# Differentiation of Fresh and Processed Fruit Juices Using Volatile Composition
Temperatures between 85 and 95 \({}^{\circ}\)C are frequently used to extend the shelf life of fruit juices However, it has been documented that the thermal process may activate the dormant ascospores of molds, which subsequently cause deterioration, hence resulting in economic loss [22]. Heat treatment with high temperature and long processing time is not recommended, due to quality reasons and consumer demands for fresh-like fruits. To overcome this problem on fruit juice preservation, non-thermal methods, such as high-pressure processing (HPP), supercritical carbon dioxide technology (SCCD), and power ultrasound in combination with mild heat have been proposed. [PERSON] et al. [23] evaluated the impact of HPP (600 MPa, 3 min) on apple (Pink Lady, Granny Smith, and Jonagold) juice quality changes and compared it to the thermal processing. The overall quality of HPP treated apple juices was much more comparable to that of the fresh juice, in particular HPP results in lower amounts of thermally induced compounds that are related to cooked notes of pasteurized apple juices. [PERSON] et al. [24] investigated the volatile changes during the shelf life of pulsed electric fields (PEF) (15.5 kV/cm and specific energy of 158 kJ/L), HPP (600 MPa for 3 min), and thermally (72 \({}^{\circ}\)C for 15 s) pasteurized Jazz apple juices, up to five weeks. The results showed that after pasteurization, PEF processing resulted in a better retention of odor active VOCs, such as 2-hexenal isomer and hexyl acetate, whereas thermal processing lowered their amount. [PERSON] et al. [25] evaluated the effects of HPP (550 MPa/10 min) and high-temperature short time (HTST; 110 \({}^{\circ}\)C/8.6 s) on microorganisms, ascorbic acid, total phenols, antioxidant capacity, color, enzyme activity, and rheological behavior in red grapefruit juice during 30 days of storage at 4 \({}^{\circ}\)C. [PERSON] et al. [26] showed that HPP pretreatment enhanced the thermosonication inactivation of _Alicyclobacillus acidoretrestris_ spores in orange juice, whereas [PERSON] et al. [27] evaluated the impact of HPP processing on the volatile profile and sensory acceptance of Pera-Rio orange juice. Moreover, several studies have demonstrated the efficiency of SCCD processing in the preservation of juices such as orange, melon, kiwi, pear, and strawberry. The findings confirm the SCCD processing as a potential promising technology to the conventional thermal treatment [28; 29; 30]. The assessment of the volatile signature of fruit juice is of great importance, since it enables researchers to help producers improve its quality, develop new products for the market, contribute to its economic valorization [27], as well as to assess the geographical origin, authenticity, and typicity of food matrices [31]. Several extractions and enrichment techniques, namely, liquid-liquid extraction (LLE) [32], simultaneous distillation extraction (SDE) [33], solid-phase trapping solvent extraction (SPTE) [33], solid-phase extraction (SPE) [34], pressurized-fluid extraction (PFE) [35], solid-phase microextraction (SPME) [3,33], and stir bar sorptive extraction (SBSE) [36] have been applied to establish the volatile signature of food matrices. Nevertheless, microextraction techniques (METs) (e.g., SPME, SBSE) compared to conventional extraction techniques (e.g., LLE, SDE, SPE) offer several advantages, such as a reduction of the amount of organic solvent, the possibility of automation, high sensitivity and concentration factors [37]. These METs, combined with analytical measurements, can be used to assess the sensory properties, chemical composition, authenticity, and typicality of juices. The establishment of the volatile signature, analysis of the nutritional composition, phenolic compounds, carotenoids, and some vitamins [3,38], in addition to sensory analysis using consumers and/or a trained taste panel, or even using an instrumental taste sensing system, like the electronic tongue [39], are the most widely used techniques to assess the quality of fruit juices [40].