Food Engineering / Gıda Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/12
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Article Citation - WoS: 15Citation - Scopus: 19Whey Protein-Pullulan (wp/Pullulan) Polymer Blend for Preservation of Viability of Lactobacillus Acidophilus(Taylor and Francis Ltd., 2015) Çabuk, Burcu; Harsa, Hayriye Şebnem; Harsa, ŞebnemIn this study, whey protein isolate-pullulan (WP/pullulan) microspheres were developed to entrap the probiotic Lactobacillus acidophilus NRRL-B 4495 by spray-drying technique. Microcapsules were analyzed for physicochemical characteristics including morphology, particle size, moisture content, water activity, dissolution time, and color properties. Results revealed that microcapsules were spherical in shape and obtained particle sizes between 5 and 160 µm, with an average size of around 50 µm. Blending pullulan with WP provided enhanced survival of probiotic bacteria during spray drying with a final viable cell number of 8.81 log CFU/g of microcapsule. Encapsulated probiotics were also found to have significantly (p ≤ 0.05) higher survived cell numbers compared to free probiotics under detrimental gastrointestinal conditions. Moreover, dissolution analysis suggested that protein-polysaccharide powdered microcapsules showed pH-sensitive dissolution properties in simulated gastric juice and simulated intestinal juice.Article Citation - WoS: 19Citation - Scopus: 22Optimization of the Associative Growth of Novel Yoghurt Cultures in the Production of Biomass, Ss-Galactosidase and Lactic Acid Using Response Surface Methodology(Elsevier Ltd., 2009) Tarı, Canan; Üstok, Fatma Işık; Harsa, Hayriye ŞebnemThe associative growth of Streptococcus thermophilus 95/2 (St 95/2) and Lactobacillus delbrueckii ssp. bulgaricus 77 (Lb 77) isolated from the Toros mountain region of Turkey was investigated with respect to lactic acid, biomass and β-galactosidase enzyme production using response surface methodology (RSM). The ratio (St 95/2:Lb 77) of the strains and media formulation had significant effect on all responses (p < 0.001). The predicted enzyme activity (2.14 U mL-1), lactic acid (22.50 g L-1) and biomass (7.11 g L-1) production at optimum conditions were very close to the actual experimental values (2.14 U mL-1, 22.94 g L-1 and 7.86 g L-1, respectively). The optimum conditions were to use these cultures in a ratio of 1.66:1.62 (St 95/2:Lb 77) in a medium containing whey (5%), corn steep liquor (4%), potassium phosphate (2%) and peptone (2%) at 43 °C for 8 h. The associative growth provided 6.4% and 39% more β-galactosidase activity and 8.73% and 44% more lactic acid compared with the results obtained using pure St 95/2 and Lb 77 strains, respectively.Article Citation - WoS: 16Citation - Scopus: 14Isolation and Characterization of Bacillus Thuringiensis Strains From Olive-Related Habitats in Turkey(John Wiley and Sons Inc., 2008) Çınar, Çelenk; Apaydın, Özgür; Yenidünya, Ali Fazıl; Harsa, Hayriye Şebnem; Güneş, HaticeAims: To isolate Bacillus thuringiensis strains from different olive-related habitats (olive groves and olive oil factories) in Turkey and to characterize these strains by molecular methods. Methods and Results: A total of 150 samples, consisting of olive grove soil, green olive leaves, olive leaf residues, animal faeces, olive pomace and dust, were examined for the presence of B. thuringiensis. One hundred B. thuringiensis strains were isolated from 54 environmental samples (36%) and characterized in terms of crystal morphology, cry and cyt gene content by polymerase chain reaction, plasmid profiles and 16S-internal transcribed spacer ribosomal DNA restriction fragment length polymorphism (16S-ITS rDNA RFLP). The highest percentage of samples containing B. thuringiensis was found in 38 out of 54 total soil samples (70%). Of the 100 B. thuringiensis isolates, the most frequent crystal shapes were irregularly shaped (24%), spherical-irregular pointed (19%), cuboidal (17%) and spherical (16%). The cry1 plus cry4 genotype was the most abundant genotype in our collection (21%). RFLP analysis of the amplified 16S-ITS rDNA revealed 11 distinct patterns for the isolates and 10 reference strains. Conclusions: Bacillus thuringiensis isolates showed a great genetic diversity and crystal shape heterogeneity. Significance and Impact of the Study: This is the first study on the isolation and characterization of B. thuringiensis from olive-related habitats in Turkey. No correlation was observed between the cry genotypes and insecticidal crystal shapes of the isolates. Restriction profiles of 23% of the isolates were found to be different from those of the 10 reference strains used.Article Citation - WoS: 21Citation - Scopus: 24Isolation and Characterization of Bacillus Thuringiensis Strains From Different Grain Habitats in Turkey(Springer Verlag, 2005) Apaydın, Özgür; Yenidünya, Ali Fazıl; Harsa, Hayriye Şebnem; Güneş, HaticeBacillus thuringiensis (Bt) is a gram-positive, spore-forming bacterium and it produces insecticidal crystal (cry) proteins during sporulation. Because the genetic diversity and toxic potential of Bt strains differ from region to region, strains have been collected and characterized all over the world. The aim of this study is to isolate Bt strains in grain-related habitats in Turkey and to characterize them on the basis of crystal morphology, cry gene content, and chromosomal and plasmid DNA profiles. Four approaches were taken analysis with phase contrast (PC) microscopy, polymerase chain reaction (PCR), pulsed field gel electrophoresis (PFGE) and plasmid isolation. Ninety-six samples were collected from Central Anatolia and the Aegean region. Bt was isolated from 61 of 96 samples (63.5) and 500 Bt-like colonies were obtained. One hundred and sixty three of the colonies were identified as Bt based on cry protein formation using PC microscopy. Among the examined colonies, the overall proportion identified (as Bt index) was 0.33. We found that 103 isolates were positive for the five different cry genes (cry1, cry2, cry3, cry4 and cry9) examined with PCR. In addition, plasmid profiling of 37 cry gene-positive isolates indicated that the 15 kb plasmid band was present in all isolates; however, 11 of 37 isolates had more than one plasmid band at different sizes. Finally, chromosomal DNA profiling by PFGE gave rise to different DNA patterns for isolates containing the same cry gene which suggests a high level of diversity among the Bt strains isolated.Article Citation - WoS: 7Citation - Scopus: 6Chromatographic Separation of Amyloglucosidase From the Mixtures of Enzymes(Elsevier Ltd., 2001) Harsa, Hayriye Şebnem; Furusaki, ShintaroAn affinity chromatographic separation of amyloglucosidase (AMG) enzyme using β-cyclodextrin-chitosan matrix was investigated in this study. The adsorbent selectively adsorbed AMG from the mixtures of enzymes (lactase and α-amylase), and this selectively bound AMG was eluted from the column in two steps with a recovery yield of about 72%. A small fraction of AMG and other contaminating proteins did not bind to the column specifically and were eluted easily. Purified AMG was visualised on the sodiumdodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) experiments