Production of feta-type cheese with selected mixed starter cultures

Cilj ovog diplomskog rada je ispitati utjecaj mješovitih starter kultura na proizvodnju sira tipa Fete od kravljeg mlijeka u laboratorijskim uvjetima. Provedeno je ispitivanje teksturalnog profila sira (čvrstoća, ljepljivost/adhezivnost, odgođena elastičnost, kohezivnost, gumenost, otpor žvakanju i elastičnost), boja sira, fizikalno-kemijska svojstva i senzorska svojstva. Primijenjena starter kultura je statistički značajno utjecala na osnovna fizikalno-kemijska svojstva proizvedenog sira tipa Feta. Rezultati su pokazali da je najveći prinos sira zabilježen u uzorcima koji su u sastavu starter kulture imali jogurtnu kulturu (uzorci 2 i 6), a koji imaju i najveći udio vode u svom sastavu, odnosno najniži udio masti, proteina i ukupne suhe tvari. L* vrijednost boje je u svim uzorcima bila veća od 94, te su svi sirevi gotovo potpuno svijetle boje, što je karakteristično za Feta sir. Starter kultura je utjecala i na profil teksture sireva, s tim da najveća odstupanja od kontrolnog uzorka pokazuje uzorak 2, proizveden pomoću mješovite jogurtno-mezofilne kulture (TY-971 ± M-179), koji je imao statistički najmanju čvrstoću i najmanji otpor žvakanju, zbog čega je dobio i najniže senzorske ocjene. Najviše senzorske ocjene dobili su kontrolni uzorci sira proizvedeni pomoću standardne kulture za Fetu (FRC-60), te uzorci sira proizvedeni pomoću mješovitih kultura s dodatkom probiotičkih bifidobakterija (FRC-60 ± BB-46, ABT-5 ± M 179).The aim of this paper is to test the influence of mixed starter cultures on the cow's milk Feta cheese production in laboratory conditions. Textural properties of cheese were examined (hardness, adhesiveness, springiness, cohesiveness, gumminess, chewiness, resilience), also the color of the cheese, the physicochemical properties and sensory properties. The used starter culture significantly affected the basic physical and chemical properties of produced Feta cheese. The results showed that the highest yield of cheese was observed in samples which contained the yoghurt culture as a part of the starter culture (samples 2 and 6), which also had the highest contend of water in their composition, and the lowest proportion of fat, protein and total dry matter. The L* value of the color was greater than 94 in all samples so all cheeses were almost fully which is characteristically for Feta cheese. Starter culture also affected the texture profile of cheeses, with the greatest deviations from the control sample shown in sample 2, which was produced using a mixed yogurt mesophilic culture (TY-971 ± M-179), and had statistically smallest hardness and the least resistance to chewing, which is reason for the lowest sensory scores. Most sensory scores were given to control samples of cheese produced using standard Feta culture (FRC-60), and to samples of cheese produced by mixed starter culture containing probiotic bifidobacteria (FRC-60 ± BB-46, ABT-5 ± M-179)