Food Engineering / Gıda Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/12
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Conference Object Citation - Scopus: 2Preparation and Characterization of Hydroxyapatite/Calcium Phosphate Powders(Trans Tech Publications, 2004) Şimşek, Deniz; Çiftçioğlu, Rukiye; Harsa, ŞebnemThe preparation of calcium phosphate based powders through chemical precipitation in order to determine the optimum conditions for the preparation of stoichiometric, thermally stable hydroxyapatite (HA) powders was investigated in this work. The effects of parameters like pH, aging time, and heat treatment temperature on the phase structure and morphology of the powders were investigated by SEM and XRD.HA was prepared at a Ca/P ratio of 1.67. The precipitation pH had a profound influence on the morphology and crystallite size of the powders in the 4-11 pH range. Relatively large 5 mum prismatic particles were obtained at low pH whereas the powders were formed from agglomerates of nano sized particles at high pH. Powders had a HA dominant phase structure above a pH of 8. Phase pure HA powders were obtained with close to theoretical yields at pH = 10 and 11. The crystallite sizes of the powders varied from about 30 nm at 90degreesC to 50-90 mn at 1250degreesC with the smallest crystallite sizes obtained for pH 10 and 11 powders at 1250degreesC. The crystallite size increased significantly with aging temperature.Conference Object Photoautotrophic and Heterotrophic Micropropagation of Sugarcane Shoots in Controlled Environments(2000) Ertürk, Handan; Walker, Paul N.We achieved successful growth and multiplication of sugarcane shoots in vitro under photoautotrophic conditions aseptically for three generations in our laboratory and proposed an experimental procedure for photoautotrophic micropropagation of sugarcane in controlled environment. The growth rate of photoautotrophic cultures in sugarless MS medium was found to be half of the growth rate of heterotrophic cultures in multiplication medium after a two-week period in the same environment. Contamination with algae in some vessels was recognized as a problem for septic photoautotrophic growth. Atrazine was found to be effective in controlling algae at a concentration of 10 ppm. But, atrazine in total was not considered to be a practical solution for the algae problem as it had a negative affect on the growth of shoots.Article Citation - WoS: 7Citation - Scopus: 11Effects of Light, Carbon Dioxide, and Hormone Levels on Transformation To Photoautotrophy of Sugarcane Shoots in Micropropagation(American Society of Agricultural Engineers, 2000) Ertürk, Handan; Walker, Paul N.Sugarcane (Saccharum spp.) shoots were transferred from a heterotrophic micropropagation environment and cultured on sugar-free Murashige and Skoog (MS) salts medium in the controlled atmosphere of a growth chamber. The purpose was to achieve photoautotrophic shoot culture to be used for micropropagation. Effects on the shoots were tested for three factors: Carbon dioxide concentration, light level, and the hormone concentration of the growth medium. Factorial design was applied for the experiment such that all combinations of high and low factor levels were utilized, and the medium level of each factor level constituted the middle point of the design. All shoots were observed to become yellowish in color and lose vigor in the sugarless environment, although the successful treatments regained their color and vigor. Average dry weights of shoots per vessel were recorded at the end of two weeks as a quantitative measure of transformation of shoots to photoautotrophy. Light and CO2 levels were found to have statistically significant and positive effects. The negative effect of hormone concentration was insignificant.Article Determination of the Effects of Biomaterials on Human Peripheral Blood Mononuclear Cells (pbmc)(IOS Press, 2002) Sudağıdan, Mert; Güneş, Hatice; Harsa, ŞebnemConference Object Risk Management of Ready-To Meat Products Contaminated With Listeria Monocytogenes(Technical Research Center of Finland, 2009) Korel, FigenNowadays, the modern life style relies heavily on the availability, quality, and safety of ready-to-eat (RTE) food products. The quality of the raw material, handling, processing, transportation and storage are the important factors influencing the microbial quality of the finished product. The mostly consumed RTE meat products are hamburgers, frankfurters, hot dogs, dry/semi-dry fermented sausages, salami, and deli meats. Several pathogens could be found on RTE meat products, including Escherichia coli O157:H7, Salmonella, Listeria monocytogenes, and Staphylococcus aureus. Vegetative pathogens are destroyed during thorough cooking and processing of these products. Contamination during post-processing in the plant, and further contamination and improper handling during storage, at retail or in home cause microbial growth. Pathogens can multiply under inappropriate conditions causing foodborne diseases and outbreaks.Conference Object Microbiological Risk Assessment and Preventive Actions in Bakery and Beverage Industries in Estonia, Slovenia and Turkey(Technical Research Center of Finland, 2008) Baş, Duygu; Baysal, Ayşe Handan; Ehavald, Helen; Eroğlu, Erdal; Filip, Sebastjan; Köksal, Fatma; Marin, Monika; Perne, Gregor; Türetgen, İrfan; Weiss, Martina; Akdoğan, Günay; Veskus, TiinaRisks from microbiological hazards are of immediate and serious concern to human health. Microbiological Risk Analysis (MRA) is a process consisting of three components: risk assessment (RA), risk management (RM), and risk communication (RC), which have the overall objective to ensure public health protection. The MRA process should include quantitative information to the greatest extent possible in the estimation of risk. A MRA should be conducted using a structured approach. Since MRA is a developing science, implementation of the guidelines may require a period of time and may also require specialized training in the countries that consider it necessary. This may be particularly the case for developing countries. This document deals with risk assessment, which is a key element in assuring that sound science is used to establish standards, guidelines and other recommendations for bakery and beverage safety to enhance consumer protection and facilitate international trade. This document will be of primary interest to governmental and research organizations, companies, and other interested parties who need to prepare a MRA will find it valuable.Conference Object Antimicrobial Effect of Natural Antimicrobial Agents Against Foodborne Pathogens(Technical Research Center of Finland, 2008) Eroğlu, Erdal; Türe, Hasan; Soyer, Ferda; Özen, BanuBesides that foodborne infections and intoxications cause great danger for human health they have also adverse impact on the economics. Alternative food preservation techniques to produce safer foods e.g. systems containing natural antimicrobial agents have recently gained popularity. The consumers prefer foods with no chemical additives without shortened shelf-life. In this sense, natural antimicrobials have become promising alternatives for hurdle technology. However, most of the natural antimicrobials have limited spectrum of activity.Conference Object Citation - Scopus: 1Short Wave Ultraviolet Light (uvc) Disinfection of Surface - Inhibition of Alicyclobacillus Acidoterrestris Spores on Agar Medium(Technical Research Center of Finland, 2008) Baysal, Ayşe Handan; Ünlütürk, SevcanAlicyclobacillus species are thermoacidophilic spoilage spore-formers found in soil. The spores can survive the normal hot fill processes that are carried out on commercial fruit juices. It seems likely that fruit in contact with soil are susceptible to contamination by Alicyclobacillus. Beverage ingredients e.g. liquid sugar are also a potential contamination sources. Alicyclobacillus has also been isolated from citrus processing lines.Conference Object Risk Assessment in Miscellaneous Food Processing Industries Including Producers of Vegetables and Spices(Technical Research Center of Finland, 2008) Güldaş, Metin; Ursu, Roxana; Lagouri, Vasiliki; Kısıkkaya, N. Aslı; Uyar, M. Fatih; Mokorel, Primoz; Türe, Hasan; Lee, Solmaz; Korel, Figen; Karpiskova, RenataTesting foods for pathogenic and spoilage bacteria is the cornerstone to ensuring a safe and wholesome food supply. The methods for monitoring of microbial contamination are based on the following principles: → Cultivation of microbes in the presence of different energy sources, → Analysis of their macromolecular composition and their metabolic byproducts, → Use of specific immunological reagents for bacterial classification and identification.Conference Object Antimicrobial Effects in Food and Prevention of Contamination in Food Industry(VTT Technical Research Center of Finland, 2007) Hütt, Pirje; Songisepp, Epp; Güldaş, Metin; Tamme, Terje; Ormancı, Fatma Seda; Ayaz, Naim Deniz; Korel, Figen; Aarnisalo, Kaarina; Hradecka, Helena; Mikelsaar, MarikaThe most commonly recognized food-borne infections are caused by Campylobacter jejuni and Salmonella spp. In the past 25 years, Listeria monocytogenes has become increasingly important as a food-associated pathogen. Though, an annual incidence of human listeriosis is between two and ten reported cases per million in EU countries. Because of its high case fatality rate, listeriosis ranks among the most frequent causes of death due to food-borne illness. L. monocytogenes and C. jejuni has been shown to adapt to different environmental stress factors, including disinfectants. Salmonella enteritidis, C. jejuni and L. monocytogenes may also form a biolfim which helps to survive in the environment. For that reason, the food industrial hygiene has become important to avoid contamination of raw food and food products with these pathogens.