Nanoemulsion-based delivery systems for nutraceuticals: Influence of carrier oil type on bioavailability of pterostilbene

•Pterostilbene-enriched nanoemulsions with olive oil or flaxseed oil were fabricated and characterized.•Nanoemulsions greatly enhanced bioaccessibility of pterostilbene after digestion.•Nanoemulsions greatly increased trans-enterocyte transport of pterostilbene after digestion.•Olive oil and flaxseed oil nanoemulsions had different impacts on the metabolism of pterostilbene in enterocytes. Nanoemulsion-based delivery systems can be utilized in functional foods and beverages to improve the bioavailability of nutraceuticals. We determined the influence of carrier oil type on the bioavailability of pterostilbene encapsulated in nanoemulsions containing either flaxseed or olive oil as the carrier oil. The nanoemulsions were then subjected to a simulated gastrointestinal tract (mouth, stomach, small intestine), and the resulting micelle phases were used to establish pterostilbene bioavailability using a Caco-2 cell model. Both nanoemulsions significantly enhanced the bioaccessibility of pterostilbene within the micelle phase. However, olive oil nanoemulsions increased trans-enterocyte transport of pterostilbene more effectively than flaxseed oil ones. Moreover, the patterns of metabolism of pterostilbene during its trans-enterocyte transport were dramatically different when pterostilbene was delivered using nanoemulsions with different carrier oil types.