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PRE-ABSORPTIVE METABOLISM OF CAROTENOIDS

Thakkar, Sagar
http://rave.ohiolink.edu/etdc/view?acc_num=osu1244048450

Abstract Details

2009, Doctor of Philosophy, Ohio State University, OSU Nutrition.
Vitamin A deficiency (VAD) is still a major public health issue in developing countries. Biofortification of staple crops with pro-VA carotenoids is proposed as a complementary and sustainable approach to alleviate VAD. However, it is unknown if the additional pro-VA carotenoids accumulated in the staple crops will be bioavailable. First, I focused on screening the relative bioaccessibility of β-carotene (BC) from ten cultivars of cassava using the coupled in vitro digestion/Caco-2 cell model. All-trans-BC, 9-cis-BC, and 13-cis-BC were the most abundant carotenoids in boiled cassava and recoveries after digestion exceeded 70%. Efficiency of micellarization of total BC was 30% for various cultivars with no significant difference among isomers and was linearly proportional to concentration in cooked cassava. Accumulation of all-trans-BC by Caco-2 cells incubated with the diluted micelle fraction for 4 h was proportional to the quantity present in micelles. In addition to boiling, cassava is also traditionally prepared by fermentation and roasting. These different methods of preparation have the potential to affect both the retention and bioaccessibility of BC. So I next focused on the effects of traditional preparation of cassava on retention and bioaccessibility of BC in boiled cassava, gari (fermentation and roasting), and fufu (fermentation and boiling the paste). Apparent retention of BC was approximately 90% for boiled cassava and fufu. In contrast, roasting fermented cassava at 195°C for 20 min to prepare gari decreased BC content by 90%. Retention was increased to 63% when temperature was decreased to 165°C and roasting was limited to 10 min. The efficiency of micellarization of all-trans and cis isomers of BC during simulated digestion was 25-30% for boiled cassava and gari and independent of cultivar. However, micellarization of BC isomers during digestion of fufu was only 12-15%. These differences in retention and bioaccessibility of BC from cassava products prepared according to traditional processing methods suggest that gari and fufu may provide less retinol activity equivalence (RAE) than isocaloric intake of boiled cassava. It is noteworthy that cassava has only BC as the primary carotenoid in the tuber. However, maize, another staple crop targeted for biofortification also has β-cryptoxanthin (B-CX) and lutein (LUT) and zeaxanthin (ZEA). Studies have demonstrated interaction between carotenoids, therefore primary aim of my next study was to examine if LUT and ZEA attenuate the bioaccessibility of pro-VA carotenoids at amounts and ratios present in maize. BC incorporation into micelles during chemical preparation and during in vitro digestion of carotenoid-enriched oil was slightly increased when the concentration of LUT was 6-fold or greater than BC. Likewise, the efficiency of BC micellarization was slightly increased during simulated small intestinal digestion of white maize porridge supplemented with oil containing 9-fold molar excess of LUT to BC. Mean efficiencies of micellarization of BC, BCX, LUT and ZEA were 16.7, 27.7, 30.3 and 27.9%, respectively, and independent of the ratio of LUT plus ZEA to pro-VA carotenoids during simulated digestion of maize porridge prepared from flours containing 0.4–11.3 µg/g endogenous pro-VA carotenoids.
Mark Failla (Advisor)
Earl Harrison (Committee Member)
Ouliana Ziouzenkova (Committee Member)
Hugo Melgar-Quinonez (Committee Member)
140 p.
Nutrition
carotenoids; bioavailability; Caco-2; vitamin A

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Citations

  • Thakkar, S. (2009). PRE-ABSORPTIVE METABOLISM OF CAROTENOIDS [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1244048450

    APA Style (7th edition)

  • Thakkar, Sagar. PRE-ABSORPTIVE METABOLISM OF CAROTENOIDS. 2009. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1244048450.

    MLA Style (8th edition)

  • Thakkar, Sagar. "PRE-ABSORPTIVE METABOLISM OF CAROTENOIDS." Doctoral dissertation, Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1244048450

    Chicago Manual of Style (17th edition)

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This open access ETD is published by The Ohio State University and OhioLINK.