Browsing by Author "Oguz, Sehriban"

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Determination of Free Fatty Acids and Volatile Compounds of Butter Oil Produced From Pasteurized and Unpasteurized Butter at Different Temperatures
(Wiley, 2024) Demir, Tekin; Andic, Seval; Oguz, Sehriban
In this study, the effects of different raw materials, different processing temperatures, and storage temperatures on some properties of butter oil were investigated. Two different kinds of butter were produced from cream containing 40% milk fat. Both butter samples were processed into butter oil at three different temperatures (60, 90, and 120 degrees C). Butter and butter oil samples were stored at +4 degrees C and analyses were performed at 0, 30, and 60 days of storage. There are no significant differences between the atherogenicity index and the saturated and unsaturated fatty acid composition of butter and butter oil samples. Free fatty acid values of all samples increased during storage. Also, in all three storage periods, it was determined that free fatty acids were higher in butter samples than in butter oil samples. During storage, saturated and unsaturated free fatty acid values are generally higher in butter oil processed at 60 degrees C than in butter oil processed at 90 degrees C and 120 degrees C. In total, 40 volatile compounds were detected, which included 8 ketones, each of 6 aldehydes, alcohols, acids, and hydrocarbons, 5 terpenes, and 3 esters in butter and butter oil samples. Aldehydes and ketones were generally highest in butter oil processed at 120 degrees C. The most dominant saturated fatty acid is hexadecanoic acid, and unsaturated fatty acid is 9-octadecenoic acid in butter samples. Free fatty acid values of all samples increased during storage. A total of 40 volatile components were identified in both butter and butter oil.image
Isolation, Identification, and Characterization of Thermophilic Lactic Acid Bacteria Isolated From Whey of Kars Kashar Cheeses
(Springer, 2024) Oguz, Sehriban; Andic, Seval
Kars Kashar cheese is an artisanal pasta-filata type cheese and geographically marked in Eastern Anatolia of Turkey. The aims of this research were to determine for the first time thermophilic lactic acid bacteria (LAB) of Kars Kashar cheese and characterize the technological properties of obtained isolates. In our research, a number of 15 samples of whey were collected from the different villages in Kars. These samples were incubated at 45 degrees C and used as the source material for isolating thermophilic LAB. A total of 250 colonies were isolated from thermophilic whey, and 217 of them were determined to be presumptive LAB based on their Gram staining and catalase test. A total of 170 isolates were characterized by their phenotypic properties and identified using the MALDI-TOF mass spectrometry method. Phenotypic identification of isolates displayed that Enterococcus and Lactobacillus were the predominant microbiota. According to MALDI-TOF MS identification, 89 isolates were identified as Enterococcus (52.35%), 57 isolates as Lactobacillus (33.53%), 23 isolates as Streptococcus (13.53%), and one isolate as Lactococcus (0.59%). All thermophilic LAB isolates were successfully identified to the species level and it has been observed that MALDI-TOF MS can be successfully used for the identification of selected LAB. The acidification and proteolytic activities of the isolated thermophilic LAB were examined, and the isolates designated for use as starter cultures were also genotypically defined.