Browsing by Author "Coskun, H"

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Degradation of Milk Proteins by Extracellular Proteinase From Brevibacterium Linens Flk-61
(Marcel dekker inc, 1999) Coskun, H; Sienkiewicz, T
The objective of this study was to investigate the specificity of an extracellular proteinase from Brevibacterium linens FLK-61 on the degradation of milk proteins (a(s1)-, beta-casein, sodium caseinate and whey proteins). Each protein and the enzyme solution were incubated at 45 degrees C for "0" 15 and 30 min and 1, 2, 3, 4 and 5 h. After that, hydrolysis of the proteins was evaluated by urea-PAGE electrophoresis and densitometry. It was found that the enzymatic degradation of alpha(s1)-casein occured much faster and it was more complete (P<0.01) than degradation of beta-casein. No degradation of whey proteins was found during 5 h incubation.
Development of Lipolysis in Homogenised Culture Added Kashar Cheeses
(indian veterinary Journal, 2006) Coskun, H; Tuncturk, Y; Ondul, E; Yarimbatman, S
The Effect of Allium Sp on the Extension of Lipolysis and Proteolysis in Van Herby Cheese During Maturation
(Wiley-v C H verlag Gmbh, 2000) Coskun, H; Tunçtürk, Y
The aim of this study was to determine the effect of herb (Allium sp.) on biochemical changes of herby cheese produced in Turkey. Raw cows' milk was used for cheese manufacture. Five groups of cheeses, containing 0 (as control). 0.5, 1, 2, and 3% herb, were produced and coded as K, A, B, C, and D respectively. All cheese groups were ripened at 8 degrees C for 90 days. Samples were taken from cheeses after 3, 15, 30, 60 and 90 days, and analysed for Lipolysis las acid degree value) and proteolysis (water-soluble nitrogen. TCA-soluble nitrogen, and PTA-soluble nitrogen). It was found that lipolysis in herby cheeses increased with increasing herb addition, and the increase in lipolysis degree was significant (P < 0.05) in cheese D. Water-soluble N, TCA-soluble N, and PTA-soluble N as indicator of proteolysis degrees were affected significantly (P < 0.05) by increasing herb ratios.
The Effects of Production and Ripening Methods on Some Properties of the Herby Cheese Otlu Peynir
(Volkswirtschaftlicher verlag, 2002) Tunctürk, Y; Coskun, H
The aim of this study was to determine the effects of two production and ripening methods on some properties of these herby cheeses. The cheeses were produced from raw and pasteurised milks and ripened with two different salting methods. In the first method, the cheeses were ripened in brine and in the second, the cheeses were dry-salted and firmly filled in a container (filling cheese). Some chemical, biochemical, microbiological and sensorial properties of the cheeses were investigated on days 3, 90, 180 and 270. It was found that dry matter and fat contents of the filling cheeses were higher than those of the brined cheeses. More proteolysis and lipolysis occurred in the cheeses made with raw milk and the dry salting method. Total aerobic count and moulds-yeasts were higher in dry-salted and raw milk cheeses. Similarly, high numbers of coliforms were detected in raw milk cheeses, especially in the earlier stages of the ripening. The filling cheeses had higher sensorial scores.
Free Fatty Acid Accumulation by Mesophilic Lactic Acid Bacteria in Cold-Stored Milk
(Microbiology Soc Korea, 2004) Coskun, H; Öndül, E
This study was aimed to determine the accumulation of free fatty acid by mesophilic lactic acid bacteria (Lactococcus lactis subsp. lactis 1471, Lactococcus lactis subsp. cremoris 1000 and Lactobacillus casei 111) in cold-stored milk. According to the results, all cold-stored milks had higher acid degree values than those of fresh milk. This phenomenon showed that a slight increase occurred in the accumulation of free fatty acids as a result of spontaneous lipolysis during cold storage. All lactic acid bacteria showed good performance in production of titratable acidity, which increased during fermentation of the milk (fresh and stored milks). Moreover, as the storage time was prolonged, more free fatty acid accumulation was obtained from the fermentation of the cold-stored milk by the investigated lactic acid bacteria. The control milk, which was without lactic acid bacteria, showed no change in the accumulation of free fatty acid during fermentation. From this result, it can be suggested that longer cold-storage time can induce higher free fatty acid accumulation in milk by lactic acid bacteria.
Histamine Contents of White Cheeses Obtained From Van Retail Markets
(indian veterinary Journal, 2004) Noyan, T; Ekici, K; Coskun, H; Dulger, HH
Microbiological and Biochemical Changes in Herby Cheese During Ripening
(Wiley-v C H verlag Gmbh, 1998) Coskun, H
The aim of this study was to determine and compare the microbiological, biochemical and sensory characteristics of herby cheese made with two different methods. In the first method (M1), milk and herbs were pasteurized at 65 degrees C for 30 min, and Lactococcus lactis subsp. lactis and L. lactis subsp. cremoris were added as starter culture at an inoculum ratio of 1.5%. In the second method (M2), the conventional cheesemaking was applied. Microbiological and biochemical changes were monitored throughout the ripening period of 90 days. Samples were taken from cheeses on days 1, 15, 30, 60, and 90. At the end of ripening, sensory characteristics of cheeses manufactured with both methods were evaluated. The obtained results suggested that most changes in pH, titratable acidity, and dry matter contents of cheese varieties were not found to differ statistically significant, but the difference in salt content was significant (P < 0.01). Total aerobic count, lac tic acid bacteria, Staphylococcus aureus, coliforms, moulds, yeasts, proteolytic and lipolytic microorganism counts were lower in M1 cheese samples than those of M2 cheese samples (P < 0.01). The numbers of psychrotrophic microorganism in both cheese types were not found to differ significantly. Moreover, the results suggested that there were significant differences (P < 0.01) in the degrees of proteolysis and lipolysis of the cheese varieties. High proteolysis and lipolysis rates were monitored in the traditional cheese samples. However, there were no significant differences between the sensory characteristics of cheese samples.
Some Properties of Fresh and Ripened Herby Cheese,: a Traditional Variety Produced in Turkey
(Faculty Food Technology Biotechnology, 2004) Tarakçi, Z; Coskun, H; Tunçtürk, Y
Herby cheese (Otlu peynir) is widely produced and consumed in eastern parts of Turkey, and is generally made from sheep milk. The objectives of this study were to determine some properties of fresh and ripened herby cheese samples. Samples (20 fresh and 20 ripened) of herby cheese were collected from retail markets in Van, and analysed chemically and biochemically. Higher levels of dry matter, salt, fat and titratable acidity (%) were found in ripened cheeses. Also lipolysis and protein degradation were higher in ripened herby cheese samples than in fresh samples. Urea-polyacrylamide gel electropherograms of ripened cheese samples showed that higher degradation of alpha(s)-casein than of beta-casein occurred.
Vitamin C Contents of Some Herbs Used in Van Herby Cheese (Van Otlu Peyniri)
(Wiley-v C H verlag Gmbh, 2000) Coskun, H; Öztürk, B