Studying the composition of a certain food is not enough to predict its health benefits. Research over the past decades has decisively strengthened the notion that any putative health benefit is best related to the fraction of compounds transferred from ingested foods into the body since the absorption may be incomplete after oral consumption. In other words, the bioavailability of food components is crucial information. Therefore, a variety of in vitro models have been developed to predict their bioaccessibility and bioavailability in the most diverse food matrices and food products. These models can also be applied to study the impact of several endogenous or exogenous factors on the bioaccessibility and bioavailability of nutrients and bioactive compounds, guiding nutrition and food scientists, technologists, and engineers towards the development of strategies to optimize the positive impact of the diet on well-being and quality of life. While bioavailability is ideally examined in human volunteers, in vitro digestion methods, as well as intestinal absorption and microphysiological models, simulate human physiological conditions. Additionally, in vitro methods are alternatives to offset ethical, economical, and experimental limitations associated with in vivo studies conducted either with individuals or animals. This graphical review draws parallels between in vitro models mimicking digestion processes, uptake, absorption, metabolism, and distribution of dietary compounds and human physiology.

Carotenoid intake has been associated with the decrease of the incidence of some chronic diseases by minimizing the in vivo oxidative damages induced by reactive oxygen (ROS) and nitrogen species (RNS). The carotenoids are well-known singlet oxygen quenchers; however, their capacity to scavenge other reactive species, such as peroxyl radical (ROO^•), hydroxyl radical (HO^•), hypochlorous acid (HOCl) and anion peroxynitrite (ONOO⁻), still needs to be more extensively studied, especially using membrane-mimicking systems, such as liposomes. Moreover, the identification of carotenoids possessing high antioxidant capacity can lead to new alternatives of drugs or nutritional supplements for prophylaxis or therapy of pathological conditions related to oxidative damages, such as cardiovascular diseases. The capacity to scavenge ROO^•, HO^•, HOCl and ONOO⁻ of seven carotenoids found in marine organisms was determined in liposomes based on the fluorescence loss of a fluorescent lipid (C₁₁-BODIPY^581/591) due to its oxidation by these reactive species. The carotenoid-bearing hydroxyl groups were generally more potent ROS scavengers than the carotenes, whilst β-carotene was the most efficient ONOO⁻ scavenger. The role of astaxanthin as an antioxidant should be highlighted, since it was a more potent scavenger of ROO^•, HOCl and ONOO⁻ than α-tocopherol.