SummaryGelled emulsions based on chia and hemp oils were used as partial (25% and 50%) fat replacer in beef burgers. The effect of formulation, frozen storage during 60 days and cooking process was assessed on lipid profile, oxidation susceptibility and technological attributes (cooking properties). Reformulated burgers showed better nutritional quality (in reference to dietary fats) than control, mainly due to the increase in PUFAs (specifically α‐linolenic (C18:3) and linoleic (C18:2) fatty acids) and decrease in SFAs which was higher in burgers with hemp‐GE than in burgers with chia‐GE and also dependent on the substitution level (the highest at 50%). This pattern was not modified by frozen storage for 60 days or by cooking process. In addition, cooking increased the susceptibility of reformulated burgers to oxidation in a more intense way than 60 days of frozen storage, being burgers with 50% chia‐GEs the most susceptible.