Effect of refrigerated storage temperature on the viability of probiotic micro-organisms in yogurt

Effect of chitosomes loaded zein on physicochemical, mechanical, microbial, and sensory characteristics of probiotic Kashk during cold storage

Functional foods like probiotics offer health benefits against various diseases, and plant bioactive compounds can enhance their growth. Zein, a protein, shows biological activity upon hydrolysis, and encapsulating it in nanoparticles improves bioavailability. This study examined chitosan-coated nanoliposomes as carriers for hydrolyzed and unhydrolyzed maize zein to fortify kashk. Combining chitosan and hydrolyzed zein in a 1:2 ratio achieves the highest encapsulation efficiency, antioxidant activity, smallest particle size, polydispersity index, and zeta potential. FTIR and XRD analyses confirm hydrolyzed zein's entrapment and crystalline nature post-encapsulation. Optimized nanoliposomes release hydrolyzed zein faster in simulated intestinal fluid than in gastric fluid, indicating high bioavailability and stability. When used to fortify kashk, these nanoliposomes slightly lower acidity but maintain standard pH over 60-day cold storage, improve elastic properties, and enhance probiotic viability. At the same time, sensory attributes remain comparable to the control, highlighting their functional food potential.

Enhanced probiotic viability in innovative double-network emulsion gels: Synergistic effects of the whey protein concentrate-xanthan gum complex and κ-carrageenan

In this study, the whey protein concentrate and xanthan gum complex obtained by specific pH treatment, along with κ-carrageenan (KC), were used to encapsulate Lactobacillus acidophilus JYLA-191 in an emulsion gel system. The effects of crosslinking and KC concentration on the visual characteristics, stability, mechanical properties, and formation mechanism of emulsion gels were investigated. The results of optical imaging, particle size distribution, and rheology exhibited that with the addition of crosslinking agents, denser and more homogeneous emulsion gels were formed, along with a relative decrease in the droplet size and a gradual increase in viscosity. Especially when the concentration of citric acid (CA) was 0.09 wt%, KC was 0.8 wt%, and K+ was present in the system, the double-network emulsion gel was stable at high temperatures and in freezing environments, and the swelling ratio was the lowest (9.41%). Gastrointestinal tract digestive treatments and pasteurization revealed that the probiotics encapsulated in the double-network emulsion gel had a higher survival rate, which was attributed to the synergistic cross-linking of CA and K+ biopolymers to construct the emulsion gels. Overall, this study highlights the potential of emulsion gels to maintain probiotic vitality and provides valuable insights for developing inventive functional foods.

Biomaterials and Encapsulation Techniques for Probiotics: Current Status and Future Prospects in Biomedical Applications

Probiotics have garnered significant attention in recent years due to their potential advantages in diverse biomedical applications, such as acting as antimicrobial agents, aiding in tissue repair, and treating diseases. These live bacteria must exist in appropriate quantities and precise locations to exert beneficial effects. However, their viability and activity can be significantly impacted by the surrounding tissue, posing a challenge to maintain their stability in the target location for an extended duration. To counter this, researchers have formulated various strategies that enhance the activity and stability of probiotics by encapsulating them within biomaterials. This approach enables site-specific release, overcoming technical impediments encountered during the processing and application of probiotics. A range of materials can be utilized for encapsulating probiotics, and several methods can be employed for this encapsulation process. This article reviews the recent advancements in probiotics encapsulated within biomaterials, examining the materials, methods, and effects of encapsulation. It also provides an overview of the hurdles faced by currently available biomaterial-based probiotic capsules and suggests potential future research directions in this field. Despite the progress achieved to date, numerous challenges persist, such as the necessity for developing efficient, reproducible encapsulation methods that maintain the viability and activity of probiotics. Furthermore, there is a need to design more robust and targeted delivery vehicles.

Incorporation of probiotics into 3D printed Pickering emulsion gel stabilized by tea protein/xanthan gum

Different xanthan gum (XG) concentrations on the rheological/texture properties of Pickering emulsion (PE) gel stabilized by tea protein/xanthan gum (TP/XG) were studied to achieve an ink feasible for 3D printing. Afterwards, the effects of 3D printing and digestion process on the viability of probiotics were studied when encapsulated in the PE gel. Results indicated that gel strength, stability, storage modulus (G') and loss modulus (G″) increased as XG concentration increased. Nozzle diameter and printing temperature of 45 and 55℃ had no significant effect on probiotic's viability, but printing temperature of 65℃ reduced viable probiotics from 8.07 to 6.59 log CFU/g. No significant change of probiotics viability in 3D printed samples was observed during 11-day storage at 4℃. PE gel encapsulated probiotic's viability was significantly improved under heat treatment and simulated gastrointestinal environment. This study gives insights on the production of 3D printed foods using PE gel incorporating probiotics.

Exploring the roles of starch for microbial encapsulation through a systematic mapping review

Microorganism encapsulation protects them from stressful conditions and assists in maintaining their viability, being especially beneficial when the carrier material is a renewable and biodegradable biopolymer, such as starch. Here, a systematic mapping was performed to provide a current overview on the use of starch-based systems for microbial encapsulation. Following well-established guidelines, a systematic mapping was conducted and the following could be drawn: 1) there was a significant increase in publications on microbial encapsulation using starch over the past decade, showing interest from the scientific community, 2) ionotropic gelation, emulsification and spray drying are the most commonly used techniques for starch-based microbial encapsulation, and 3) starch play important functions in the encapsulation matrix such as assisting in the survival of the microorganisms. The information gathered in this systematic mapping can be useful to guide researchers and industrial sectors on the development of innovative starch-based systems for microbial encapsulation.

Whey protein isolate- and carrageenan-based edible films as carriers of different probiotic bacteria

The use of polymer blends as carriers for probiotic cells or using multi-strain probiotic culture mixture in film formulations has a high potential to maintain the stability of probiotics throughout storage. In this study, the survival of Lactobacillus acidophilus, Lactobacillus plantarum, and mixed culture (Lactobacillus spp., Lactococcus spp., and Bifidobacterium spp.) in whey protein isolate (W), carrageenan (C), and W/C blend (W to C on a wt/wt basis at 100 to 0, 75 to 25, 50 to 50, and 0 to 100) films were investigated during 30 d of storage at 4 and 25°C. The water vapor, mechanical, optical, and morphological properties of film samples were also determined. A significant decrease in total lactic acid bacteria counts of all strains (5-6 log cfu/g in reduction) for W and C films was observed during storage at 25°C, whereas blended films had 2 to 3 log cfu/g reduction. The mixed culture-incorporated films had higher cell counts during all storage temperatures. The incorporation of probiotic bacteria significantly influenced the water vapor permeability and color values of films while decreasing tensile strength and elongation at break values. This study reveals that a multi-strain mixed culture presented more chance for survival inside the polymer matrix, especially when carbohydrate- and protein-based polymers were blended.

Microencapsulation of Lactiplantibacillus plantarum with inulin and evaluation of survival in simulated gastrointestinal conditions and roselle juice

Abstract This study aimed to evaluate the survivability of Lactiplantibacillus plantarum 299v encapsulated in chitosan-coated calcium alginate beads with inulin as prebiotic in simulated gastrointestinal conditions and roselle juice. The concentration of calcium chloride and inulin for L. plantarum 299v microencapsulation was optimised and the survivability of free and microencapsulated L. plantarum was assessed under simulated gastrointestinal conditions. Storage stability of the optimised encapsulated L. plantarum 299v-inulin was determined throughout four (4) weeks of storage in roselle juice at 4 °C and 25 °C. The optimized formula for L. plantarum 299v was 2.0% (w/v) of calcium chloride and 3.0% (w/v) of inulin. Optimized calcium alginate-chitosan L. plantarum 299v microbeads with inulin did not affect (p > 0.05) the bead diameter, with a mean diameter of 685.27 μm, and microencapsulation efficiency of 95%. Encapsulated L. plantarum 299v with inulin showed higher survivability (>107 CFU/mL) than free cells and encapsulated L. plantarum 299v without inulin under simulated gastrointestinal conditions and after four (4) weeks of storage in roselle juice at 4 °C. The results indicate that co-extrusion encapsulation and addition of inulin had improved the viability of L. plantarum 299v in roselle juice by protecting probiotic against unfavourable gastrointestinal conditions and prolonged storage.

Comparative effects of probiotic and paraprobiotic addition on microbiological, biochemical and physical properties of yogurt

Paraprobiotics are inactivated probiotics that exert various health and technological benefits making them suitable for production of functional yogurt. In the present study, probiotic yogurt containing Lactobacillus acidophilus ATCC SD 5221 and Bifidobacterium lactis BB-12 and paraprobiotic yogurt containing inactivated form of the mentioned bacteria were produced and were compared regarding microbiological, biochemical, and physical properties during 28 days of storage at refrigerated temperature. Results revealed that the greatest mean pH drop rate, mean acidity increase rate, mean redox potential increase rate, final acidity and final redox potential were observed in yogurt containing inactivated L. acidophilus added before fermentation. The highest lactic acid after 28 days of storage was obtained in samples prepared by addition of paraprobiotic form of L. acidophilus after fermentation. Yogurt samples with B. lactis and L. acidophilus added after fermentation showed the highest and lowest acetic acid level, respectively after 28 days of storage. The samples containing L. acidophilus and B. lactis had the highest acetaldehyde on day 0 while on day 28, L. acidophilus had more impact on acetaldehyde generation in yogurts. Addition of paraprobiotics increased viability of starter cultures. In addition, incorporation of inactivated probiotic cells into yogurt resulted in lower syneresis and the higher WHC compared to probiotic yogurt samples. Regarding color parameters, it was observed that color parameters (a*, b* and L*) were not influenced by paraprobiotic in probiotic and paraprobiotic yogurts. Overall, it can be concluded that incorporation of paraprobiotics into yogurt involves less technological challenges and can be considered as a suitable appropriate alternative for probiotics in development of functional yogurt.

Arthrospira platensis as Natural Fermentation Booster for Milk and Soy Fermented Beverages

Arthrospira platensis, commercially known as Spirulina, is a fresh-water cyanobacterium that has been gaining increasing attention in recent years due to its high biological and nutritional value. For this reason, it has been employed in several food applications, to obtain or enhance functional and technological properties of cheese, yogurt, bread, cookies or pasta. The aim of this work was to evaluate the potential boosting effect of two different concentrations (0.25% and 0.50% w/v) of A. platensis on the fermentation capability of several starter lactic acid bacteria (LAB) strains, 1 probiotic and 4 commercial mix culture. These strains were used to ferment three different substrates and their fermentation behaviors were evaluated by impedance analyses together with rheological and color measurements. In tryptic soy broth (TSB), the A. platensis boosting effect was significantly higher if compared to yeast extract for all the starter LAB strains except for Lb. casei, which was equally stimulated. Different results were found when the same LAB strains were cultivated in SSM. The most evident boosting effect was found for S. thermophilus and Lb. casei. LAB growth was promoted by A. platensis, confirming that it could be a useful tool in the production of novel functional fermented dairy foods. The potential boosting effect was evaluated on four commercial mix cultures used to produce milk and soy fermented beverages. It was demonstrated that the booster effect took place, but it was variable and dependent not only on the mix culture used, but also on the substrate and A. platensis concentration. Also, rheological and color modifications were found to be dependent on these factors.

Influence of Storage Temperature and Packaging on Bacteria and Yeast Viability in a Plant-Based Fermented Food

Optimization of food storage has become a central issue for food science and biotechnology, especially in the field of functional foods. The aim of this work was to investigate the influence of different storage strategies in a fermented food product (FFP) and further determine whether the regular storage (room temperature (RT) and standard packaging (SP)) could be refined. Eight experimental conditions (four different temperatures × two packaging) were simulated and changes in FFP's microbial ecology (total bacteria, lactic acid bacteria (LAB), and yeasts) and physicochemical characteristics (pH and moisture content (MC)) were determined following 1, 3, 6, and 12 months. All conditions tested showed a decline in microbial content due to the effect of the temperature, 37 °C being the most detrimental condition, while -20 and 4 °C seemed to be better than RT in some parameters. Vacuum packaging (VP) only had a major effect on MC and we found that VP preserved greater MC values than SP at 3, 6, and 12 months. The correlation analysis revealed that total bacteria, LAB, and yeasts were positively associated, and also both pH and MC showed a correlation. According to our results and with the purpose to maintain the load of viable microorganisms, we observed that the best storage conditions should contemplate SP and freezing or cooling temperature during a period no longer than 3 months.

Uncovering Akkermansia muciniphila resilience or susceptibility to different temperatures, atmospheres and gastrointestinal conditions

Data regarding Akkermansia muciniphila viability under stress remains scarce despite its beneficial potential. Therefore, the main goal was to assess A. muciniphila culturability when exposed to different temperatures, atmospheres and gastrointestinal simulated conditions. Cultivable cell numbers A. muciniphila remain high after refrigerated and room temperatures oxygen exposure, and gastrointestinal passage.

Incorporation of probiotics (Bifidobacterium animalis subsp. Lactis) into 3D printed mashed potatoes: Effects of variables on the viability

3D printing is an emerging technology with the potential to revolutionize people's eating habits. This study firstly optimized the mashed potatoes (MP) formulation and correlated its 3D performance with rheological properties. Yield stress and consistency index (K) were closely related with MP's extrusion behavior, and too high values of them (like 2558 Pa and 2794 Pa·sⁿ) caused the difficulty in extrusion process. Yield stress and elastic modulus (G') were critical to MP's self-supporting performance and too low values of them resulted in the deformation of printed parts during storage. The feasibility of incorporation of probiotics (Bifidobacterium animalis subsp. Lactis BB-12) into 3D printed mashed potatoes (MP) was then studied. MP with probiotics was printed with different nozzle diameter (0.6, 1.0 and 1.4 mm), printing temperature (25, 35, 45 and 55 °C) and evaluated for survival during extrusion and storage at 5 °C. It was found only the small nozzle diameter (0.6 mm) resulted in the reduction of probiotic viability from 9.93 log CFU/g to 9.74 log CFU/g. Greater reduction of viable counts of probiotics (from 10.07 log CFU/g to 7.99 log CFU/g) was found when the MP was held in a heating nozzle barrel at 55 °C for 45 min. No significant difference of probiotics viability in 3D printed samples was found during 12-day storage period at 5 °C. This study provides a new dimension on the development of functional foods by 3D printing.

Staying alive: growth and survival of Bifidobacterium animalis subsp. animalis under in vitro and in vivo conditions

Members of the Bifidobacterium genus are widely used as probiotics in fermented milk products. Bifidobacterium animalis subsp. animalis CNCM I-4602 grows and survives poorly in reconstituted skimmed milk (RSM). Availing of genome and transcriptome information, this poor growth and survival phenotype in milk was substantially improved by the addition of certain compounds, such as yeast extract, uric acid, glutathione, cysteine, ferrous sulfate, and a combination of magnesium sulfate and manganese sulfate. Carbohydrate utilization of CNCM I-4602 was also investigated, allowing the identification of several carbohydrate utilization gene clusters, and highlighting this strain's inability to utilize lactose, unlike the type strain of this subspecies, B. animalis subsp. animalis ATCC25527 and the B. animalis subsp. lactis subspecies. In addition, the ability of B. animalis subsp. animalis CNCM I-4602 to colonize a murine model was investigated, which showed that this strain persists in the murine gut for a period of at least 4 weeks. Associated in vivo transcriptome analysis revealed that, among other genes, a gene cluster encoding a predicted type IVb tight adherence (Tad) pilus was upregulated, indicating that this extracellular structure plays a role in the colonization/adaptation of the murine gastrointestinal tract by this strain.

Evaluation and application of prebiotic and probiotic ingredients for development of ready to drink tea beverage

Ready-to-drink (RTD) ice tea is a ready prepared tea, produced from green and black tea originating from same plant Camellia sinensis. The objective of this study was to determine the effect of prebiotics [galacto-oligosaccharide (GOS), fructo-oligosaccharide (FOS), and inulin] or synbiotic ingredients (GOS, FOS, inulin, and Lactobacillus acidophilus) on the sensory properties and consumer acceptability of RTD. The quality of green tea extract (GTE) and black tea extract (BTE) was improved with pretreatment of cellulase and pectinase enzymes. The combined enzymatic extraction amplified total extractives up to 76% in GTE and 72% in BTE. Total polyphenol was found to be enhanced to 24% in GTE and 19% in BTE. GTE was further selected for development of RTD in two different formats; synbiotic RTD and prebiotic RTD premix and analyzed for sensory attributes (colour, aroma, taste, and acceptability). Synbiotic RTD was also evaluated for stability over a period of 28 days at 4 °C. Synbiotic RTD developed an unpleasant flavor and aroma during the shelf life. Premix format of RTD developed using spray drying was reconstituted and found to be functionally and sensorially acceptable.

Effect of immobilisation materials on viability and fermentation activity of dairy starter culture in whey-based substrate

BACKGROUND

The main objectives of the paper were to study influence of immobilisation of dairy starter culture 'Lactoferm ABY 6' on fermentation and probiotic potential of fermented whey-based substrate.

RESULTS

Fermentation with free cells takes 1.5 h less than fermentation with encapsulated cells, but samples with encapsulated cells have better characteristics after 28 days of storage. Chitosan coating provides additional protection of cells in bile salt solution (95.86% of viable cells compared to the initial number) and simulated gastric juice (37.8% for pH 2.5) compared to the alginate beads (94.54% in bile salt solution and 36.18% in simulated gastric juice for pH 2.5). Free cells had a drastic reduction in the number of viable cells (83.0% in bile salt solution and no viable cells in simulated gastric juice for pH 2.5).

CONCLUSION

Samples with alginate beads and chitosan-coated alginate beads have significantly (P < 0.05) higher viable cell count than samples with free cells, during 4 h monitoring survival at pH 2.5, pH 3.0 and 0.3% bovine bile solution. These beads can be used to improve survival of probiotic cells in fermented whey-based beverage during storage and consummation, which improves the quality of the product.

Probiotic viability and storage stability of yogurts and fermented milks prepared with several mixtures of lactic acid bacteria

Currently, the food industry wants to expand the range of probiotic yogurts but each probiotic bacteria offers different and specific health benefits. Little information exists on the influence of probiotic strains on physicochemical properties and sensory characteristics of yogurts and fermented milks. Six probiotic yogurts or fermented milks and 1 control yogurt were prepared, and we evaluated several physicochemical properties (pH, titratable acidity, texture, color, and syneresis), microbial viability of starter cultures (Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus) and probiotics (Lactobacillus acidophilus, Lactobacillus casei, and Lactobacillus reuteri) during fermentation and storage (35 d at 5°C), as well as sensory preference among them. Decreases in pH (0.17 to 0.50 units) and increases in titratable acidity (0.09 to 0.29%) were observed during storage. Only the yogurt with S. thermophilus, L. delbrueckii ssp. bulgaricus, and L. reuteri differed in firmness. No differences in adhesiveness were determined among the tested yogurts, fermented milks, and the control. Syneresis was in the range of 45 to 58%. No changes in color during storage were observed and no color differences were detected among the evaluated fermented milk products. Counts of S. thermophilus decreased from 1.8 to 3.5 log during storage. Counts of L. delbrueckii ssp. bulgaricus also decreased in probiotic yogurts and varied from 30 to 50% of initial population. Probiotic bacteria also lost viability throughout storage, although the 3 probiotic fermented milks maintained counts ≥ 10(7)cfu/mL for 3 wk. Probiotic bacteria had variable viability in yogurts, maintaining counts of L. acidophilus ≥ 10(7) cfu/mL for 35 d, of L. casei for 7d, and of L. reuteri for 14 d. We found no significant sensory preference among the 6 probiotic yogurts and fermented milks or the control. However, the yogurt and fermented milk made with L. casei were better accepted. This study presents relevant information on physicochemical, sensory, and microbial properties of probiotic yogurts and fermented milks, which could guide the dairy industry in developing new probiotic products.

Technology and potential applications of probiotic encapsulation in fermented milk products

Fermented milk products containing probiotics and prebiotics can be used in management, prevention and treatment of some important diseases (e.g., intestinal- and immune-associated diseases). Microencapsulation has been used as an efficient method for improving the viability of probiotics in fermented milks and gastrointestinal tract. Microencapsulation of probiotic bacterial cells provides shelter against adverse conditions during processing, storage and gastrointestinal passage. Important challenges in the field include survival of probiotics during microencapsulation, stability of microencapsulated probiotics in fermented milks, sensory quality of fermented milks with microencapsulated probiotics, and efficacy of microencapsulation to deliver probiotics and their controlled or targeted release in the gastrointestinal tract. This study reviews the current knowledge, and the future prospects and challenges of microencapsulation of probiotics used in fermented milk products. In addition, the influence of microencapsulation on probiotics viability and survival is reviewed.

Use of Lactobacillus acidophilus and Lactobacillus casei for a potential probiotic legume-based fermented product using pigeon pea (Cajanus cajan)

The aim of the present study was to evaluate the use of pigeon pea (Cajanus cajan) as an appropriate substrate in the production of a legume-based fermented product with Lactobacillus acidophilus ATCC 314 or Lactobacillus casei ATCC 393 and then to ascertain the effects of the addition of ingredients such as powdered milk and banana or strawberry sauce. The products were analyzed for viable cell counts, pH, and sensory attributes during product manufacture and throughout the refrigerated storage period at 3, 7, 14, 21, and 28 days. Nine types of products were produced. At the end of the storage period, the viability of L. acidophilus was above 7 log CFU/g in the presence of milk and 20% sucrose fruit sauce. For products with L. casei, the lack of ingredients such as milk caused no significant loss in viability; however, a high concentration of sucrose in the fruit sauce was an important factor in maintaining a high L. casei population. L. casei had high viability and good sensory attributes. Both strains could be considered suitable for a pigeon pea-based fermented potential probiotic product and a low-cost protein source.