Shelf life and quality of probiotic yogurt produced with Lactobacillus acidophilus and Gobdin

This study evaluated the effect of dry white mulberry and walnut paste (Gobdin, a traditional Turkish food) in probiotic yogurt on the survival of Lactobacillus acidophilus and yogurt properties. Six different yogurts were produced with 0%, 5% and 10% Gobdin using Lactobacillus bulgaricus + Streptococcus thermophilus and with 0%, 5% and 10% Gobdin using L. bulgaricus + S. thermophilus + L. acidophilus. The physical, chemical, microbiological and sensorial properties of the yogurts were evaluated based on storage at 4 ± 1 °C. Probiotic shelf life and the most suitable combinations were determined. The highest L. acidophilus count (8.65 log cfu g^?1) was found in the 5% Gobdin‐supplemented yogurt on the 7th day of storage, while the lowest count (8.11 log cfu g^?1) was found in the probiotic control yogurt on the 21st day. Although the L. acidophilus counts in the probiotic yogurts declined during storage, all values found throughout the 21‐day storage period were >8 log cfu g^?1. This is above the level necessary to provide the desired therapeutic effect in probiotic products (10⁶–10⁷ cfu g^?1). The highest overall acceptability score was obtained on the first day from the yogurt with 5% Gobdin. However, all yogurt samples had general acceptability scores between 7 and 8 points from a 9‐point maximum. Thus, this study determined that a new functional yogurt can be produced using L. acidophilus with 5% Gobdin.     

Application of antimicrobial ice for extending shelf life of fish

In this study, we investigated whether wild-thyme (Thymus serpyllum) hydrosol had a preserving effect against spoilage of freshwater fish. Sensorial characteristics, chemical freshness indicator contents, and microbial counts (total aerobes, psychrotrophics, Enterobacteriaceae, fecal coliform bacteria, Aeromonas spp., and Pseudomonas spp.) of whole ungutted and gutted Transcaucasian barb (Capoeta capoeta capoeta Guldenstaedt, 1772) stored on ice produced from wild-thyme hydrosol and tap water at 4 degrees C for 20 days were compared. The results did not reveal any significant (P > 0.05) differences in the microbial counts, sensorial characteristics, pH, and total volatile basic nitrogen values between gutted and ungutted groups. Sensory evaluation and microbiological and chemical analyses indicated that the storage of the fish on ice produced from wild-thyme hydrosol had a significant increase in shelf life by at least 15 to 20 days.     

Ionic liquid intercalated clay nanofillers for chromatographic applications

In this study, the preparation and characterization of ionic liquid (IL) intercalated montmorillonite (MMT) and their application as a micro-solid phase extraction material for the determination of Chlorpyrifos (CP) pesticide in water samples were reported. The ionic liquids bearing different chain lengths [1-methyl-3-octylimidazolium bromide (C₈mimBr), 1-methyl-3-undecyl-imidazolium bromide (C₁₂mimBr) and 1-methyl-3-octadecyl-imidazolium bromide (C₁₈mimBr)] were intercalated in the galleries of MMT. The IL-intercalated MMTs were characterized by means of XRD and TG methods. The (C₁₂mimBr)-intercalated MMT had the highest sorption efficiency for the CP, which was 32 times higher than the original MMT. We also optimized the parameters for extracting CP from the (C₁₂mimBr)-intercalated MMT.     

Synthesis and characterization of N‐ and O‐alkylated poly[aniline‐co‐N‐(2‐hydroxyethyl) aniline]

Poly[aniline‐co‐N‐(2‐hydroxyethyl) aniline] was synthesized in an aqueous hydrochloric acid medium with a determined feed ratio by chemical oxidative polymerization. This polymer was used as a functional conducting polymer intermediate because of its side‐group reactivity. To synthesize the alkyl‐substituted copolymer, the initial copolymer was reacted with NaH to obtain the N‐ and O‐anionic copolymer after the reaction with octadecyl bromide to prepare the octadecyl‐substituted polymer. The microstructure of the obtained polymers was characterized by Fourier transform infrared spectroscopy, ¹H‐NMR, and X‐ray diffraction. The thermal behavior of the polymers was investigated by thermogravimetric analysis and differential scanning calorimetry. The morphology of obtained copolymers was studied by scanning electron microscopy. The cyclic voltammetry investigation showed the electroactivity of poly [aniline‐co‐N‐(2‐hydroxyethyl) aniline] and N and O‐alkylated poly[aniline‐co‐N‐(2‐hydroxyethyl) aniline]. The conductivities of the polymers were 5 × 10^?5 S/cm for poly[aniline‐co‐N‐(2‐hydroxyethyl) aniline] and 5 ×10^?7 S/cm for the octadecyl‐substituted copolymer. The conductivity measurements were performed with a four‐point probe method. The solubility of the initial copolymer in common organic solvents such as N‐methyl‐2‐pyrrolidone and dimethylformamide was greater than polyaniline. The alkylated copolymer was mainly soluble in nonpolar solvents such as n‐hexane and cyclohexane. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and characterization of waterborne and phosphorus-containing flame retardant polyurethane coatings

Phosphorus-containing flame retardant water-dispersed polyurethane coatings were produced by incorporating different amounts of a phosphorus compound onto the polyurethane main chain. The novel phosphorus containing compound (phosphorus phenyl dihydroxy) was synthesized in three steps using benzaldehyde, pentaerythritol, phenyl phosphonic dichloride, and acetic acid. The addition of phosphorus phenyl dihydroxy to the main chain of polyurethane, in which NCO/OH ratio was kept constant at 1.5 and the amount of dimethylolpropionic acid (DMPA) at 3.5 wt%, increased the hardness and abrasion resistance, but only slightly decreased the gloss values of the polyurethane paints. All the samples showed superior impact resistance and flexibility. Moreover, increasing the phosphorus content increased the char yield, and the maximum fire retardancy was reached at 1.5% P content with a limiting oxygen index (LOI) value of 29. Kimya B?lümü, 06531 Ankara, Turkey.     

Exergy Analysis of Drying Process: An Experimental Study in Solar Greenhouse

This article examines the exergy variation during drying in solar greenhouses. Exergy efficiencies were derived as functions of drying time and temperature of the drying air. An illustrative example is considered to verify Dincer and Sahin's model and to show the applicability of the model to actual drying processes at different drying air temperatures. This work is intended not only to demonstrate the usefulness of exergy analysis in thermodynamic assessments of drying processes but to provide insights into their performances and efficiencies. In this study, the drying performance of the passively heated solar greenhouse has been investigated. Experimental results under the meteorological conditions of Izmir, Turkey (latitude 38.24 N, longitude 27.50 E), are presented.     

Preparation of comb‐type grafted hydrogels composed of polyacrylamide and chitosan and their use for DNA adsorption

Comb‐type grafted hydrogels composed of polyacrylamide (PAAm) and chitosan (CT) were prepared and used for DNA adsorption. Instead of direct grafting of the acrylamide monomer onto the CT chain, semitelechelic PAAm with carboxylic acid end groups (PAAm–COOH) was synthesized by free‐radical polymerization with mercaptoacetic acid as the chain‐transfer agent, and it was grafted onto CT with amino groups. The synthesis of telechelic PAAm–COOH and the formation of comb‐type grafted hydrogels were confirmed by attenuated total reflectance/Fourier transform infrared spectroscopy and scanning electron microscopy measurements. The prepared comb‐type grafted hydrogels were used as sorbents in DNA adsorption experiments conducted at +4°C in a tris(hydroxymethyl)aminomethane/ethylenediaminetetraacetic acid solution of pH 7.4. DNA adsorption capacities as high as 2.0 × 10³ μg of DNA/g of dry gel could be achieved by the comb‐type hydrogels with higher PAAm contents. This value was approximately 6 times higher than that of CT alone. In addition, the comb‐type hydrogels showed a high adsorption/desorption rate depending on the PAAm content in the hydrogel. As a result, these comb‐type hydrogels carrying higher amounts of DNA may be considered good candidates for achieving higher removal rates for anti‐DNA antibodies and for effective gene therapy systems. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009