Investigations on organoleptic, chemical and microbiological features of tulum chese with starter culture during maturation

101 7. SUMMARY In this study, the aim of which is to acquire fundamental information on improvement of tulum cheese quality experimental tulum cheese samples are made with raw milk (type A) and pasteurized milk by using different culture combinations. On the 0, 15th, 30th, 60th and 90th days of the ripening period, changes in microbiological and chemical - qualities, and on the 60th and 90th days, changes in sensorial qualities were examined. To produce pasteurized milk cheese, Streptococcus lactis (type B), Streptococcus lactis + Lactobacillus casei (type C) and Streptococcus lactis + Streptococcus cremoris + Leuconostoc cremoris (type D) combinations were used. Cultures were inoculated into pasteurized milk at the rate of %1 and %2. Therefore, in respect of inoculation amount, two different series of cheese samples were prepared. In all experimental tulum cheese samples, the number of total aerobic mezophilic microorganisms increased continually in the beginning of ripening. The number of general microorganisms in %1 cultured cheese increased the highest level on the 15th and 30th days of ripening, and in %2 cultured cheese it increased the highest level on the 30th day and then decreased in both types in the course of time. At the end of ripening the numbers of microorganisms were very near each other in all series. Lactobasillus - leuconostoc - pediyococcus group of microorganisms increased continually from the first day of ripening and reached the highest level on the 15th and 30th days depending on the cheese kinds and then decreased in the course of time. During ripening in cheese samples with laktobasillus strains (type C), the number of lactobasillus - leuconostoc - pediyococcus was more than that of other cheese types.102 The number of Streptococcus lactis increased in all samples on the 15th day of ripening and then it decreased in the course of time. It was observed that during ripening Streptococcus lactis in type A samples, made with raw milk, was less than that of the others. Besides, in comparison with %1 cultured samples, in %2 cultured tulum cheese samples, the number of Streptococcus lactis was more. During ripening the number of Staphylococcus-micrococcus microorganisms was different according to the cheese types. The number of Stafilokokkus-mikrokokkus in samples increased between the 15th and 30th days and later on it decreased gradually. In different ripening phases, the number in raw milk cheese was more than it was in pasteurized milk cheese. Besides, it was observed that in comparison with the series of %2, in series of %1 the number of Staphylococcus- micrococcus microorganisms was more. In raw milk cheese and cultured pasteurized milk cheese, coliform microorganisms and fecal streptococcus decreased continually from the very first day to the end of ripening. Coliform and fecal streptococcus microorganisms in different cheese types disappeared in different days during ripening. In tulum cheese samples produced with %2 starter culture, above mentioned microorganisms disappeared more quickly. The number of ferment and mould increased on the 30th -60th days depending on" the types of cheese and later on increased gradually. In comparison with pasteurized milk cheese samples, in raw milk (A) cheese, ferment and mould number was more excluding the 0 and 15th days of ripening. Besides, it was stated that the number of ferment mould microorganisms decreased evidently depending on the increase of culture amount. Amount of acidity in all cheese samples increased continually beginning from the first day of ripening and reached the highest level on the 90th day. Amount of acidity in103 the samples produced with raw milk was less than the amount in cheese with cultured, pasteurized milk. pH value in samples decreased continually during ripening. It was stated that pH value in pasteurized milk cheese was less than pH value in raw cheese milk. Salt amount in all samples increased continually from the beginning of ripening and reached the highest level on the last day. Salt amount in raw milk cheese was more than salt amount in pasteurized milk cheese. During ripening, amount of humidity in all samples decreased continually and reached the lowest level on the 90th day. Amount of humidity in raw cheese samples was less than that of the others (excluding D samples on the 30th day of ripening). Besides, amount of humidity in cheese of %1 series was more than that of %2 series. In organoleptic control, some important differences were seen between cheese types. On the 90th day of ripening, from the characteristic point of view, D type of cheese with S. lactis + S. cremoris + Leu. cremoris combination got the top point. After that came raw milk cheese and B type cheese. Consequently, it was stated that in order to produce standart quality, good tulum cheese milk should be pasteurized; using starter culture is very useful combination including S. lactis + S. cremoris + Leu. cremoris strains effects the sensorial qualities of the product more positively.