Removal of cyclolinopeptides leads to reduced bitter taste of flaxseed oil

Cyclolinopeptides (CLP) are natural constituents of flaxseed oil. The methionine-containing derivatives 1-Met-CL2 (cyclo(M-L-L-P-F-F-V-I)) and 1-Met-CL4 (cyclo(M-L-V-F-P-L-F-I)) are precursors of key bitter compounds, as they are oxidized during storage into the sulfoxides 1-Mso-CL2 (cyclo(Mso-L-I-P-P-F-F-V-I)) and 1-Mso-CL4 (cyclo(Mso-L-V-F-P-L-F-I)), potent ligands for the human bitter taste receptor TAS2R14. We investigated the hypothesis that removing the precursors would lead to a reduction in the formation of bitter-tasting sulfoxides and, consequently, a decrease in the development of bitter taste in flaxseed oil upon storage. Several minerals were evaluated for CLP removal, with some resulting in undesirable changes to color or odor. Stirring flaxseed oil with 5 % Mg/Al silicate effectively reduced the dominant CLP to 14.1 – 17.6 % in a laboratory-scale procedure using 200 g flaxseed oil. This process preserved the yellow color and did not alter the odor or fatty acid profile. The flaxseed oil with reduced CLP content exhibited significantly less bitterness compared to the original oil. Storing both the original and CLP-reduced flaxseed oil samples at room temperature for 66 and 64 days, respectively, resulted in a significant increase in bitterness. However, the increase in bitterness in CLP-reduced flaxseed oil was notably lower than in the original oil, indicating enhanced taste stability.