Influence of high intensity ultrasound and high hidrostatic pressure on size distribution of fat globules of cow milk

Cilj ovog rada je bio istražiti utjecaj ultrazvuka visokog intenziteta i visokog hidrostatskog tlaka na raspodjelu veličine masnih globula kravljeg mlijeka, kao i na stupanj homogenizacije, te usporediti stupanj homogenizacije mlijeka homogeniziranog ovim dvjema metodama s onim konvencionalno homogeniziranog mlijeka. Praćen je utjecaj ultrazvuka amplitude 60 i 100 %, duljine tretiranja od 2,6 i 15 minuta, pri sondama od 7, 10 i 14 mm. Također je praćen utjecaj visokog hidrostatskog tlaka od 200, 400 i 600 MPa u trajanju tretiranja 3, 6 i 9 min. Dobiveni rezultati statistički su obrađeni pomoću programskog paketa „Statistica 10“. Mikroskopske slike masnih globula obrađene su „Image J“ programskim paketom i promjer masnih globula prikazana je Log–N distribucijom. Ultrazvuk pokazuje značajni utjecaj na raspodjelu veličine masnih globula, dok visoki hidrostatski tlak ne pokazuje statistički značajan utjecaj. Mlijeko homogenizirano ultrazvukom ima veći stupanj homogenizacije nego mlijeka homogenizirana konvencionalnom metodom ili visokih hidrostatskim tlakom.Main goal of this research is analysis of the influence of ultrasound and high hydrostatic pressure on size distribution of fat globules of cow milk, as well as the degree of homogenization, and to compare the degree of homogenization of milk homogenized by these two methods with a conventional homogenized milk. Influence of different conditions: amplitude (A=60 and 100 %), processing time (t=2, 10 and 15 min) and different probe diameters was also tested. Different high pressures (200, 400 and 600 MPa) and processing time (t=2, 10 and 15 min) were also tested. Obtained results were processed in the Statistica 8 software. Microscopic images of fat globules were edited in ImageJ software, while size of the fat globules was represented with Log-N distribution. Ultrasound showed a statistically significant effect on size distribution of fat globules, while high pressure didn't. Ultrasound homogenized milk has a higher degree of homogenization than milk homogenized by conventional method or high hydrostatic pressure