Probiotics viability in frozen food products

Fabrication of synbiotic carbohydrate polymer-based microcapsules: Effect of prebiotics on probiotic viability during freeze-drying, gastrointestinal transit and storage

The stability and efficacy of probiotics can be significantly enhanced through advanced encapsulation technologies. This study aimed to investigate the impact of co-encapsulating probiotic with prebiotics in chitosan coated-alginate/gellan gum microcapsules on their viability during freeze-drying, gastrointestinal transit, and storage. Five prebiotics were added to microcapsules to assess their impact on probiotic viability during freeze-drying, including inulin, fructo-oligosaccharide (FOS), galacto-oligosaccharide (GOS), xylo-oligosaccharide (XOS), and resistant dextrin (RD). Notably, FOS-integrated microcapsules at concentration of 4 wt% exhibited the highest stability, achieving 83.36 % probiotic survival rate post-freeze-drying, a 28 % increase over those without FOS. Physicochemical analysis revealed that 4 % FOS-integrated microcapsules exhibited a particle size of 523.53 μm, a pore size of 17.2 μm, a moisture content of 3.57 %, and aw of 0.246, contributing to enhanced probiotic retention. The addition of FOS maintained probiotic viability at ∼6.4 log CFU/g after gastrointestinal digestion, following Korsmeyer-Peppas release kinetics (R2 = 0.9035). Additionally, these microcapsules sustained probiotic levels (> 6 log CFU/g) for 90 days at 4 °C and 7 days at 25 °C, highlighting their long-term storage potential. These findings provide valuable insights into designing resilient synbiotic-microcapsules for functional foods, supplements, and therapeutic applications, ensuring enhanced probiotic stability and efficacy under real-world conditions.

Structural and functional characteristics of esterified starch and microencapsulation for urate-lowering probiotic: Effect of hydrophobic side-chain length

Esterified starch exhibits desirable freeze-thaw stability and emulsifying properties; however, there are limited reports on how the side-chain length of the acid anhydride affects the antifreeze activity and microencapsulation ability of starch. In this study, four types esterified starch with different hydrophobic chains were prepared and their physicochemical characteristics were explored. The results indicated that acid anhydride modification decreased the amylose content and relative crystallinity of native starch and altered its surface composition. Dodecenyl and hexadecenyl succinic anhydrides rendered the starch with relatively low degree of substitution but strong surface hydrophobicity (>120°). The order of anhydrides with different chain lengths to impart emulsifying ability to starch was dodecenyl succinic anhydride > octenyl succinic anhydride > hexadecenyl succinic anhydride > maleic anhydride, whereas the O/W Pickering emulsion storage stability of hexadecenyl succinic anhydride-esterified starch significantly decreased. Moreover, modified starches with superior freeze-thaw stability for microencapsulation improved the freeze-drying resistance of urate-lowering probiotics. Meanwhile, the encapsulated probiotics which passage through a simulated digestion exhibited superior xanthine oxidase inhibition. These results indicate that the appropriate chain-length acid-anhydride-modified starch is a promising cryoprotectant for frozen products.

Microparticles of Pereskia aculeata miller mucilage and sodium alginate for the encapsulation of Lactobacillus acidophilus ATCC 4356

Pereskia aculeata Miller (OPN) is a cactus species whose mucilage (MOPN) is rich in arabinogalactan, giving it great technological potential for the encapsulation of different compounds. This study aimed to synthesize microparticles of MOPN and sodium alginate (ALG) for the encapsulation of Lactobacillus acidophilus. The microparticles, produced by ionic gelation, were then coated with whey protein concentrate (WPC), or chitosan (CHI), or left uncoated (UC). Samples were characterized based on morphology, size, chemical structure, thermal properties, and performance under simulated digestion. The microparticles were porous and spherical, with average diameters ranging from 172.50 to 272.25 μm and encapsulation efficiency ranging from 74.73 % to 99.56 %. UCp microparticles produced with 0.6 % (w/w) MOPN and 0.9 % (w/w) ALG protected the probiotics against the extreme pH levels and digestive enzymes in the gastrointestinal tract, achieving a survival rate of 68.65 %. Coating with WPC (5.25 % w/w) did not improve microbial protection. The survival rate of the probiotic with WPC was 67.45 % and statistically equal to the value found for UCp microparticles Coating with CHI (1.2 % w/w) significantly reduced the survival rate to 63.27 %, likely due to increased porosity, lower microparticle stability, and the antimicrobial activity of chitosan. In comparison, the survival rate of free (unencapsulated) microorganisms was 56.58 %. These results indicate that the microparticles provided greater protection to L. acidophilus, suggesting that MOPN, in combination with other biopolymers, is an effective material for microbial encapsulation.

Plant-based oat peptides as cryoprotectants mitigate freezing damage to Lactobacillus bulgaricus CICC 22163

The freezing process leads to the death of lactic acid bacteria (LAB), making cryoprotection a significant research focus. In this study, plant-derived oat peptides demonstrated effective cryoprotective effects against Lactobacillus bulgaricus. First, the oat peptide extraction process was optimized with cell viability as the indicator: the yield was found to be 59.51 %. After freezing, it was identified that a 40 mg/mL oat peptide solution provided the best protective effect. The oat peptides enhanced fermentation vigor and reduced cell membrane damage. The mechanisms of action were explored. The oat peptides preserved the intact morphology of cells and significantly improved the viability of lactic dehydrogenase and β-galactosidase. Additionally, the peptides lowered the freezing point to -2.1 °C, which mitigated ice crystal edge formation and reduced both ice crystal diameter and area. The oat peptides physically absorbed onto the surface of the bacteria, exerting an antifreeze effect. Finally, based on amino acid evaluation, three peptide fragments (LSCDKYCFME, FDGCFMEN, and QHCWLGGK) were synthesized, and these synthesized peptides effectively increased the survival rate of L. bulgaricus, with QHCWLGGK also exhibiting protective effects. Therefore, plant-based oat peptides can be utilized as cryoprotectants for freezing LAB.

High-Pressure Processing Influences Antibiotic Resistance Gene Transfer in Listeria monocytogenes Isolated from Food and Processing Environments

The study aimed to assess the high-pressure processing (HPP) impact on antibiotic resistance gene transfer in L. monocytogenes from food and food processing environments, both in vitro (in microbiological medium) and in situ (in carrot juice), using the membrane filter method. Survival, recovery, and frequency of antibiotic resistance gene transfer analyses were performed by treating samples with HPP at different pressures (200 MPa and 400 MPa). The results showed that the higher pressure (400 MPa) had a significant effect on increasing the transfer frequency of genes such as fosX, encoding fosfomycin resistance, and tet_A1, tet_A3, tetC, responsible for tetracycline resistance, both in vitro and in situ. In contrast, the Lde gene (the gene encoding ciprofloxacin resistance) was not transferred under any conditions. In the food matrix (carrot juice), greater variability in results was observed, suggesting that food matrices may have a protective effect on bacteria and modify HPP efficacy. In general, an increase in MIC values for antibiotics was noted in transconjugants compared to donors. Genotypic analysis of transconjugants showed differences in genetic structure, especially after exposure to 400 MPa pressure, indicating genotypic changes induced by pressure stress. The study confirms the possibility of antibiotic resistance genes transfer in the food environment, even from strains showing initial susceptibility to antibiotics carrying so-called silent antibiotic resistance genes, highlighting the public health risk of the potential spread of antibiotic-resistant strains through the food chain. The findings suggest that high-pressure processing can increase and decrease the frequency of resistance gene transfer depending on the strain, antibiotic combination, and processing conditions.

Development of Pickering water-in-oil emulsions using a dual stabilization of candelilla wax and acylated EGCG derivatives to enhance the survival of probiotics (Lactobacillus plantarum) powder

Probiotics have considerable interest due to their inseparable link to human health. However, probiotic products are seriously challenged during processing, preservation, and intake. Food-grade probiotic delivery systems need to be further explored as an effective way to enhance cell viability. In this study, water-in-oil (W/O) Pickering emulsions were fabricated by adding candelilla wax (CLW) as a network stabilizer based on acylated EGCG derivatives in the crystalline form as a Pickering stabilizer. The effects of acylated EGCG derivatives' concentration, CLW concentration, and oil phase volume fraction on the droplet size distribution, microstructure, and physical stability of Pickering emulsions were explored. The presence of CLW reduced the particle size and improved the physical stability of acylated EGCG-based emulsions, and the effect was more positive with increasing concentration. The protective effect of emulsions with different oil phase volume fractions on Lactobacillus plantarum during freeze-thaw cycles, storage, and gastrointestinal digestion was evaluated. The outer-phase physical barrier of W/O emulsions co-stabilized with acylated EGCG derivatives and CLW facilitated the sensitivity of probiotics to ice crystal growth, temperature changes, acidic environments, and digestive enzymes. The emulsions formulated with 40% oil phase volume fractions allowed Lactobacillus plantarum to survive up to 7.75 log CFU g-1 in the harsh gastrointestinal environment. The results offer promising strategies for applying W/O emulsion probiotic delivery systems in food processing, storage, and oral administration.

Comparing Nutritional Values and Bioactivity of Kefir from Different Types of Animal Milk

The growing interest in fermented dairy products is due to their health-promoting properties. The use of milk kefir grains as a starter culture made it possible to obtain a product with a better nutritional and biological profile depending on the type of milk. Cow, buffalo, camel, donkey, goat, and sheep milk kefirs were prepared, and the changes in sugar, protein, and phenol content, fatty acid composition, including conjugated linoleic acids (CLAs), as well as antioxidant activity, determined by ABTS and FRAP assays, were evaluated and compared. The protein content of cow, buffalo, donkey, and sheep milk increased after 24 h of fermentation. The fatty acid profile showed a better concentration of saturated and unsaturated lipids in all fermented milks, except buffalo milk. The highest content of beneficial fatty acids, such as oleic, linoleic, and C18:2 conjugated linoleic acid, was found in the cow and sheep samples. All samples showed a better antioxidant capacity, goat milk having the highest value, with no correlation to the total phenolic content, which was highest in the buffalo sample (260.40 ± 5.50 μg GAE/mL). These findings suggested that microorganisms living symbiotically in kefir grains utilize nutrients from different types of milk with varying efficiency.

Bigel Matrix Loaded with Probiotic Bacteria and Prebiotic Dietary Fibers from Berry Pomace Suitable for the Development of Probiotic Butter Spread Product

This study presents a novel approach to developing a probiotic butter spread product. We evaluated the prebiotic activity of soluble dietary fibers extracted from cranberry and sea buckthorn berry pomace with different probiotic strains (Limosilactobacillus reuteri, Lacticaseibacillus paracasei, and Lactiplantibacillus plantarum), uploaded selected compatible combination in the bigel matrix, and applied it in the probiotic butter spread formulation. Bigels and products were characterized by physical stability, rheological, textural properties, and viability of probiotics during storage at different conditions. The highest prebiotic activity score was observed in soluble cranberry (1.214 ± 0.029) and sea buckthorn (1.035 ± 0.009) fibers when cultivated with L. reuteri. The bigels loaded with probiotics and prebiotic fiber exhibited a significant increase in viscosity (higher consistency coefficient 40-45 Pa·sn) and better probiotic viability (>6 log CFU/g) during long-term storage at +4 °C temperature, surpassing the bigels loaded with probiotics alone. Bigels stored at a lower temperature (-18 °C) maintained high bacterial viability (above 8.5 log CFU/g). The butter spread enriched with the bigel matrix was softer (7.6-14.2 N), indicating improved spreadability. The butter spread product consistently met the required 6 log CFU/g for a functional probiotic food product until 60 days of storage at +4 °C temperature. The butter stored at -18 °C remained probiotic throughout the entire storage period, confirming the protective effect of the bigel matrix. The study's results showed the potential of the bigel to co-encapsulate, protect, and deliver probiotics during prolonged storage under different conditions.

Inulin Can Improve Red Blood Cell Cryopreservation by Promoting Vitrification, Stabilizing Cell Membranes, and Inhibiting Ice Recrystallization

In transfusion medicine, the cryopreservation of red blood cells (RBCs) is of major importance. The organic solvent glycerol (Gly) is considered the current gold-standard cryoprotectant (CPA) for RBC cryopreservation, but the deglycerolization procedure is complex and time-consuming, resulting in severe hemolysis. Therefore, it remains a research hotspot to find biocompatible and effective novel CPAs. Herein, the natural and biocompatible inulin, a polysaccharide, was first employed as a CPA for RBC cryopreservation. The presence of inulin could improve the thawed RBC recovery from 11.83 ± 1.40 to 81.86 ± 0.37%. It was found that inulin could promote vitrification because of its relatively high viscosity and glass transition temperature (Tg'), thus reducing the damage during cryopreservation. Inulin possessed membrane stability, which also had beneficial effects on RBC recovery. Moreover, inulin could inhibit the mechanical damage induced by ice recrystallization during thawing. After cryopreservation, the RBC properties were maintained normally. Mathematical modeling analysis was adopted to compare the performance of inulin, Gly, and hydroxyethyl starch (HES) in cryopreservation, and inulin presented the best efficiency. This work provides a promising CPA for RBC cryopreservation and may be beneficial for transfusion therapy in the clinic.

Physicochemical, microbiological and metabolomics changes in yogurt supplemented with lactosucrose

Lactosucrose (LS) is a known prebiotic that has gained recognition for its low caloric content and various health benefits. However, its potential in food applications remains largely unexplored. In this study the effects of adding LS to milk at concentrations (0 %, 2 %, 5 % and 8 % w/v) for yogurt production, and the relevant changes in yogurt texture, microbial composition and metabolomics were investigated. Our findings revealed that LS played a role in promoting the formation of a structured gel during fermentation, resulting in increased elasticity and viscosity while reducing fluidity. Additionally incorporating high doses of LS into yogurt led to reduced post-acidification, enhanced survival of starter bacteria, improved water retention capacity and overall texture throughout a refrigerated storage period of 21 days. Notably higher concentrations of LS (8 % w/v) exhibited effects on enhancing yogurt quality. Furthermore, untargeted metabolomics analysis using UPLC Q TOF MS/MS revealed 45 differentially expressed metabolites, including up-regulated L-arginine, L-proline and L-glutamic acid along with the down-regulated glutathione, L-tyrosine, L-phenylalanyl and L-proline. These differential metabolites were primarily associated with amino acid metabolism such as thiamine metabolism, nicotinic acid salt and nicotinamide metabolism, and pyrimidine metabolism. As a result, the inclusion of LS in yogurt had an impact on the production of various beneficial metabolites in yogurt, highlighting the importance of combining prebiotic LS with probiotics to obtain desired physiological benefits of yogurt.

What are the main obstacles to turning foods healthier through probiotics incorporation? a review of functionalization of foods by probiotics and bioactive metabolites

Functional foods are gaining significant attention from people all over the world. When added to foods, probiotic bacteria can turn them healthier and confer beneficial health effects, such as improving the immune system and preventing cancer, diabetes, and cardiovascular disease. However, adding probiotics to foods is a challenging task. The processing steps often involve high temperatures, and intrinsic food factors, such as pH, water activity, dissolved oxygen, post-acidification, packaging, and cold storage temperatures, can stress the probiotic strain and impact its viability. Moreover, it is crucial to consider these factors during food product development to ensure the effectiveness of the probiotic strain. Among others, techniques such as microencapsulation and lyophilization, have been highlighted as industrial food functionalization strategies. In this review, we present and discuss alternatives that may be used to functionalize foods by incorporating probiotics and/or delivering bioactive compounds produced by probiotics. We also emphasize the main challenges in different food products and the technological characteristics influencing them. The knowledge available here may contribute to overcoming the practical obstacles to food functionalization with probiotics.

Probiotics, prebiotics, and postbiotics in health and disease

The gut microbiota and its homeostasis play a crucial role in human health. However, for some diseases related to the gut microbiota, current traditional medicines can only relieve symptoms, and it is difficult to solve the root causes or even cause side effects like disturbances in the gut microbiota. Increasing clinical studies and evidences have demonstrated that probiotics, prebiotics, and postbiotics can prevent and treat various diseases, but currently they can only be used as dietary supplements rather than medicines, which restricts the application of probiotics in the field of medicine. Here, this review analyzes the importance of gut microbiota in human health and the current problems of traditional medicines, and systematically summarizes the effectiveness and mechanisms of probiotics, prebiotics, and postbiotics in maintaining health and treating diseases based on animal models and clinical trials. And based on current research outcomes and development trends in this field, the challenges and prospects of their clinical application in maintaining health, alleviating and treating diseases are analyzed. It is hoped to promote the application of probiotics, prebiotics, and postbiotics in disease treatment and open up new frontiers in probiotic research.

Probiotics: mechanism of action, health benefits and their application in food industries

Probiotics, like lactic acid bacteria, are non-pathogenic microbes that exert health benefits to the host when administered in adequate quantity. Currently, research is being conducted on the molecular events and applications of probiotics. The suggested mechanisms by which probiotics exert their action include; competitive exclusion of pathogens for adhesion sites, improvement of the intestinal mucosal barrier, gut immunomodulation, and neurotransmitter synthesis. This review emphasizes the recent advances in the health benefits of probiotics and the emerging applications of probiotics in the food industry. Due to their capability to modulate gut microbiota and attenuate the immune system, probiotics could be used as an adjuvant in hypertension, hypercholesterolemia, cancer, and gastrointestinal diseases. Considering the functional properties, probiotics are being used in the dairy, beverage, and baking industries. After developing the latest techniques by researchers, probiotics can now survive within harsh processing conditions and withstand GI stresses quite effectively. Thus, the potential of probiotics can efficiently be utilized on a commercial scale in food processing industries.

Journey of the Probiotic Bacteria: Survival of the Fittest

This review aims to bring a more general view of the technological and biological challenges regarding production and use of probiotic bacteria in promoting human health. After a brief description of the current concepts, the challenges for the production at an industrial level are presented from the physiology of the central metabolism to the ability to face the main forms of stress in the industrial process. Once produced, these cells are processed to be commercialized in suspension or dried forms or added to food matrices. At this stage, the maintenance of cell viability and vitality is of paramount for the quality of the product. Powder products requires the development of strategies that ensure the integrity of components and cellular functions that allow complete recovery of cells at the time of consumption. Finally, once consumed, probiotic cells must face a very powerful set of physicochemical mechanisms within the body, which include enzymes, antibacterial molecules and sudden changes in pH. Understanding the action of these agents and the induction of cellular tolerance mechanisms is fundamental for the selection of increasingly efficient strains in order to survive from production to colonization of the intestinal tract and to promote the desired health benefits.