Yazar "Gurkan, H." seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • Küçük Resim Yok
    Öğe
    Thermal stability of chymosin or microbial coagulant in the manufacture of Malatya, a Halloumi type cheese: Proteolysis, microstructure and functional properties
    (Elsevier Sci Ltd, 2014) Hayaloglu, A. A.; Karatekin, B.; Gurkan, H.
    The thermal inactivation behaviour of calf rennet and Rhizomucor miehei protease and the effects of different concentrations of these enzymes on chemical composition, proteolysis, microstructure, hardness and meltability of Malatya cheese were studied. Thermal stability and inactivation behaviour of the two enzymes were different and influenced the level of proteolysis during ripening and the meltability of the cheeses. This influence depended not only on the type of coagulant, but also on its concentration. Salt and protein contents and pH of the cheeses were influenced by the type and concentration of the coagulant enzyme. Only small effects on the microstructure of the cheeses were visualised, also related to the type and concentration of coagulant enzyme. Hardness of the cheeses was influenced by the type and concentration of the coagulant as well. In conclusion, the microbial coagulant provided & higher level of thermal stability, proteolysis and meltability values than calf rennet. (C) 2014 Elsevier Ltd. All rights reserved.
  • Küçük Resim Yok
    Öğe
    Volatile compounds and biogenic amines during the ripening of mold-ripened Civil cheese manufactured using three different strains of Penicillium roqueforti
    (Wiley, 2018) Gurkan, H.; Yilmaztekin, M.; Cakmakci, S.; Hayaloglu, A. A.
    Practical applications Three different strains of Penicillium roqueforti were used for the manufacture of mold-ripened Civil cheese and these cheeses were ripened at 4 and 10 degrees C for 90 days. Sixty-five volatile compounds were identified in the volatile fractions of the cheeses. The concentration of volatile compounds in cheeses was significantly affected ripening time temperature and by mold strains a lesser extent. 3-Methyl-1-butanol, 2-nonanol, methyl dodecanoate, butanoic acid, and decanoic acid were the most frequently identified volatiles. Tryptamine, 2-phenylethylamine, putrescine, cadaverine, tyramine, spermidine, and spermine were also found. The most abundant biogenic amine was cadaverine. The formation of biogenic amines was significantly influenced by strain, ripening time, and temperature. The biogenic amine content was found to be between 2.41 and 228.94 mu g/g cheese. Ripening temperature and ripening time significantly influenced the formation of volatile compounds and biogenic amines. Moldy Civil is a traditional cheese variety produced in the eastern Anatolian region of Turkey and it is protected by geographical indication by Turkish Patent and Trademark Office (TURKPATENT) by 2010. It is manufactured using skimmed milk which is spontaneously acidified with native lactic acid bacteria and also the addition of preacidified whey. Three strains of P. roqueforti was used in Moldy Civil cheese-making and strains of the mold changed the volatile profiles and the levels of biogenic amines less than ripening time and temperature. Methyl ketones and alcohols were the dominant groups in volatiles, while cadaverine was found to be principal biogenic amine in Moldy Civil cheese. Use of P. roqueforti strains contributed to the formation of the volatile fraction of the cheese; however, the level of biogenic amines changed by P. roqueforti strains a lesser extent.
  • Küçük Resim Yok
    Öğe
    Volatiles and sensory characteristics of yogurt manufactured by incorporating basil (Ocimum basilicum L.)
    (Taylor & Francis Inc, 2017) Gurkan, H.; Hayaloglu, A. A.
    Purple basil was used as powder or water extract forms in the manufacture of yogurt for possible contribution on its taste and flavour of yogurt. The volatiles were extracted by solid-phase micro-extraction and then determined by gas chromatography-mass spectrometry (GC-MS) system. Effects of the addition of purple basil as powder or water extract form on the volatile composition and sensory characteristics during 3 weeks of storage at 4 degrees C were evaluated. Forty-nine compounds were identified in the volatile composition of yogurt samples, including 12 ketones and aldehydes, 9 esters, 7 acids, 8 alcohols, 9 terpenes, and 4 miscellaneous compounds. Acetoin, ethyl acetate, hexanoic acid, acetic acid, 1-hexenol, 3-hexen-1-ol, 2-ethylhexenol, dL-limonene, and linalool were most frequently identified volatiles in the yogurt samples. The level of linalool, which was main volatile in basil, was higher in powder basil flavoured yogurt samples than those in extracted basil flavoured yogurt samples. Principal component analysis of the GC-MS data showed that use of basil as powder or water extract form significantly changed the volatile profile of yogurt during storage. Also, sensory scores for basil-free yogurt were higher than yogurt samples manufactured by incorporating basil. In conclusion, use of basil enhanced the volatile composition of yogurt, and basil-flavoured yogurt may be offered for consumers as an alternative type of flavoured yogurt.