Production of a potential multistrain probiotic in co-culture conditions using agro-industrial by-products-based medium for fish nutrition.

BACKGROUND: Probiotics are viable microorganisms that when administered in adequate amounts confer health benefits to the host. In fish, probiotic administration has improved growth, and immunological parameters. For this reason, it is necessary production of probiotic bacteria, however, commercial culture mediums used for probiotic growth are expensive, so the design of a "low" cost culture medium is necessary. Therefore, this research aimed to produce a potential multistrain probiotic preparation composed of L. lactis A12 and Priestia species isolated from Nile tilapia (Oreochromis niloticus) gut using an agro-industrial by-products-based culture medium. RESULTS: A Box-Behnken design with three factors (whey, molasses, and yeast extract concentration) was used. As the main results, a high concentration of three components enhanced the viability of L. lactis A12, however, viable cell counts of Priestia species were achieved at low molasses concentrations. The Optimal conditions were 1.00% w/v whey, 0.50% w/v molasses, and 1.50% w/v yeast extract. L. lactis A12 and Priestia species viable counts were 9.43 and 6.89 Log10 CFU/mL, respectively. L. lactis A12 concentration was higher (p < 0.05) in the proposed medium compared to commercial broth. CONCLUSIONS: It was possible to produce L. lactis A12 and Priestia species in co-culture conditions. Whey and molasses were suitable components to produce the multistrain preparation. The cost of the proposed culture medium was 77.54% cheaper than the commercial medium. The proposed culture medium could be an alternative to commercial mediums for the production of this multistrain probiotic.

Effect of wall material on lipophilic functional compounds of high oleic palm oil emulsions encapsulated by Refractance Window drying.

High-oleic palm oil is a food-grade oil with desirable properties, as it is characterised by having an oleic acid concentration above 50 % and a high vitamin E and provitamin A content. This study investigated the effect of different combinations of two wall materials (whey protein (WP) and Capsul®, a commercial octenyl succinic anhydride modified starch (OSA-MS)) on the concentration of provitamin A, vitamin E and oleic acid, and the physical properties of high oleic palm oil emulsions encapsulated by Refractance Window drying technology. Wall material composition significantly affected (p < 0.05) all response variables, and R2 values were above 0.75 for all responses. Phytonutrient preservation showed its highest at an OSA-MS: WP concentration ratio of 1: 3. Optimal results were achieved (minimum moisture content, water activity and hygroscopicity, and maximum encapsulation efficiency and phytonutrient preservation) at an OSA-MS concentration of 8.13 % and WP concentration of 91.87 %. Flakes were obtained as a solid structure that protects oil's phytonutrients with 94 %, 75 % and 87 % of preservation of oleic acid, vitamin E and carotenoids, respectively. It shows that the wall material combination and encapsulation technique are suitable for obtaining lipophilic functional compounds.

Probiotic Encapsulation: Bead Design Improves Bacterial Performance during In Vitro Digestion.

The stability and release properties of all bioactive capsules are strongly related to the composition of the wall material. This study aimed to evaluate the effect of the wall materials during the encapsulation process by ionotropic gelation on the viability of Lactobacillus fermentum K73, a lactic acid bacterium that has hypocholesterolemia probiotic potential. A response surface methodology experimental design was performed to improve bacterial survival during the synthesis process and under simulated gastrointestinal conditions by tuning the wall material composition (gelatin 25% w/v, sweet whey 8% v/v, and sodium alginate 1.5% w/v). An optimal mixture formulation determined that the optimal mixture must contain a volume ratio of 0.39/0.61 v/v sweet whey and sodium alginate, respectively, without gelatin, with a final bacterial concentration of 9.20 log10 CFU/mL. The mean particle diameter was 1.6 ± 0.2 mm, and the experimental encapsulation yield was 95 ± 3%. The INFOGEST model was used to evaluate the survival of probiotic beads in gastrointestinal tract conditions. Upon exposure to in the vitro conditions of oral, gastric, and intestinal phases, the encapsulated cells of L. fermentum decreased only by 0.32, 0.48, and 1.53 log10 CFU/mL, respectively, by employing the optimized formulation, thereby improving the survival of probiotic bacteria during both the encapsulation process and under gastrointestinal conditions compared to free cells. Beads were characterized using SEM and ATR-FTIR techniques.

Electrospinning Microencapsulation of Lactobacillus fermentum K73 Using Gelatin as the Main Component of a Food-Grade Matrix.

This work aimed to establish the conditions that improve the viability of Lactobacillus fermentum K73 during and after the electrospinning process. A mixture of experimental designs were performed to select the formulation (gelatin and bacterial culture) that improves the probiotic viability after blending and under simulated gastrointestinal conditions. A Box-Behnken design was performed to improve the encapsulation yield and survival during the electrospinning process. For the Box-Behnken design, the factors were soy lecithin and bacteria culture concentration at the blend and collector distance for electrospinning. It was hypothesized that soy lecithin improved the electrospinnability, acting as a surfactant in the mixture and allowing lower voltage to be used during the process. The selected volume ratio of the gelatin (25%)/bacterial culture mixture was 0.66/0.34. The physicochemical parameters of the selected blend were in the recommended range for electrospinning. The conditions that improved the encapsulation yield and survival during electrospinning were 200 g/L of bacterial culture, 2.5% (w/v) soy lecithin, and 7 cm collector distance. The experimental encapsulation yield and survival was 80.7%, with an experimental error of 7.2%. SEM micrographs showed the formation of fibers with gelatin/bacterial culture beads. Encapsulation improved the viability of the probiotic under simulated gastrointestinal conditions compared to free cells.

Evaluation of dietary single probiotic isolates and probiotic multistrain consortia in growth performance, gut histology, gut microbiota, immune regulation, and infection resistance of Nile tilapia, Oreochromis niloticus, shows superior monostrain performance.

The probiotic potential of a designed bacterial consortia isolated from a competitive exclusion culture originally obtained from the intestinal contents of tilapia juveniles were evaluated on Nile tilapia alevins. The growth performance, intestinal histology, microbiota effects, resistance to Streptococcus agalactiae challenge, and immune response were assessed. In addition, the following treatments were included in a commercial feed: A12+M4+M10 (Lactococcus lactis A12, Priestia megaterium M4, and Priestia sp. M10), M4+M10 (P. megaterium M4, and Priestia sp. M10) and the single bacteria as controls; A12 (L. lactis A12), M4 (P. megaterium M4), M10 (Priestia sp. M10), also a commercial feed without any probiotic addition was included as a control. The results showed that all probiotic treatments improved the growth performance, intestinal histology, and resistance during experimental infection with S. agalactiae in comparison to the control fish. Also, the administration of probiotics resulted in the modulation of genes associated with the innate and adaptive immune systems that were non-dependent on microbial colonization. Surprisingly, L. lactis A12 alone induced benefits in fish compared to the microbial consortia, showing the highest increase in growth rate, survival during experimental infection with S. agalactiae, increased intestinal fold length, and the number of differentially expressed genes. Lastly, we conclude that a competitive exclusion culture is a reliable source of probiotics, and monostrain L. lactis A12 has comparable or even greater probiotic potential than the bacterial consortia.

Evaluation of the Survival of Lactobacillus fermentum K73 during the Production of High-Oleic Palm Oil Macroemulsion Powders Using Rotor-Stator Homogenizer and Spray-Drying Technique.

This study aimed to evaluate the survival of the probiotic Lactobacillus fermentum when it is encapsulated in powdered macroemulsions to develop a probiotic product with low water activity. For this purpose, the effect of the rotational speed of the rotor-stator and the spray-drying process was assessed on the microorganism survival and physical properties of probiotic high-oleic palm oil (HOPO) emulsions and powders. Two Box-Behnken experimental designs were carried out: in the first one, for the effect of the macro emulsification process, the numerical factors were the amount of HOPO, the velocity of the rotor-stator, and time, while the factors for the second one, the drying process, were the amount of HOPO, inoculum, and the inlet temperature. It was found that the droplet size (ADS) and polydispersity index (PdI) were influenced by HOPO concentration and time, ζ-potential by HOPO concentration and velocity, and creaming index (CI) by speed and time of homogenization. Additionally, HOPO concentration affected bacterial survival; the viability was between 78-99% after emulsion preparation and 83-107% after seven days. The spray-drying process showed a similar viable cell count before and after the drying process, a reduction between 0.04 and 0.8 Log10 CFUg-1; the moisture varied between 2.4% and 3.7%, values highly acceptable for probiotic products. We concluded that encapsulation of L. fermentum in powdered macroemulsions at the conditions studied is effective in obtaining a functional food from HOPO with optimal physical and probiotic properties according to national legislation (>106 CFU mL-1 or g-1).

The modulatory effect of encapsulated bioactives and probiotics on gut microbiota: improving health status through functional food.

The gut microbiota can be a determining factor of the health status of the host by its association with some diseases. It is known that dietary intake can modulate this microbiota through the consumption of compounds like essential oils, unsaturated fatty acids, non-digestible fiber, and probiotics, among others. However, these kinds of compounds can be damaged in the gastrointestinal tract as they pass through it to reach the intestine. This is due to the aggressive and changing conditions of this tract. For this reason, to guarantee that compounds arrive in the intestine at an adequate concentration to exert a modulatory effect on the gut microbiota, encapsulation should be sought. In this paper, we review the current research on compounds that modulate the gut microbiota, the encapsulation techniques used to protect the compounds through the gastrointestinal tract, in vitro models of this tract, and how these encapsulates interact with the gut microbiota. Finally, an overview of the regulatory status of these encapsulates is presented. The key findings are that prebiotics are the best modulators of gut microbiota fermentation metabolites. Also, probiotics promote an increase of beneficial gut microorganisms, which in some cases promotes their fermentation metabolites as well. Spray drying, freeze drying, and electrodynamics are notable encapsulation techniques that permit high encapsulation efficiency, high viability, and, together with wall materials, a high degree of protection against gastrointestinal conditions, allowing controlled release in the intestine and exerting a modulatory effect on gut microbiota.

Chemical Characterization of Quality-Related Compounds in Cocoa Matrices: An Overview of Analytical Methods Applied for Their Analysis.

Cocoa currently faces differentiation processes toward niches of specialty products, leading to greater competitiveness for producers who must compete with products differentiated by their integral quality regarding their organoleptic characteristics, such as fine-flavor cocoa and their functional characteristics. Quality is influenced by the genetic variety of the cultivars on the one hand, and the correct postharvest processing operations of cocoa seeds, on the other. During the transformation operations, the native chemical compounds of the seeds, especially proteins, carbohydrates, and polyphenols, are transformed and generate other compounds called flavor precursors, which are responsible for defining the product quality. In this sense, the analysis of the most relevant chemical compounds in cocoa is essential to guarantee higher overall quality. Similarly, understanding the fundamental aspects that affect fine-flavor cocoa production is crucial for improving transformation processes. Therefore, reliable and robust analytical techniques are required to detect and quantify these chemical compounds. This review highlights the main techniques used to analyze essential cocoa metabolites and derived products throughout all postharvest transformation stages: from cocoa seeds to chocolate bar, offering an overview of the sample preparation methods and the analytical and imaging methodologies often employed to characterize qualifying cocoa products.

Bioaccessibility assay, antioxidant activity and consumer-oriented sensory analysis of Beta vulgaris by-product encapsulated in Ca(II)-alginate beads for different foods.

Bioaccessibility analysis and antioxidant activity along in vitro digestion and a consumer-oriented sensory analysis were conducted in three potential functional foods based on Ca(II)-alginate beads containing bioactive compounds extracted from beet stems. Ca(II)-alginate beads per se, and two selected products (cookies and turkish delights supplemented with the beads) were prepared. Regarding the beads, among the attributes rated by consumers, visual appreciation predominates, being color in the just-as-right (JAR) category and in the like preference. Instead, both flavor and sweet taste were attributes highly penalized and should be improved in beads to be accepted as food per se. A higher percentage of customers preferred cookies and turkish delights instead of only beads, considering global satisfaction. Regarding in vitro digestion, there was a significant content of phenolic compounds in the products with beads, showing a bioaccessibility greater than 80% (for cookies) and 26% (for turkish delights). Also, the antioxidant capacity measured by ABTS ranged between 50 and 109% for cookies and turkish delights, being lower when measured by FRAP (between 20 and 30%, respectively). Thus, including the beads with beet stem extract in both products leads to a significant increase in the content of phenolic compounds and in the antioxidant capacity compared to their counterparts, protecting the compound during oral and gastric phases. These results allow the generation of improved Ca(II)-alginate systems with promising functional properties for the development of ingredients and functional foods.

Preparation and Characterization of an Electrospun Whey Protein/Polycaprolactone Nanofiber Membrane for Chromium Removal from Water.

Chromium pollution represents a worldwide concern due to its high toxicity and bioaccumulation in organisms and ecosystems. An interesting material to remove metal ions from water is a whey-protein-based material elaborated by electrospinning, which is an emerging method to produce adsorbent membranes with diverse applications. The aim of this study was to prepare an adsorbent membrane of whey protein isolate (WPI) and polycaprolactone (PCL) by electrospinning to remove chromium ions from water. The adsorbent membrane was synthesized by a central composed design denaturing WPI using 2-Mercaptoethanol and mixing it with PCL to produce electrospun nanofibers. The adsorbent membrane was characterized by denaturation, Scanning Electron Microscope, Fourier-Transform Infrared Spectroscopy, Contact Angle, Thermogravimetric Analysis, and X-ray Photoelectron Spectrometry. The adsorption properties of this membrane were assessed in the removal of chromium. The removal performance of the membrane was enhanced by an increase in temperature showing an endothermic adsorption process. The adsorption process of chromium ions onto the nanofiber membrane followed the Sips adsorption isotherm, while the adsorption kinetics followed a pseudo-second kinetics where the maximum adsorption capacity was 31.0 mg/g at 30 °C and pH 2. This work provides a novel method to fabricate a hybrid membrane with amyloid-type fibrils of WPI and PCL, which is a promising adsorbent to remove heavy metal ions from water.

Preparation of a Hybrid Membrane from Whey Protein Fibrils and Activated Carbon to Remove Mercury and Chromium from Water.

Water contamination by mercury and chromium has a direct effect in human health. A promising technology to remove heavy metals by membrane filtration is the use of hybrid membranes produced with whey protein fibrils (WPF) and activated carbon (AC). In this study, the best conditions to produce WPF by heat treatment were determined to maximize the removal of mercury and chromium from water using a central composed design. The results indicated that the best conditions to prepare WPF were 74 °C, 7 h and 3.8% of whey protein with adsorption capacities of 25 and 18 mg/g and removal efficiencies of 81 and 57% for mercury and chromium, respectively. WPF and AC were used to prepare a hybrid membrane that was characterized using transmission electron microscopy, atomic force microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy and Brunauer-Emmett-Teller surface area measurements. Batch filtration experiments were performed with the hybrid membrane for chromium and mercury removal at 25, 50 and 100 mg/L to determine its adsorption capacities. A high performance of the hybrid membrane was demonstrated removing efficiently mercury and chromium from water, thus supporting more than ten filtration cycles.

Encapsulation of Lactobacillus fermentum K73 by Refractance Window drying.

The purpose of this work was to model the survival of the microorganism and the kinetics of drying during the encapsulation of Lactobacillus fermentum K73 by Refractance Window drying. A whey culture medium with and without addition of maltodextrin were used as encapsulation matrices. The microorganism with the encapsulation matrices was dried at three water temperatures (333, 343 and 353 K) until reaching balanced moisture. Microorganism survival and thin layer drying kinetics were studied by using mathematical models. Results showed that modified Gompertz model and Midilli model described the survival of the microorganism and the drying kinetics, respectively. The most favorable process conditions found with the mathematical modelling were a drying time of 2460 s, at a temperature of 353 K. At these conditions, a product with 9.1 Log CFU/g and a final humidity of 10% [wet basis] using the culture medium as encapsulation matrix was obtained. The result shows that Refractance Window can be applied to encapsulate the microorganism probiotic with a proper survival of the microorganism.

Multifunctional Role of the Whey Culture Medium in the Spray Drying Microencapsulation of Lactic Acid Bacteria.

This study aims to evaluate the multifunctional role of whey culture medium during the spray drying microencapsulation of Lactobacillus fermentum K73. Whey culture medium containing growing microorganisms served to hydrate different mixtures (gum arabic, maltodextrin and whey). We evaluated the use of these mixtures as carbon sources and their protective effects on simulated gastrointestinal conditions. The optimal mixture was spray-dried while varying the outlet temperature and atomizing pressure using a response surface design. These conditions served to evaluate microorganism survival, tolerance to gastrointestinal conditions in vitro, physicochemical properties, morphometric features and stability at 4, 25 and 37 °C. Lactobacillus fermentum K73 replicated in the carrier material. Bacterial change cycles were (-1.97±0.16) log CFU/g after the drying process and (-0.61±0.08) and (-0.23±0.00) log CFU/g after exposure of the capsules to simulated gastric pH and bile salt content, respectively. The physicochemical properties and morphometric features were within the normal ranges for a powder product. The powder was stable at a storage temperature of 4 °C. The spray drying of the whey culture medium with growing microorganisms using the optimized drying conditions was successful. This study demonstrates the use of whey culture medium as a component of carrier material or as the carrier material itself, as well as its protective effects during drying, under simulated gastrointestinal conditions, and at varied storage temperatures.

Physical, thermal and thermodynamical study of high oleic palm oil nanoemulsions.

Nanoemulsions are useful for encapsulating nutritionally compounds of the high oleic palm oil (HOPO) including ß-carotene and tocopherols. However, some nanoemulsions can be thermodynamically unstable. For this reason, it is important to understand the thermal and thermodynamic stability of nanoemulsions and to investigate both the parameters that cause, and the mechanisms associated with, the destabilization. In this sense, the DSC, TGA and destabilization analysis were used. In this work, the average droplet size (ADS) and zeta potential (ζ) had a significant influence over HOPO nanoemulsions stability. The range of ADS and ζ were between 162 and 839 nm and -9 to -40 mV, respectively. Furthermore, the HOPO nanoemulsions were establish until temperatures of 80 °C, showing lower loss of weight when the ADS was higher. Additionally, the destabilization of nanoemulsions occurred by the Ostwald ripening mechanism. The Ostwald ripening rate was provided as stability parameter which increased to nanoemulsions with ADS higher between 5 × 10-23 and 8 × 10-23 m3/s.

Changes of the water-holding capacity and microstructure of panga and tilapia surimi gels using different stabilizers and processing methods.

Surimi gel is a food product traditionally manufactured from marine species; it has functional features including a specific texture and a high protein concentration. The objective of this study was to evaluate and compare the effect of the ultrasound extraction protein method and different stabilizers on the water-holding capacity (WHC), texture, and microstructure of surimi from panga and tilapia to potentially increase the value of these species. For this purpose, WHC was determined and texture profile analysis, scanning electron microscopy, and texture image analysis were carried out. The results showed that the ultrasound method and the sodium citrate can be used to obtain surimi gels from panga and tilapia with optimal textural properties such as the hardness and chewiness. Moreover, image analysis is recommended as a quantitative and non-invasive technique to evaluate the microstructure and texture image properties of surimis prepared using different processing methods and stabilizers.

Water droplet spreading and recoiling upon contact with thick-compact maltodextrin agglomerates.

BACKGROUND: The food and pharmaceutical industries handle a number of compounds in the form of agglomerates which must be put into contact with water for rehydration purposes. In this work, liquid-solid interaction between water and maltodextrin thick-compact agglomerates was studied at different constituent particle sizes for two compression forces (75 and 225 MPa). RESULTS: Rapid droplet spreading was observed which was similar in radius to the expected one for ideal, flat surfaces. Contact angle determinations reported oscillations of this parameter throughout the experiments, being indicative of droplet recoiling on top of the agglomerate. Recoiling was more frequent in samples obtained at 225 MPa for agglomerate formation. Agglomerates obtained at 75 MPa exhibited more penetration of the water. Competition between dissolution of maltodextrin and penetration of the water was, probably, the main mechanism involved in droplet recoiling. Micrographs of the wetting marks were characterized by means of image analysis and the measurements suggested more symmetry of the wetting mark at higher compression force. CONCLUSION: Differences found in the evaluated parameters for agglomerates were mainly due to compaction force used. No significant effect of particle size in recoiling, penetration of water into the agglomerate, surface texture and symmetry was observed.