Investigation of storage stability and <i>in vitro</i> digestion of nanoemulsions loaded carotenoids from <i>Gracilaria dura</i>, <i>Sargassum acinarium</i> and <i>Ulva rigida</i> macroalgae

This research determined the potential utilization of carotenoids extracted from macroalgae collected in the coastal water of T & uuml;rkiye in the food industry. Carotenoids were extracted from Gracilaria dura, Sargassum acinarium and Ulva rigida collected from T & uuml;rkiye seas by using ultrasound-assisted enzymatic extraction. Then, physical and storage stabilities of nanoemulsions including carotenoid and bioaccessibility of beta-carotenoid during in vitro digestion were investigated. According to the study findings, carotenoid nanoemulsions were prepared with an encapsulation efficiency ranging approximately between 87% and 94%. The encapsulated carotenoids exhibited a superior ability to maintain stability in terms of both carotenoid content and antioxidant activity during in vitro digestion as compared to their non-encapsulated counterparts (p < 0.05). Chromatographic analysis of carotenoid profiles revealed the presence of beta-carotene in nanoemulsions derived from Gracilaria dura, Sargassum acinarium and Ulva rigida. A reduction in the amount of beta-carotene was observed in the nanoemulsions during in vitro digestion (p < 0.05). Results from the storage stability study indicate that the oxidative stability of algal carotenoid nanoemulsions was better than that of the control (p < 0.05). Conversely, destabilization occurred in algal carotenoid nanoemulsions on the seventh day of storage due to creaming. Lightness (L*) and color intensity (a*, b*) of the nanoemulsions gradually decreased over the 28-day storage period (p < 0.05). This study emphasizes the potential application of carotenoids from Gracilaria dura, Sargassum acinarium and Ulva rigida macroalgae in food products.