Effects of Wild-Type Starter Culture (Artisanal Strains) on Volatile Profile of Urfa Cheese Made from Ewe Milk

摘要

In the present study, the development of volatile flavor compounds in sheep's milk Urfa cheese made by using three different combinations of wild-type strains including Lactococcus lactis subsp. lactis 1B4, Lactococcus garvieae IMAU 50157, Enterococcus faecium ATCC 19434, Enterococcus durans IMAU 60200, and Enterococcus faecalis KLDSO.034 was investigated over 180 days. Three batches of cheese were made using above strains as follows: Cheese A (strains ATCC 19434+1B4+IMAU 50157); Cheese B (strains IMAU 60200+ATCC 19434+1B4); Cheese C (strains KLDSO.034+ IMAU 60200+ ATCC 19434+1B4+ IMAU 50157). The fourth batch was produced from raw sheep's milk as control (Cheese D). The volatile compounds were identified using a gas chromatography/mass spectrometry system combined with solid-phase microextraction. In total, 70 volatile compounds were recovered from the cheeses including 10 alcohols (mainly ethanol, 2-methyl-1-propanol, 3-methyl-1-propanol), 20 aldehydes and ketones (mainly 2-pentanone, 2-heptanone), 11 esters (mainly ethyl acetate), 10 acids (mainly acetic acid, 2-hydroxy-4-methyl pentanoic acid), 6 terpenes (mainly alpha-pinene), and 13 miscellaneous compounds (mainly 3,7-dimethyl-1,6-octadiene). While total aldehydes concentration in the control cheese was higher than those made from combinations of wild-type strains (Cheeses A to C), the concentration of alcohols was lower in the former sample. Regarding other volatile compounds there was no clear differences between the cheeses. Results showed that strain combination A or C (Cheese A or C, respectively) could be employed in the manufacture of Urfa cheese made from pasteurized sheep's milk. However, to reach a fair judgement on the proper strain combination for Urfa cheese, aroma profile (i.e., active compounds) released by the strains should be laid open in detail.