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Iranian drinking yogurt (Doogh) is one of the traditional beverages that are commonly consumed and commercialized in Iran. The spoilage of Doogh is caused by a wide diversity of microorganisms such as bacterial and fungal flora. In the present study, twenty contaminated Doogh samples with signs of spoilage such as swelling, off-odor and bitter taste were collected from an industrial dairy factory of Khorasan Razavi province in Iran. In total, 20 isolates of bacteria were identified. Initially, biochemical tests such as catalase, oxidase, sugars fermentation, starch hydrolysis, Voges–Proskauer, indole, ability to grow at 6.5% NaCl salt concentration, motility and citrate utilization tests were conducted for identification. Also, for final confirmation, all the isolates were subjected to molecular investigation using 16S rRNA. The existence of five bacterial genera including Acinetobacter (50%), Bacillus (35%), Klebsiella (5%), Moraxella (5%), and Lactococcus (5%) was verified. Acinetobacter johnsonii and Bacillus licheniformis were the predominant species in all Doogh samples. Identification of the exact type of microorganisms will be playing, effective role to apply appropriate strategies to control (reduce or eliminate) the microbial spoilage.

Lactobacillus plantarum and Bifidobacterium lactis were co-encapsulated separately with either inulin or resistant starch in Ca-alginate/chitosan microcapsules by electro-hydrodynamic atomization (EHDA). Encapsulation yield of core materials and their release profile were studied. Protective role of polysaccharide matrix on bacteria under gastrointestinal (GI) conditions and storage at 25, 4 or −18 °C were investigated. Encapsulation yield was calculated to be 98, 79 and 99 percent for bacteria, inulin and resistant starch, respectively. Ten percent of inulin was expelled from the Ca-alginate network into water after 24 h; however, no resistant starch was released. Chitosan coating reduced the release of inulin by up to 5 percent. Survival studies showed 5.90 ± 0.3 log CFU/g of Lb. plantarum and 7.19 ± 0.15 log CFU/g of B. lactis survived GI conditions in starch-containing microcapsules. Viability loss of Lb. plantarum was successfully restricted during storage at room temperature by encapsulation in Inulin-containing microcapsules as 6.33 ± 0.21 log CFU/g survived after 90 days storage. The findings revealed EHDA can be employed for co-encapsulation of probiotics and high molecular weight prebiotics in micron-sized capsules which could open up a new perspective for targeted delivery of live cells to the colon through foods.

Background Today, there is an increasing concern about the consumption of synthetic colorants in food because of their possible health hazards. Monascus purpureus has attracted a great deal of attention as it produces various coloured pigments with high chemical stability, but it also produces citrinin, a secondary toxic metabolite, along with the pigments. This study aims to investigate the amount of pigment and citrinin reduction by different treatments with Saccharomyces cerevisiae such as heat treatment and suspension concentration. Results The results indicated that the ability of S. cerevisiae regarding citrinin adsorption increased with increase of temperature and yeast concentration. The maximum extent of citrinin adsorption was related to heat treatment at 121 °C and a yeast concentration of 105 cells mL-1 , for which citrinin reduced from 4.43 mg L-1 in control to 0.1 mg L-1 . Heat treatment of 103 cells mL-1 suspension of S. cerevisiae cells at 50 °C, with 0.56 mg L-1 citrinin remaining in the medium, showed the lowest ability for citrinin binding. The optimum absorbance of all red, orange and yellow pigments was observed for the heat treatment at 50 °C and yeast concentrations of 103 and 104 cells mL-1 which was greater than that for the control. Conclusions We can conclude from this study that heat treatment with S. cerevisiae can be a useful way to reduce citrinin to below the standard limits. © 2019 Society of Chemical Industry.

In this study, we aimed to evaluate the possibility of obtaining natural high-resistant protein capsules from aqueous solution of whey protein containing transglutaminase (TG) enzyme through electrohydrodynamic atomization (EHDA) as an appropriate system, and freeze-drying (FD) technique as the control method for encapsulation of Lactobacillus casei. A stable cone jet was achieved in a certain electrical conductivity, surface tension, and viscosity values equal to 1681 ± 8.49 μS, 48.97 ± 0.02 mN/m, and 51.96 ± 0.78 cP, respectively. Spherical water-resistant capsules with an average diameter of 3.09 ± 1.04 μm were obtained through the EHDA process. A comparison between the EHDA and FD revealed higher encapsulation efficiency of the electrospraying technique as well as greater viability of L. casei under the simulated gastrointestinal (GI) tract. DSC results showed that the enthalpy of cross-linked samples was decreased by incorporating TG enzyme. In contrast to freeze-dried structures, electrosprayed capsules revealed better protection during the storage, especially in the second and third months.

This work reports on a simple, fast and food-grade encapsulation approach with potential for probiotic protection, which consists on the formation of agarose-based hydrogel particles. These were generated by the supramolecular self-assembly of the probiotic-containing carbohydrate solutions by dripping them into a biphasic bath with an upper oil layer, which acted as the particle-forming antisolvent, and a lower aqueous layer, where the hydrogel particles were collected. This technique, which we have named “oil-induced biphasic hydrogel particle formation”, has been used to encapsulate the sensitive strain Bifidobacterium pseudocatenulatum CECT 7765. In order to avoid agarose gelling at 40 °C before the encapsulation process, this seaweed-derived carbohydrate was combined with other hydrocolloids (alginate, whey protein concentrate, and gelatin), and the obtained probiotic-containing hydrogel particles were subsequently freeze-dried. The protection ability of this method versus directly freeze-drying the probiotic-containing solutions was demonstrated during storage and simulated in-vitro digestion. Both the formation of a continuous layer surrounding the bacteria and the optimal combination of materials (agarose providing suitable oxygen barrier and WPC with proven probiotic affinity) rendered encapsulation systems keeping viability levels required for commercial applications., A. Alehosseini received a scholarship by the Ministry of Science, Research and Technology of Iran. M.J. Fabra is recipient of a Ramon y Cajal (RYC-2014-158) contract from the Spanish Ministry of Economy, Industry and Competitiveness. The authors would like to thank the Spanish MINECO project AGL2015-63855-C2-1 and the Agencia Estatal de Investigación for financial support. ABP and EMGP are contracted with the grant no 613979 of the European Union's Seventh Framework Program (MyNewGut).

The objective of this work was to investigate whether the use of unpurified agar-based fractions extracted from the seaweed Gelidium as microencapsulation matrices has an impact on probiotic protection during storage. Therefore, unpurified and pure agar and agarose-based microcapsules were produced through emulsification/internal gelation for the protection of Bifidobacterium pseudocatenulatum CECT 7765. Initially, agarose-based formulations with other biopolymers were evaluated, given the excellent oxygen barrier properties of this polysaccharide. The optimal combination in terms of probiotic protection was selected for further experiments and this agarose-based formulation was compared with microcapsules produced using both pure and unpurified agar-based fractions. The presence of other compounds (mainly proteins and polyphenols) in the unpurified agar fractions significantly improved the viability of these sensitive probiotic bacteria both at ambient and refrigerated storage conditions. Furthermore, the presence of impurities allowed the increase of solids content in the formulation giving raise to stronger gel particles, which could contribute to limited oxygen diffusion, thus, partly explaining the improved protection. Therefore, this work demonstrates the potential of more cost-effective less purified carbohydrate-based fractions for probiotic protection., This work was financially supported by the “Agencia Estatal de Investigación” and co-funded by the European Union's Horizon 2020 research and innovation programme (ERA-Net SUSFOOD2) and the European Union's Seventh Framework Program under the grant agreement no 613979 (MyNewGut). Marta Martinez-Sanz, Maria José Fabra and Laura G. Gómez-Mascaraque are recipients of a Juan de la Cierva (IJCI-2015-23389), Ramon y Cajal (RYC-2014-158) and predoctoral (BES-2013-065883) contracts, respectively, from the Spanish Ministry of Economy, Industry and Competitiveness.

Aflatoxin M1 (AFM1) contamination presents one of the most serious concerns in milk safety. In this study, the immobilization of Saccharomyces cerevisiaewas used to detoxify AFM1‐contaminated milk. The yeasts were immobilized on perlite for 24 and 48 hr, and the best immobilization time was achieved at 48 hr. Microscopic examination confirmed successful immobilization. The milk samples with 0.08, 0.13, 0.18, and 0.23 ppb AFM1 contamination were passed through the biofilter for 20, 40, and 80 min. The results showed a significant reduction in AFM1 concentration for all the milk samples with various initial AFM1 contents. The contaminated milk with 0.08 ppb AFM1 was completely cleared after 40 min of circulation while for the milk solution with 0.23 ppb, the highest AFM1 reduction was obtained at about 81.3% after 80 min circulation. In addition, the biofilter was saturated after the third step of milk circulation, containing 0.23 ppb AF, in which each step duration was 20 min. This study showed the excellent capability of the immobilized cells on the perlite beads to detoxify the AFM1‐contaminated milk without any side effects on its physicochemical properties. The immobilization of Saccharomyces cerevisiaecells on perlite beads can be used to detoxify AFM1‐contaminated milk. The perlite can provide a perfect support for immobilization. With respect to qualitative properties, 20 min, was suggested as the optimum time for milk decontamination. This study indicated that the detoxification of contaminated milk using immobilized S. cerevisiaecells on the perlite support did not affect the different properties of detoxified milk. This method can lead to a practical solution to address aflatoxin contamination in dairy products considered high‐risk foods.

Pomegranate peel extract (PPE) is a valuable source of bioactive compounds, with antimicrobial activity. On the other hand, reducing the extract particle size to a nano-scale due to the increase in the surface-to-volume ratio can increase its effectiveness. The alginate nanospheres containing PPE were prepared through water in oil (W/O) emulsification and external gelation with calcium chloride nanoparticles. The optimum ratios for alginate:PPE and alginate:calcium chloride nanoparticles, based on encapsulation efficiency and nanospheres size, were 4:1 and 9:1, respectively (p

The aims of this work were to investigate the influence of solution parameters on Ca-alginate/chitosan hydrogel microcapsules generated by electrospraying through a single-stage procedure and subsequently employing it for encapsulation of live probiotics ( Lactobacillus plantarum ). The encapsulation yield of bacteria and their survival under simulated gastrointestinal conditions were evaluated. The protective role of chitosan, either included in the alginate matrix or deposited as an outer layer after formation of microcapsules, on the viability of bacteria was also investigated. Increasing the Na-alginate concentration resulted in larger and more uniform microcapsules. However, the size of microcapsules decreased and their size distribution became narrower by increasing surfactant concentration. Altering the concentration of Ca 2+ and chitosan in the collector solution did not affect the size of microcapsules significantly. Encapsulation yield showed that almost 97 and 98% of probiotic bacteria were encapsulated viably within spherical Ca-alginate/chitosan microcapsules by single- and double-stage procedures, respectively. However, it was revealed that the different microcapsule matrices formed by the two fabrication procedures played an important role in survivability of bacteria during storage and exposure to acid. It was also found that the outer layer of chitosan, which was deposited on Ca-alginate microcapsules by double-stage procedure, more efficiently protected bacteria at low pH environments.

Ca-alginate/chitosan microcapsules were made by electro-hydrodynamic processing. Two different microstructures were formed through the application of single- or double-stage procedures. Inulin or resistant starch, as prebiotic components, and Lactobacillus plantarum, as a probiotic strain, were incorporated into the microcapsules and viability of bacteria was monitored during the storage for 90 days. Microcapsules containing probiotic-prebiotic blends were employed as an ingredient in the formulation of ice-cream. The bacterial survival was also studied after the production and storage of the ice-cream. FTIR spectra confirmed the formation of polyelectrolyte complexes between alginate and chitosan. SEM images revealed that a chitosan layer thoroughly coated the Ca-alginate microcapsules formed through the double-stage procedure. After incorporation of either inulin or resistant starch into the microcapsules, the signal of the inulin was detected at 935 cm−1, and signals of the starch were traced at 1157 and 930 cm−1 in their FTIR spectra. Both polysaccharide matrices significantly improved probiotic survival during the storage of microcapsules. However, inulin-containing microcapsules showed a better performance than starch-containing ones as 7.23 ± 0.21 and 9.15 ± 0.33 log CFU g−1 of probiotics remained viable in them after storage at 25 and 4 °C, respectively. The microcapsules also improved the viability of probiotics after incorporating into the ice-cream as 7.37 ± 0.12 and 7.82 ± 0.39 log CFU g−1 of bacteria were viable after 90 days in inulin- and starch-containing microcapsules, respectively. These findings suggest that such microcapsules could be used as an ingredient for formulated functional foods.