Svojstva i trajnost svježeg ovčjeg sira proizvedenog dodatkom protektivne kulture

master's thesis

• Title (english): Characteristics and shelf life of fresh sheep cheese producted by adding protective culture
• Author: Ivan Martić
• Mentor: Irena Barukčić (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Technology of Milk and Milk Products); Zagreb
• Defense date and country: 2018-09-21, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Svježi ovčji sirevi proizvedeni su na tri različita načina: dodatkom mezofilnih sirarskih kultura, sirarskih kultura i tekućeg sirila te dodavanjem sirarske kulture, tekućeg sirila i protektivne kulture. Pakirani su u normalnoj atmosferi i skladišteni u hladnjaku 28 dana. Uzorci sireva izuzimani su i analizirani svaka četiri dana. Tijekom skladištenja bilježi se porast pH vrijednosti te smanjenje titracijske kiselosti sireva, a mikrobiološkom analizom utvrđen je porast broja naraslih kolonija mikroorganizama. Sirevi proizvedeni dodatkom sirarske kulture, tekućeg sirila i protektivne kulture (KSP) imaju najdužu trajnost (21 dan) i kod njih se bilježi najsporiji rast mikroorganizama tijekom skladištenja. Svi sirevi postigli su vrlo dobre ocjene (raspon bodova 17,7 - 20) prilikom senzorske analize, a uzorci proizvedeni dodatkom protektivne kulture zadržavaju odlična senzorska svojstva (20 bodova) čak do 14. dana skladištenja. Na osnovu rezultata provedenih analiza može se zaključiti da dodatak protektivne kulture u proizvodnji svježeg ovčjeg sira produljuje rok trajanja za 12 dana u odnosu na kontrolni uzorak uz očuvanje poželjnih fizikalno - kemijskih i senzorskih svojstava.

Abstract (english)

Fresh sheep cheeses are produced in 3 different ways: by adding mesophilic starter cultures, mesophilic cultures and liquid rennet and by adding starter culture, rennet and protective culture. Fresh cheeses were packed under normal atmosphere and stored in fridge for 28 days. Cheese samples were analyzed every 4 days. During the storage period the pH value of fresh cheeses increased, while titratable acidity decreased. Microbiological analysis showed that the viable cell counts of the examined microorganisms increased progressively. Fresh cheeses produced by adding starter culture, liquid rennet and protective culture (KSP) had the longest shef life (21 days) and showed the slowest growth of microorganisms during storage. All samples were evaluated by high sensory scores and those produced by adding protective culture retained excellent sensory properties until the 14th day of storage. All analysis confirmed that addition of protective culture in the production of fresh sheep cheese significantly prolonged its shelf life while preserving desirable physico – chemical and sensory characteristics.

• Keywords: svježi sir; ovčje mlijeko; trajnost; protektivna kultura
• Keywords (english): fresh cheese; sheep milk; shelf life; protective culture
• Language: croatian
• URN:NBN: urn:nbn:hr:159:483051
• Study programme: Title: Food Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka prehrambenog inženjerstva (magistar/magistra inženjer/inženjerka prehrambenog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2019-11-27 11:59:57