Influence of high intesity ultrasound with different probe diameter on the stability of goat and sheep milk expressed by the emulsion stability index

Cilj ovog istraživanja bio je ispitati utjecaj promjera sonde (7, 10 i 14 mm) ultrazvuka visokog intenziteta konstantne frekvencije od 30 kHz na stabilnost emulzija kod kozjeg i ovčjeg mlijeka izraženog preko Indeksa stabilnosti emulzije (ISE). Praćen je utjecaj ultrazvuka visokog intenziteta nominalne snage od 100 W na početnu apsorbanciju i apsorbanciju nakon 24 sata pri slijedećim procesnim parametrima ultrazvuka: amplituda (A = 20, 60, 100 %); vrijeme obrade (t = 2, 6, 10, 15 minuta); primijenjeni ciklus (c = 0,6; 0,8; 1). Dobiveni rezultati statistički su obrađeni pomoću programskog paketa „Statistica 9“. Vrijednosti ISE izračunate su preko izmjerenih vrijednosti apsorbancija kozjeg i ovčjeg mlijeka. Utjecaji promjera sonde i procesnih parametara prikazani su Pareto dijagramom (ANOVA). Utjecaj promjera sonde pokazuje najveći utjecaj na povećanje vrijednosti ISE kozjeg mlijeka, zatim slijede ciklus i amplituda, a vrijeme obrade nema značajan utjecaj. Kod ovčjeg mlijeka najveći utjecaj na povećanje vrijednosti ISE ima ciklus, zatim slijede vrijeme obrade i amplituda, a promjer sonde nema značajan utjecaj.Main purpose of this research was to examine the influence of the probe diameters (7, 10 and 14 mm) of high-intensity ultrasound with constant frequency of 30 kHz on the stability of emulsions in goat and sheep milk expressed by the emulsion stability index (ESI). The influence of high-intensity ultrasound (nominal power of 100 W) on starting absorbance and absorbance after 24 hours was observed under following conditions: amplitude (A = 20, 60, 100 %); processing time (t = 2, 6, 10, 15 minutes); applied cycle (c = 0,6; 0,8; 1). Obtained results were statistically analyzed using the software package “Statistica 9”. Values of the ESI were calculated over measured values of absorbance of goat and sheep milk. Influence of probe diameter and process parameters is shown in Pareto chart (ANOVA). Changes in probe diameter shows the greatest impact on increasing the value of ESI for goat's milk, followed by a cycle and amplitude, a processing time has no significant impact. In sheep's milk greatest impact on increasing the value of the ESI has a cycle, followed by processing time and amplitude, a diameter of the probe had no significant impact