Stinging nettle (Urtica dioica L.) as a functional food additive in egg pasta: Enrichment and bioaccessibility of Lutein and β-carotene

The use of stinging nettles as an ingredient in egg pasta has been evaluated with respect to food enrichment with carotenoids. Bioaccessibility of lutein and β-carotene has been estimated by dynamic simulation of the digestion process, with particular attention to duodenum and colon stages. Higher bioaccessibility for the two carotenoids occurs between 2 and 24 h of colonic fermentation and it is around 35% for lutein and 10% for β-carotene. However, the results reveal that the food matrix has a significant role in carotenoid release during the digestion process. In general, nettle enriched pasta has a lower carotenoid bioaccessibility than dietary supplement at duodenum and after 48 h of colonic fermentation. Nettle capsules release carotenoids with a maximum bioaccessibility at 24 h of colonic fermentation, similarly to non-enriched egg pasta. Nettle enriched egg pasta shows the highest levels for bioaccessibility at a lower colonic fermentation time (i.e., 2 h).