Ayşe Gürsoy

Volatile compound profiling of Turkish Divle Cave cheese during production and ripening

The formation of volatile compounds in Turkish Divle Cave cheese produced in 3 different dairy farms was determined during production and ripening, revealing 110 compounds including acids, alcohols, ketones, esters, and terpenes. The presence and concentration of these volatile compounds varied between specific phases of the production and the 120-d ripening process. Smaller differences were also detected between cheeses produced at different farms. Carboxylic acids were established as a major class at the end of ripening. The relative amounts of acids and ketones increased until d 90 of ripening, whereas alcohols increased for the first 30d and tailed off during the remaining part of the ripening process. The level of esters increased gradually until the end of ripening. Butanoic, acetic, and valeric acids, 2-butanol, 2-butanone, 2-heptanone, ethyl butanoate, α-pinene, and toluene were the most abundant compounds, likely contributing to the characteristic aroma of this traditional cheese.

Role of milk protein–based products in some quality attributes of goat milk yogurt

Goat milk yogurts were manufactured with the fortification of 2% (wt/vol) skim goat milk powder (SGMP), sodium caseinate (NaCn), whey protein concentrate (WPC), whey protein isolate (WPI), or yogurt texture improver (YTI). Yogurts were characterized based on compositional, microbiological, and textural properties; volatile flavor components (with gas chromatography); and sensory analyses during storage (21d at 5 °C). Compared with goat milk yogurt made by using SGMP, the other goat milk yogurt variants had higher protein content and lower acidity values. Goat milk yogurts with NaCn and WPC, in particular, had better physical characteristics. Using WPI caused the hardest structure in yogurt, leading to higher syneresis values. Acetaldehyde and ethanol formation increased with the incorporation of WPI, WPC, or YTI to yogurt milk. The tyrosine value especially was higher in the samples with NaCn and YTI than in the samples with WPC and WPI. Counts of Streptococcus thermophilus were higher than the counts of Lactobacillus delbrueckii ssp. bulgaricus, possibly due to a stimulatory effect of milk protein-based ingredients other than SGMP on the growth of S. thermophilus. Yogurt with NaCn was the best accepted among the yogurts. For the parameters used, milk protein-based products such as NaCn or WPC have promising features as suitable ingredients for goat milk yogurt manufacture.

Keçi Sütü Somatik Hücre Sayısının Vanilyalı Dondurmanın Bazı Fiziksel, Kimyasal ve Duyusal Özellikleri Üzerine Etkileri

Bu calismada keci sutu somatik hucre sayisinin (SHS) vanilyali dondurmanin bazi fiziksel, kimyasal ve duyusal ozellikleri uzerine etkileri arastirilmistir. Dondurma uretiminde dusuk (1200 x 103 hucre/ml), orta (1500 x 103 hucre/ml) ve yuksek (1800 x 103 hucre/ml) SHS’ye sahip sut ornekleri kullanilmistir. Cig sutun (pH, yag icerigi, yagsiz kuru madde icerigi, titrasyon asitligi degeri) ve dondurma miksinin (pH, titrasyon asitligi degeri, viskozite degeri) bilesim ve bazi ozellikleri kaydedilmistir. Ayrica, dondurma orneklerinin yag icerigi, toplam kuru madde icerigi, hacim artisi, erime orani ve duyusal ozellikleri belirlenmistir. Sonuclar, yuksek SHS’ye sahip cig sutun yag iceriginin dustugunu, pH ve titrasyon asitligi degerinin arttigini gostermistir (P<0.01). Ancak, sutlerin yagsiz kuru madde icerikleri farklilik gostermemistir (P˃0.05). Dondurma miksleri (pH, titrasyon asitligi degeri, viskozite degeri) SHS degisiminden etkilenmemistir. Dondurma orneklerinin hacim artisi, erime orani, yag ve toplam kuru madde icerigi 3 grup arasinda benzer bulunmustur. Gorunus ve tekstur skorlari farklilik gostermemistir. Ancak, SHS arttikca aroma skorunun azaldigi belirlenmistir (P<0.05). Sonuc olarak, keci sut SHS cig sutun bazi ozelliklerini ve vanilyali dondurmanin aromasini etkilemistir.