Effect of different types of encapsulation on the survival of Lactobacillus plantarum during storage with inulin and in vitro digestion

Effect of Sodium Alginate-Bulk Chitosan/Chitosan Nanoparticle Wall Matrix on the Viability of Lactobacillus plantarum Under Simulated Gastrointestinal Fluids

The viability of probiotic cells decreases during passage through the gastrointestinal tract. The process of probiotics encapsulation with sodium alginate and chitosan polymers was carried out to protect the Lactobacillus plantarum in adverse conditions. Lactobacillus plantarum was entrapped in sodium alginate/chitosan (SA/BChi) and sodium alginate/nano-chitosan (SA/NChi) wall materials. Encapsulating L. plantarum with SA/BChi and SA/NChi resulted in a high encapsulation efficiency % of ~ 86.41 to 91.09%. In addition, coating bacteria cells in encapsulants improved the survivability of the cells under the simulated gastrointestinal fluids by ~ 52.61% in SA/Chi and 58.04% in SA/NChi compared to 29% for unencapsulated forms. Probiotic beads under field emission-scanning electron microscopy (FE-SEM) were morphologically compact with a cracked appearance of SA/NChi beads. The Fourier transform-infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) showed vigorous electrostatic interaction between polymers, as well as the high melting points, which corroborate the previous investigations in the field for using SA/BChi or SA/NChi as a promising encapsulating agent for ameliorating the survivability of probiotics under harsh conditions. The distinctive properties possessed by the two coatings make them excellent candidates for use as polymeric carriers in probiotic delivery systems.

Assessing biofilm formation and resistance of vibrio parahaemolyticus on UV-aged microplastics in aquatic environments

UV degradation of marine microplastics (MPs) could increase their vector potential for pathogenic bacteria and threaten human health. However, little is known about how the degree of UV aging affects interactions between MPs and pathogens and how various types of MPs differ in their impact on seafood safety. This study investigated five types of UV-aged MPs and their impact on Vibrio parahaemolyticus, a seafood pathogen. MPs exposed to UV for 60 days showed similar physicochemical changes such as surface cracking and hydrophobicity reduction. Regardless of the type, longer UV exposure of MPs resulted in more biofilm formation on the surface under the same conditions. V. parahaemolyticus types that formed biofilms on the MP surface showed 1.4- to 5.0-fold upregulation of virulence-related genes compared to those that did not form biofilms, independently of UV exposure. However, longer UV exposure increased resistance of V. parahaemolyticus on MPs to chlorine, heat, and human gastrointestinal environment. This study implies that the more UV degradation occurs on MPs, the more microbial biofilm formation is induced, which can significantly increase virulence and environmental resistance of bacteria regardless of the type of MP.

Protein-polysaccharide based double network microbeads improves stability of Bifidobacterium infantis ATCC 15697 in a gastro-Intestinal tract model (TIM-1)

Microencapsulation of probiotics is a main technique employed to improve cell survival in gastrointestinal tract (GIT). The present study investigated the impact of utilizing proteins i.e. Whey Protein Isolates (WPI), Pea Protein Isolates (PPI) or (WPI + PPI) complex based microbeads as encapsulating agents on the encapsulation efficiency (EE), diameter, morphology along with the survival and viability of Bifidobacterium infantis ATCC 15697. Results revealed that WPI + PPI combination had the highest EE% of the probiotics up to 94.09 % and the smoothest surface with less visible holes. WPI based beads revealed lower EE% and smaller size than PPI based ones. In addition, WPI based beads showed rough surface with visible signs of cracks, while PPI beads showed dense surfaces with pores and depressions. In contrast, the combination of the two proteins resulted in compact and smooth beads with less visible pores/wrinkles. The survival in gastrointestinal tract (GIT) was observed through TNO in-vitro gastrointestinal model (TIM-1) and results illustrated that all microbeads shrank in gastric phase while swelled in intestinal phase. In addition, in-vitro survival rate of free cells was very low in gastric phase (18.2 %) and intestinal phase (27.5 %). The free cells lost their viability after 28 days of storage (2.66 CFU/mL) with a maximum log reduction of 6.76, while all the encapsulated probiotic showed more than 106-7 log CFU/g viable cell. It was concluded that encapsulation improved the viability of probiotics in GIT and utilization of WPI + PPI in combination provided better protection to probiotics.

Application of inulin for the formulation and delivery of bioactive molecules and live cells

Inulin is a fructan biosynthesized mainly in plants of the Asteraceae family. It is also found in edible vegetables and fruits such as onion, garlic, leek, and banana. For the industrial production of inulin, chicory and Jerusalem artichoke are the main raw material. Inulin is used in the food, pharmaceutical, cosmetic as well biotechnological industries. It has a GRAS status and exhibits prebiotic properties. Inulin can be used as a wall material in the encapsulation process of drugs and other bioactive compounds and the development of their delivery systems. In the review, the use of inulin for the encapsulation of probiotics, essential and fatty oils, antioxidant compounds, natural colorant and other bioactive compounds is presented. The encapsulation techniques, materials and the properties of final products suitable for the delivery into food are discussed. Research limitations are also highlighted.

Encapsulation of probiotic bacteria using polyelectrolytes stabilized nanoliposomes for improved viability under hostile conditions

Probiotics viability and stability is a core challenge for the food processing industry. To prolong the viability of probiotics (Lactobacillus acidophilus), gelatin (GE)-chitosan (CH) polyelectrolytes-coated nanoliposomes were developed and characterized. The average particle size of the nanoliposomes was in the range of 131.7-431.6 nm. The mean zeta potential value of the nanoliposomes differed significantly from -42.2 to -9.1 mV. Scanning electron micrographs indicated that the nanoliposomes were well distributed and had a spherical shape with a smooth surface. The Fourier transform infrared spectra revealed that the GE-CH polyelectrolyte coating has been effectively applied on the surface of nanoliposomes and L. acidophilus cells were successfully encapsulated in the lipid-based nanocarriers. X-ray diffraction results indicated that nanoliposomes are semicrystalline and GE-CH polyelectrolyte coating had an influence on the crystalline nature of nanoliposomes. Moreover, the coating of L. acidophilus-loaded nanoliposomes with GE-CH polyelectrolytes significantly improved its viability when exposed to simulated gastrointestinal environments. The findings of the current study indicated that polyelectrolyte-coated nanoliposomes could be used as an effective carrier for the delivery of probiotics and their application to food matrix for manufacturing functional foods.

Application of polysaccharides for the encapsulation of beneficial microorganisms for agricultural purposes: A review

Intensive farming practices have increased the consumption of chemical-based pesticides and fertilizers thereby creating health issues for humans and animals and also causing a deterioration in the natural ecosystem. The promotion of biomaterials synthesis could potentially lead to the replacement of synthetic products and improve soil fertility, protect plants from pathogen attacks, and enhance the productivity of the agricultural sector resulting in less environmental pollution. Microbial bioengineering involving the use and improvement of encapsulation using polysaccharides has the required potential to address environmental issues and promote green chemistry. This article describes various encapsulation techniques and polysaccharides which have an immense applicable capability to encapsulate microbial cells. The review elucidates the factors that may result in a reduced viable cell count during encapsulation, particularly using the spray drying method, where a high temperature is required to dry the suspension, this may damage the microbial cells. The environmental advantage of the application of polysaccharides as carriers of beneficial microorganisms, which do not pose a risk for soil due to their full biodegradability, was also shown. The encapsulated microbial cells may assist in addressing certain environmental problems such as ameliorating the unfavourable effects of plant pests and pathogens, and promoting agricultural sustainability.

Effect of Cellulose–Chitosan Hybrid-Based Encapsulation on the Viability and Stability of Probiotics under Simulated Gastric Transit and in Kefir

Encapsulation comprises a promising potential for the targeted delivery of entrapped sensitive agents into the food system. A unique combination of cellulose/chitosan (Cl-Ch)-based hybrid wall material was employed to encapsulate L. plantarum by emulsion technique. The developed beads were further subjected to morphological and in vitro studies. The viability of free and encapsulated probiotics was also evaluated in kefir during storage. The developed beads presented porous spherical structures with a rough surface. A 1.58 ± 0.02 log CFU/mL, 1.26 ± 0.01 log CFU/mL, and 1.82 ± 0.01 log CFU/mL reduction were noticed for Cl-Ch hybrid cells under simulated gastro-intestinal and thermal conditions, respectively. The encapsulated cells were found to be acidic and thermally resistant compared to the free cells. Similarly, encapsulated probiotics showed better viability in kefir at the end of the storage period compared to free cells. In short, the newly developed Cl-Ch hybrid-based encapsulation has a promising potential for the targeted delivery of probiotics, as career agents, in gastric transit, and in foods.

The Protein-Rich Powdered Beverages Stabilized with Flax Seeds Gum—Antioxidant and Antiproliferative Properties of the Potentially Bioaccessible Fraction

The functional beverages market is one of the fastest-growing sectors of functional food production. An innovative recipe for powdered fruit and vegetable drinks fortified with lentil proteins (AGF) and stabilized with flax seed gums (FSG) was developed. The study focused on the analysis of potentially bioaccessible fractions from the produced beverages in terms of their antioxidant, antiproliferative activities and physicochemical properties. The contents of bioactive components were tailored by the incorporation of lyophilized fruits and vegetables, the FSG and the AGF. Digestion in vitro effectively released phenolics from all matrices. The highest contents of potentially bioavailable polyphenols were recorded for the AGF based beverages enriched with 5% of FSG and green-leafy vegetables (58 mg/100 mL) and those with lyophilized fruit (54 mg/100 mL). The reducing power of the beverages was mainly affected by the presence of the AGF, while the FSG and lyophilized fruit improved the chelating power. The digests applied in the concentrations mimicking physiological concentrations showed antiproliferative properties against gastric and colon adenocarcinoma—they seemed to be tailored by bioactive peptides and phenolics, respectively. The addition of the FSG improved the stability of the beverages increasing the time required for a reduction of 20% of the initial optical density by 16- and 28-times in the beverages without additives or enriched with vegetables. Both, the AGF and FSG stabilize the beverages after rehydration and are sources of bioaccessible antioxidant and anticancer components, which create their functionality.

Polyelectrolytes-stabilized liposomes for efficient encapsulation of Lactobacillus rhamnosus and improvement of its survivability under adverse conditions

To improve the survivability of Lactobacillus rhamnosus probiotics, nanoliposomes (NLs) coated with chitosan (CH)-gelatin (GE) polyelectrolytes have been synthesized and characterized. The produced CH-GE-coated NLs containing L. rhamnosus had mean sizes in the range of 134.8-495.8 nm. HRTEM showed the smooth spherical shape of the vesicles. ATR-FTIR findings indicated the successful coating of the produced NLs by the used CH-GE polyelectrolytes. According to DSC results, CH-GE polyelectrolytes desorption on the surface of NLs altered the physical characteristics of the phospholipid bilayers. Here, an increase in the melting temperature (T_m) from 119.9 to 127.5 °C in L. rhamnosus-loaded CH-GE-coated NLs made this system more stable than uncoated liposomes. Furthermore, the CH-GE coated nanoparticles loaded with L. rhamnosus exhibited a significant enhancement in the viability of cells under simulated gastrointestinal fluids (SGF/SIF). These results may guide the potential application of polyelectrolytes-coated NLs as a carrier of probiotic cells in functional food development.

Viability, Storage Stabilityand In Vitro Gastrointestinal Tolerance of Lactiplantibacillus plantarum Grown in Model Sugar Systems with Inulin and Fructooligosaccharide Supplementation

This study aims to investigate the effects of inulin and fructooligosaccharides (FOS) supplementation on the viability, storage stability, and in vitro gastrointestinal tolerance of Lactiplantibacillus plantarum in different sugar systems using 24 h growth and 10 days survival studies at 37 °C, inulin, and FOS (0%, 0.5%, 1%, 2%, 3% and 4%) supplementation in 2%, 3%, and 4% glucose, fructose, lactose, and sucrose systems. Based on the highest percentage increase in growth index, sucrose and lactose were more suitable sugar substrates for inulin and FOS supplementation. In survival studies, based on cell viability, inulin supplementation showed a better protective effect than FOS in 3% and 4% sucrose and lactose systems. Four selected sucrose and lactose systems supplemented with inulin and FOS were used in a 12-week storage stability study at 4 °C. Inulin (3%, 4%) and FOS (2%, 4%) supplementation in sucrose and lactose systems greatly enhanced the refrigerated storage stability of L. plantarum. In the gastrointestinal tolerance study, an increase in the bacterial survival rate (%) showed that the supplementation of FOS in lactose and sucrose systems improved the storage viability of L. plantarum. Both inulin and FOS supplementation in sucrose and lactose systems improved the hydrophobicity, auto-aggregation, co-aggregation ability of L. plantarum with Escherichia coli and Enterococcus faecalis.

Aggrandizement of fermented cucumber through the action of autochthonous probiotic cum starter strains of Lactiplantibacillus plantarum and Pediococcus pentosaceus

Purpose

Cucumber fermentation is traditionally done using lactic acid bacteria. The involvement of probiotic cultures in food fermentation guarantees enhanced organoleptic properties and protects food from spoilage.

Methods

Autochthonous lactic acid bacteria were isolated from spontaneously fermented cucumber and identified to species level. Only strains adjudged as safe for human consumption were examined for their technological and functional characteristics. Strain efficiency was based on maintaining high numbers of viable cells during simulated GIT conditions and fermentation, significant antioxidant activity, EPS production, nitrite degradation, and antimicrobial ability against Gram-positive and Gram-negative foodborne pathogens.

Result

Two strains, Lactiplantibacillus plantarum NPL 1258 and Pediococcus pentosaceus NPL 1264, showing a suite of promising functional and technological attributes, were selected as a mixed-species starter for carrying out a controlled lactic acid fermentations of a native cucumber variety. This consortium showed a faster lactic acid-based acidification with more viable cells, at 4% NaCl and 0.2% inulin (w/v) relative to its constituent strains when tested individually. Sensory evaluation rated the lactofermented cucumber acceptable based on texture, taste, aroma, and aftertaste.

Conclusion

The results suggest that the autochthonous LAB starter cultures can shorten the fermentation cycle and reduce pathogenic organism’ population, thus improving the shelf life and quality of fermented cucumber. The development of these new industrial starters would increase the competitiveness of production and open the country’s frontiers in the fermented vegetable market.

Effect of co-encapsulation using a calcium alginate matrix and fructooligosaccharides with gelatin coating on the survival of Lactobacillus paracasei cells

The demand for functional foods is increasing each year because consumers are gaining awareness about the importance of a healthy diet in the proper functioning of the body. Probiotics are among the most commonly known, commercialized, and studied foods. However, the loss of viability of probiotic products is observed during their formulation, processing, and storage. This study aimed to investigate the co-encapsulation of two Lactobacillus paracasei probiotic strains (LBC81 and ELBAL) with fructooligosaccharides (FOS) in a calcium alginate matrix using extrusion technology with gelatin as a coating material. The viability of the strains under gastrointestinal conditions and in storage at low temperature was also assessed. An immobilization yield of more than 59% was observed for both bacterial strains. Exposure to 2% biliary salts led to a decrease in the viability of free cells in the two L. paracasei strains, whereas the viability of microencapsulated cells increased up to 47%. After 35 days of storage at 4°C, the population of free cells was reduced, but microencapsulated cells remained stable after storage at low temperature. LBC81 bacteria microencapsulated with 1.5% FOS coated with gelatin were the most resistant to the stressful environments tested. Therefore, these results showed that co-encapsulation with FOS in a calcium alginate matrix coated with gelatin improved L. paracasei survival and may be useful for the development of more resistant probiotics and new functional foods.

Influence of Different Prebiotics on Viability of Lactobacillus casei, Lactobacillus plantarum and Lactobacillus rhamnosus Encapsulated in Alginate Microcapsules

As the production and maintenance of a sufficient number of microencapsulated probiotics is still a test for the food industry, the present study addressed the testing of three prebiotics: chicory inulin, soluble potato starch, oligofructose and a control carbon source, namely glucose, as a component part of the encapsulation matrix. Using the extrusion encapsulation technique, it was possible to obtain microcapsules whose matrix composition and dimensions correspond to the requirements of the food industry. The microcapsules obtained showed significantly different physicochemical properties, with different survival rates during processing, storage and in simulated gastrointestinal conditions. The encapsulation efficiency was very high in relation to the dimensions of the microcapsules and the technique used (between 87.00–88.19%). The microcapsules obtained offered a very good viability (between 8.30 ± 0.00–9.00 ± 0, 02 log10 cfu/g) during the 30 days of storage at 2–8 degrees and also in the simulated gastrointestinal conditions (between 7.98–8.22 log10 cfu/g). After 30 days, the lowest viability was registered in the microcapsules with glucose 6.78 ± 0.15 log10 cfu/g. It was found that after 4 h of action of gastrointestinal juices on the microcapsules stored for 30 days, cell viability falls within the limits recommended by the Food and Agriculture Organization of the United Nations (FAO) (10⁶–10⁷ CFU/mL or g of food. This study demonstrated that using prebiotic encapsulation matrix increases cell viability and protection and that the extrusion encapsulation method can be used in the production of probiotic microcapsules for the food industry.

Effect of Microencapsulation on Survival at Simulated Gastrointestinal Conditions and Heat Treatment of a Non Probiotic Strain, Lactiplantibacillus plantarum 48M, and the Probiotic Strain Limosilactobacillus reuteri DSM 17938

Cells of the probiotic strain Limosilactobacillus reuteri DSM 17938 and of the non-probiotic strain Lactiplantibacillus plantarum 48M were microencapsulated in alginate matrix by emulsion technique. Survival of microorganisms in the microcapsules was tested against gastrointestinal (GI) simulated conditions and heat stress. Results demonstrated that the microencapsulation process improved vitality of Lactiplantibacillus plantarum 48M cells after GI conditions exposure, allowing survival similarly to the probiotic Limosilactobacillus reuteri DSM 17938. Moreover, microencapsulation was able to protect neither Limosilactobacillus reuteri DSM 17938 nor Lactiplantibacillus plantarum 48M cells when exposed to heat treatments. Microencapsulated Limosilactobacillus reuteri DSM 17938 cells were still able to produce reuterin, an antimicrobial agent, as well as free cells.

Co-encapsulation of probiotics with prebiotics and their application in functional/synbiotic dairy products

Oral administration of live probiotics along with prebiotics has been suggested with numerous beneficial effects for several conditions including certain infectious disorders, diarrheal illnesses, some inflammatory bowel diseases, and most recently, irritable bowel syndrome. Though, delivery of such viable bacteria to the host intestine is a major challenge, due to the poor survival of the ingested probiotic bacteria during the gastric transit, especially within the stomach where the pH is highly acidic. Although microencapsulation has been known as a promising approach for improving the viability of probiotics in the human digestive tract, the success rate is not satisfactory. For this reason, co-encapsulation of probiotics with probiotics has been practised as a novel alternative approach for further improvement of the oral delivery of viable probiotics toward their targeted release in the host intestine. This paper discusses the co-encapsulation technologies used for delivery of probiotics toward better stability and viability, as well the incorporation of co-encapsulated probiotics and prebiotics in functional/synbiotic dairy foods. The common encapsulation technologies (and the materials) used for this purpose, the stability and survival of co-encapsulated probiotics in the food, and the release behavior of the co-encapsulated probiotics in the gastrointestinal tract have also been explained. Most studies reported a significant improvement particularly in the viability of bacteria associated with the presence of prebiotics. Nevertheless, the previous research has mostly been carried out in the simulated digestion, meaning that future systematic research is to be carried out to investigate the efficacy of the co-encapsulation on the survival of the bacteria in the gut in vivo.

Linoleic acid inhibits Lactobacillus activity by destroying cell membrane and affecting normal metabolism

BACKGROUND

The reason why dietary polyunsaturated fatty acids (PUFAs) affect the activity of Lactobacillus remains unclear. In this study, linoleic acid was used to study the mechanism underlying its inhibition function against Lactobacillus activity.

RESULTS

The growth curve of Lactobacillus rhamnosus LGG and the metabolite content in bacterial liquid were determined at varying linoleic acid concentration. The degree of cell membrane damage of L. rhamnosus LGG was determined by flow cytometry and fluorescence microscopy, and the cell structure was observed by scanning electron microscopy and transmission electron microscopy. The effect of linoleic acid on Lactobacillus activity was assessed in a simulated gut environment. Results showed that L. rhamnosus LGG grew slowly, cell metabolites leaked into the liquid, cell membrane was damaged, and the cell structure changed at a linoleic acid concentration of 50 μg mL^-1 .

CONCLUSION

The mechanism of action of linoleic acid on Lactobacillus showed that that linoleic acid destroyed the cell membrane of bacteria, thereby affecting the normal metabolism of the bacteria and ultimately leading to their death. © 2019 Society of Chemical Industry.

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.

A Brief Review of Edible Coating Materials for the Microencapsulation of Probiotics

The consumption of probiotics has been associated with a wide range of health benefits for consumers. Products containing probiotics need to have effective delivery of the microorganisms for their consumption to translate into benefits to the consumer. In the last few years, the microencapsulation of probiotic microorganisms has gained interest as a method to improve the delivery of probiotics in the host as well as extending the shelf life of probiotic-containing products. The microencapsulation of probiotics presents several aspects to be considered, such as the type of probiotic microorganisms, the methods of encapsulation, and the coating materials. The aim of this review is to present an updated overview of the most recent and common coating materials used for the microencapsulation of probiotics, as well as the involved techniques and the results of research studies, providing a useful knowledge basis to identify challenges, opportunities, and future trends around coating materials involved in the probiotic microencapsulation.

Evaluación de Lactobacillus plantarum microencapsulado y su viabilidad bajo condiciones gastrointestinales simuladas e inhibición frente a Escherichia coli O157:H7

Se evaluó la viabilidad de Lactobacillus plantarum microencapsulado, su efecto de inhibición sobre Escherichia coli O157:H7 y crecimiento en condiciones gastrointestinales simuladas. Se utilizaron a L. plantarum ATCC 8014® y E. coli ATCC 43888®. Se realizó pruebas de Inhibición de L. plantarum sobre E. coli y test de susceptibilidad a CTX (30 µg), P (10 IU), GN (10 µg) DCX (1 µg), CIP (5 µg) y KF (30 µg) para ambas cepas. En la bacteria láctica se determinó la cinética de fermentación, y la presencia de péptidos y aminoácidos por HPLC en ambas cepas. Se evaluó el crecimiento a 37°C y 45°C de L. plantarum y se valoró la viabilidad de su microencapsulación mediante condiciones gastrointestinales (Bilis, Sales biliares y pH ácido), al igual que la supervivencia y estabilidad de preparado y sus características físicas y morfológicas. Los resultados indicaron que L. plantarum inhibió a E. coli y el  microencapsulado resultados positivos con una viabilidad del 83,3%, eficiencia 88,4%, Humedad 7,79%, actividad de agua 0.4, humectabilidad de 1 min: 56 s, solubilidad del 96%, morfología esférica y tamaño entre 15,18 a 35,68 µm. Finalmente, se observó un alto potencial de L. plantarum como agente inhibidor para E. coli O157:H7.

Lactobacillus plantarum 299V improves the microbiological quality of legume sprouts and effectively survives in these carriers during cold storage and in vitro digestion

Probiotics improve consumers' health and additionally may positively influence the microbiological and organoleptic quality of food. In the study, legume sprouts were inoculated with Lactobacilllus plantarum 299V to produce a new functional product ensuring the growth and survival of the probiotic and high microbiological quality of the final product. Legume sprouts, which are an excellent source of nutrients, were proposed as alternative carriers for the probiotic. The key factors influencing the production of probiotic-rich sprouts include the temperature (25°C) of sprouting and methods of inoculation (soaking seeds in a suspension of probiotics). Compared to the control sprouts, the sprouts enriched with the probiotic were characterized by lower mesophilic bacterial counts. In the case of fresh and stored probiotic-rich sprouts, lactic acid bacteria (LAB) accounted for a majority of total microorganisms. The Lb. plantarum population was also stable during the cold storage. The high count of LAB observed in the digest confirmed the fact that the studied sprouts are effective carriers for probiotics and ensure their survival in the harmful conditions of the digestive tract in an in vitro model. Enrichment of legume sprouts with probiotics is a successful attempt and yields products for a new branch of functional foods.

Encapsulation of Probiotics: Proper Selection of the Probiotic Strain and the Influence of Encapsulation Technology and Materials on the Viability of Encapsulated Microorganisms

Probiotic encapsulation is an entire system that not only involves but also depends on many factors. Elements such as the encapsulation method itself, materials, environmental conditions, and last, but not least, the strain; all play an important role in the encapsulation process. The current paper focuses on the right selection of probiotics, the various stress factors that impact the survival capacity of probiotics during and after encapsulation, and the rational selection of appropriate protection strategies to overcome these factors and achieve the highest possible encapsulation efficiency under optimal conditions. This review discusses the effects of temperature, moisture content, and water activity as well as pH, oxygen, and pressure on the viabilities of microorganisms. The effect of the surface and structure of the capsules on the encapsulated microorganisms and the impact of the materials used for the encapsulation are discussed as well. Last, but not least, the importance of choosing the right bacteria is reviewed.

Aflatoxin B1 adsorption/desorption dynamics in the presence of Lactobacillus rhamnosus RC007 in a gastrointestinal tract-simulated model

AIMS

(i) To determine the aflatoxin B₁ (AFB₁ ) adsorption and desorption dynamics in the presence of Lactobacillus rhamnosus RC007 under simulated transit of AFB₁ at each gastrointestinal tract (GIT-saliva, stomach and intestine) stage consecutively and then, separately, (ii) to study the ability of L. rhamnosus RC007 to biotransform AFB₁ as a strategy that complements the adsorption process.

METHODS AND RESULTS

The AFB₁ adsorption and desorption assay simulating the GIT passage of AFB₁ (93·89 ng g^-1 ) in the presence of L. rhamnosus RC007 (10⁸ CFU per ml) was conducted. Moreover, lactic acid production was determined. Results demonstrated that predominant environmental conditions in salivary solution induced a low AFB₁ adsorption, while the transit through the gastric solution and intestinal solution allowed high percentages of adsorption and did not generate significant AFB₁ desorption.

CONCLUSIONS

The AFB₁ adsorption and desorption dynamics in the presence of L. rhamnosus RC007 was favoured by gastric and intestinal environment.

SIGNIFICANCE AND IMPACT OF THE STUDY

The knowledge of the adsorption dynamics of AFB₁ with a micro-organism of interest will allow predicting its behaviour at each stage of the GIT.

Probiotic Incorporation in Edible Films and Coatings: Bioactive Solution for Functional Foods

Nowadays, the consumption of food products containing probiotics, has increased worldwide due to concerns regarding healthy diet and wellbeing. This trend has received a lot of attention from the food industries, aiming to produce novel probiotic foods, and from researchers, to improve the existing methodologies for probiotic delivery or to develop and investigate new possible applications. In this sense, edible films and coatings are being studied as probiotic carriers with many applications. There is a wide variety of materials with film-forming ability, possessing different characteristics and subsequently affecting the final product. This manuscript aims to provide significant information regarding probiotics and active/bioactive packaging, to review applications of probiotic edible films and coatings, and to discuss certain limitations of their use as well as the current legislation and future trends.

Influence of Fermentation with Different Lactic Acid Bacteria and in Vitro Digestion on the Biotransformation of Phenolic Compounds in Fermented Pomegranate Juices

This study describes the effect of fermentation and the impact of simulated gastrointestinal digestion (SGD) of four fermented pomegranate juices with different lactic acid bacteria (LAB) on the biotransformation of phenolic compounds. The changes of the antioxidant capacity (AOC) and of LAB growth and survival in different fermented juices were also studied. Two new phenolic derivatives (catechin and α-punicalagin) were identified only in fermented juices. During SGD, the AOC increased together with the phenolic derivatives concentration mainly in the juices fermented with Lactobacillus. These derivatives were formed due to the LAB metabolism of the ellagitannins, epicatechin, and catechin after fermentation and during SGD. The FRAP assay performance might be associated with the degradation and biotransformation of catechin. The fermented pomegranate juices with these LAB increased the bioaccessibility of phenolic compounds, ensuring the survival of LAB after SGD, suggesting a possible prebiotic effect of phenolic compounds on LAB.

Effect of Inulin on the Viability of L. plantarum during Storage and In Vitro Digestion and on Composition Parameters of Vegetable Fermented Juices

The prebiotic effect of different concentrations of inulin (0, 1 and 2%) on the growth and survival of Lactobacillus plantarum (LP) CECT 220 in blended carrot and orange juices was investigated after 24 h of fermentation, during 30 days of storage at 4 °C and through the phases of gastrointestinal digestion after different storage periods. Microbiological and chemical determinations were also carried out in all juices. The lactic fermentation increased the shelf life of the fermented juices with inulin. The hygienic-sanitary quality in fermented juices was better than the control juices. During storage, the inulin improved the viability of LP and the monosaccharide concentration remained higher with respect to the juice without inulin (40% lower). At 30 days, the fermented juices with 2% inulin after in vitro digestion presented the highest survival of L. plantarum.

Micro- and nano bio-based delivery systems for food applications: In vitro behavior

Micro- and nanoencapsulation is an emerging technology in the food field that potentially allows the improvement of food quality and human health. Bio-based delivery systems of bioactive compounds have a wide variety of morphologies that influence their stability and functional performance. The incorporation of bioactive compounds in food products using micro- and nano-delivery systems may offer extra health benefits, beyond basic nutrition, once their encapsulation may provide protection against undesired environmental conditions (e.g., heat, light and oxygen) along the food chain (including processing and storage), thus improving their bioavailability, while enabling their controlled release and target delivery. This review provides an overview of the bio-based materials currently used for encapsulation of bioactive compounds intended for food applications, as well as the main production techniques employed in the development of micro- and nanosystems. The behavior of such systems and of bioactive compounds entrapped into, throughout in vitro gastrointestinal systems, is also tracked in a critical manner. Comparisons between various in vitro digestion systems (including the main advantages and disadvantages) currently in use, as well as correlations between the behavior of micro- and nanosystems studied through in vitro and in vivo systems were highlighted and discussed here for the first time. Finally, examples of bioactive micro- and nanosystems added to food simulants or to real food matrices are provided, together with a revision of the main challenges for their safe commercialization, the regulatory issues involved and the main legislation aspects.