## 1 Introduction  
Juice flavor is key to consumer acceptance and preference [1]. Conventional thermal processing of fruit juices is the most widely used technology for preserving and extending their shelf life. However, the drawbacks of this protocol are well known and include the degradation of thermosensitive compounds and loss of aroma, flavor, and nutritional quality [2, 3, 4]. Industrial thermal processing of pineapple juices often present undesirable aroma notes described as \"cooked vegetables\" and \"intense artificial aroma\", which are due to the production of thermal degradation compounds such as methyl butanoate, ethyl 2-methylbutanoate, methyl hexanoate, and ethyl hexanoate, and by the formation of off-flavors such as methional, and dimethyl di-, tri-, and tetrasulfide. These are the main reasons for the relatively low use of pineapple as a raw material in the industrialized juice market [5, 6, 7]. Cold plasma (CP) is a non-thermal technology with great potential for fruit product applications. Positive results have been achieved in terms of sanitization and preservation, removing pesticides and mycotoxins, and reducing allergens in different food groups [8, 9]. Depending on the process conditions, it is possible to observe better retention and, in some cases, the increase of bioactive compounds [10]. All these effects result from chemical reactions between the reacting plasma species and the compounds from the food matrix. Due to the high complexity and diversity of food compounds, the changes induced by cold plasma application are variable and strongly dependent on the food matrix composition [11]. Thus, the effects of cold plasma on food properties, quality, and composition must be studied throughly. Greater emphasis has been given to studies on the mechanisms of plasma action and chemical changes on different macro and micro molecules of fruit juices, including sugars, amino acids, lipids, vitamins, carotenoids, phenolics, anthocyanins, and other bioactive compounds [12; 13; 14]. Despite all the information available about plasma, the impact of this technology on aromas still needs to be better understood. Studies investigating the nature of changes in volatile profiles are scarce and predominantly attribute the changes to reactive oxygen species (ROS) and reactive nitrogen species (RNS), presenting no or simplistic statements about the reaction mechanisms [15]. More comprehensive studies on the changes in the volatile composition of tomato [16], orange [17], camu-camu [18], and apple [19] juices treated by atmospheric cold plasma were reported. However, they still cover only a fraction of the many volatile compounds in fruit juices. A recent approach to plasma applications demonstrates the possibility of aroma modulation [17; 18; 20]. In other words, applying plasma in fruit products could reduce unpleasant aromas, accentuate desired aromas, and produce new notes for a new perception experience [18; 21]. Reactions induced by dielectric barrier discharge plasma can be used to reduce off-flavors in orange juice, converting the undesired a-terpineol to limonene or sabinene, which gives the characteristic aroma of this beverage [17]. In camu-camu pulp, the changes in the volatile compounds directly affected the aroma profile, increasing or decreasing the woody, citrus, and herbal notes of the pulp fragrance, conferring different aromas to the juice and conferring new perception experiences [21]. Pineapple juice has a wide variety of esters, aldehydes, furanone, alcohols, acids, hydrocarbons, and sulfur-containing compounds [22; 23; 24]. However, its volatile composition is mainly characterized by several esters and thioesters. Compounds that have yet to be thoroughly studied regarding how plasma application affects them. This work aimed to identify and discuss the chemical pathways of the reactions induced by dielectric barrier discharge (DBD) plasma application in pineapple juice and to evaluate how these chemical changes alter the aroma profile of juice rich in esters and thioesters.