The effect of the milk standardisation on chemical composition and sensory atributes of Škripavac cheese

Sir škripavac je hrvatski autohtoni punomasni sir. Tradicionalno se proizvodi na obiteljskim poljoprivrednim gospodarstvima Like, Gorskog Kotara, dijela Korduna te ogulinskog kraja. Standardizacija mlijeka je postupak optimizacije sadržaja proteina i mliječne masti na optimalan omjer 0,9 : 1. Može se provoditi dodatkom obranog mlijeka u prahu, obiranjem dijela mliječne masti ili dodatkom vrhnja i obranog mlijeka. Standardizacija nije uobičajeni postupak na obiteljskim poljoprivrednim gospodarstvima te je posljedica toga manja financijska dobit gospodarstva zbog smanjene iskoristivosti proteina i masti te nižeg randmana uslijed smanjene čvrstoće gruša. Cilj rada je bio utvrditi promjene kemijskog sastava i senzorskih svojstava sira škripavca tijekom postupka standardizacije, dodatkom obranog mlijeka u prahu te obiranjem dijela vrhnja. U pokusnim uvjetima u mini sirani nedaleko od Karlovca proizvelo se 10 šarži sira škripavca u kojima se mlijeko svake šarže podijelilo u 3 grupe, mlijeko za sirenje bez standardizacije (kontrolni sir), mlijeko za sirenje standardizirano na omjer protein : mast 0,9:1 dodavanjem obranog mlijeka u prahu, te mlijeko za sirenje standardizirano na omjer protein mast 0,9:1 obiranjem dijela vrhnja. Standardizacija je u pokusu provedena na dva načina: dodavanjem mlijeka u prahu u mlijeko za sirenje te obiranjem dijela vrhnja. Standardizacija mlijeka nije imala značajan utjecaj na udio suhe tvari u siru škripavcu (P>0,05), međutim imala je na udio mliječne masti i udio proteina sira. Udio mliječne masti dodatkom mlijeka u prahu značajno (P<0,05) se smanjio za 2,37% u odnosu na kontrolni sir, dok se obiranjem dijela vrhnja također smanjio, za 1,6% u odnosu na kontrolni sir (P>0,05). Udio proteina se u siru škripavcu značajno (P<0,05) povećao dodatkom obranog mlijeka u prahu za 1,2% u odnosu na kontrolni sir, odnosno obiranjem dijela vrhnja, za 2,05% u odnosu na kontrolni sir. Senzorska analiza je pokazala kako je najbolje ocijenjen sir bio sa dodatkom mlijeka u prahu u odnosu na kontrolni sir i sir dobiven obiranjem dijela vrhnja.Škripavac cheese is an autochthonous Croatian full-fat cheese. It is traditionally produced on family farms in Lika, Gorski Kotar, parts of Kordun and Ogulin’s region. Standardization of milk is a method of optimizing protein and milk fat content at an optimum ratio of 0.9 : 1. It can be carried out by adding skimmed milk powder, by skimming part of milk fat or with addition of cream and skimmed milk. Standardization is not a usual process at family farms, which results with lower financial profit for the farm, due to the reduced protein and fat recovery and lower firmness of the curd, as well as cheese yield. The purpose of this study was to determine the effect of the milk standardization on the chemical composition of Škripavac cheese as well as on sensory attributes after adding skimmed milk powder and after skimming part of the milk fat. In the small scare dairy plant close to Karlovac 10 batches of cheeses were produced. The milk of 3 batches was divided into three groups milk for cheese production without standardization (control group), milk with standardized ratio protein : fat = 0.9 : 1 with addition of skimmed milk powder, milk standardized to the ratio of protein : fat = 0.9 : 1 by skimming the part of the milk fat. Milk standardization did not have significant effect on total solids (P>0.05) in Škripavac cheese, but it has affected fat and protein content in cheese. After the addition of milk powder, the milk fat content has significantly (P<0.05) decreased for 2.37% while by skimming the part of the fat, it has also decreased for 1, 6%, in comparison to the control cheese. Protein content of Škripavac cheese by addition of the skimmed powder milk significantly (P