## 1 Introduction  
One of the main challenges in the fruit juice industry is to produce juices with a flavor close to that of freshly squeezed fruits and that remains consistent during storage. This has led to the development and introduction of emerging processing technologies such as High-Pressure Processing (HPPP) and Pulsed Electric Fields (PEF) that have been attracting a lot of research interest [1; 2; 3].  
HPPP involves the application of hydrostatic pressure, while high-voltage pulses are used in PEF processing [4; 5]. HPP- and PEF-treated foods are generally claimed to have superior sensorial and nutritional quality compared to their thermally treated counterparts [1; 6; 7; 8; 9]. Today, both technologies are being used increasingly on a commercial basis, with high-quality labelled fruit juices being one of the most important promotion strategies [3; 10; 11; 12]. However, HPP- and PEF-processed juices might have a limited shelf life since quality-related enzymes (e.g., polyphenol oxidases and peroxidase) are still active after HPP and PEF pasteurization, and can cause undesirable aroma changes during storage [9; 13].  
Apple juice is one of the most popular juices due to its pleasant organoleptic qualities and incredible health benefits [14; 15]. Considering the importance of aroma compounds for apple juice quality, it is crucial to investigate the change in volatile compounds during processing and storage. Previously, some studies investigated the most potent odorant(s) contributing to apple juice aroma through linking the sensory attribute to a single (group of) compound(s) [16]. For instance, some esters have been identified as main contributors to the overall apple juice aroma. It is known that perceived odor is not due to a single (group of) volatile compound(s) but rather a result of a large number of volatile compounds [17]. Advanced analytical and data analysis procedures offer an opportunity to overcome these limitations [9].  
The present work aims at comparing the impact of thermal, HPP, and PEF pasteurization technologies on the volatiles of Jazz apple juice after processing and during refrigerated storage of up to five weeks. The study on volatiles change was conducted systematically by integrating the currently available instrumental (GC-MS) and the state-of-the-art data analysis (chemometrics) techniques. The GC-MS data were analyzed using multivariate data analysis (MVDA) techniques, namely partial least squares (PLS) regression. To compare the process impact immediately after processing, a partial least squares-discriminant analysis (PLS-DA) model was used. For the PLS-DA model, different processing techniques were used as categorical Y-variables. To investigate the volatile changes during shelf life, a PLS regression model was constructed, using the storage time as a continuous Y-variable. Compounds that are differently affected by a certain processing technology or compounds changing the most during storage, which are discriminant markers, were selected using a variable identification (VID) procedure. These selected compounds were linked to apple juice aroma in order to draw a conclusion about the relevance and consequences of the detected differences [9; 18; 19; 20; 21; 22].