Exploring the formation pathways of characteristic volatile organic compounds after walnut roasting based on...

The characteristic flavor of roasted walnuts (RW) mainly comes from the formation of volatile organic compounds (VOCs) during roasting process. This study systematically explored the formation pathway of characteristic VOCs in RW by constructing simulation systems using walnut protein-glucose-walnut oil, walnut protein, walnut oil, walnut oil-glucose, and walnut protein-glucose (WP-G), combined with HS-SPME-GC-MS and multivariate statistical analysis. The results showed that roasting slightly affected lipid and protein content but significantly altered sugar levels. The WP-G was closest to the VOCs composition of the actual RW, highlighting the core role of Maillard reaction in the formation of walnut flavor. Strecker degradation driven by amino acids such as lysine (reduced by 89.58%), phenylalanine (reduced by 27.19%) and leucine (reduced by 48.90%) was considered to be the main pathway for the formation of roasted walnut flavor. The findings offer insights into walnut roasting flavor formation and a basis for developing flavored walnut products.