Mechanistic insights into volatile odor changes in surimi gels with typical cross-linking degrees during frozen storage based on lipidomics analysis.

This study investigated the potential mechanisms underlying odor changes in surimi gel during frozen storage, focusing on lipid alterations. Frozen storage significantly impacted the odor characteristics of surimi gel, with a noticeable decline in fish aroma and an intensification of fishy, oily, and earthy odors after 90 days of freezing. Using liquid nitrogen spray freezing at -80 °C and increasing the cross-linking degree to 62.99 % was beneficial in maintaining the original odor profile of surimi gel. Odor changes during storage were driven by enhanced lipid oxidation and altered lipid distribution. Most lipids significantly associated with odor compounds were unsaturated fatty acids primarily found in phosphatidylcholine (PC) and phosphatidylethanolamine (PE). Notably, PC(14:0_20:5), PC(16:0_20:4)(rep), PC(16:0_20:5), PC(18:0_20:4), PC(18:3e_22:6), PC(20:3_22:6), PE(20:4_20:4), and PE(20:4_22:6)(rep) showed negative correlations with volatile compounds such as acetoin, hexanal, heptanal, benzaldehyde, nonanal, 1-octen-3-ol, and 1-hexanol. The oxidation of these lipids resulted in alterations to the odor profile of the surimi gel.