Browsing by Author "Coskun, Hayri"

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The Contribution of Herbs To the Accumulation of Histamine in "otlu" Cheese
(Wiley, 2006) Ekici, Kamil; Coskun, Hayri; Tarakci, Zekai; Ondul, Eda; Sekeroglu, Ramazan
The aim of this study was to determine the effect of herbs and the use of raw milk on histamine accumulation in "Otlu" (Herby) cheese during ripening. Cow's milk was used for the cheese production. The milk was divided into two main groups: one was used raw and the other was pasteurized at 65C for 30 min. Each group was further divided into two subparts, one of which was used as control (without herbs), while 2% (w/v) of the herbs were added into the other to produce Herby cheese. All cheeses were ripened at 7C for 90 days. The cheese samples were analyzed in terms of histamine content, titratable acidity, dry matter, salt and degree of ripening on days 5, 30, 60 and 90. Total mesophilic aerobic bacteria (MAB) were also counted during ripening. The use of raw milk and the addition of herb both increased histamine formation in Otlu cheeses (P < 0.05). Moreover, higher water-soluble nitrogen values, as degree of ripening, were obtained from both raw milk and herb-added cheeses. The number of MAB was higher in raw cheeses (P < 0.05) and also herb-added cheeses. The study suggests that the addition of herbs may facilitate histamine formation in Herby cheese.
The Effect of Homogenized Lactic Cultures on the Development of Proteolysis in Kashar Cheese
(Japanese Soc Food Sci & Technology, 2007) Tuncturk, Yusuf; Coskun, Hayri
The goal of the study was to determine the effect of homogenization of lactic cultures at 30 MPa on the development of proteolysis in Kashar cheese during ripening. The cultures Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. cemoris, Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus and Lactobacillus helveticus were used in the study. After propagation, the cultures were homogenized at 30 MPa and 40 degrees C for 5 cycles. Cow milk was used to make Kashar cheese in the study. The cheeses were ripened at 8 +/- 1 degrees C for 90 days. Chemical analyses, determinations of water soluble nitrogen (WSN), trichloroacetic acid-soluble nitrogen (TCA-SN) and phosphotungsticacid-soluble nitrogen (PTA-SN) contents and electrophoresis of casein bands were done on days 3, 30, 60 and 90. The results indicated that there was no significant effect of homogenization of the cultures on the chemical composition of Kashar cheeses (P>0.05). However, higher proteolysis values measured as WSN, TCA-SN, and PTA-SN were obtained from homogenized culture-added cheeses. Accumulation of PTA-SN content in the cheeses was significantly (P< 0.05) affected by homogenization of the cultures. At the end of ripening, the homogenized culture-added cheeses had lower residual alpha(s1)- and beta-caseins than the unhomogenized culture-added ones. The effect of homogenization of the cultures on the breakdown of alpha(s1)-casein was significant (P<0.05).