## 3 Results
### Volatile Organic Compounds  
Coffee volatile compounds include several chemical classes, like hydrocarbons, alcohols, aldehydes, ketones, carboxylic acids, esters, pyrazines, pyrroles, pyridines, other bases (e.g., quinoxalines and indoles), sulfur compounds, furans, furanones, phenols, and oxazoles, among others [18]. In Tables 2 and 3, the volatile organic compounds (VOCs) contents found in the coffee pod and capsule samples stored at 25 \({}^{\circ}\)C and 40 \({}^{\circ}\)C, respectively, are reported. In both samples, the most abundant classes of VOCs were furans and pyrazines (>27%). Figure 2: (**a**) Peroxides value (meq O\({}_{2}\)/Kg oil) in coffee pods (100% _Arabica_ variety) packaged with standard (STD) and alternative (ALT) multilayer films and stored at 25 and 40 \({}^{\circ}\)C for 180 days. \({}^{\mathrm{a-c}}\) Different letters at the same time indicate statistically significant differences (\(p\) < 0.05); (**b**) peroxides value (meq O\({}_{2}\)/Kg oil) in coffee capsules (50% Arabica and 50% Robusta varieties) packaged with standard (STD) and alternative (ALT) multilayer film and stored at 25 and 40 \({}^{\circ}\)C for 180 days. \({}^{\mathrm{a-b}}\) Different letters at the same time indicate statistically significant differences (\(p\) < 0.05). In the pods (Table 2), furans were present in the highest content in the coffee stored in the alternative packaging at all analyzed time and temperatures, with an increase during the shelf life found, while in the capsules (Table 3), the furan content increased during the shelf life compared to time 0, but only at 90 days and 180 days was a higher content in ALT compared to STD found. [PERSON] et al. [42] showed no significant differences in total furans content in coffee brews storage at 25 \({}^{\circ}\)C and 4 \({}^{\circ}\)C, but 2-methylfuran, 3-methylfuran, and 2,5-dimethylfuran decreased in samples stored at 25 \({}^{\circ}\)C, while other furans such as 2-vinylfuran, 2-vinyl-5-methylfuran, 2-furfuryl acetate, and 2-furfurylfuran, showed, in general, a significant decrease at both storage temperatures. Roasted coffee beans contain furan in the highest concentration compared with other food, and in coffee, the concentration depends on roasting temperature, roasting time, particle size of coffee ground, and type of preparation [43]. Pyrazines during shelf life decreased and were most present in the standard packaging compared to the alternative in both capsules and pods. Among this class, alkylpyrazines are considered to be key aroma components of coffee brew and these compounds contain the lowest odor threshold, so they contribute to developing the coffee aroma [21]. Aldehydes could be derived from the oxidative degradation of amino acids during their interactions with sugars at high temperatures or polyphenols in the presence of polyphenol oxidase [21]. Furthermore, aldehydes are secondary compounds of oxidation and influence coffee acceptability. It is interesting to note that hexanal was not found, indicating a good preservation of the samples in all the packaging films used. This compound, in fact, is responsible for rancid flavor and its presence in coffee during storage could be used as a marker of coffee staling or freshness index [44]. The predominant aldehyde detected was 2-butenal. It increased in the coffee pods during the storage period and its concentration was higher in the standard packaging compared to the alternative packaging after 180 days of storage both at 25 and 40 \({}^{\circ}\)C. Furthermore, it was also found in the coffee capsules after 180 days of storage at both temperatures, with a higher increase in the coffee packaged in the standard packaging compared to the alternative packaging. This compound could be derived from the oxidation of \(\omega\)-3 polyunsaturated fatty acids (PUFAs) and subsequent decomposition of hydroperoxides [45]. Among ketones, 3-hydroxy-2-butanone was found. This compound, derived from the sugar decomposition reaction, occurs in the Maillard reaction, as well as in caramelization [46].