Fermentacija rižinog, bademovog, kravljeg i lješnjakovog mlijeka nacijepljenih kefirnim zrncima

undergraduate thesis

• Title (english): Fermentation of rice, almond, cow and walnut milks inoculated with kefir grains
• Author: Kristina Kožić
• 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: 2015-09-10, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology; Engineering

Abstract

Kefir je fermentirani mliječni napitak dobiven djelovanjem združene kulture bakterija mliječne kiseline i kvasaca, simbiotički snažno povezanih u strukturu koja se naziva kefirna zrnca. 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 (rižinog, bademovog, kravljeg i lješnjakovog). Uzorci mlijeka su inokulirani s 1,25 % kefirnih zrnaca i prirodno fermentirani pri 28°C tijekom 21-og dana uzgoja. Uočeno je da su promjene pH vrijednosti bile povezane sa simbiotskim metaboličkim aktivnostima bakterija i kvasaca te linearni odnos prinosa biomase kefirnih zrnaca i povećanja koncentracije glukonske, mliječne i octene kiseline. Rižino, bademovo i lješnjakovo mlijeko mogu poslužiti kao hranjiva podloga za proizvodnju napitaka sličnih kefiru proizvedenom na mlijeku

Abstract (english)

Kefir is a fermented milk beverage produced by action of lactic acid bacteria and yeasts that exist in powerful symbiotic association in kefir grains. 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 (rice, almond, cow and walnut) kefir. Milk samples were fermented naturally at 28 oC with 1.25 % kefir grains over a period up to 21 days. Changes in pH were related to the symbiotic metabolic activities of bacteria and yeasts. The yield of kefir grain biomass increased with fermentation time resulting in linear increment of gluconic, lactic and acetic acid formation. Rice, almond and walnut milks may serve as culture medium for the production of kefir-like beverages similar to milk kefir.

• Keywords: fermentacija; kefirna zrnca; mliječni napitak; nastajanje organskih kiselina
• Keywords (english): Fermentation; kefir grains; milk beverage; organic acids formation
• Language: croatian
• URN:NBN: urn:nbn:hr:159:133432
• 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: 2015-12-15 11:01:10