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Carotenoids refer to a wide class of lipophilic pigments synthesized by plants, exert photoprotective and antioxidant properties that are lost upon carotenoid degradation. Their inclusion into hydrophilic host-molecules could improve their stability. Cyclodextrins, provide a hydrophobic cavity in the core of their structure while the outer configuration is suitable with aqueous environments. Carotenoids can accommodate into the hydrophobic core of cyclodextrins and therefore, they are protected from exogenous stress. Literature reported that carotenoid structure could modulate stability of the complexes, however no conclusions can be drawn as the studies performed so far were not completely analogous. We describe the synthesis of several carotenoids/β-CDs inclusion complexes and provide experimental evidences that β-CDs inclusion renders these compounds more stability towards the oxidizing agents (2,2′-azobis, 2-methylpropionamidine dihydrochloride and hydrogen peroxide). Esterified carotenoids were also used in this work to screen the influence of this particular structural configuration of xanthophylls against oxidation. [ABSTRACT FROM AUTHOR]

Photoprotection by dietary carotenoids has been linked to their antioxidant properties, in particular quenching of singlet molecular oxygen and scavenging of peroxyl radicals. Here, we compared the DNA-protection and antioxidant effects of selected carotenoids exclusively synthesized in red pepper (capsanthin and capsorubin) to the xanthophyll lutein. Preincubation of human dermal fibroblasts (hdf) with capsanthin and capsorubin significantly counteracted UVB induced cytotoxicity at doses between 0 and 300 mJ cm−2. Pretreatment of hdf with capsanthin, capsorubin or lutein (1 μM) significantly decreased the formation of DNA strand breaks following irradiation with UVB light. All carotenoids studied decreased caspase-3 cleavage (a marker for UVB-induced apoptosis), however, caspase dependent PARP-1 cleavage was not affected suggesting that the remaining caspase activity is sufficient to promote UVB-induced apoptosis. It is conceivable that carotenoids selectively interfere with cellular responses activated by UVB-mediated damage. Our findings indicate that capsanthin and capsorubin exhibit similar properties to lutein and could be used as a dietary supplement to improve natural photoprotection. [ABSTRACT FROM AUTHOR]

Abstract: Carotenoid pigments are a group of bioactive compounds that are of interest to the food scientists, nutritionists and food industries due to their positive impact on human health and their economic benefits. Carotenoids are responsible for the attractive colour of many plant food (mainly fruit and vegetables), which is perhaps the first attribute that consumers assess when determining the quality and appearance of a product, and therefore conditions its acceptability. In addition, carotenoids have diverse biological functions and activities, such as the well known provitamin A activity, antioxidant capacity and enhancement of the immune system. There are an extensive number of factors affecting the efficient incorporation of these phytochemicals from the diet, although in many cases no biological activity will be put in action within the consumer body (animal or human) without a first visual attraction. The term bioaccessibility is used to evaluate the amount of a nutrient that is released from a food during the digestion process. The bioaccessibility of lipophilic compounds, such as carotenoids, in natural foods (mainly fruits and vegetables) is usually fairly low and is constrained by various factors, particularly the degree of food processing and matrix composition. There are evidences that homogenisation and thermal treatment have positive effects on the bioaccessibility of these compounds, whereas the presence of dietary fibre has a negative effect. The presence and co-ingestion of fat in the diet are a key factor, with a minimum quantity needed to facilitate carotenoid absorption, and this seems to be one of the advantages of the Mediterranean diet. Most of the relevant data on the bioaccessibility of carotenoids from natural or processed foods has been obtained in postprandial absorption studies and supplementation studies. This approach, although highly valuable, is insufficient for a detailed analysis of the food matrix composition effects, and also it does not take into consideration other factors that may be involved in carotenoid absorption in each stage of the bioaccessibility process (digestibility and absorption). In vitro experimental processes that reproduce the physiological conditions and events that take place in the human gastrointestinal tract during digestion have been developed and fine-tuned in recent years. These digestion models become an excellent analytical resource to establish both the significance and scope of diverse factors in the efficiency of digestibility of carotenoids allowing a detailed analysis of the influence of the food matrix composition on the digestive process. [Copyright &y& Elsevier]

Abstract: The term “bioaccessibility” is a key concept to ascertain nutritional efficiency of food and food formula developed with the aim of improving human health. In this review, working definitions of bioavailability, bioaccessibility, and bioactivity are examined, taking into account the complete sequence of events that take place during the digestive transformation of food into material that can be assimilated by the body, the absorption/assimilation into the cells of the intestinal epithelium, the presystemic metabolism, and, lastly, the development of biologic actions. Comparison among in vivo and in vitro techniques to assess bioaccessibility is accomplished, considering the strengths and limitations of each experimental approach, with a complete description of in vitro procedures applied to determine bioaccessibility of carotenoids. Although a great development has been achieved on the in vitro approaches, these are especially intended for initial screening and should be complemented with in vivo studies, which will remain as the criterion standard for bioaccessibility of nutrients and bioactive compounds at specific target populations. Application of bioaccessibility assessment in foods claiming a health benefit because of their nutrients or bioactive compounds content is described. Measurement of bioaccessibility provides valuable information to select the appropriate dosage and source of food matrices to ensure nutritional efficacy of food products. In addition, in vitro bioactivity measurements to support health benefits of bioactive compounds should be accomplished with estimation of their bioaccessibility, to adequately give nutritional significance to health claims. [Copyright &y& Elsevier]

Abstract: Here we describe the profiles of volatile compounds from the thermal degradation of carotenoids present in oleoresins of marigold, tomato and paprika. The profiles obtained by SPME-GC were complex, with identical compounds, such as toluene and m-xylene, being detected in all three oleoresins. Intramolecular cyclisation is proposed as the main reaction mechanism in the formation of the volatile compounds detected; this process is activated by the thermal impact generated during the processing and is followed by a reaction of elimination in the chain or a heterolytic fragmentation reaction. The presence of other compounds, such as various methyl benzaldehydes or isophorone (1,1,3-trimethyl-3-cyclohexene-5-one), also indicates the concurrence of carotenoid oxidation reactions that affect either the central polyenoic chain or the end-groups (β or ε rings). Ethanone,1-(methylphenyl), (4prime-methylacetophenone) not previously reported as a compound resulting from the thermal degradation of carotenoids, was also characterised and the same mechanism is proposed for its formation. [Copyright &y& Elsevier]

Abstract: Efficiency of the micellar incorporation of carotenoids was determined through the application of an in vitro digestion procedure, and in function of the composition of the lipophilic environment, where digestion was carried out. Analysed factors affecting micellization level were presence of oil in the digestion mixture, class of pigment, and cholesterol. The addition of oil to the digestion mixture caused changes of different extent in function of the class of pigment, and significant interactions between the factors presence of oil and class of pigment were detected. Accessibility of lycopene was affected negatively by an increase of the amount of vegetable oil, while lutein ester increased its presence in micelles. Although cholesterol was not a significant factor affecting the micellization efficiency, when cholesterol and oil were added to the digestion process, the amount of micellarized pigment was significantly affected, positively or negatively depending on lipophilic characteristics of the pigment. Therefore, an interaction between the factors cholesterol and presence of oil with different effects on the micellization of pigments was analysed. The physical–chemical differences of carotenoids, that are consequence of their structural features, generated diverse requirements of the lipophilic environment to facilitate their emulsion and subsequent incorporation into micelles. Industrial relevance: Carotenoid pigments are widely used by the food industry as colorants, although nutritional and functional properties make them to be applied for other purposes, as in the enhancement of functional foods. The physico-chemical characteristics of carotenoids make them to be low bioavailable, so that a correct formulation of the food matrix is required in order to achieve an appropriate bioavailability. The development of in vitro digestion methods, which allow the measurement of the potential bioavailability of carotenoids, could be considered as a useful tool to screen those factors and components that modify the bioavailability of these compounds in a given matrix composition so selection of the formulation conditions that gives the higher availability may be performed. The aim of this work was the development and application of an in vitro method to measure the potential bioavailability of carotenoids considering several factors that modulate it. [Copyright &y& Elsevier]