Conventional and Innovative Drying/Roasting Technologies: Effect on Bioactive and Sensorial Profiles in Nuts and Nut-Based Products

Nuts are widely recognized for their exceptional nutritional value, being rich in bioactive compounds such as polyphenols, mono- and polyunsaturated fatty acids, dietary fiber, and essential minerals. This review focuses on the effects of roasting technologies, specifically of pistachios, hazelnuts, and almonds, evaluating the changes in polyphenol contents, lipid profiles, and the release of volatile organic compounds through the Maillard reaction. Roasting, a common processing technique, enhances the sensory attributes of nuts, including flavor, aroma, and texture, while simultaneously influencing their nutritional and chemical profiles. The Maillard reaction, triggered during roasting, plays a crucial role in developing the characteristic flavors of roasted nuts, but can also lead to the formation of acrylamide under certain conditions. Understanding the balance between enhancing sensory quality and retaining nutritional properties is essential for optimizing roasting conditions. Innovative technologies offer sustainable and efficient alternatives to traditional methods. By focusing on these three major nut varieties, this review provides valuable insights into the changes that occur before and after roasting, highlighting strategies to balance sensory qualities and nutritional preservation. Further research is essential to refine these techniques, enabling the production of high-quality nuts that deliver superior health benefits while meeting consumer expectations.