Composition and in vitro bioacessibility of carotenoids in foods

Orientador: Delia B. Rodriguez-AmayaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de AlimentosAbstract: Carotenoids are among the phytochemicals of greater interest in terms of human health benefits. Brazil has the largest database on carotenoid concentrations, but studies on bioavailability are lacking. Chapter 1 is a review of the literature describing the mechanism of digestion, transport and absorption of carotenoids, the factors that can affect bioavailability and the in vivo and in vitro methods used for determining bioavailability. In vitro methods have been developed to determine bioaccessibility of carotenoids rapidly and inexpensively, but comparative evaluation of the different methods has not been carried out. Chapter 2 presents a comparison of the results obtained by a methodology for the determination of bioaccessibility in vitro and with modifications suggested to simulate human physiology better. The bioaccessibility of the carotenoids of carrot, tomato, and raw and cooked New Zealand spinach was, in general, significantly greater when the method of Reboul et al. (2006) was used. The oral phase proposed to integrate the digestion in vitro before the gastric phase did not alter the bioaccessibility of the carotenoids of the samples studied, but the addition of lipase and carboxyl ester lipase increased the bioaccessibility. The homogeneization time also affects significantly the percent micelarization of the carotenoids. Chapter 3 presents the bioaccessibility of commercial and native leafy vegetables, aside from the evaluation of the effect of cooking on bioaccessibility. Among the raw samples analyzed, New Zealand spinach had the highest bioaccessibility for ß-carotene (14%) and lutein (46%), correlating with its low fiber content (2.1 g/100g). The native leaf ¿caruru¿, richer in fiber (4.5 g/100g) had the lowest bioaccessibility for ß-caroteno (2.3%) and for lutein (6.9%). Cooking increased the bioaccessibility for ß-carotene (3.3 to 16% and 14 to 15%, respectively) and lutein (18 to 38% and 46 to 59%, respectively) in kale and New Zealand spinach. The bioaccessibility of carotenoids in fruits and their processed derivatives was studied in Chapter 4. Among the raw fruits, the papaya 'Solo¿ had the highest bioaccessibility for ß-carotene (36%) and ß-cryptoxanthin (39%) and pitanga had the lowest bioaccessibility for these carotenoids (6.3% e 10%, respectively). The percent micelarization of carotenoids was higher in the processed products. In mango, the bioaccessibility for ß-carotene increased from 19% in the raw fruit to 57% in the juice, and in guava , the bioaccessibility of lycopene increased from 1.4% to 27% in ¿goiabada¿. Chapter 5 deals with the bioaccessibility of the Amazonian fruits ¿buriti¿, ¿tucuma¿ and pupunha (raw and cooked). Aside from being excellent sources of provitamin A carotenoids (150, 142, 48 µg/g of ß-carotene for ¿tucuma¿, ¿buriti¿ and ¿pupunha¿, respectively), all three fruits presented greater bioaccessibility of ß-carotene than those of the fruits analyzed in the previous chapter, the cooked¿pupunha¿ having the highest percentage (40%). Chapter 6 provides inforrmation about the bioaccessibility of pitanga pulp and pitanga microencapsulated with different wall materials to protect the carotenoids from oxidative degradation. Lycopene had low bioaccessibility (1%) in all samples analyzed. Lutein was the most bioaccessible carotenoid in all samples (6 a 21%). Micelarization with maltodextrin substantially decreased the bioaccessibilitiy of all the carotenoids, while there was practically no loss of bioaccessibility with gum Arabic. The modified starch had an intermediate effectDoutoradoDoutor em Ciência de Alimento