries. This study targeted the production of probiotic fermented camel milk fortified with date syrup. In addition, the effect of adding date syrup as a prebiotic and flavoring agent to probiotic fermented camel milk on the physicochemical, phytochemical, microbiological, and sensory properties of probiotic fermented camel milk during storage was investigated. Probiotic fermented camel milk without adding date syrup served as a control, and the other two treatments were supplemented with date syrup at ratios of 6.0% and 8.0%. Probiotic fermented camel milk was analyzed after 1 day and 15 days from storage at 5 ± 1 °C. Interestingly, the present study revealed that the addition of date syrup significantly (p ≥ 0.05) increased total solids (TS), ash, Na, K, Fe, acetaldehyde, total phenolic contents, and titratable acidity, viscosity, and antioxidant values of resultant synbiotic fermented camel milk, and this increase was proportional to the level of date syrup fortification. In addition, non-significant changes in these components were observed during the storage period. However, total protein and fat content did not show significant changes. Furthermore, the addition of date syrup significantly increased (p ≥ 0.05) the total bacterial and Bifidobacteria counts, and this increase was associated with the level of the addition of date syrup. The addition of date syrup also significantly (p ≥ 0.05) improved the sensory scores for flavor, consistency, appearance, and total scores of resultant products. Moreover, the addition of date syrup at a level of 8% showed the highest sensory scores. In conclusion, probiotic fermented camel milk could be produced using a probiotic strain and flavored with date syrup at a level of 8%.

Effects of sucrose, carnosine, and their mixture on the glass transition behavior and storage stability of freeze-dried lactic acid bacteria at various water activities

Effects of sucrose, carnosine, and their mixture on the glass transition behavior and storage stability of freeze-dried Lactobacillus reuteri at various water activities (a_w) were investigated. At a_w = 0.328, the control (non-additive sample) showed viable cells as uncountable after storage at 25 °C for 4 weeks. The sucrose and sucrose-carnosine samples showed clear glass transition at a slightly lower temperature than the storage temperature, and maintained a large number of viable cells after storage. The carnosine sample crystalized during the storage, and a large reduction in viable cells was observed. At a_w = 0.576, the samples showed a small endothermic shift due to glass transition, suggesting partial crystallization. The T_g decreased with increases in a_w because of the water plasticizing effect. After storage, the sucrose-carnosine sample showed much higher viable cell numbers than the other samples. At a_w = 0.753, the sucrose and sucrose-carnosine samples showed clear glass transition. The carnosine sample showed freeze-concentrated glass transition and subsequent ice melting. After storage, the sucrose and carnosine samples showed an uncountable and a low number of viable cells, respectively, but sucrose-carnosine maintained relatively high viable cell numbers. In addition, carnosine strongly supported the stabilizing effect of sucrose (even at low additive levels) depending on the a_w. These results suggest that sucrose-carnosine shows a synergistic stabilizing effect.

Efficacy of the incorporation between self-encapsulation and cryoprotectants on improving the freeze-dried survival of probiotic bacteria

AIMS

This study aimed to improve the viability of probiotic bacteria during freeze-drying by the combination of self-encapsulation and cryoprotectants.

METHODS AND RESULTS

Lactiplantibacillus plantarum VAL6 and Lactobacillus acidophilus VAR1 were exposed to environmental stresses including temperature, pH, and increased CO₂ concentration before performing freeze-drying with the addition of cryoprotectants. The results proved that tested stresses can stimulate the bacteria to synthesize more extracellular polymeric substances to form self-encapsulation that increases their freeze-dried viability. In combination with cryoprotectants to form double-layered microencapsulation, L. plantarum VAL6 stressed at pH 3.5 in combination with whey protein isolate could achieve the highest Improving Cell Viability of 4,361 fold, while L. acidophilus VAR1 stressed at 25^o C in combination with alginate gave a maximum Improving Cell Viability of 73.33 fold.

CONCLUSIONS

The combination of self-encapsulation and cryoprotectants significantly improves the freeze-dried viability of probiotics.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first report that uses environmental stress to stimulate EPS synthesis for self-encapsulation formation combined with the addition of cryoprotectants to enhance to the freeze-dried survival of probiotics. This could be a novel approach in improving the viability of probiotic strains for various applications.

Emerging Technologies and Coating Materials for Improved Probiotication in Food Products: a Review

From the past few decades, consumers' demand for probiotic-based functional and healthy food products is rising exponentially. Encapsulation is an emerging field to protect probiotics from unfavorable conditions and to deliver probiotics at the target place while maintaining the controlled release in the colon. Probiotics have been encapsulated for decades using different encapsulation methods to maintain their viability during processing, storage, and digestion and to give health benefits. This review focuses on novel microencapsulation techniques of probiotic bacteria including vacuum drying, microwave drying, spray freeze drying, fluidized bed drying, impinging aerosol technology, hybridization system, ultrasonication with their recent advancement, and characteristics of the commonly used polymers have been briefly discussed. Other than novel techniques, characterization of microcapsules along with their mechanism of release and stability have shown great interest recently in developing novel functional food products with synergetic effects, especially in COVID-19 outbreak. A thorough discussion of novel processing technologies and applications in food products with the incorporation of recent research works is the novelty and highlight of this review paper.

Resistant Starch-Based Edible Coating Composites for Spray-Dried Microencapsulation of Lactobacillus acidophilus, Comparative Assessment of Thermal Protection, In Vitro Digestion and Physicochemical Characteristics

Polysaccharides have excellent potential as food-grade coating materials for microencapsulation in pro- and prebiotics-based functional food industry. In this study, potato, maize, and rice resistant starches composite coatings with D-mannose, maltodextrin, and whey protein concentrate were prepared for the spray-dried microencapsulation of Lactobacillus acidophilus KLDS 1.1003. Assessment of different polysaccharide coatings to enhance the longevity of probiotics at high temperatures of spray-drying process, storage, and targeted delivery in the gastrointestinal tract were the key objectives of the present study. The highest microencapsulation efficiencies were shown by maize (95.80%) and potato (94.30%) resistant starches. Similarly, maize resistant starch (MRS)-based composites provided the highest thermal resistance, with Tg 38.77 ± 1.10–93.13 ± 0.81 °C and showed the least 2.1 log cycles viability loss in simulated GI tract. Viability losses during storage were in the following order: control > RRS > PRS > MRS, and the inactivation rate of the microencapsulated cells followed the first-order kinetics (R2 = 0.9264–0.9918). The resistant starch-based spray-dried microcapsules possessed 27.00 ± 0.03 to 52.28 ± 1.02 µm size range and SEM micrographs showed a unified smooth surface without cracks and ruptures. These findings will expand the potential use of natural food-grade coatings in functional foods and allied industries involving spray-dried products.

Probiotics in the dairy industry-Advances and opportunities

The past two decades have witnessed a global surge in the application of probiotics as functional ingredients in food, animal feed, and pharmaceutical products. Among food industries, the dairy industry is the largest sector where probiotics are employed in a number of dairy products including sour/fermented milk, yogurt, cheese, butter/cream, ice cream, and infant formula. These probiotics are either used as starter culture alone or in combination with traditional starters, or incorporated into dairy products following fermentation, where their presence imparts many functional characteristics to the product (for instance, improved aroma, taste, and textural characteristics), in addition to conferring many health-promoting properties. However, there are still many challenges related to the stability and functionality of probiotics in dairy products. This review highlights the advances, opportunities, and challenges of application of probiotics in dairy industries. Benefits imparted by probiotics to dairy products including their role in physicochemical characteristics and nutritional properties (clinical and functional perspective) are also discussed. We transcend the traditional concept of the application of probiotics in dairy products and discuss paraprobiotics and postbiotics as a newly emerged concept in the field of probiotics in a particular relation to the dairy industry. Some potential applications of paraprobiotics and postbiotics in dairy products as functional ingredients for the development of functional dairy products with health-promoting properties are briefly elucidated.

Physicochemical design rules for the formulation of novel salt particles with optimised saltiness

Novel sodium reduction strategies are urgently required by the food industry. We hypothesised that redesigning salt crystals (size, density, hydrophobicity and flow properties) will offer a new route to increase saltiness and therefore reduce sodium. Eight salts were compared with different physicochemical properties, the resultant particles were characterised and adhesion to product, loss in-pack, rate of dissolution and ultimately saltiness perception were evaluated. Principle findings included that particle adhesion was driven by particle size (r = -0.85, p = 0.008), bulk density (r = -0.80, p = 0.017) and flow properties (r = 0.77, p = 0.015); loss in-pack was associated with particle size and hydrophobicity of the salt particle while dissolution and/or saltiness perception was also driven by particle size and hydrophobicity of the salt particle. The findings offer a new set of design rules for future ingredient design for the food and flavour industries.

Exploring the interactions between Lactobacillus rhamnosus GG and whey protein isolate for preservation of the viability of bacteria through spray drying

Protective agents used in spray drying protect the activity of lactic acid bacteria (LAB) by stabilizing the subcellular structures, constituting a protective layer at the cellular surface, or having mild drying kinetics. The effects of a reputed protectant, whey protein isolate (WPI), on Lactobacillus rhamnosus GG (LGG) were examined by exposing the cells to WPI solution to induce protein adsorption at the cellular surface prior to spray drying. WPI-treated LGG demonstrated enhanced thermotolerance with cell survival increased by 1.64 log after heat treatment. The survival after spray drying was significantly decreased from 45.75% to 8.6% and from 32.96% to 10.44%, when the WPI-treated cells were resuspended in trehalose solution or reconstituted skimmed milk as protectant, respectively, associated with decreased growth capability and metabolic activity. The contact with WPI appeared to stimulate the cellular response of LGG. With well-maintained cell viability and intact cellular membrane, the metabolic activity of WPI-treated LGG was decreased, and subsequent resuspension of the cells in trehalose solution led to a reduction in the stability of the cellular surface charge. The WPI-treated cells showed marginally increased surface roughness, indicating possible WPI attachment, but there was no thick protein coverage at the cellular surface and the size distribution of cells was unaffected. It was proposed that the enhanced thermotolerance and the decreased survival of spray-dried LGG could be linked to the cellular response toward WPI and protectant media, which may vary among individual LAB strains. Modulating the strain-specific interactions between the LAB cells and the protectant constituents could be crucial to maximizing cell viability retention after spray drying.

Microencapsulation of probiotic lactobacilli with shellac as moisture barrier and to allow controlled release

BACKGROUND

Rapid dissolution in digestive tract and moisture sorption during ambient storage are the two challenges of dry probiotic preparations. To solve these problems, microcapsules with shellac (LAC) addition containing Limosilactobacillus reuteri TMW 1.656 were designed in this work to provide a good moisture barrier and to provide controlled release in digestive tract, based on the hydrophobicity and acid-resistance of LAC. Four microcapsules were prepared using the method of emulsification/external gelation based on the crosslinking reaction between alginate or LAC with calcium ion, including alginate/sucrose (ALG), alginate/shellac/sucrose (ALG/LAC), alginate/whey protein isolate/sucrose (ALG/WPI) and alginate/whey protein isolate/shellac/sucrose (ALG/WPI/LAC).

RESULTS

Measurements of physical properties showed that microcapsules with LAC addition (ALG/WPI/LAC and ALG/LAC) had larger particle size, much denser structure, lower hygroscopicity and slower solubilization in water, which agreed with the primary microcapsule design. Probiotic survivals in digestive juices followed the order of ALG/WPI/LAC ≥ ALG/WPI ≥ ALG/LAC > ALG. Probiotic stability after heating and ambient storage both exhibited the order of ALG/WPI/LAC > ALG/LAC ≈ ALG/WPI > ALG, which can be explained by the decreased hygroscopicity with adding LAC.

CONCLUSION

LAC addition contributed to better probiotic survivals after freeze drying, simulated digestion, heating and ambient storage, and whey protein isolate (WPI) addition had a synergistic effect. Microcapsule hygroscopicity was closely related with probiotic survivals after heating and ambient storage, while microcapsule solubilization was closely related with probiotic survivals in simulated juices. Within our knowledge, this is the first report to improve probiotic stability during ambient storage based on LAC hydrophobicity. © 2020 Society of Chemical Industry.

Functionalizing and bio-preserving processed food products via probiotic and synbiotic edible films and coatings

Edible films and coatings constitute an appealing concept of innovative, cost-effective, sustainable and eco-friendly packaging solution for food industry applications. Edible packaging needs to comply with several technological pre-requisites such as mechanical durability, low permeability to water vapor and gases, good optical properties, low susceptibility to chemical or microbiological alterations and neutral sensory profile. Over the past few years, functionalization of edible films and coatings via the inclusion of bioactive compounds (antioxidants, micronutrients, antimicrobials, natural coloring and pigmentation agents) and beneficial living microorganisms has received much attention. As for living microorganisms, probiotic bacterial cells, primarily belonging to the Lactobacilli or Bifidobacteria genera, have been exploited to impart bespoke health and biopreservation benefits to processed food. Given that the health benefit conferring and biopreservation potential of probiotics is dependent on several extrinsic and intrinsic parameters, the development of probiotic and synbiotic edible packaging concepts is a quite challenging task. In the present chapter, we aimed at a timely overview of the technological advances in the field of probiotic, symbiotic and synbiotic edible films and coatings. The individual or combined effects of intrinsic (matrix composition and physical state, pH, dissolved oxygen, water activity, presence of growth stimulants or inhibitors) and extrinsic (film forming method, food processing, storage time and conditions, exposure to gastrointestinal conditions) factors on maintaining the biological activity of probiotic cells were addressed. Moreover, the impact of living cells inclusion on the mechanical, physicochemical and barrier properties of the edible packaging material as well as on the shelf-life and quality of the coated or wrapped food products, were duly discussed.

Technological variables influencing the growth and stability of a silage inoculant based on spray-dried lactic acid bacteria

AIMS

To investigate the influence of different culture media and fermentation conditions on growth performance and viability of three lactic acid bacteria (LAB) strains with potential as silage inoculants, and to optimize spray-drying in order to enhance survival to dehydration and storage stability.

METHODS AND RESULTS

In house-formulated MRS was a suitable low-cost culture medium for Lactobacillus plantarum Hv75, Pediococcus acidilactici 3903 and L. buchneri B463. Uncontrolled pH biomass production conferred enhanced stability during storage at 4°C after spray-drying. The use of whey protein concentrate 35 (WPC)-maltodextrin (M) as matrix, inlet temperature of 145-150°C and air flow rate of 601 l h^-1 was adequate for the production of dehydrated LAB. According to the desirability function, at this optimized condition, moisture content, yield and solubility were predicted to be 3·96, 73·68 and 90·36% respectively. Those conditions also showed a decrease of 0·855 log CFU per gram after drying, no loss in viability at 4°C for 6 months and 1 log CFU per gram reduction at 25°C.

CONCLUSIONS

Stable and economically feasible dehydrated LAB cultures were obtained using alternative culture media, fermentation under uncontrolled pH and optimizing spray-drying process conditions through the desirability function method.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our results can be utilized for efficient production and commercialization of several dry LAB.

Development of Chitosan/Mannitol Microparticles as Delivery System for the Oral Administration of a Spirulina Bioactive Peptide Extract

Spirulina platensis contains several compounds showing nutritional and therapeutic benefits. Recently, a series of peptides able to reduce the blood pressure level and to enhance the endothelial vasorelaxation was isolated from the hydrolyzed highly water-soluble Spirulina extract (HSE). However, HSE shows critical organoleptic characteristics also having poor intestinal permeability, limiting absorption when orally delivered. This research aims to overcome the critical issues through the encapsulation of HSE in Chitosan/Mannitol—(CM)-based microparticles by spray drying. The produced powders (CM-HSE) showed good process yield (≈70%) and encapsulation efficiency (≈100%) also having good derived flow properties as well as stability up to six months storage. The microparticles constituting the spray-dried powder resulted in an amorphous micrometric state (d₅₀ ≈ 14 µm) able to retain dark colour and unpleasant smell of raw HSE. Moreover, the in vitro permeation study by Franz cell indicated that the engineered microparticles are able to enhance the permeation of HSE through an intestinal biomimetic barrier (551.13 μg/cm² CM-HSE vs. 315.46 μg/cm² HSE at 270 min).

The Effect of the Ultra-High-Pressure Homogenization of Protein Encapsulants on the Survivability of Probiotic Cultures after Spray Drying

Interest in probiotic foods and ingredients is increasing as consumers become more aware of their potential health benefits. The production of these products often involves the use of dry culture powders, and the techniques used to produce such powders often suffer from significant losses of viable cells during drying or require the use of expensive drying technologies with limited throughput (e.g., freeze drying). In this study, the authors examined whether culture survivability during spray drying could be increased via the treatment of two common protein encapsulants with ultra-high-pressure homogenization (UHPH). Lactobacillus plantarum NRRL B-1927 (also known as ATCC 10241), a probiotic strain, was suspended in either soy protein isolate (SPI) or whey protein isolate (WPI) which had been either treated with UHPH at 150 Mpa or left untreated as a control. The suspensions were then dried using either concurrent-flow spray drying (CCSD), mixed-flow spray drying (MFSD) or freeze drying (FD) and evaluated for cell survivability, particle size, moisture content and water activity. In all cases, UHPH resulted in equal or greater survivability among spray dried cultures, showed reductions in particle size measures and, except for one marginal case (CCFD SPI), significantly reduced the moisture content of the dried powders. The combination of these findings strongly suggests that UHPH could allow probiotic powder manufacturers to replace freeze drying with spray drying while maintaining or increasing product quality.

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.

Microencapsulation of cocoa liquor nanoemulsion with whey protein using spray drying to protection of volatile compounds and antioxidant capacity

The aim of this study was microencapsulated a nanoemulsion of cocoa liquor with whey protein by spray drying, and evaluate the effect of different inlet drying temperatures on the properties of microcapsules. The nanoemulsion showed a particle size of 202.13 nm, PdI of 0.424, and ζ-potential of -25.20 mV. The inlet drying temperature showed differences in physicochemical properties of microcapsules. Microcapsules presented good thermal stability and protection against the melting of cocoa liquor. Microcapsules obtained showed excellent yields of polyphenolic compounds (78-93%), and high retention of volatile compounds, especially of pyrazines. Greater microencapsulation yield of bioactive compounds and retention of volatile compounds was obtained at higher drying temperature (180 °C). Excellent stability of polyphenols content, antioxidant capacity, and volatile compounds of cocoa liquor were observed during storage of the microcapsules at different temperature conditions, indicating the feasibility of this powder for its incorporation into functional foods.