Research Progress on Aroma Compounds in Almonds and Factors Influencing Its Flavor Quality

Raw almonds are rich in aldehydes, alcohols and other odorants contributing to fresh fruity and hay-like aromas. The flavor of almonds can change significantly due to various chemical reactions during thermal processing and storage, which can greatly affect its flavor quality. In this context, this review summarizes the major aroma compounds in raw almonds and the major aroma compounds formed by the Maillard reaction, the oxidation of fatty acids, and the degradation of amino acids and soluble sugars in roasted almonds, and it compares the effects of different thermal processing methods and conditions on the aroma compounds and aroma properties of almonds. In addition, this review summarizes the changes of the major aroma compounds and off-odor compounds in almonds during storage and the rational storage methods and conditions. Finally, possible future directions for research on almonds and other nuts are outlined. This review could provide a theoretical basis and reference for flavor quality control of almonds and other nuts during thermal processing and storage.