| Abstract | Otočki kozji i ovčji sirevi tradicionalno se mogu čuvati u ulju. Suprotno od zrenja sira na zraku, uranjanjem sira u ulje sprječava se gubitak vode iz sira. Udio vode jedan je od važnijih parametara koji utječe na tijek zrenja sira, a time i na njegov fizikalno-kemijski sastav i senzorna svojstva.
Cilj ovog rada je utvrditi utjecaj zrenja polutvrdog kozjeg sira u ulju na njegov fizikalno-kemijski sastav i senzorna svojstva.
Polutvrdi kozji sir proizveden je od punomasnog kozjeg mlijeka u tri šarže u pilot pogonu Zavoda za mljekarstvo. Proizvedeni sirevi iste šarže podijeljeni su u dvije grupe s obzirom na način zrenja: 1) zrenje na zraku (kontrolna grupa) i 2) zrenje u ulju nakon 10 dana zrenja na zraku. Ukupno trajanje zrenja sira bilo je 60 dana. Za zrenje sira u ulju koristila se mješavina ekstra djevičanskog mljetskog maslinovog i rafiniranog suncokretovog ulja (50 : 50). Uzorkovanje sira provedeno 0., 10., 20., 30., 45. i 60. dana zrenja te je određen: udio suhe tvari, mliječne masti, proteina, soli te pH sira. Panel od 5 stručnih ocjenjivača koristeći sustav bodovanja ocijenio je senzorna svojstva sireva (vanjski izgled, struktura, presjek, boja, miris i okus) nakon završenog postupka zrenja.
Posljedica zrenja kozjeg sira u ulju su promjene fizikalno-kemijskog sastava sira (sprečavanje gubitka vlage, porast pH vrijednosti, stagnacija sadržaja mliječne masti, proteina i soli) te poboljšavanje senzorskih svojstava sira (vanjski izgled, struktura, presjek, boja, miris i okus). Stoga se može zaključiti da se zrenjem polutvrdog kozjeg sira u ulju mijenjaju njegova fizikalno-kemijska svojstva uvjetujući značajno bolja senzorska svojstva što omogućuje konzumaciju ovog sira i izvan sezone proizvodnje i prerade kozjeg mlijeka. |
| Abstract (english) | Island goat and sheep cheeses can traditionally be stored in oil. Unlike air-ripened cheeses, immersion the cheese in oil prevents moisture loss. The moisture content is one of the most important parameters that affects the cheese ripening pathway, and consequently its physico-chemical composition and sensory properties.
The aim of this thesis is to determine the influence of ripening of semi-hard goat cheese in oil on its physico-chemical composition and sensory properties.
Semi-hard goat cheese was produced from full-fat goat milk in three batches in the pilot plant of the Department of Dairy Science. The cheeses from the same batches were divided into two groups according to the ripening method: 1) ripening in air (control group) and 2) ripening in oil after 10 days of ripening in air. The total duration of cheese ripening was 60 days. A mixture of extra virgin Mljet’s olive oil and refined sunflower oil (50 : 50) was used. Cheese sampling was conducted on the 0th, 10th, 20th, 30th, 45th and 60th day of ripening and the following were determined: the content of dry matter, milk fat, proteins, salt, and pH. A panel of 5 cheese experts evaluated the sensory properties of the cheeses (external appearance, texture, cross-section, colour, odour, and taste) after the ripening process was completed.
The consequences of preserving goat cheese in oil are changes in the physico-chemical composition of the cheese (increased moisture content and pH value, stagnation milk fat, protein, and salt content), and improvement in the sensory properties of the cheese (external appearance, texture, cross-section, colour, odour, and taste). Therefore, it can be concluded that ripening of semi-hard goat cheese in oil changes its physico-chemical properties, causing significantly better sensory properties that allow this cheese to be consumed outside the season of production and processing of goat’s milk. |
