Optimization of exopolysaccharide production by probiotic yeast Lipomyces starkeyi VIT-MN03 using response surface methodology and its applications

Purification, structural characterization, and bioactive properties of exopolysaccharides from Saccharomyces cerevisiae HD-01

Exopolysaccharides (EPSs), which show excellent biological activities, like anti-tumor, immune regulation, and anti-oxidation activities, have gained widespread attention. In this study, an EPS-producing Saccharomyces cerevisiae HD-01 was identified based on 18S rDNA sequence analysis and an API 20C test. The purified HD-01 EPS was obtained by gel filtration chromatography. High-performance liquid chromatography (HPLC), gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR), and nuclear magnetic resonance (NMR) revealed that it was a heteropolysaccharide composed of α-1 (38.3%), α-1, 2 (17.5%), α-1, 6 (14.8%)-linked mannose and α-1, 2, 3, 6 (24.3%), α-1 (3.3%), β-1, 4 (1.8%)-linked glucose. Chemical composition and elemental analysis indicated the existence of sulfation modifications. A scanning electron microscope (SEM) and an atomic force microscope (AFM) revealed that it exhibited a flaky structure with thorn-like protrusions on the three-dimensional surface. X-ray diffraction (XRD) revealed that it was an amorphous non-crystalline substance. HD-01 EPS had great thermostability; probiotic properties; strong antioxidant properties to DPPH, ABTS, and hydroxyl; and good reducing power. The MTT, NO, and neutral red assays demonstrated that it had a great immunomodulatory effect on macrophages RAW264.7. All results suggested that the HD-01 EPS had the potential to be applied in the food and pharmaceutical fields.

Bioprospecting of exopolysaccharides from the endophytic fungi Epicoccum sorghinum AMFS4, for its structure, composition, bioactivities and application in seed priming

The endophytic fungi, Epicoccum sorghinum AMFS4 was investigated for its metabolic components and composition of bioactive exopolysaccharides (EPS). Metabolic analysis of the ethyl acetate extract majorly detected sugars derivatives such as, 4-Cholesten-3-one semicarbazone (20.9%), d-Fructose (18.96%), and α-d-Galactopyranosiduronicacid (1.71%). The growth curve and EPS yield were determined as 12.22 ± 1.02 g/L and 7.41 ± 0.32 g/L (dry weight) respectively on day 8. The deproteined EPS has been characterised with pyranose ring linked by α-glycosidic bonds, composing fructose, galactose and glucose monosaccharides validated by HPLC. Total sugar content was found to be 93.18 ± 0.81% with detection of proteins and uronate. The viscous EPS appeared filamentous under SEM observation and behaves as emulsifier with notable antioxidant properties. Priming of EPS on tomato seeds showed early induction of secondary rooting than in the control seedlings. Thus, E. sorghinum AMFS4 synthesises bioactive EPS with simple carbohydrate structure, good water absorption and significant metabolic influence on seed germination.

Fabrication and characterisation of human gut microbiome derived exopolysaccharide mediated silver nanoparticles - An in-vitro and in-vivo approach of Bio-Pm-AgNPs targeting Vibrio cholerae

Utilising bacteria to produce silver nanoparticles was highly favoured due to its ability to minimise costs and mitigate any potential negative environmental impact. Exopolysaccharides (EPS) extracted from the human gut microbe have demonstrated remarkable efficacy in combating various bacterial infections. Exopolysaccharide (EPS), a naturally occurring biomolecule found in the human gut isolate Proteus mirabilis DMTMMR-11, was characterised using analytical techniques such as Fourier transform infrared spectroscopy (FTIR), 1H-nuclear magnetic resonance, 13C-nuclear magnetic resonance (NMR), and chemical composition analysis, which confirms the presence of carbohydrates (81.03 ± 0.23), proteins (4.22 ± 1.2), uronic acid (12.1 ± 0.12), and nucleic acid content (2.44 ± 0.15) in exopolysaccharide. The one factor at a time (OFAT) and response surface methodology (RSM) - central composite design (CCD) approaches were used to optimise the production of Bio-Pm-AgNPs, leading to an increase in yield of up to 1.86 g/l. The Bio-Pm-AgNPs were then subjected to Fourier transform infrared spectroscopy (FTIR) which determines the functional groups, X-ray diffractometer confers that Bio-Pm-AgNPs are crystalline in nature, field emission-scanning electron microscopy (FE-SEM) reveals the morphology of Bio-Pm-AgNPs, energy dispersive X-ray spectroscopy (EDX) confirms the presence of elements like Ag, C and O, high-resolution transmission electron microscopy (HR-TEM) determines that the Bio-Pm-AgNPs are sphere-shaped at 75 nm. Dynamic light scattering (DLS) and zeta potential analysis were also carried out to reveal the physiological nature of Bio-Pm-AgNPs. Bio-Pm-AgNPs have a promising effect on the inhibitory mechanism of Vibrio cholerae cells at a MIC concentration of 20 μg/ml which significantly affects cellular respiration and energy metabolism through glycolysis and TCA cycles by deteriorating the enzyme responsible for ATP and NADH utilisation. The action of Bio-Pm-AgNPs reduces the purity and concentration of nucleic acids, which leads to higher DNA damage. In-vivo analysis reveals that the treatment of Bio-Pm-AgNPs decreased the colonisation of V. cholerae and improved the survival rates in C. elegans.

Fungi-derived natural antioxidants

In humans, exogenous antioxidants aid the endogenous antioxidant system to detoxify excess ROS generated during oxidative stress, thereby protecting the body against various diseases and stressful conditions. The majority of natural antioxidants available on the consumer market are plant-based; however, fungi are being recognized as alternative sources of various natural antioxidants such as polysaccharides, pigments, peptides, sterols, phenolics, alkaloids, and flavonoids. In addition, some exogenous antioxidants are exclusively found in fungi. Fungi-derived antioxidants exhibit scavenging activities against DPPH, ABTS, hydroxyl, superoxide, hydrogen peroxide, and nitric oxide radicals in vitro. Furthermore, in vivo models, application of fungal-derived antioxidants increase the level of various antioxidant enzymes, such as catalases, superoxide dismutases, and glutathione peroxidases, and reduce the level of malondialdehyde. Therefore, fungi-derived antioxidants have potential to be used in the food, cosmetic, and pharmaceutical industries. This review summarizes the antioxidant potential of different fungi (mushrooms, yeasts, and molds)-derived natural compounds such as polysaccharides, pigments, peptides, ergothioneine, ergosterol, phenolics, alkaloids, etc.

Evaluation of antioxidation, regulation of glycolipid metabolism and potential as food additives of exopolysaccharide from Sporidiobolus pararoseus PFY-Z1

At present, there are relatively few studies on the production of exopolysaccharide (EPS) by yeasts. Therefore, exploring the properties of EPS produced by yeast can not only enrich the source of EPS, but also play an important role in its future application in the food field. The aim of this study was to explore the biological activities of EPS (named SPZ) from Sporidiobolus pararoseus PFY-Z1, as well as the dynamic changes in physical and chemical properties that occur during simulated gastrointestinal digestion, and the effects of SPZ on microbial metabolites during fecal fermentation in vitro. The results revealed that SPZ had good water solubility index, water-holding capacity, emulsifying ability, coagulated skim milk, antioxidant properties, hypoglycemic activities, and bile acid-binding abilities. Furthermore, the content of reducing sugars increased from 1.20 ± 0.03 to 3.34 ± 0.11 mg/mL after gastrointestinal digestion, and had little effect on antioxidant activities. Moreover, SPZ could promote the production of short-chain fatty acids during fermentation for 48 h, in particular, propionic acid and n-butyric acid increased to 1.89 ± 0.08 and 0.82 ± 0.04 mmol/L, respectively. Besides this, SPZ could inhibit LPS production. In general, this study can help us to better understand the potential bioactivities, and the changes in bio-activities of compounds after digestion of SPZ.

Characterizing and demonstrating the role of Klebsiella SSN1 exopolysaccharide in osmotic stress tolerance using neutron radiography

Exopolysaccharides (EPS) are organic macromolecules naturally secreted by many microorganisms. EPS is increasingly used for agriculture and industrial purposes. This study focuses on isolate Klebsiella pneumonia SSN1, Klebsiella quasipeumonniae SGM81 isolated from rhizosphere to explore its water retention efficiency under drought conditions. Neutron Radiography was used to visualise water distribution in the sand under normal and drought conditions in the presence and absence of EPS producing bacteria. The EPS production was studied by applying Box Behnken design (BBD) under drought stress which was artificially induced by using polyethene glycol 6000 under osmotic stress condition 3.65% w/v of EPS dry weight was obtained. The relative water content (RWC) is used to calculate the amount of water present in the sand and was further studied by Neutron Radiography imaging with appropriate controls. FTIR and HPLC were also carried out for the characterisation of the extracted EPS. The sand experiments revealed that after 24 h of evaporation, the highest RWC was maintained by SSN1 at 29.7% compared to SGM81 (19.06%). SSN1 was found to release L-arabinose as the main sugar of its EPS under drought stress conditions by HPLC method. The FTIR data indicated the presence of β-glucans and polysaccharide α-pyranose between wavenumber 700 cm^-1-1500 cm^-1 and 1017 cm^-1-1200 cm^-1 respectively. The HPLC characterization of extracted EPS from osmotic stressed cells (run 3) displayed a peak designated to L-arabinose at 10.3 retention time (RT) for 132.4 mM concentration. While from run 5 with the controlled condition indicated the presence of L-rhamnose at 7.3 RT for 87 mM concentration. Neutron radiography enables the visualisation of water distribution in the sand as well as water transport in root-soil systems in situ. SSN1 has elicited EPS production in drought conditions with a low level of nitrogen and carbon.

Socio-ecological well-being perspectives of wetland loss scenario: A review

Previous original research focused on wetland loss and finding out its drivers across different regional units of the world. A few reports also tried to account world's condition on wetland loss. A couple of review articles articulated the causes of wetland loss and services. The present study intended to explore the linkage between wetland loss rate and processes concerning socio-ecological well-being parameters to highlight alternative ways to adopt wetland conservation policies. A total of 132 pieces of Scopus index literature were taken analysing loss rate and drivers of loss from 22 sample countries where publication frequency is relatively high. Meta-analysis was done to explain the publication trend and spatial change in publication polarity. Results distinctly revealed that the rate of wetland loss varies from 0.06% to 4.81% annually, with substantially low in developed countries (DC) than in developing (DeV) and least developed countries (LDC). Six drivers, such as agricultural land expansion, the built-up area, the conversion to grassland area, construction of the dam, climate change and tourism, were the primary drivers. But all these are not equally active across the DC, DeV and LDC. Climate change, tourism development in DC, agriculture and built-up expansions in the Dev and LDC appeared as the major causes behind wetland loss. Socio-ecological well-being parameters like human development, environmental performance, social progression, and economic status were found to be significantly negatively (-0.48 to -0.57), and the poverty rate was positively (0.27) associated with the rates of wetland loss. Drivers also varied with respect to the socio-ecological conditions. These findings are not merely added knowledge to the state-of-arts but are also helpful in re-directing global policies toward wetland conservation.

Characterization of Probiotic Pichia sp. DU2-Derived Exopolysaccharide with Oil-in-Water Emulsifying and Anti-biofilm Activities

Probiotic-derived exopolysaccharides are considered as promising sources of carbohydrate with extensive applications in many industries. In the current study, yeast strains were isolated from chicken ingluvies and gizzard samples. According to molecular identification, EPS-producing yeast (Pichia sp. DU2) showed the most similarity to Pichia cactophila (99.67%). Pichia sp. DU2 showed probiotic properties. EPS of Pichia sp. DU2 showed emulsifying activity. The formed emulsions showed 53% (colza oil) and 100% (p-xylene) stability after 24 h. These emulsions were oil-in-water and have stability in the presence of NaCl, KCl, and also acidic and basic conditions. Also, the EPS showed anti-biofilm (29.7-47.6% and 19.06-55.26% against B. cereus and Y. enterocolitica, respectively) and flocculating activities (31.4%). FT-IR showed the presence of various functional groups in EPS structure. Also, its heteropolysaccharide nature was revealed in ¹H-NMR and HPLC analysis. This emulsifying EPS showed significant thermal stability and negative zeta potential, which make it a promising carbohydrate for various industries. Finally, according to the predicted model, the maximal EPS production was achieved at reaction time 36 h, pH 6, yeast extract concentration 1.0%, and sucrose concentration 5%. Pichia sp. DU2 with probiotic properties and producing EPS with emulsifying, anti-biofilm, and flocculating activities can be considered as promising yeast strain in various industries like food and pharmaceutical industries.

Chemical characterization and biological effect of exopolysaccharides synthesized by Antarctic yeasts Cystobasidium ongulense AL101 and Leucosporidium yakuticum AL102 on murine innate immune cells

The current study aimed to investigate exopolysaccharides (EPSs) produced by two Antarctic yeasts isolated from soil and penguin feathers samples collected on Livingston Island (Antarctica). The strains were identified as belonging to the species Leucosporidium yakuticum (LY) and Cystobasidium ongulense (CO) based on molecular genetic analysis. The EPS production was investigated using submerged cultivation. Different chemical, chromatographic, and spectral analyses were employed to characterize EPSs. LY accumulated 5.5 g/L biomass and 4.0 g/L EPS after 120 h of cultivation, while CO synthesized 2.1 g/L EPS at the end of cultivation, and the biomass amount reached 5.5 g/L. LY-EPS was characterized by a higher total carbohydrate content (80%) and a lower protein content (18%) by comparison with CO-EPS (62%, 30%). The LY-EPS mainly consisted of mannose (90 mol%), whereas CO-EPS had also glucose, galactose, and small amounts of uronic acids (8-5 mol%). Spectral analyses (FT-IR and 1D, 2D NMR) revealed that LY-EPS comprised a typical β-(1 → 4)-mannan. Branched (hetero)mannan, together with β/α-glucans constituted the majority of CO-EPS. Unlike LY-EPS, which had a high percentage of high molecular weight populations, CO-EPS displayed a large quantity of lower molecular weight fractions and a higher degree of heterogeneity. LY-EPS (100 ng/mL) elevated significantly interferon gamma (IFN-γ) production in splenic murine macrophages and natural killer (NK) cells. The results indicated that newly identified EPSs might affect IFN-γ signaling and in turn, might enhance anti-infectious responses. The data obtained also revealed the potential of EPSs and yeasts for practical application in biochemical engineering and biotechnology.

Artificial neural network modeling and statistical optimization of medium components to enhance production of exopolysaccharide by Bacillus sp. EPS003

Microbial Exopolysaccharides (EPS) have a wide range of applications in food, cosmetics, agriculture, pharmaceutical industries, and environmental bioremediation. The present study aims at enhancing the production of EPS from a soil-isolate Bacillus sp. EPS003. Effects of carbon and nitrogen sources and process conditions were evaluated one factor at a time. Box-Behnken design has been used and a 2.5-fold increase in yield is reported after optimizing the most influential parameters sucrose, yeast extract, and peptone as identified by the Plackett-Burman method. An artificial neural network (ANN) with two different topologies (EPS-NN1 and EPS-NN2) was developed. On comparing prediction accuracy, EPS-NN2 formulated as one input layer with four input variables (sucrose, yeast extract, peptone, biomass), a single hidden layer with seven neurons and EPS yield in the output layer showed a high coefficient of determination (R²-0.98) and low error (NRMSE-0.024). This study concludes that the consideration of biomass value has increased the prediction accuracy of the model.

Exopolysaccharide from the yeast Papiliotrema terrestris PT22AV for skin wound healing

INTRODUCTION

Exopolysaccharides (EPSs) are high-value functional biomaterials mainly produced by bacteria and fungi, with nutraceutical, therapeutic and industrial potentials.

OBJECTIVES

This study sought to characterize and assess the biological properties of the EPS produced by the yeast Papiliotrema terrestris PT22AV.

METHODS

After extracting the yeast's DNA and its molecular identification, the EPS from P. terrestris PT22AV strain was extracted and its physicochemical properties (structural, morphological, monosaccharide composition and molecular weight) were characterized. The EPS's in vitro biological activities and in vivo wound healing potential were also evaluated.

RESULTS

The obtained EPS was water-soluble and revealed an average molecular weight (M_w) of 202 kDa. Mannose and glucose with 97% and 3% molar percentages, respectively, constituted the EPS. In vitro antibacterial activity analysis of the extracted EPS exhibited antibacterial activity (>80%) against Escherichia coli, Staphylococcus aureus, and Staphylococcus epidermidis at a concentration of 2 mg/mL. The EPS showed cytocompatibility against the human fibroblast and macrophage cell lines and the animal studies showed a dose-dependent wound healing capacity of the EPS with higher wound closure at 10 mg/mL compared to negative and positive control after 14 days.

CONCLUSION

The EPS from P. terrestris PT22AV could serve as a promising source of biocompatible macromolecules with potential for skin wound healing.

Exploring biotechnological and functional characteristics of probiotic yeasts: A review

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In this review, the probiotic attributes of yeasts other than Saccharomyces boulardii and the various applications of probiotic yeast in biotechnology have been explored.

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This review comprises of the probiotic attributes, antagonistic activity against pathogens, plant growth promoting attributes, industrial application and their biotherapeutic potentials.

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Advanced and additional studies on non-Saccharomyces yeasts are necessary prior to administer these yeasts as potential probiotics for health and wellbeing.

Probiotics are vital and beneficial organisms which offers the health benefits to the host organisms. The fungal probiotic field is one of the developing fields nowadays. Yeast has an enormous and diverse group of microorganisms that is attracting and expanding the attention from researchers and industries. Saccharomyces boulardii, the only patented strain belonging to yeast genera for the human use, has been broadly evaluated for its probiotic effect. Yeasts belonging to the genera Debaryomyces, Pichia, Yarrowia, Meyerozyma, Kluyveromyces etc.., have attained more interest because of their beneficial and probable probiotic features. These yeast probiotics produce VOCs (Volatile organic compounds), mycocins and antimicrobials which shows the antagonistic effect against pathogenic fungi and bacteria. Additionally, those yeasts have been recorded as good plant growth promoting microorganisms. Yeast has an important role in environmental applications such as bioremediation and removal of metals like chromium, mercury, lead etc., from waste water. Probiotic yeasts with their promising antimicrobial, antioxidant, anticancer properties, cholesterol assimilation and immunomodulatory effects can also be utilized as biotherapeutics. In this review article we have made an attempt to address important yeast probiotic attributes.

Production and Chemical Characterization of Exopolysaccharides by Antarctic Yeasts Vishniacozyma victoriae and Tremellomycetes sp

The study aimed to investigate exopolysaccharides (EPSs) produced by two Antarctic yeasts isolated from Livingston Island. The species were identified as Vishniacozyma victoriae (V) and Tremellomycetes sp. (T) based on a molecular genetic analysis of ITS1-5.8S-ITS4 regions of the 18S rRNA gene. The EPS production was investigated under stress conditions in culture flasks and a bioreactor. Different chromatographic (HPLC-RID, HPSEC-RID) and spectral (FT-IR) analyses were employed to characterize EPSs. Tremellomycetes sp. accumulated 7 g/L biomass and 4.5 g/L EPS after 120 h of cultivation. The total carbohydrate content of V-EPS and T-EPS was 75.4% and 79.0%, respectively. The EPSs mainly consisted of mannose (30–32%), which was followed by glucose, xylose, galactose, and small amounts of uronic acids (6.3–7.0%). EPSs had appreciable amounts of proteins (11–12%). The FT-IR spectra contained absorption bands typical for hetero-mannans and β-glucans (797–1033 cm−1). EPSs were heterogeneous with a broad molecular weight distribution range (47 × 104–68 × 104 g/mol). In conclusion, both yeasts synthesized high-molecular-weight heteromannans, and Tremellomycetes sp. stood out as being a better producer than V. victoriae. The current study also formed a basis for a better assessment of the potential for practical application of EPSs and yeasts in biochemical engineering and biotechnology.

Physicochemical Characterization of an Exopolysaccharide Produced by Lipomyces sp. and Investigation of Rheological and Interfacial Behavior

The present study aimed to evaluate the rheological and interfacial behaviors of a novel microbial exopolysaccharide fermented by L. starkeyi (LSEP). The structure of LSEP was measured by LC-MS, ¹H and ¹³C NMR spectra, and FT-IR. Results showed that the monosaccharide composition of LSEP was D-mannose (8.53%), D-glucose (79.25%), D-galactose (7.15%), and L-arabinose (5.07%); there existed the anomeric proton of α-configuration and the anomeric carbon of α- and β-configuration; there appeared the characteristic absorption peak of the phosphate ester bond. The molecular weight of LSEP was 401.8 kDa. The water holding capacity (WHC, 2.10 g/g) and oil holding capacity (OHC, 12.89 g/g) were also evaluated. The results of rheological properties showed that the aqueous solution of LSEP was a non-Newtonian fluid, exhibiting the shear-thinning characteristics. The adsorption of LSEP can reduce the interfacial tension (11.64 mN/m) well and form an elastic interface layer at the MCT–water interface. Such functional properties make LSEP a good candidate for use as thickener, gelling agent, and emulsifier to form long-term emulsions for food, pharmaceutical, and cosmetic products.

The response surface optimization of exopolysaccharide produced by Saccharomyces cerevisiae Y3 and its partial characterization

Response surface methodology (RSM) was used to optimize the conditions of exopolysaccharides (EPSs) by Saccharomyces cerevisiae Y3. The results indicated that the yield of EPS reached 4.52 ± 0.14 g/L with 10.30% (w/v) sucrose, 0.64% (w/v) yeast extract, liquid volume 141.5 mL, which was 2.40 times the original EPS yield. Y3 EPS contained 83.65 ± 0.16% of total sugars, 15.27 ± 0.26% of uronic acid, 0.78 ± 0.02% of protein and 0.30 ± 0.12% of sulfuric acid groups. Y3 EPS maintained a relatively low viscosity, with intrinsic viscosities of 306.58 mL/g (25 °C) and 200.91 mL/g (35 °C), respectively. The EPS had high water solubility index (WSI), high water holding capacity (WHC) and good emulsifying ability (EA). Meanwhile, the EPS could absorb metal ions such as Cu²⁺, Fe²⁺ and Zn²⁺. In addition, Y3 EPS exhibited good antioxidant properties and coagulated skim milk with a concentration-dependent manner. These results indicated that S. cerevisiae Y3 EPS had applicable prospects in medicine, food, especially the dairy industry.

Exopolysaccharides from microalgae: production, characterization, optimization and techno-economic assessment

Microalgae cultivation for exopolysaccharide production has getting more attention as a result of their high hydrocarbon biosynthesis skill. The aim of this study is to examine the exopolysaccharide production potential of different species of microalgae. In this context, exopolysaccharides were produced from Chlorella minutissima, Chlorella sorokiniana and Botryococcus braunii microalgae and the effects of carbon and nitrogen content in the growth medium and illumination time on exopolysaccharide production were analyzed statistically using Box-Behnken experimental design. In addition, techno-economic assessment of exopolysaccharide production were also performed by using the most productive microalgae and optimum conditions determined in this study. As a result of the experiments, it was seen that C. minutissima, C. sorokiniana and B. braunii produced 0.245 ± 0.0025 g/L, 0.163 ± 0.0016 g/L and 0.117 ± 0.0007 g/L exopolysaccharide, respectively. Statistically, it was observed that there was an inverse relationship between the exopolysaccharide production and investigated parameters such as illumination period and carbon and nitrogen amounts of culture mediums. The techno-economic assessment comprising microalgal exopolysaccharide (EPS) bioprocess was carried out, and it showed that the system can be considered economically viable, yet can be improved with biorefinery approach.

Yeast exopolysaccharides and their physiological functions

Mounting evidence indicated the capability of various microorganisms in biosynthesis of exopolysaccharides (EPSs). A wide range of evidence extensively investigated the ability of bacterial species for EPS synthesis and their favorable effects, so little is known regarding yeast species. Many factors like composition of growth media and fermentation conditions are related to the structural and physical properties of EPSs. The EPS protects the producer yeast strain against extreme environment. Researchers proposed that yeast EPSs have priority over bacterial EPSs because of high yields of EPS biosynthesis and easy separation methods from growth media. Besides, they have drawn increasing attention due to their interesting biological activities, food, pharmaceutical, and cosmetics applications. Although a limited number of studies exist, this review aims to highlight the EPS structure and various applications of known yeast species in detail.

Potential of natamycin to control growth of Zygosaccharomyces spp. in apple juice during storage

In this research, anti-yeast activity of natamycin in apple juice inoculated with both Zygosaccharomyces rouxii and Z. bailii during the storage at different temperatures was investigated. For this purpose, a response surface methodology approach was used to test and optimize effects of some processing variables; storage time (1, 21 and 41 days), storage temperature (4, 12 and 20 °C), sodium benzoate as a positive control (0, 0.05 and 0.1%) and natamycin concentration (0, 30 and 60 mg/L) on several physicochemical and bioactive properties of the apple juice samples. The results showed that the natamycin performed a remarkable anti-yeast effect on Z. bailii rather than on Z. rouxii. The brix levels of the samples decreased and so the turbidity values increased significantly due to the yeast activity during the storage. Bioactive properties were also significantly affected by the natamycin which was also revealed to increase the antioxidant capacity of apple juice during storage. Using multiple response optimization technique, it was calculated that minimum yeast count (YC) values would occur at storage time = 38.64 and 40.9 days, storage temperature = 19.81 and 14.4 °C, sodium benzoate level (fixed to 0%) and natamycin concentration = 40 and 51.9 mg/L for the samples inoculated with Z. bailii and Z. rouxii, respectively. It was concluded that the bioactive properties of apple juice could be preserved by addition of natamycin which is suggested to be a natural inhibitor during the storage.

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.