## 5 Aroma Profile of Nut Products After and Before Roasting Conditions
### Pistachios  
A total of 39 compounds were identified in raw pistachios, encompassing a diverse range of chemical classes, including carbonyl compounds, terpenes, alcohols, phenols, furanic compounds, pyrazines, pyrroles, lactones, acids, and phenolic and benzene derivatives. These compounds were detected in varying concentrations in both raw and roasted pistachios. While five pyrazines, including methylpyrazine, trimethylpyrazine, and 2-ethyl-5-methylpyrazine, were found in raw pistachios, sixteen pyrazines were detected in roasted pistachios [67]. Other compounds that have been identified in raw pistachios are \(\alpha\)-pinene (in concentrations of 1.68 \(\mu\)g/g), limonene (1.17 \(\mu\)g/g), and nonanal (0.63 \(\mu\)g/g) [40]. [PERSON] et al. (2019) reported that \(\alpha\)-pinene (333 \(\mu\)g/g) and 1-methylpyrrole (48 \(\mu\)g/g) were the most detectable compounds. Other compounds detected include acetic acid (3.3 \(\mu\)g/g), hexanal (9.1 \(\mu\)g/g), hexanol (1 \(\mu\)g/g), \(\beta\)-pinene (6.5 \(\mu\)g/g), limonene (1 \(\mu\)g/g), benzyl acetate (1.8 \(\mu\)g/g), and other trace compounds [68].  
[PERSON] et al., (2013) conducted a comprehensive analysis of the volatile compound profile of pistachio oil extracted via solvent-assisted flavor evaporation. The study identified 43 classes of compounds, including terpenes, acids, aldehydes, alcohols, esters, phenols, pyrazines, pyrroles, and others. The most abundant compounds were found to be \(\alpha\)-pinene, myrrene, hexanal, hexanol, \(\beta\)-pinene, limonene, and acetic acid [69].  
The roasting process significantly enhances the intensity of aroma compounds in roasted pistachios compared to in raw pistachios. [PERSON] et al. (2012) studied Iranian pistachios and found that \(\alpha\)-pinene (3.06 \(\mu\)g/g), limonene (4.96 \(\mu\)g/g), and nonanal (0.86 \(\mu\)g/g) were the most abundant compounds [40]. Additionally, [PERSON] et al. (2015) identified hexanal, pentanal, benzaldehyde, and (E)-2-pentenal, which are derived from the Strecker degradation, along with other compounds such as short-chain acids and lactones [67]. [PERSON] et al. (2015) found that limonene (3.49 \(\mu\)g/g) was the most abundant compound after microwave roasting. \(\alpha\)-Pinene (2.38 \(\mu\)g/g) was the second most abundant, followed by nonanal, camphene, and phenylacetaldehyde, and others in lower concentrations [70]. [PERSON] et al. (2011) reported a positive correlation between roasting time and the number of volatile organic compounds (VOCs) in pistachios at a constant temperature of 200 \({}^{\circ}\)C. The number of VOCs increased from 32 at 0 min to a peak of 106 at 20 min, followed by a slight decrease to 104 at 25 min. Pyrazine levels exhibited a significant increase after 15 min of roasting, reaching a maximum of 3.7% at 20 min. In addition, 5-Methylfurfurful levels steadily increased throughout the roasting process, reaching 5% at the end. However, furanones constituted a relatively small proportion of the total VOCs, accounting for only 15%. Regarding terpene compounds, limonene decreased from 9% to 5%, \(\beta\)-pinene decreased from 5% to 2%, and \(\alpha\)-pinene decreased from 10% to 4%. In contrast, xylene and furfurral increased from 0% to 1.7% and 1.8%, respectively, while pyrrole increased from 0% to 1.8% [71].