Selected methods for yeast cell disruption were evaluated to establish their suitability for cell wall preparation in the process of β-glucan isolation. The effect of different disruption methods on contents of total saccharides, β-glucans and proteins in the produced cell walls preparations was analyzed. The degree of cell wall purification from intracellular components was established on the basis of the ratio of solubilised material. The investigated methods included: cell exposure to hot water (autoclaving), thermally-induced autolysis, homogenization in a bead mill, sonication and their combinations. Experimental systems were prepared in water (pH 5.0 and pH 7.0) and Tris-HCl buffer (pH 8.0). The Saccharomyces cerevisiae yeast cell wall preparations with the highest degree of cytosol component release and purification of β-glucans were produced by 30 min of cell homogenization with zirconium-glass beads (0.5 mm in diameter). This was confirmed by the highest ratio of solubilised material (approx. 64%-67%). The thus-produced preparations contained ca. 60% of total saccharides, 13%-14% of β(1,3)/(1,6)-glucans, and approx. 35% of crude proteins. Similar results were obtained after autolysis coupled with bead milling as well as with sonication, but the time OPEN ACCESSMolecules 2014, 19 20942 required for these processes was more than 24 h. Homogenization in a bead mill could be valuable for general isolation procedures because allows one to eliminate the different autolytic activity of various yeast strains.

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The purpose of this paper is twofold: on the one hand, we verify effectiveness of alternatives solutes to sucrose solution as osmotic agents, while on the other hand we intend to analyze modeling transfer parameters, using different models. There has also been proposed a new mass transfer parameter—true water loss, which includes actual solid gain during the process. Additional consideration of a new ratio (Cichowska et al. Ratio) can be useful for better interpretation of osmotic dehydration (OD) in terms of practical applications. Apples v. Elise were dipped into 30% concentrated solutions of erythritol, xylitol, maltitol, and dihydroxyacetone (DHA) to remove some water from the tissue. To evaluate the efficiency of these solutes, 50% concentrated sucrose solution was used as a control. All of the tested osmotic agent, except maltitol, were effective in the process as evidenced by high values in the true water loss parameter. Solutions of erythritol and xylitol in 30% concentrate could be an alternative to sucrose in the process of osmotic dehydration. Peleg’s, Kelvin–Voigt, and Burgers models could fit well with the experimental data. modeling of mass transfer parameters, using Peleg’s model can be satisfactorily supplemented by Kelvin–Voigt and Burgers model for better prediction of OD within the particular periods of the process.

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a b s t r a c t 7 a r t i c l e i n f o 8 Available online xxxx 12 13 14 15 16 17Background: The exopolysaccharides (EPS) produced by yeast exhibit physico-chemical and rheological 18 properties, which are useful in the production of food and in the cosmetic and pharmaceutical industries as 19 well. The effect was investigated of selected carbon sources on the biosynthesis of EPS by Candida famata and 20 Candida guilliermondii strains originally isolated from kefirs. 21 Results: The biomass yields were dependent on carbon source (sucrose, maltose, lactose, glycerol, sorbitol) and 22 ranged from 4.13 to 7.15 g/L. The highest biomass yield was reported for C. guilliermondii after cultivation on 23 maltose. The maximum specific productivity of EPS during cultivation on maltose was 0.505 and 0.321 for 24 C. guilliermondii and C. famata, respectively. The highest EPS yield was found for C. guilliermondii strain. The 25 EPS produced under these conditions contained 65.4% and 61.5% carbohydrates, respectively. The specific 26 growth rate (μ) of C. famata in medium containing EPS as a sole carbon source was 0.0068 h -1 and 0.0138 h -1 27 for C. guilliermondii strain.28 Conclusions: The most preferred carbon source in the synthesis of EPS for both Candida strains was maltose, 29 wherein C. guilliermondii strain showed the higher yield of EPS biosynthesis. The carbon source affected the 30 chemical composition of the resulting EPS and the contribution of carbohydrate in the precipitated preparation 31 of polymers was higher during supplementation of maltose as compared to sucrose. It was also found that the 32 EPS can be a source of carbon for the producing strains. 33 34

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Can microbial cellulose (MC) be used as a bio-carrier for 1,3-dihydroxy-2-propanone (DHA)? The aim of this study was to examine the possibility of using MC as a biomaterial for DHA transferring into the stratum corneum and inducing changes in skin color. The MC patches were obtained from Gluconacetobacter xylinus strain and incubated in solutions with various concentrations of DHA (g·L−1: 20; 50; 80; 110) at 22 °C for 24 h. Afterwards; the patches were applied onto the skin for 15, 30, or 60 min. Skin color changes were assessed visually compared to a control patches without DHA. The intensity of skin color was increasing with the increase of DHA concentration and time of patches application. Application of MC patches with DHA (50 g·L−1) for 30 min ensured the color which was considered the closest to the desired natural tan effect. MC patches containing DHA can be biocarriers enabling DHA transport into the stratum corneum and causing skin color changes. Study results indicate a new possibility for industrial applications of MC; e.g., as a biocarrier in masking the symptoms of vitiligo or production of self-tanning agents in the form of masks.

Probiotics are recommended, among others, in the diet of children who are under antibiotic therapy, or that suffer from food allergies or travel diarrhea, etc. In the case of toddlers taking probiotic preparations, it is highly recommended to first remove the special capsule, which normally protects probiotic strains against hard conditions in the gastrointestinal tract. Otherwise, the toddler may choke. This removal can impair probiotic survival and reduce its efficacy in a toddler’s organism. The aim of this study was to evaluate the survivability of five strains of lactic acid bacteria from the commercial probiotics available on the Polish market under simulated conditions of the gastrointestinal tract. Five probiotics (each including one of these strains: Bifidobacterium BB-12, Lactobacillus (Lb.) rhamnosus GG, Lb. casei, Lb. acidophilus, Lb. plantarum) were protective capsule deprived, added in a food matrix (chicken–vegetable soup) and subjected under simulated conditions of the gastric and gastrointestinal passage. Strain survivability and possibility to growth were evaluated. Obtained results showed that, among all analyzed commercial probiotic strains, the Lb. plantarum was the most resistant to the applied conditions of the culture medium. They showed a noticeable growth under both in vitro gastric conditions at pH 4.0 and 5.0, as well as in vitro intestinal conditions at all tested concentrations of bile salts.