Mechanistic insights into aroma enhancement of Robusta coffee through ultrasound synergistic oil-solvent pretreatment: A combined lipidomics and volatilomics approach.

The relatively low lipid content of Robusta coffee is a major factor contributing to its monotonous aroma profile. In this study, Robusta green coffee beans were pretreated with ultrasound-assisted oil-solvent (coconut oil/palm oil/butter/camellia oil/walnut oil) to regulate the formation of aroma compounds during roasting by modifying their lipid composition, thereby enhancing the aroma profile of Robusta coffee. Lipidomic analysis showed that pretreatment significantly increased total lipid content and remodeled fatty acids and lipid molecules, with butter and coconut oil yielding the strongest effects. Volatilomic analysis indicated that pretreatment enhanced the accumulation of total aroma compounds by 8.56-12.89 % (p < 0.05), particularly esters, aldehydes, furans, pyrazines, ketones, alcohols, and terpenes. Butter and walnut oil pretreatments produced the most pronounced improvements in aroma. Correlation analysis further revealed complex relationships between differential lipid molecules and key volatile compounds, indicating that lipid composition strongly regulates the accumulation of volatile compounds. This study provides novel insights into strategies for enhancing and precisely modulating the sensory quality of Robusta coffee.