ARS | Publication request: No effect of pH on in-vitro digestion of carotenoids from sweet potatoes and mandarin oranges [abstract]

Submitted to: Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: February 13, 2012
Publication Date: April 21, 2012
Citation: Burri, B.J., Devin, C.M., Rajaonary, M., Roman, M., La Porte, D. 2012. No effect of pH on in-vitro digestion of carotenoids from sweet potatoes and mandarin oranges [abstract]. Experimental Biology. A31.1.

Technical Abstract: Beta-carotene (BC) and beta-cryptoxanthin (CX) can form vitamin A physiologically. Recent observational studies suggest that CX has greater bioavailablity than BC from most diets. This means that CX-rich foods such as mandarin oranges might be better than expected sources of vitamin A. We hypothesized that CX might be easily digested from its major food sources, possibly because these foods are acidic. We used a static in vitro digestion model to compare the apparent bioavailability of CX from mandarin oranges to BC from orange-fleshed sweet potatoes (OFSP) at several different physiological pHs. The model included saliva, gastric fluid, duodenal fluid, and bile components. BC and CX concentrations were measured by reversed-phase HPLC or by spectrophotometry at 450 nm. BC from both varieties of boiled OFSP had very low bioavailability (0.65 – 1.08%). These values are comparable to those reported for OFSP without fat in the literature. CX from mandarin oranges had better bioavailability (approximately 2.21 – 4.25%). Changes in saliva, gastric, and bile fluid pH did not change bioavailability significantly for either mandarin oranges or OFSP. Our results support the hypothesis that CX is more bioavailable from a major food source (mandarin oranges) than BC is from orange-fleshed sweet potatoes (OFSP), a common intervention food used to increase VA status.