Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 3Citation - Scopus: 5Assessing the Impact of Non-Thermal and Thermal Treatment on the Shelf-Life of Onion Juice(Czech Academy of Agricultural Sciences, 2018) Demir, Hande; Yıldız, Mustafa Kemal; Becerikli, İsmail; Ünlütürk, Sevcan; Kaya, ZehraOnion (Allium cepa L.) juice is a marinating agent for meat and fish marination and readily usable sauce for any meal that has onion in its formulation. This study aims to assess the microbiological and physicochemical changes in the onion juice processed by UV-C irradiation (0.5 mm sample depth, 30 min exposure time, 7.5 mW/cm(2) UV incident intensity) and conventional heat treatment (74.5 degrees C, 12 min) during its storage. Microbiological results showed processing by UV-C irradiation or heat treatment under optimum conditions extended the microbial shelf-life of untreated onion juice by minimum 6-times. Total colour change of heat-treated samples was lower than that of untreated and UV-C treated samples for 12 weeks. Also, pH, total titratable acidity, total soluble solids content, turbidity, NEBI and total phenolic content were monitored for 12 weeks. The results of this study will form scientific infrastructure for onion juice manufacturers to decide on the processing method with respect to its shelf-life.Article Citation - WoS: 12Citation - Scopus: 15Effect of Heat Treatment on the Blast Loading Response of Combined Geometry Shell Core Sandwich Structures(Elsevier Ltd., 2016) Taşdemirci, Alper; Kara, Ali; Turan, Kıvanç; Şahin, Selim; Güden, MustafaThe effect of heat treatment on the dynamic crushing and energy absorption behavior of combined geometry shell cores (hemisphere and cylinder) of sandwich structures were investigated both experimentally and numerically. The applied heat treatment on the combined geometry shell cores relieved the stress caused by deep drawing, diminishing the peak transmitted forces. The verified numerical models of the as-received and heat-treated combined geometry shells were used to model blast loading of various sandwich configurations and the additional sandwich configurations of reversing the cylindrical side of the cores to the impacted side. Both the applied heat-treatment and the reversing process decreased the magnitude of the force transmitted to the protected structure. The applied heat treatment increased the arrival time of blast force wave to the protected structure, while the reversing resulted in opposite.Article Citation - WoS: 82Citation - Scopus: 103Effect of Uv-C Irradiation and Heat Treatment on the Shelf Life Stability of a Lemon-Melon Juice Blend: Multivariate Statistical Approach(Elsevier Ltd., 2015) Kaya, Zehra; Yıldız, Semanur; Ünlütürk, SevcanHeat treatment and UV-C irradiation of lemon and melon juice (LMJ) blends were comparatively evaluated by examining their impact on E. coli K12 (ATCC 25253) and their physicochemical properties, i.e., total soluble solids (TSS), pH, titratable acidity (TA), color, turbidity and absorbance coefficient, both immediately after processing and during 30 days of refrigerated storage. The newly formulated LMJ blend containing 12% (v/v) lemon juice (pH 3.92 ± 0.01) scored the highest in the consumer acceptance test. Upon UV-C irradiation (2.461 J/mL) and heat treatment (72 °C, 71 s), the E. coli K12 population in LMJ blend was reduced by > 6 log10 CFU/mL. Principal component analysis (PCA) and hierarchical cluster analyses (HCA) showed a clear discrimination among the physicochemical properties of the control and the UV-C and heat-treated LMJ blends during storage, suggesting that UV-C irradiation has a comparable effect on microbial stability at 4 °C and better quality preservation performance than heat treatment. Industrial relevance Melon juice has many beneficial health effects. It has high sugar content, pH (5.6-6.0) and a fairly short shelf life. Therefore, pasteurization is required. But the thermal pasteurization has some undesired effects on the juice quality. Consumer demands for high quality fruit juice with fresh-like characteristics has markedly expanded in recent years. In this study, an alternative lemon-melon juice (LMJ) blend formulation was developed, and pasteurized using both UV-C irradiation and mild heat treatment. The shelf life stability of pasteurized LMJ blends was assessed by means of principal component analysis and hierarchical cluster analysis. The shelf life of LMJ blends treated by both methods was increased from 2 days to 30 days. The multivariate data analysis was successfully applied as a tool for an overall evaluation of the shelf-life of the product. UV-C irradiation has a comparable effect on microbial stability at 4 °C and better quality preservation performance than heat treatment for obtaining both shelf-stable and fresh-like LMJ blends. This would be a major advantage in processing of nutritious juice products.Article Citation - WoS: 44Citation - Scopus: 50Thermal Behaviour of a Zeolitic Tuff(Elsevier Ltd., 2007) Çağlar Duvarcı, Özlem; Akdeniz, Yelda; Özmıhçı Ömürlü, Filiz; Ülkü, Semra; Balköse, Devrim; Çiftçioğlu, MuhsinNatural zeolites undergo structural changes after heating which open their possible use in different fields, related to their chemical and physical properties, such as building stone, lightweight aggregate, ceramic foam, concrete bricks, tiles, porcelain stoneware and additive in puzzolonic cements. In this study, thermal behavior of zeolitic tuff quarried from Gördes-Manisa, region of Turkey was investigated. Zeolitic rocks were first reduced to 2 μm and pellets were prepared by dry-pressing. The pellets were heated for 30 min in the temperature range of 200-1200 °C. Heating the tuff up to 600 °C did not cause any structural change detectable by X-Ray powder diffraction (X-Ray), Fourier Transform Infrared Spectroscopy (FTIR) and thermal characterization methods with regard to the original sample, while further increase in the temperature caused structural breakdown of zeolitic tuff. The appearance of the broad low intensity peaks in X-Ray diffraction diagrams indicated most probably a partial transformation of crystal structure into an amorphous structure. The Scanning Electron Microscopy (SEM) micrographs showed that the crystals seen in the original rock sample were broken during grinding and pressing processes. The crystal structure disappeared above 1000 °C and the spherical pores was observed at 1200 °C. Chemical composition of the zeolitic tuff did not change significantly with respect to temperature. The highest density (2.28 g/cm3) and hardness (387 Hv) were obtained by sintering the pellets at 1000 °C for 30 min.