Browsing by Author "Tunçtürk, Y"

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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 Enzymatic Hydrolysis of Casein on Apparent Yield Stress and Some Emulsion Properties
(Elsevier Sci Ltd, 2006) Tunçtürk, Y; Zorba, Ö
In this investigation, casein was proteolysed at different levels using a neutral proteinase (Neutrase) and the effects of proteolysis on emulsion capacity (EC) of casein, emulsion stability (ES), emulsion density (ED), and apparent yield stress (AYS) values of emulsions have been investigated. In order to clarify the effect of proteolysis on proteins, the proteolysis-applied proteins at different levels went through urea-PAGE and SDS-PAGE analysis. The proteolysis level exerted a statistically very significant difference on proteolysis degree, EC, ES, ED, AYS values (p < 0.01). In the trial, no significant effect of enzyme and enzyme inhibitor (ethylenediaminetetraacetic acid, EDTA) on parameters was determined (P > 0.05); the difference was found to be associated with an outcome from proteolysis. While proteolysis increased rapidly up to 20th minute, it increased slowly from 80 min. It was also observed that urea-PAGE and SDS-PAGE patterns belonging to casein fractions were quite in perfect harmony with proteolysis degrees, whereas a remarkable weakening in main protein bands due to the period was seen. A constitution of new peptide bands was observed up to 80 min, but these bands vanished after this period. Another finding, which became the chief focus of our concern throughout our experimental trials was that EC, ES, ED and AYS values generally improved up to 5 min; however, it did not change from that period up to 20 min. From that period, these values were negatively affected, whereas from 80 min (0.136 AN/TN) a remarkable deterioration was observed in emulsion properties. (c) 2005 Elsevier Ltd. All rights reserved.
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.