Changes occurring in plain, straining and winter yoghurt during the storage periods

Abstract

In this study, winter yoghurt, straining yoghurt and yoghurt samples produced from homogenized and non-homogenized sheep and a mixture of sheep and cows milks were evaluated during the storage periods. Winter yoghurt, straining yoghurt and yoghurt samples were stored in sterile jars in the refrigerator (4°C). Some chemical and physical analyses were made to determine the effect of milk types (cow and sheep), homogenization (homogenized and nonhomogenized) and storage times in winter yoghurt samples on the 3rd, 7th, 15th, 30th, 60th, 90th, 120th, 150th and 180th days, in straining yogurt samples on the 3rd, 7th, 15th, 30th and 60th days and in plain yoghurt samples on 3rd, 7th, 15th and 30th. Contents of the average dry matter, fat, protein, pH, titratable acidity, lipolysis, proteolysis, clot firmness and stickiness in winter yoghurt samples were determined as follows respectively: 23.79, 9.29, 8.99, 3.96, 1.75, 0.72%, 97.91 mM, 9.44 N and 5.50 N. No serum separation existed in winter yoghurts.

Key words: Winter yoghurt, storage, milk type, homogenization