## 1 Introduction  
The inclusion of nuts in the diet has significantly increased, due to their unique nutritional value, flavor, nutraceuticalal properties, and abundance of healthy bioactive compounds including high-quality proteins, dietary fiber, minerals, tocopherols, phytosterols, and phenolic compounds. Moreover, nuts are a good source of many nutrients, such as monounsaturated and polyunsaturated fatty acids, micronutrients like vitamins E and K, magnesium, copper, potassium, and selenium [1]. In general, the most commonly consumed tree nuts worldwide include almonds (_Prunus amygdalus_ [PERSON]), Brazil nuts (_Bertholletia excelsa_ [PERSON]. & [PERSON]), cashews (_Annaro-ardium cecidentale_ [PERSON]), hazelnuts (_Cryylus avellana_ [PERSON]), macadamias (_Macadamia integifolia_ [PERSON]. [PERSON]), pecans (_Carya illinoinensis_ [PERSON]), pine nuts, pistachios (_Pistacia vera_ [PERSON]), and walnuts (_Juglams regia_ [PERSON]) [2]. Nuts are consumed as snacks, desserts, or as a part of meals. Some epidemiological studies have associated nut consumption with a diminished incidence of coronary heart disease, and have consistently demonstrated that nut intake lowers cholesterol, promotes healthy diets, reduces oxidative stress and inflammation, and improves vascular reactivity. Indeed, it is clear that regular nut consumption has a beneficial effect on many cardiovascular risk factors and may even aid in weight loss [3]. It is well reported that nuts are rich sources of phytochemical compounds. Among these, flavonoids, characterized by a chalcone structure, are a major class. Flavan-3-ols are the most abundant flavonoids in nuts, followed by flavonoids and anthocyanins [4]. Chlorophylls and carotenoids are pigments that contribute to the color of nuts, including pistachios. Monitoring these pigments can help control the roasting process. The green color of pistachios is primarily due to the presence of chlorophyll. However, during roasting, this vibrant green color can fade, transitioning to brown or dark shades. This loss of color can negatively impact consumer perception and ultimately influence product selection [5]. Proanthocyanidins, oligomers of flavan-3-ols such as catechin, epicatechin, and epigallocatechin, are another important class of polyphenols. Stilbenes, characterized by two phenyl groups connected by an ethene bond, are another class of polyphenols with a high value in nuts. Resveratrol is the primary example of stilbenes. Another class is represented by phytosterols, which are plant-based steroids. In nuts, carotenoids compounds, a class of polyisoprenes, are generally present in low concentrations in nuts, with \(\alpha\)-carotene, \(\beta\)-carotene, lutein, and zexanathin typically amounting in \(\mu\)g/100 g quantities. However, pistachios are an exception, containing higher concentrations of \(\beta\)-carotene and lutein, often measured in mg/100 g [4]. In general, the nutritional values of nuts can vary depending on the cultivar and harvest year. For this reason, in 2015, [PERSON] et al. investigated the possibility of differentiating between Italian and Chilean _Tonda Gentile Tribdata_ hazelnuts based on their post-roasting chemometric profiles. This was achieved by the possibility of identifying and comparing specific chemicals markers that could distinguish between the two varieties, such as fatty acid profile, the presence of polyphenols, antioxidant activity, and protein fingerprint [6]. As documented by [PERSON] et al. (2017), the outer layer of nuts, particularly the brown skin, is a significant reservoir of phenolic compounds, both in free and bound forms. The predominant phenolic acids identified include caffeic, chlorogenic, coumaric, ferulic, gallic, hydroxybenzoic, protocatechuic, and vanillic acids. Furthermore, nut skins are rich in flavonoids such as quercetin, catechin, and epicatechin [7].