Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Microbiological Characterization of 'hurma Olives Grown in Karaburun Peninsula(Izmir Institute of Technology, 2013) Karslı, Gözde Seval; Baysal, Ayşe Handan; Baysal, Ayşe Handan; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyErkence variety olive (Olea europea L.) cultivar growing in the Aegean Region of Turkey is a naturally black olive. Debittered Erkence variety called "Hurma" olive is an unusual olive type which is characterized by the sweet taste of its fruit. This olive which is grown mainly in Karaburun Peninsula differs from other varieties since it ripens on the tree losing its bitterness caused by phenolic compounds especially oleuropein. Thus, Hurma olives can be directly consumed from the tree without a further debittering process to make them edible. Total aerobic mesophilic microorganisms, lactic acid bacteria (LAB), Enterobacteriacaae, Pseudomonadaceae, Staphylococcaceae-Micrococcaceae, moulds and yeasts were enumerated in the olive drupes, leaves and orchards' air of Erkence and Gemlik cultivars during the maturation period. Moreover, bacterial microflora of Hurma olive fruit, leaf and orchards' air were characterized in terms of DNA sequencing. Microbial loads of naturally debittered "Hurma" olive were higher when compared with Gemlik olive's and non-debittered Erkence variety olive's. But no Pseudomonadaceae, Staphylococcaceae-Micrococcaceae and LAB were detected in all samples. Bacterial microflora genera of Hurma olive comprised of Bacillus, Pantoea, Acinetobacter and Pseudomonas while the other samples have also similar bacterial genera. The common genus found in all samples was Bacillus. Besides, more diversified genera were obtained from phylloplane and air microflora of Erkence variety olive orchard was substantially similar to bacterial phylloplane of leaf. This is the first study about microbiological characterization of Hurma olive type and will lead up to new studies about it.Master Thesis Disinfection of White Grape Juice by Using Continuous Flow Uv Reactor(Izmir Institute of Technology, 2011) Kaya, Zehra; Ünlütürk, Sevcan; Ünlütürk, Sevcan; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyAlthough continuous flow UV irradiation process is applied to several kind of fruit juices as a non-thermal method, it hasnot treated to white grape juice before. The main objective was to study the effect of commercial UV disinfection system on the spoilage microorganisms in white grape juice. Physical, chemical and optical properties were measured after and before irradiation. Biodosimetric studies were performed by using Bench Top UV apparatus and continuous flow commercial UV reactor. Bench top UV study showed that 228.96 mJ/cm2 UV dose provided complete inactivation of S. cerevisiae in the pasteurized juice at 0.91 mW/cm2 UV intensity.. 3.00±0.16 log cfu/ml yeasts and 4.32±0.03 log cfu/ml lactic acid bacteria reduction were detected in naturally fermented juice after 282.24 mJ/cm2 UV dose. D(10) of yeasts (43.86 mJ/cm2) were higher than lactic acid bacteria (33.78 mJ/cm2) because of showing higher resistance to UV light. In the continuous flow UV reactor, the highest reduction of S. cerevisiae was achieved as 3.39±0.044 log cfu/ml at 56.06 mJ/cm2 UV dose and low flow rate (820 ml/min) in pasteurized juice. However, highest reduction was observed in yeast and lactic acid bacteria count as 1.70±0.028 log cfu/ml and 2.49±0.0031 log cfu/ml respectively at 19.96 mJ/cm2 UV dose in medium flow rate (1516 ml/min) of fresh squeezed juice. Absorbance, color, and titratable acidity were changed by irradiation. As a result of 13 days shelf life study, no significant increase was seen in spoilage microorganisms after irradiation.