The encapsulation of cold pressed pomegranate and grape seed oil wastes extracts and effect on shelf life of salad dressing

Cold pressed oils waste are rich in some bioactive compounds and are considered as food materials due to containing no any chemicals such as solvent residue. In this study, cold-pressed pomegranate seed oil waste (POW) and grape seed oil waste (GOW) is used as a bioactive compound source. POW and GOW were dried and powdered after the cold-pressing process. Watery extracts of POW and GOW were prepared (10:90). Extraction was carried out at room temperature for 2 hours. The total phenolic content of the extract was found to be 2959,10 mg/L for POW and 3737,38 mg/L for GOW. The extracts were encapsulated by coating with maltodextrin and drying with a spray dryer. Extracts of encapsulated POW and GOW were incorporated into the salad dressing composition. The emulsion characterization of the samples enriched by encapsulated materials was performed based on the rheological properties, emulsion stability, zeta potential, particle diameter and oxidative stability. It was not observed significant differences regarding the emulsion stability and rheological properties of the sample (p>0.05). Zeta potential value of the samples with enriched by POW was similar with control (p>0,05) while the zeta potential of the sample enriched by GOW was significantly lower than control the sample. The accelerating oxidation stability test was performed at a different temperature, and significant differences were found. The samples enriched by encapsulated material showed high induction period according to control samples. The oxidative degradation data obtained from different temperature value were modeled by zero, first and second order kinetic equation. Physicochemical analyses showed no significant difference between control samples and enriched samples. This study suggests that POW and GOW could be used as an enriching bioactive compound source for salad dressings.