Naslov
Influence of high power ultrasound on selected moulds, yeasts and Alicyclobacillus acidoterrestris in cranberry juice and nectar

Autori
Režek Jambrak, Anet ; Šimunek, Marina ; Evačić, Silva ; Frece, Jadranka ; Markov, Ksenija ; Vukušić, Tomislava ; Herceg, Zoran

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, ostalo

Izvornik
Sustainable innovation based on science and applied research of nonthermal technologies / Taoukis, Petros ; Stoforos, Nikolaos ; Gogou, Eleni - Atena, 2015

ISBN
978-618-82196-2-5

Skup
2015 International Nonthermal Processing Workshop

Mjesto i datum
Atena, Grčka, 12.11.2015. - 13.11.2015

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Ultrasonication; Alicyclobacillus acidoterrestris; fruit juices

Sažetak
Ultrasonication is a non‐thermal method in food processing that has the advantage of preserving fruit juices without causing the common side‐ effects associated with conventional heat treatments. Special attention was drawn to Alicyclobacillus acidoterrestris that can be found in concentrated fruit juices and which it is very difficult to inactivate by heat treatment proceedings. The purpose of this study was to investigate the effect of non‐ thermal technology, high power ultrasound (HPU) on inactivation of Aspergillus ochraceus 318, Penicillium expansum 565, Rhodotorula sp. 74, Saccharomyces cerevisiae 5 and Alicyclobacillus acidoterrestris DSM 3922 in clear juices and nectars made cranberry juice concentrate. Inoculated juice and nectars were treated by high power ultrasound (20 kHz) according to procedure set by central composite design (CCD). Three operational parameters, amplitude (60, 90 and 120 μm), temperature (20, 40 and 60oC), and treatment time (3, 6 or 9 min) were varied in order to observe the influence of ultrasound and combination of ultrasound and slight heating (thermosonication) on growth and inactivation of selected microorganisms. Number of vegetative cells of A. acidoterrestris DSM 3922 were not significantly reduced by high power ultrasound (p>0.05). Contrary to expectations there was a growth activation of A. acidoterrestris DSM 3922. The value of reduction of cells of selected yeasts and moulds for ultrasound treatments at 60°C and the duration of the 3, 6 and 9 minutes ranged from 4.580 to 5.869 log units, depending on the initial number of selected yeasts and moulds before treatment. The effect of ultrasound was mainly attributed to physical (cavitation, mechanical effects, micro‐mechanical shocks) and/or chemical effects due to formation of free radicals (H+ and OH‐ due to sonochemical reaction) formed by the decomposition of water inside the oscillating bubbles. Power ultrasound caused complete inactivation of the growth of yeasts and moulds at 60 °C and treatment times of 3, 6 and 9 minutes, regardless of the value of the amplitude. Number of vegetative cells of A. acidoterrestris were not reduced.

Izvorni jezik
Engleski

Znanstvena područja
Prehrambena tehnologija

POVEZANOST RADA