Determination of content and bioaccessibility of carotenoids from different cultivars of chilli peppers (Capsicum)

Peppers are a good source of carotenoids, which can vary in composition and concentration owing to differences in genetics and maturation1. All the carotenoid pigments present in the pepper are C40 isoprenoids containing nine conjugated double bonds in the central polyenic chain, although with different end groups, which change the chromophore properties of each pigment, allowing them to be classified into two isochromic families: red and yellow. Many studies have associated the health benefits of consuming carotenoid-rich foods with a reduced risk of several human chronic diseases2. The absorption of carotenoids requires release from the food matrix, partitioning into mixed micelle and uptake into intestinal mucosal cells. The transfer from the food matrix to micelles is referred to as bioaccessibility and represents the potential for their bioavailability. The objective of the present study was to compare the content and the bioaccessibility of xanthophyll and carotene carotenoids from 10 different cultivars of pepper fruits (Capsicum) characterized by a different colours of the fruit (red, yellow and orange). All fruits were subjected to an in-vitro digestion procedure which simulates gastrointestinal digestion3. Briefly, raw fruits were homogenized before the simulated gastric and intestinal digestion procedure, and digesta were ultracentrifuged to isolate the aqueous micellar fraction. The carotenoids from fruit homogenate and micelles were extracted and quantified using high-performance liquid chromatography (HPLC). In the present study, two provitamin A carotenoids, β-carotene and β-cryptoxanthin, as well as three non-provitamin A carotenoids, capsanthin, lutein and zeaxanthin, were analyzed. Generally yellow and orange peppers contained lower amounts of capsanthin, zeaxanthin β-cryptoxanthin and β-carotene, but had higher levels of lutein. Lutein was present in low concentrations in red peppers and was only detected in the micelles of yellow and orange peppers. Capsanthin was bioaccessible from all of the red peppers and the concentrations transferred to the micelle fraction ranged from 15.8% to 69.3%. The average bioaccessibility of zeaxanthin from the 10 peppers was approximately 30%. Generally, the bioaccessibility of β-cryptoxanthin and β-carotene from the peppers was lower than that of lutein, capsanthin and zeaxanthin, averaging 13.2% for β-cryptoxanthin and 7.6% for β-carotene. These results suggest that both the content and bioaccessibility of carotenoids varied between the different pepper varieties and depends on the cultivar and the colour of the peppers. References 1 Markus, F., Daood, H.G., Kapitany, J., & Biacs, P.A. 1999. Journal of Agricultural and Food Chemistry, 47(1), 100–107. 2 Rao, A.V., Rao, L.G., 2007. Pharmacology Research, 55, 207–216. 3 O'Sullivan, L., Jiwan, M., Daly, T., O'Brien, N.M. and Aherne S.A. 2010. Journal of Agricultural and Food Chemistry, 12, 5374–5379.