Influence of starter cultures on the properties of fresh cheese

Cilj ovog rada bio je ispitati utjecaj starter i protektivnih kultura na svojstva svježeg sira. Svježi sir proizveden je od pasteriziranog mlijeka na nekoliko različitih načina koji su uključivali primjenu samo mezofilne kulture, primjenu kombinacije mezofilne kulture i sirila, te primjenu protektivne kulture. Svim proizvedenim uzorcima sireva određivala se kiselost (aktivna i titracijska), mikrobiološka kvaliteta, tekstura i boja te senzorska svojstva. Prvi je dan sirevima određen udio mliječne masti, pepeo, udio suhe tvari i proteina te prinos. Tijekom skladištenja kiselost je padala, a broj naraslih kolonija mikroorganizama postupno rastao. Promjene kod sira proizvedenog uz dodatak protektivne kulture bile su znatno usporene. Senzorske su ocjene bile visoke sve dane skladištenja te je sir uz dodatak protektivne kulture imao najbolje senzorske ocjene (18,56). Nakon mikrobioloških, senzorskih i fizikalno- kemijskih analiza zaključeno je da je rok trajnosti za sir proizveden uz dodatak protektivne kulture produžen za 12 dana u odnosu na ostale uzorke te iznosi 21 dan.The aim of this study was to examine the influence of starter and protective cultures on the properties of fresh cheese. Fresh cheeses were produced from pasteurized milk in few different ways, by adding mesophilic starter cultures, mesophilic cultures and liquid rennet and by adding protective culture. On all samples it was analysed acidity (active and titratable), microbiological quality, texture and colour and sensory analysis. First day was also analysed milk fat, ashes, dry matter and protein content and yield. During storage acidity was decreased and number of microorganisms increased. Changes in cheese produced by adding of protective culture were significantly slowed down. Scores of sensory evaluations were high for all days of storage and cheese made by adding of protective culture had best result (18.56). After microbiological, sensory and physico-chemical analyses it is concluded that shelf life for the cheese made by adding protective culture is prolonged for 12 days and it was 21 day