pubs.acs.org/JAFC Published on Web 03/23/2010 © 2010 American Chemical Society 5374 J. Agric. Food Chem. 2010, 58, 5374–5379 DOI:10.1021/jf100413m Bioaccessibility, Uptake, and Transport of Carotenoids from Peppers (Capsicum Spp.) Using the Coupled in Vitro Digestion and Human Intestinal Caco-2 Cell Model LAURIE O’SULLIVAN,MARVIN A. JIWAN,TREVOR DALY,NORA M. O’BRIEN, AND S. AISLING AHERNE* School of Food and Nutritional Sciences, University College Cork, Cork, Republic of Ireland Spanish bell peppers (Capsicum annuum L.) and chili peppers sourced from Kenya and Turkey were analyzed for their carotenoid content, bioaccessibility, and bioavailability. The order of total carotenoid content in peppers and their respective micelles was red > green > yellow. In terms of cellular carotenoid transport as a percentage of original food and micelle content, the order was yellow peppers > green > red; however, the opposite trend was seen for the actual amount of total carotenoids transported by Caco-2 cells. Although lutein was generally the most abundant carotenoid in the micelles (496.3-1565.7 μg 100 g -1 ), cellular uptake and transport of β-carotene were the highest, 8.3-31.6 and 16.8-42.7%, respectively. Hence, the actual amount of carotenoids present in the original food and respective micelles seems to reflect the amount transported by Caco-2 cells. Therefore, color influenced the carotenoid profile, bioaccessibility, and bioavailability of carotenoids rather than pepper type. KEYWORDS: Bioaccessibility; bioavailability; Capsicum; Caco-2 cells; carotenoids; peppers INTRODUCTION Peppers (Capsicum annuum L.) are commonly consumed vegetables because they provide a variety of color and flavor to food products and meals. According to Sun et al. ( 1 ), the color of sweet bell peppers is the major factor associated with consumer purchasing decisions. Depending on flavor intensity and texture, their culinary use changes from that as a vegetable (bell pepper) to a spice (chili pepper) or a colorant (paprika). Peppers have been reported to possess certain biological properties ( 1 , 2 ) that may have positive effects on human health and chronic disease. For instance, reduced risks of prostrate cancer have been asso- ciated with increased intake of certain vegetables including bell peppers ( 3 ). In addition, peppers have been shown to possess radical scavenging activity ( 1 , 2 , 4 ) as well as prevent the oxidation of cholesterol and docosahexaenoic acid (DHA) during heat- ing ( 1 ). Peppers are one of the top 10 contributors to the dietary intake of the carotenoids lutein and zeaxanthin in both the Republic of Ireland and Spain ( 5 , 6 ). These plant foods are a rich source of bioactive phytochemicals including capsaicinoids and carotenoids ( 7 ). Numerous epidemiological studies have shown an association between the consumption of carotenoid-rich foods and a reduc- tion in the risk of several human chronic diseases ( 8 , 9 ). The major interest in studying carotenoids is because of their bioactive effects, which include provitamin A activity, antioxidant actions, immune modulation, and involvement in cell signaling ( 6 , 10 ). Bioavailability is a critical feature in the assessment of the role of dietary components, plant food consumption, and human health ( 11 ). Therefore, to enhance our knowledge about the amounts of carotenoids that are potentially available for absorp- tion from commonly consumed carotenoid-rich foods such as peppers, carotenoid bioavailability from these foods should be investigated. In addition, factors that influence the content and bioavailability of carotenoids from peppers should be identified and established to evaluate the actual health effects obtained from consuming such foods. Consequently, in the present study, we determined the content, bioaccessibility, and bioavailability of carotenoids from bell peppers (red, green, and yellow) and chili peppers (red and green) that were available to the Irish consumer at the time of testing, by using the in vitro digestion model coupled with differentiated human intestinal Caco-2 cells. Furthermore, we investigated if carotenoid content and bioacces- sibility varied between chili peppers sourced from Kenya and from Turkey. MATERIALS AND METHODS Material. All reagents including DMEM growth media, nonessential amino acids, Hank’s balanced salts solution (HBSS), β-carotene, zeax- anthin (Fluka), lutein (Fluka), and cholesterol esterase (Fluka) were purchased from Sigma-Aldrich Chemical Co. (Dublin, Ireland). β-Cryp- toxanthin (>95% purity) was purchased from LGC Prochem (Middlesex, U.K.). Fetal bovine serum was sourced from Bio-Sciences (Co. Dublin, Ireland). All solvents employed were of HPLC grade. Sample Preparation and in Vitro Digestion. During one season, uniformly ripe healthy peppers were purchased from a well-known super- market chain. The red, green, and yellow bell peppers originated from Spain. Chili peppers (red and green) were from Turkey and Kenya. The peppers were not identical in genotype (i.e., seven different varieties). *Corresponding author (telephone þ353 21 4902496; fax þ353 21 4270244; e-mail a.aherne@ucc.ie).