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Svrha je ovoga rada bila ispitati utjecaj udjela κ-kazeina B u mlijeku na prinos mozzarelle s velikim udjelom vlage. Tijekom istraživanja praćena je proizvodnja osam šarži mozzarelle u četiri sirane. U svakoj sirani su provedena dva paralelna postupka proizvodnje sira: jedan iz spremnika za mlijeko talijanskog smeđeg goveda i drugi iz spremnika za mlijeko talijanskog frizijskog goveda. Prosječni udjel κ-kazeina B u mlijeku talijanskog frizijskog goveda bio je 0,04 g u 100 g, dok je u mlijeku talijanskog smeđeg goveda bio četerostruko veći i iznosio 0,16 g u 100 g. Udjel κ-kazeina B i omjer κ-kazeina B i kazeina u mlijeku bili su u pozitivnoj korelaciji sa stvarnim prinosom sira. Za oba je parametra koeficijent korelacije bio veći od 0,9; veći nego za bilo koju drugu frakciju proteina. Povećanje prinosa sira dobivenog od mlijeka s većim udjelom κ-kazeina B vjerojatno je posljedica prisutnosti manjih i homogenijih kazeinskih micela koje pospješuju koagulaciju mlijeka nakon dodatka sirila. Shodno tome, iz mlijeka s većim udjelom κ-kazeina B dobiva se elastičniji gruš, koji bolje podnosi daljnje tehnološke postupke i smanjuje gubitke što mogu nastati prilikom njegovog usitnjavanja i rastezanja. Može se zaključiti da je prinos sira dobivenog od mlijeka talijanskog smeđeg goveda, kojeg karakterizira veći udjel κ-kazeina, za 2,65 % veći od prinosa sira dobivenog od mlijeka talijanskog frizijskog goveda, što je značajan podatak i za uzgajivače goveda i za sirare., The aim of the present study is to investigate the effect of κ-casein B content in milk on the yield of high-moisture mozzarella cheese. The study was carried out by monitoring the production of eight mozzarella cheese batches at four cheesemaking factories. At each factory, two cheesemaking trials were performed in parallel: one using bulk milk from Italian Brown cattle and the other using bulk milk from Italian Friesian cattle. The average κ-casein B content was 0.04 g per 100 g in the Italian Friesian cows’ milk, whereas it was four times higher in the Italian Brown cows’ milk, reaching values of 0.16 g per 100 g. Both the κ-casein B content and κ-casein B to casein ratio were positively correlated with actual cheese yield. Both parameters showed correlation coefficient values over 0.9, higher than for any other protein fraction. The influence of the level of κ-casein on the increase of the yield is probably due to smaller and more homogeneous micelles, with more efficient rennet coagulation. Consequently, milk with higher κ-casein B content produces a more elastic curd that withstands better the technological treatments and limits losses during curd mincing and stretching. In conclusion, the Italian Brown cows’ milk, characterized by higher κ-casein content than the Italian Friesian’s one, allowed a yield increase of about 2.65 %, which is a very relevant result for both farms and cheesemaking factories.

Talijanski tvrdi kuhani sirevi, kao što su Parmigiano Reggiano i Grana Padano, imaju veliku nutritivnu vrijednost. Prema definiciji Europske Unije smatraju se funkcionalnom hranom, jer sadržavaju spojeve koji imaju specifična biološka svojstva. U ovom su preglednom radu ukratko opisani ti spojevi te njihov pozitivan učinak na zdravlje, i to u nekoliko poglavlja: proteini i peptidi, masti i lipidi, ugljikohidrati i prebiotici, probiotičke bakterije, vitamini, mineralne tvari, te sastojci mliječnih proizvoda s aktivnom ulogom u prevenciji bolesti. U uzorcima sira Parmigiano Reggiano pronađeno je nekoliko peptida s dokazanim biološkim svojstvima, npr. fosfopeptidi, koji imaju sposobnost vezivanja mineralnih tvari i funkciju prijenosnika funkcionalnih skupina, peptidi s imunomodulacijskim učinkom, te peptidi s antihipertenzijskim svojstvima i sposobnošću inibicije enzima koji konvertira angiotenzin. Među lipidima su opisane uloge konjugirane linolne kiseline i drugih masnih kiselina u siru. Također su opisani oligosaharidi s prebiotičkim svojstvima i probiotičke bakterije. Na kraju je posebno naglašena iskoristivost kalcija iz sireva, što je bitno za zdravlje kostiju., Italian hard cooked types of cheese, like Parmigiano Reggiano and Grana Padano, are characterised by positive nutritional qualities. In fact, they contain substances that have particular biological activities, and therefore they can be fully considered, according to the definition given by the European Unit, as ‘functional’ foods. This short review concisely describes these components and the beneficial effects related to their activities. The description of the biologically active components has been organised in the following paragraphs: protein and peptides, fat and lipids, carbohydrates and prebiotics, probiotic bacteria, vitamins, mineral salts, and components of dairy products active in disease prevention. In particular, several known bioactive peptides were found in Parmigiano Reggiano cheese samples: for example, phosphopeptides, which are known for their mineral-binding capacity and vehiculation activity, peptides with immunomodulatory activity, and angiotensin-converting enzyme-inhibitory peptides with anti-hypertensive effects. Among lipids, the role of conjugated linoleic acid and other fatty acids present in these cheese types was taken into consideration. The presence of oligosaccharides with prebiotic properties and probiotic bacteria was also described. Finally, particular emphasis was given to highly available calcium and its impact on bone health.