Oxidative stability of the salad dressing enriched by microencapsulated phenolic extracts from cold-pressed grape and pomegranate seed oil by-products evaluated using OXITEST

This study aimed to investigate the potential use of cold-pressed pomegranate seed oil by-product (PGOB) and grape seed oil by-product (GOB) as a natural antioxidant in a salad dressing. Firstly, bioactive compounds from oil by-product were extracted and powdered by spray drier to produced grape seed oil by-product powder (GOBP) and pomegranate seed oil by-product powder (PGOBP). This study was the first attempt to evaluate the oxidative stability of the salad dressing by OXITEST at 90, 100, and 110 degrees C, and at 6 bar (the oxygen pressure). The samples enriched by GOB (3.22-26.76h) and PGOB (2.49-24.76h) showed high IP compared to control samples (0.43-8.82 h). The oxidation rate was modeled by zero, first and second-order kinetic models, and the oxidation kinetics constant (k) value estimated. PGOBP and GOBP significantly reduced k value. The activation enthalpy (Delta H++), activation entropy (Delta S++) and activation energy (E-a) were 69.78-101.93 kJ/mol, 59.55-81.07 J/mol and (-18.36)-(-83.37) J/mol respectively. The Delta G(++) of the control, PGOBP and GOBP enriched samples were 87.36-88.10 Kj/mol, 88.65-91.61 Kj/mol, and 88.14-91.48 kJ/mol respectively. This study suggests that PGOBP and GOBP could be used as a natural antioxidant source for salad dressings.

Automated summary

This study investigated the potential use of cold-pressed pomegranate seed oil by-product (PGOB) and grape seed oil by-product (GOB) as natural antioxidants in salad dressings. The samples enriched with PGOB and GOB showed high oxidative stability compared to control samples. The oxidation rate was modeled using kinetic models and the activation energy values were estimated. PGOBP and GOBP significantly reduced the oxidation rate. This study suggests that PGOBP and GOBP could be used as natural antioxidant sources for salad dressings.