Fermentacija sirutke tretirane ultrazvukom prije i nakon inokulacije

master's thesis

• Title (english): Fermentation of whey treated with ultrasound before and after inoculation
• Author: Marina Cimaš
• Mentor: Rajka Božanić (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: 2011-07-15, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

U radu je proučavan utjecaj ultrazvuka na fermentaciju sirutke prije i nakon inokulacije. Uzorci sirutke predgrijani na 55°C tretirani su ultrazvukom amplitude 100, 90 i 80% u trajanju 8 i 6,5 minuta. Na temelju redukcije broja mikroorganizama (u odnosu na pasterizaciju) i dobre senzorske ocijene, izabran je tretman ultrazvuka amplitude 80% kroz 8 minuta. Ovaj je uzorak sirutke, zajedno sa pasteriziranim uzorkom inokuliran jogurtnom kulturom. Utjecaj djelovanja ultrazvuka nakon inokulacije promatran je na pasteriziranim i inokuliranim uzorcima sirutke koji su ultrazvučno tretirani pri 15°C na amplitudama 80, 60 i 40% u trajanju 8 minuta. Nakon tretmana svi uzorci su inkubirani na 43°C do postizanja pH=4,7-4,6. Rezultati su pokazali da ultrazvuk visoke snage ima baktericidno djelovanje u rangu sa pasterizacijom, no senzorska svojstva tretirane sirutke su loša. Ultrazvuk nije utjecao na skraćivanje vremena fermentacije. Rast jogurtnih bakterija bio je nešto bolji u uzorku tretiranom ultrazvukom prije inokulacije. Utjecaj ultrazvuka na senzorska svojstva fermentirane sirutke izaziva negativne učinke.

Abstract (english)

Purpose of this research si to test the effects of ultrasound on whey fermentation before and after inoculation.The methods used to treat whey prior to culturing were pasteurization and thermosonication. Thermosonication off preheated (55°C) whey is being treated with amplitude 100, 90 and 80% for 8 and 6.5 min. Sample amplitude 80% for 8 min gave a good reduction of microorganisms and satisfying sensory analysis. To investigate effect of ultrasound in order to improve fermentation and growth of yoghurt culture, inoculated whey is treated at 15°C to offset temperature increase due to ultrasonic cavitation, with ultrasound amplitude 80, 60 and 40 % for 8 min. After sonication, the samples were incubated at 43°C until reaching pH 4.7. Stimulating effect of ultrasound after inoculation didn´t improve fermentation time, but ultrasound applied before inoculation somehow stimulated growth of yoghurt bacteria.

• Keywords: ultrazvuk; sirutka; mikroorganizmi; fermentacija
• Keywords (english): ultrasound; whey; microorganisms; fermentation
• Language: croatian
• URN:NBN: urn:nbn:hr:159:200628
• Study programme: Title: Food Technology; specializations in: Food Engineering; Course: Food Engineering; Study programme type: university; Study level: graduate; Academic / professional title: diplomirani inženjer prehrambene tehnologije; smjer prehrambeno inženjerstvo (diplomirani inženjer prehrambene tehnologije; smjer prehrambeno inženjerstvo)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-05-31 11:29:23