Roasting is a common practice used to improve the flavour, aroma, colour, and texture of almonds (Prunus dulcis). However, this process can also promote the formation of chemical contaminants, such as acrylamide. While acrylamide regulations were established in 2017 for potatoes, cereals, and coffee, the European Commission extended its recommendations in 2019 to include the monitoring of acrylamide levels in additional food items, such as roasted nuts. This study aimed to thoroughly examine how roasting temperature and duration influence acrylamide formation in almonds. Peeled raw (untreated) almonds were tested in two different formats (whole and ground) and subjected to various roasting conditions, with temperatures ranging from 120 195°C and times from 10 30 minutes. Samples were analysed for acrylamide precursors, including reducing sugars (ion chromatography) and asparagine (AccQ-Tag method), as well as for colour (CIELAB space) and acrylamide concentration (LCESI-MS/MS). During roasting, the levels of both reducing sugars and free asparagine in whole and ground almonds decreased over time and with increasing temperature, directly influencing acrylamide formation. Acrylamide concentrations ranged between 24-480 μg/kg in whole roasted almonds and from 20 to 414 μg/kg in ground roasted almonds. Levels increased progressively from light to medium roasting, peaking before declining in the dark roast stage. The structure of the almonds affected acrylamide levels only in the dark roast category, where ground almonds exhibited higher concentrations than whole almonds. In contrast, changes in colour, free asparagine, and reducing sugar content were similar for both almond formats. The results clearly indicate that temperature has a greater impact on acrylamide formation than roasting time. Therefore, careful control of these parameters is recommended to minimize the formation of high acrylamide concentrations during almond roasting.

Research partly supported by the Community of Madrid and European funding from FSE and FEDER programs (project S2018/BAA-4393, AVANSECAL-II-CM) and CSIC (project 202070E193).

Resumen del trabajo presentado a la XXIII European Conference on Food Chemistry (EUROFOODCHEM), celebrada en Bratislava (Slovakia) del 11 al 13de junio de 2025.

Peer reviewed