Aroma Profile and Sensory Properties of Ultrasound-Treated Apple Juice and Nectar

Marina Šimunek¹, Anet Režek Jambrak²*, Marinko Petrović³, Hrvoje Juretić⁴, Nikola Major², Zoran Herceg², Mirjana Hruškar² and Tomislava Vukušić<sup>2

1</sup>Vindija d.d., Međimurska 6, HR-42000 Varaždin, Croatia
²Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, HR-10000 Zagreb, Croatia
³Food Control Center, Jagićeva 31, HR-10000 Zagreb, Croatia
⁴Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Ivana Lučića 5, HR-10000 Zagreb, Croatia

Article history:
Received May 28, 2012
Accepted November 14, 2012

Key words:
high power ultrasound, apple juice and nectar, aroma profile, sensory properties, electronic tongue

Summary:                                                                                                                                                                                 
Ultrasonication is a nonthermal food processing method that is used in several applications (extraction, treatment before drying, freezing, inactivation of microorganisms, etc.) in ultrasound processing. The objective of this study is to investigate the effect of high power ultrasound and pasteurisation on the aroma profile and sensory properties of apple juice and nectar. Samples were treated according to the experimental design, with high power sonicator at ultrasound frequency of 20 kHz under various conditions (treatment time: 3, 6 and 9 min, sample temperature: 20, 40 and 60 °C, and amplitude: 60, 90 and 120 µm). The aromatic profiles of juices showed that, compared to the untreated samples of juices and nectars, ultrasonic treatment led to the formation of new compounds (which were not present in the untreated samples) or to the disappearance of compounds that were found in the untreated samples. Samples treated at the highest amplitude (120 µm) were used for evaluation and comparison with untreated and pasteurised samples using electronic tongue study. Principal component analysis confirmed the results of electronic tongue study, which showed that the ultrasound-treated and pasteurised juices had different scores compared to the untreated samples.

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