Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Anti-Microbial Properties and Biochemical Characterization of Maillard Reaction Products From Legume Protein Hydrolysates and D-Glucose(01. Izmir Institute of Technology, 2024) Gündoğan, Bengihan; Ceylan, Çağatay; Baysal, Ayşe HandanBu tez, çeşitli termal koşullarda (175°C ila 275°C) D-glukoz ile reaksiyona sokulan nohut, bakla, adi fasulye ve soya fasulyesi protein hidrolizatlarından elde edilen Maillard Reaksiyon Ürünlerinin (MRP'ler) antimikrobiyal özelliklerini ve biyokimyasal karakterizasyonunu araştırmaktadır. Çalışmada bu MRP'lerin Escherichia coli, Staphylococcus aureus, Lactococcus lactis, Candida albicans, Saccharomyces var. boulardii ve Saccharomyces cerevisiae'ye karşı antimikrobiyal aktivitesi değerlendirilmiştir. Sonuçlar nohut MRP'lerinin en yüksek antimikrobiyal aktiviteyi sergilediğini, bunu bakla MRP'lerinin izlediğini, bakteri ve maya sayılarında önemli azalmalar olduğunu göstermiştir; antimikrobiyal etkinlik işleme sıcaklığına göre değişiklik göstermiş ve belirli koşullarda optimum aktiviteye işaret etmiştir. UV-Vis spektroskopisi, FTIR, HPLC ve NMR analizleri kullanılarak yapılan biyokimyasal karakterizasyon, melanoidin içeriğinde ve yapısal özelliklerinde baklagil kaynağına ve ısıl işleme bağlı olarak farklılıklar olduğunu ortaya koymuştur. Kolorimetrik analiz ve esmerleşme indeksi tayini, daha yüksek sıcaklıkların daha koyu MRP'lere yol açtığını ve esmerleşme indekslerinin arttığını göstermiştir. Bu bulgular, baklagil bazlı MRP'lerin gıda muhafazasında doğal antimikrobiyal ajanlar olarak potansiyele sahip olduğunu ve gelişmiş sağlık yararları ve güvenliği ile yeni gıda ürünlerinin geliştirilmesine katkıda bulunduğunu göstermektedir.Master Thesis Environmental Factors Influencing Bacterial Biofilm Formation and Inactivation(Izmir Institute of Technology, 2020) Üreğen, Mert; Baysal, Ayşe Handan; Özçivici, EnginObjective of this study was to evaluate effect of UV-C radiation (0, 1.16 and 3.21 kJ/cm2), pomegranate (Punica granatum) seed essential oil (PGEO) and lemon (Citrus lemonum) plant essential oil (CLEO) on decontamination of Candida albicans, Listeria monocytogenes, Staphylococcus aureus and Esherichia coli O157:H7 biofilms formed at +4°C and 20°C on polystyrene, stainless steel and glass surfaces. After 16, 32 and 64 sec UV-C treatment 0.24 log CFU/cm2, 1.61 log CFU/cm2, 1.59 log CFU/cm2 reductions were achieved in the numbers of C. albicans biofilms formed at 20°C on polystyrene. In the numbers of S. aureus biofilms formed at 20°C on polystyrene 0.99 log CFU/cm2, 1.9 log CFU/cm2, 3.91 log CFU/cm2 reductions were obtained after 16, 32 and 64 sec UV-C treatments, respectively. In general C. albicans biofilm formed at 20°C on stainless steel was found as the most UV-C resistant biofilm. CLEO inhibited the growth of C. albicans, L. monocytogenes and S. aureus at MIC values of 186 µg/ml, 103.5 µg/ml and 103.5 µg/ml, respectively. The results of the study showed that UV-C radiation and CLEO can be used as an anti-biofilm agent to control or to prevent biofilm formation of foodborne bacterial pathogens. It was suggested that UV-C radiation and CLEO treatments have potential as a biofilm control interventions for the food industry.Master Thesis Developing Probiotic Lozenges To Improve Oral Health(Izmir Institute of Technology, 2019) Elvan, Menşure; Harsa, Hayriye Şebnem; Baysal, Ayşe HandanRecently, there is a great need to overcome complaints about oral health from children, mental and physically handicapped people who are inadequate in oral hygiene and after chemotherapy of cancer patients. With reduced body resistance, opportunistic Streptococcus mutans and Candida albicans in the mouth become dominant, causing disruption of oral health. Therefore, the effect of lactic acid bacteria on pathogens was investigated in order to protect oral health with the thesis study. Lactobacillus pentosus NRRL-B 227 was determined among the probiotic bacteria tested for this purpose and its activity on the pathogen Streptoccocus mutans ATCC 25175 and Candida albicans DSMZ 5817 was found in broth microdilution, agar overlay and planktonic culture assays except disc diffusion test. To reduce the number of pathogens in oral microflora, lozenges containing L. pentosus were developed. Three different lozenges with encapsulated and free bacteria and control lozenge were produced, kept at different temperatures; 4⁰C and 25⁰C. No significant decrease in viability of the encapsulated probiotic strain after lozenge production and storage at 4°C was observed, the probiotic amount in the lozenge initially counted as 7.84 log CFU/g, while 7.73 log CFU/g at the end of 3 months shelf life. However, lozenges stored at 25⁰C probiotics lost their vitality after one month. Additionally, lozenges containing free bacteria have lost viability rapidly. Color and water activity were observed differently in the formulations (p <0.05). The formulations maintained their microbiological safety during storage. Lozenge with L. pentosus NRRL-B 227 has a significant potential for improving oral health and provides an alternative to the diversification of products containing probiotics.