Fermentacija kozjeg, pirovog i sojinog mlijeka s dodatkom vanilije nacijepljenih kefirnim zrncima

undergraduate thesis

• Title (english): Fermentation of goat, spelt and soy milk with vanilla inoculated with kefir grains
• Author: Antonela Kovačina
• Mentor: Sunčica Beluhan (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Biochemical Engineering); (Laboratory for Biochemical Engineering, Industrial Microbiology and Malting and Brewing Technology); Zagreb
• Defense date and country: 2016-06-30, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Kefir je jedinstveni mliječni proizvod dobiven fermentacijom laktoze do mliječne kiseline i alkohola. Proizvodi se zahvaljujući mikrobnoj aktivnosti kefirnih zrnaca, koja imaju relativno stabilan i na specifičan način ujednačen udjel bakterija i kvasaca. Kefir predstavlja kompleksnu i snažnu simbiozu više od 30 mikroorganizama, koji tvore nakupinu sličnu cvatu cvjetače i povezani su u polisaharidni matriks naziva kefiran. Sastav kefira različit je ovisno o čimbenicima kao što su tip mlijeka i mikrobiološki sastav radne kulture (kefirna zrnca ili komercijalno dostupna starter kultura). Cilj ovog rada bio je odrediti učinkovitost kefirnih zrnaca kao inokuluma za pripravu kefira od različitih tipova mlijeka (kozjeg, pirovog i sojinog s dodatkom vanilije). Uzorci mlijeka su inokulirani s 5 % kefirnih zrnaca i prirodno fermentirani na sobnoj temperaturi tijekom 14 dana uzgoja. Promjene pH vrijednosti bile su u korelaciji s metaboličkim aktivnostima bakterija i kvasaca. Uočen je linearni odnos prinosa biomase kefirnih zrnaca i povećanja koncentracije mliječne, glukonske i octene kiseline tijekom fermentacije. Pirovo i sojino mlijeko s dodatkom vanilije mogu poslužiti kao hranjiva podloga za proizvodnju napitaka sličnih kefiru proizvedenom na kozjem mlijeku.

Abstract (english)

Kefir is a unique cultured dairy product due to combined lactic acid and alcoholic fermentation of lactose in milk. Kefir is produced by microbial activity of kefir grains, which have a relatively stable and specific balance of lactic acid bacteria and yeast. It is a complex and powerful symbiosis of more than 30 microorganisms that form a cluster or cauliflower-like structure held together in a polysaccharide matrix named kefiran. The composition of kefir varies according to factors such as milk type and the microbiological composition of culture types (kefir grain or commercial starter culture). The aim of the present study was to evaluate the use of kefir grains as inoculum for the preparation of different milk types (goat, spelt and soy milk with vanilla) kefir. Milk samples were inoculated with 5 % kefir grains and fermented naturally at room temperature over a period up to 14 days. Changes in pH were correlated to the symbiotic metabolic activities of bacteria and yeasts. The yield of kefir grain biomass increased with fermentation time resulting in linear increment of lactic, gluconic and acetic acid formation. Spelt milk and soy milk with vanilla may serve as culture medium for the production of kefir-like beverages similar to goat kefir.

• Keywords: kefir; kefirna zrnca; fermentacija; mliječni napitak; nastajanje organskih kiselina
• Keywords (english): Kefir; Kefir grains; Fermentation; Milk beverage; Organic acids formation
• Language: croatian
• URN:NBN: urn:nbn:hr:159:234885
• Study programme: Title: Biotechnology; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka biotehnologije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka biotehnologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2017-04-24 07:43:23