Bioaccessibility of pomegranate seed oil using INFOGEST in vitro digestion model

Pomegranate seed oil has been widely studied for its health-promoting properties. However, the bioavailability of its conjugated linolenic acids, an essential factor for assessing their impact on health, remains poorly understood. This study used the harmonized in vitro protocol INFOGEST to investigate the bioaccessibility of pomegranate seed oil in comparison to olive oil. Bioaccessibility, key aspect of bioavailability, refers to the proportion of a nutrient released in the gastrointestinal tract and available for intestinal absorption. It was determined by measuring the ratio of fatty acids present in the absorbable fraction (monoglycerides and free fatty acids) to total fatty acids quantified by gas chromatography following solid-phase extraction. Results showed that the overall bioaccessibility of pomegranate seed oil was equivalent to that of olive oil. Notably, punicic acid (in pomegranate seed oil) and oleic acid (in olive oil) - both 18‑carbon fatty acids present in equivalent quantities in the two oils, showed high and equivalent bioaccessibility. The presence of proteins (whey and soy protein isolates) did not affect the bioaccessibility of the major fatty acids under experimental conditions. The recovery index was high for all fatty acids, indicating minor degradation during in vitro digestion, and was not affected by the presence of oxygen. In conclusion, punicic acid is efficiently released by digestive lipases, suggesting good bioaccessibility of pomegranate seed oil. This finding paves the way for its potential application in oral therapeutic use.