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Öğe Çeşitli gıdalardan izole edilmiş farklı laktik asit bakterilerinin bakteriyosin üretme yeteneklerinin ve bakteriyosin kısmi karakteristiklerinin belirlenmesi(Selçuk Üniversitesi Fen Bilimleri Enstitüsü, 2013-07-29) Demirci, Talha; Akın, NihatÇalışmada hardaliye turşusu ve Sürk peynirinden izole edilmiş 72 adet laktik asit bakterisinin indikatör patojen bakteriler üzerine bakteriyosin benzeri aktiviteleri belirlenmiştir. Metot olarak çeşitli antibakteriyal etki belirleme metotları arasından Agar-Sandviç Yöntemi seçilmiştir. Bu metot uyarınca her deneme 3?er tekrarlı olarak gerçekleştirilmiş ve bu bakteriyosin benzeri aktivite için optimum besiyeri başlangıç pH?sı ve inkübasyon sıcaklığı belirlenmeye çalışılmıştır. Bunun yanında çeşitli enzimlerin bu bakterilerin oluşturduğu bakteriyosin benzeri aktivite üzerine etkisi de gözlenmiştir. Sonuç olarak en ideal inkübasyon sıcaklığı olarak 35°C, en ideal besiyeri başlangıç pH?sı olarak 4,5 bulunmuştur. Yine bazı bakteri izolatlarının oluşturduğu aktivitenin kısmen proteolitik enzimlerden etkilendiği bazılarının ise hiç etkilenmediği görülmüştür. Fakat hiçbir izolatın aktivitesi proteolitik enzim muamelesi sonrası tamamen kaybolmamıştır. Bakteriyosin benzeri aktiviteye en duyarlı bakterinin S.aureus olduğu görülmüştür.Öğe CHEMICAL COMPOSITION AND MICROBIOLOGICAL PROPERTIES OF TARHANA ENRICHED WITH IMMATURE WHEAT GRAIN(WILEY, 2015) Aktaş, Kübra; Demirci, Talha; Akın, NihatIn this study, the effect of immature wheat grain (IWG) supplementation on the tarhana formulation was investigated by determining color values and some chemical and microbiological properties. Flours obtained from IWG, harvested at 26 (IWG-1) and 36 days (IWG-2) after anthesis, were used in the tarhana formulation as a replacement of white wheat flour in concentrations of 10, 30 and 50%. Ash, Ca, Mg, K, P and Zn contents of tarhana samples increased by IWG-1 addition. IWG-2 addition resulted in an increase in moisture and protein contents. IWG-1 addition into the tarhana provided an increase in the antioxidant activity and total phenolic contents of the samples. The total counts of mesophilic aerobic bacteria and lactic acid bacteria of tarhana with IWG-1 were higher than those of other tarhana samples.Öğe Enumeration of Bifidobacterium Spp., Lactobacillus Acidophilus and Starter Cultures from Commercial Probiotic Yogurts and Freeze-Dried Yogurt Starter Mixes(Selçuk Üniversitesi, 2022) Demirci, TalhaProbiotic yogurt is a popular functional food to deliver of probiotic cells for the health-enhancing effects worldwide. The viability of probiotics in yogurt before consumption is the most important factor to providing desired effects, however, probiotic microorganisms have occasionally inadequate viability in marketable food products. In this current study, Bifidobacterium spp., L. acidophilus and yoghurt starter bacteria enumerations were made in commercial probiotic yoghurt and freeze-dried yogurt mixes. RCA 5.3 and MRS 5.2 media were used for L. delbrueckii subsp. bulgaricus counting, ST Agar and M17 Agar were used for Stretococcus thermophilus counts. While using MRS-Bile Agar and RCAClindamycin Agar for L. acidophilus enumeration, Bifidobacterium spp. counts were performed using MRS-NNLP medium. 5 out of yoghurt samples (A, C, D, and E) did not reveal satisfactory recovery (< 5 log CFU/g) for L. delbrueckii subsp. bulgaricus colonies on MRS 5.2 Agar while L. delbrueckii subsp. bulgaricus colony counts on RCA 5.3 Agar below 5 log CFU/g for same tested 4 samples (A, C, D, and E). The recovery rates over 9 log CFU/g were obtained in the enumerations made for all yogurt samples on both ST and M17 media. The problem of insufficient recovery rates that occurred for L. delbrueckii subsp. bulgaricus in some yogurt samples was not valid for S. thermophilus. This work indicated that high amounts of L. acidophilus were detected on both media in both of the two yoghurt samples declared as L. acidophilus on the label (F and G). On the other hand, bifidobacteria was determined above 5 log CFU/g in only 1 yoghurt sample (B) out of 7 probiotic yoghurts claimed to be Bifidobacterium spp. This study reveals relevant information on probiotic and starter counts of commercial probiotic yogurts in Turkey and discusses in detail the possible reasons for the results obtained.Öğe Fortification of set-type yoghurts with Elaeagnus angustifolia L. flours: Effects on physicochemical, textural, and microstructural characteristics(ELSEVIER SCIENCE BV, 2018) Ozturk, Hale Inci; Aydin, Sumeyye; Sozeri, Didem; Demirci, Talha; Sert, Durmus; Akin, NihatThe effect of peeled oleaster (Elaeagnus angustifolia L.) flour (PO) and unpeeled oleaster flour (UPO) in different levels (1% and 2%) on the quality parameters of set type yoghurt was investigated throughout 28 days of storage. Acidification kinetics, water holding capacity, syneresis level, textural characteristics and microstructure were firstly measured. Additionally, influence of oleaster flours on DPPH and ABTS(+) radical scavenging activity and total phenolic content of yoghurt samples was also assessed. Besides, all the products were subjected to sensorial preference test. Enrichment with 2% PO and UPO reduced fermentation time by 31 and 37 min, respectively. Addition of PO and UPO increased cohesiveness and the viscosity index, furthermore, syneresis decreased. Oleaster supplementation to yoghurt significantly increased scavenging activities of DPPH and ABTS radicals and the highest activities were determined in yoghurts fortified with 2% UPO. The results demonstrated that yoghurt with reduced syneresis, improved functional properties, and enhanced some textural characteristics can be achieved by a 2% UPO addition. Also, surprisingly yoghurts containing 2% UPO had similar consumer overall preference scores comparing to plain yoghurt.Öğe Immature wheat grain as a potential prebiotic ingredient in set-type yoghurts: impact on antioxidative, textural properties and survival of different probiotics(SPRINGER INDIA, 2019) Demirci, Talha; Negis, Hale İnci Öztürk; Orac, Aysun; Göktepe, Çiğdem Konak; Atik, Didem Sözeri; Aktaş, Kübra; Demirci, Sümeyye; Sert, Durmuş; Akın, NihatThe aim of this study was to investigate the effect of immature wheat grain (IWG) on the survival of Lactobacillus acidophilus NCFM (LNCFM), Lactobacillus casei 431 (L431) and Lactobacillus acidophilus 20079 (L20079) in yoghurts under cold storage. Furthermore, the impact of IWG on physicochemical, textural and antioxidative properties of yoghurts was evaluated. Fortification of yoghurt with IWG positively affected LNCFM and L20079 counts during cold storage whereas no statistical improvement was observed in the viability of L431. The addition of IWG clearly supported the antioxidative activity and total phenolic content in yoghurt. No statistical differences were discovered regarding syneresis and water holding capacity in all probiotic applications. Although, enrichment with IWG enhanced the firmness of probiotic yoghurts, it simultaneously reduced the cohesiveness and viscosity index. This study demonstrated that IWG may be used as a food additive for enhancing probiotic LNCFM and L20079 survival and providing functional aspects in yoghurt.Öğe Influence of hot and cold break tomato powders on survival of probiotic L. paracasei subsp. paracasei F19, texture profile and antioxidative activity in set-type yoghurts(ELSEVIER, 2020) Demirci, Talha; Sert, Durmuş; Aktaş, Kübra; Atik, Didem Sözeri; Negiş, Hale İnci Öztürk; Akın, NihatThe yoghurt samples enriched with hot and cold break tomato powders (HBT and CBT) were evaluated by monitoring the changes in some physicochemical properties and bacterial viability during storage. Besides, radical scavenging activity, total phenolic contents, and textural parameters of samples were determined. Tomato powders were added at different levels (0.5, 1, 2%) and L. paracasei F19 was used with starter culture in yoghurt production. Total solids and ash content of yoghurt without powders were lower than the others. HBT supplementation significantly increased DPPH and ABTS + scavenging activities and the highest activities were determined in yoghurt samples containing 2% HBT (197.7 g/kg, 4.84 mol trolox/kg respectively). Total phenolic content of samples ranged from 5.00 to 14.92 g GAE/kg. The addition of tomato powders decreased firmness and viscosity and plain yoghurt was found to be more consistence (12161.80 g s) and cohesive (219.50 g). The pH values of samples decreased whereas titratable acidity values increased throughout 21 days of storage and L. pantacasei F19 counts was higher than 10(6) CFU/g at the end of storage.Öğe Isolation, technological characterization and in vitro probiotic evaluation of Lactococcus strains from traditional Turkish skin bag Tulum cheeses(SPRINGER, 2019) Kazancıgil, Erhan; Demirci, Talha; Negiş, Hale İnci Öztürk; Akın, NihatPurpose The present study was undertaken to evaluate in vitro prerequisite probiotic and technological characteristics of ten Lactococcus strains isolated from traditional goat skin bags of Tulum cheeses from the Central Taurus mountain range in Turkey. Methods All isolates were identified based on the nucleotide sequences of the 16S rRNA gene. Eight isolates belonged to Lactococcus lactis and two belonged to Lactococcus garvieae. Probiotic potential was determined from resistance to acid and bile salt, resistance to gastric and pancreatic juices, resistance to antibiotic, auto-aggregation, co-aggregation, diacetyl, hydrogen peroxide and exopolysaccharide productions. Technological properties were verified by alcohol, NaCl and hydrogen peroxide resistance and temperature tests. Results L. lactis NTH7 displayed high growth at all alcohol concentrations while L. lactis NTH4 grew very well even at NaCl concentrations of 10%. All strains showed to some extent resistance to acid and bile. Five strains exhibited desirable survival in gastric juice (pH 2.0), while three strains survived in pancreatic juice (pH 8.0). All Lactococcus isolates were sensitive to ampicillin, chloramphenicol, erythromycin, vancomycin, kanamycin, gentamycin and tetracycline. Also, only L. lactis NTH7 from among the isolates showed resistance against penicillin. L. lactis NTH10 and L. lactis NTH7 had higher auto-aggregation values in comparison with all other strains. All the strains demonstrated a co-aggregation ability against model food pathogens, particularly, L. lactis NTH10 which showed a superior ability with L. monocytogenes. All the ten strains produced H2O2 and exopolysaccharide (EPS); however, diacetyl production was detected for only four strains including L. lactis NTH10. Conclusion These results demonstrate that the L. lactis NTH10 isolate could be regarded as a favorable probiotic candidate for future in vivo studies.Öğe Orta Toroslar yöresinde geleneksel yöntemlerle üretilen deri tulum peynirlerinin olgunlaşma periyodu boyunca mikrobiyal kompozisyonlarının belirlenmesi(Selçuk Üniversitesi Fen Bilimleri Enstitüsü, 2019) Demirci, Talha; Akın, NihatBu tez çalışmasında Orta Toroslar bölgesinde geleneksel yollarla üretilen deri Tulum peynirlerinin 180 günlük olgunlaşma periyodu süresince kimyasal özelliklerinin, bakteriyal kompozisyonlarının değişimi izlenmiştir. Çalışmanın amacı, Orta Toroslar yöresi peynirlerine has mikroflora ve aroma bileşenlerini tespit etmek, bunların olgunlaşma boyunca değişimlerini ortaya koyup ileri aşamalarda bu peynirler için florada tespit edilen bakterilerden starter denemeleri yapılabilmesine temel oluşturmaktır. Bu amaç doğrultusunda kültüre-bağlı ve kültürden-bağımsız (PCR-DGGE) yöntemlerle bakteriyal flora olgunlaşma boyunca takip edilmiştir. Kültüre-bağlı yöntemle yapılan analizlerde Anamur, Mut, Karaman ve Ereğli yörelerinde Enterococcus suşları, özelinde de Enterococcus faecium türüne ait suşların baskın olduğu tespit edilmiştir. Kültüre-bağlı yöntemle yapılan analizler sonucunda toplam 1365 adet bakteri saflaştırılmış ve bunların 432 adeti tanımlanmıştır. Kültürden-bağımsız yöntemle yapılan analizlerde ise Enterococcus ve Streptococcus cinsine ait türlerin en fazla bulunan türler olduğu görülmüştür. Kültüre bağlı yöntemde toplam 13 farklı laktik asit bakterisi tespit edilirken, kültürden-bağımsız yöntemde 20 farklı laktik asit bakterisi türü saptanmıştır. Tez çıktısı olarak elde edilen saf laktik kültürler ve bilgilerin önemli bir kültürel miras olan Orta Toroslar yöresi deri Tulum peynirlerinin korunması ve devamının sağlanmasına katkıda bulunması ve bu konuda yapılacak ileri araştırmalara temel teşkil etmesi umulmaktadır.Öğe Production of functional probiotic ice creams with white and dark blue fruits of Myrtus communis: The comparison of the prebiotic potentials on Lactobacillus casei 431 and functional characteristics(ELSEVIER SCIENCE BV, 2018) Ozturk, Hale Inci; Demirci, Talha; Akin, NihatIn the present study, dark blue (BM) and white (WM) Myrtus communis (M. communis) pulps were added to probiotic goat milk ice cream formulations containing Lactobacillus casei (L. casei) 431 to evaluate prebiotic potentials of BM and WM fruits on L. casel 431. Additionally, the effects of storage and freezing process on viable L. casei 431 counts, total phenolic content (TPC) and antioxidant activity were examined. According to the results, it was determined that the BM and WM fruits had prebiotic potentials on L. casei 431. The freezing process of mixes reduced the counts of L. casei 431 by about 0.80-1.32 log CFU g(-1) and this strain maintained high viability throughout the storage. After freezing process, TPC values of ice cream samples containing WM and BM fruits increased by 5.00 and 8.50 mg GAE 100 g(-1), respectively. No alteration was detected in antioxidant activity during the storage.Öğe Rice bran improve probiotic viability in yoghurt and provide added antioxidative benefits(ELSEVIER SCIENCE BV, 2017) Demirci, Talha; Aktaş, Kübra; Sözeri, Didem; Öztürk, Hale İnci; Akın, NihatExperimental yoghurts were made with 13% reconstituted skim milk supplemented with 1, 2, 3% rice bran (RB) and inoculated with probiotic culture of Lactobacillus casei 431. The products were stored at 4 degrees C for 3 weeks. During this period, the viability of the probiotic L. casei 431 strain and yoghurt starter cultures were evaluated. In addition to this, some physicochemical, antioxidative and sensory properties of yoghurts were also determined. L casei 431 remained above the 8 log CFU/g throughout the storage period in yoghurts fortified with 2% and 3% RB. Addition of rice bran decreased the syneresis and viscosity values whereas it increased scavenging activities of DPPH radical. However, yoghurts with RB had less sensory scores compared to plain yoghurt. (C) 2017 Elsevier Ltd. All rights reserved.
