Acta Scientiarum Polonorum Technologia Alimentaria

Abstract The aim of the study was physicochemical and sensory characterization of kefir manufactured from sheep milk following its production and storage at refrigerated conditions. Sheep milk inoculated with different starter cultures was incubated at the temperature of 23°C (culture DA) and 26°C (culture DC) for the period of 16-18 h until it reached pH of 4.6. The obtained kefir was assessed on the basis of: the extent of its acidification, the content of taste and smell substances and the results of sensory evaluation. The initial titratable acidity of the kefir manufactured with the assistance of the DA culture reached 48.2°SH and was by 14% higher than that of the kefir manufactured with the DC culture. After 21 days of storage, the titrable acidity of the kefir was by 6.5°SH higher in comparison with the values obtained directly after its manufacture. With the passage of storage time, the amount of free fatty acids (FFA) in the examined kefir samples increased significantly. Higher quantities of FFA were found in the kefir with the DA culture than with the DC culture. Kefir obtained with the assistance of the DA culture contained less acetaldehyde and diacetyl directly after manufacture. The quantities of these compounds underwent significant changes during storage. Kefirs manufactured using the DC cultures were more desirable from the sensory point of view than those manufactured using the DA culture. Irrespective of the applied starter culture, the highest overall acceptability scores were awarded to the kefir on the 7th day of storage.