Utjecaj ultrazvuka visokog intenziteta na stupanj homogenizacije i fizikalna svojstva sojinog, kravljeg, ovčjeg i kozjeg mlijeka

doctoral thesis

• Title (english): Influence of high intensity ultrasound on degree of homogenization and physical properties of soybean, cow, sheep and goat milk
• Author: Tomislav Bosiljkov; MBZ: 300916
• Mentor: Branko Tripalo (mentor); MBZ: 50483
• Committee member: Damir Ježek (predsjednik povjerenstva); MBZ: 193346
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; Zagreb
• Defense date and country: 2011-07-15, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology
• Universal decimal classification (UDC): 636/637 - Animal husbandry and breeding. Produce of domestic animals and game

Abstract

U ovom radu ispitivanja su provedena na uzorcima sojinog, kravljeg, ovčjeg i kozjeg mlijeka ultrazvučnim procesorom od 100 W (30 kHz) i 400 W (24 kHz) pri različitim vrijednostima amplitude, vremena obrade i ciklusa, sa sondama različitog promjera. Nakon obrade mjerene su vrijednosti temperature, gustoće, pH – vrijednosti, prividne viskoznosti, apsorbancije (500 nm) i apsorbancije (nakon 24h). Iz izmjerenih vrijednosti apsorbancije izračunate su vrijednosti indeksa stabilnosti emulzije. Stupanj homogenizacije uzoraka mlijeka prikazani su vrijednošću varijance dok je raspodjela veličine masnih globula prikazana Log – N raspodjelom. Prikazan je i utjecaj procesnih parametara na parametre deskriptivne statistike. Statistička analiza dobivenih rezultata pokazuje utjecaj svih procesnih parametara na promjenu svih promatranih fizikalnih svojstava kao i na promjenu parametara deskriptivne statistike uzoraka mlijeka. Optimalna raspodjela veličine masnih globula u rasponu od 0,3 – 5 μm postiže se pri nižim vrijednostima procesnih parametara pri čemu se dobivaju stabilne emulzije kroz duži vremenski period.

Abstract (english)

In this dissertation research is conducted on soybean, cow, sheep and goat milk samples using 100 W (30 kHz) and 400 W (24 kH) ultrasonic processor. Various amplitudes, processing times, cycles and different probe diameters were used. After treatment changes in temperature, density, pH-values, apparent viscosity, absorbance (at 500 nm) and absorbance (after 24 h) were measured. From measured values of absorbance, indexes of emulsion stability were calculated. Degree of homogenization of milk in samples were represented as values of variance, while particle size distribution was shown using Log-N distribution. Influence of process parameters on parameters of descriptive statistics is also indicated. Statistical analysis of obtained results indicates impact of all process parameters on change of all observed physical parameters and descriptive statistics parameters of milk samples. Optimal size distribution of fat globules in the span from 0,3 to 5 μm is achieved under lower values of process parameters, during which stable emulsions during longer time periods were obtained.

• Keywords: ultrazvuk visokog intenziteta; homogenizacija; fizikalna svojstva; emulzije; varijanca
• Keywords (english): high intensity ultrasound; homogenization; physical properties; emulsion; variance
• Language: croatian
• URN:NBN: urn:nbn:hr:159:235520
• Promotion: 2012-07-01
• Study programme: Title: Postgraduate PhD Study in Food Technology; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje biotehničkih znanosti, polje prehrambena tehnologija (doktor/doktorica znanosti, područje biotehničkih znanosti, polje prehrambena tehnologija)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2018-05-16 07:45:12