Development of A Reduced‐Fat Mayonnaise Using Double Emulsions ( W 1 /O/W 2 ) With the Addition of Natural Rosemary Antioxidants Obtained by Green Chemistry Extraction

W 1 /O/W 2 double emulsions are promising systems for formulating reduced‐fat foods, as part of the fat is replaced by water (W 1 ) while maintaining texture and rheological properties. However, their high susceptibility to lipid oxidation requires the addition of antioxidants. Rosemary ( Rosmarinus officinalis ) contains phenolic compounds with strong antioxidant properties, offering a natural alternative to synthetic additives. This study developed a reduced‐fat mayonnaise‐type sauce (16% w/w oil) based on double emulsions, optimizing polyglycerol polyricinoleate (PGPR) concentration to ensure physical stability. The internal W 1 /O and external W 1 /O/W 2 ratios were 20:80 (w/w). Rosemary extracts were obtained by maceration extraction (ME) (ethanol: water 75:25, 4 h), supercritical CO 2 extraction (SFE, 10% ethanol, 400 bar, 50°C), and pressurized liquid extraction (PLE, ethanol: water 75:25, 100 bar, 140°C). PLE yielded the highest extract recovery (17.5%) and showed the greatest total polyphenol content (69.0 mg GAE/g) and antioxidant capacity (926.9 μmol TE/g), surpassing ME and SFE extracts. The PLE, SFE, ME extracts were incorporated into the oil phase of the emulsion, and its oxidative stability was compared with samples containing TBHQ. After 3 days at 65°C, the emulsion with 1000 mg/kg PLE extract doubled the induction period compared to TBHQ, demonstrating superior oxidative protection. In vitro digestion (INFOGEST) of double emulsions containing the PLE rosemary extract had a significant ( p < 0.05) increase in total polyphenol content and antioxidant capacity post‐digestion, indicating that the emulsion matrix protects phenolic compounds. In conclusion, the PLE rosemary extract represents a promising natural alternative to synthetic antioxidants in reduced‐fat sauces formulated with double emulsions, improving oxidative stability and contributing to potential health benefits.