ESTUDOS SOBRE CAROTENÓIDES COM ATIVIDADE DE PROVITAMINA "A" EM CULTIVARES DE MANDIOCA (Manihot esculentaCRANTZ) EM ECOSSISTEMA DE TERRA FIRME DE MANAUS, AMAZONAS, BRASIL.

Abstract

RESUMO -Foram conduzidos experimentos de competição entre cultivares de mandioca (Manihot esculenta Crantz) em ecossistema de terra firme (Manaus -Amazonas), com objetivo de obter melhores cultivares de mandioca com relação a produtividade e teor de caroteno pró-vitamínico A. Raízes de sete cultivares de mandioca amarela foram selecionadas para identificação e quantificação de carotenos com atividade de vitamina A, mediante o método descrito por Rodriguez. Observou-se, também, as perdas de pró-vitamina A pelo processamento e armazenamento de farinha. Constatou-se a presença de três isômeros do β -caroteno (o 13 -eis -β -caroteno, o β -caroteno todo trans e o 9 -eis -β -caroteno U). Quanto aos teores de vitamina A, expressos em equivalente de retinol, nas raízes variaram de 4,4 a 18,8. Com relação a perda de atividade da vitamina A pelo processamento variou de 25,0 a 40,0 %, enquanto que o armazenamento por 6 meses em sacos plásticos transparentes, à temperatura ambiente e à exposição de luz, resultou em degradação total de seus carotenóides. Os resultados permitem concluir que três cultivares (IM 232; IM 104 e BGM 021) apresentaram os maiores teores de pró-vitamina A.Palavras-Chave: Caroteno, mandioca, farinha e vitamina A. ABSTRACT-Competition experiments were carried out between different cultivars of manioc (Manihot esculenta Crantz) in the terra firme ecosystem (Manaus, Amazonas, Brazil), with the productivity and pro-vitamin A carotene content. Roots from sevem cultivars of yellow manioc were selected for the identification and quantification of carotenes with vitamin A activity, according to the method described by Rodriguez. Pro-vitamin A loss due to processing and storage of the flour was also determined. The presence of three b -carotene isomers was noted (13 -cis -β -carotene, all trans β -carotene and 9 -cis -β -carotene). The amount of vitamin A present in the roots varied from 4.4 to 18.8 retinol equivalents. The loss of vitamin A due to processing was high, ranging from 25.3 to 40.0 %. The storage of the roots for six months in transparent plastic bags at room temperature and exposure to the sun, resulted in a total degradation of the carotenoids. The results allow one to conclude that three cultivars (IM 232; IM 104 and BGM 021) containt the highest pro-vitamin A content. Studies of Carotenoids with Provitamin

Natural variation in expression of genes associated with carotenoid biosynthesis and accumulation in cassava (Manihot esculenta Crantz) storage root

“…1 . Similar ratios and observations have also been partially reported for CSR of Amazonian landraces before [ 19 ].…”

“…Thus, studies to elucidate the carotenoid profiles from CSR with diverse color may provide new insights on unknown functions of carotenoids in this non-green organ. In addition, the diversity in color observed in cassava landraces [ 19 ] could contribute to a human diet that combines macronutrients (starch) and micronutrients (β-carotene, lutein and lycopene) in the same source of staple food. To take advantage of the existing genetic resources regarding the agro biodiversity of cassava in the Amazon region, its origin and center of domestication [ 19 , 20 ], the primary focus of this study was four fold: (1) to identify natural genetic variations in the carotenoid synthesis pathway that could be of importance in elucidating the functions of carotenoids in non-green tissues, (2) to identify variations in carotenoid content and types in relation to tissue age of the CSR, (3) to identify differences in expression of genes associated with carotenoid synthesis and accumulation, and (4) propose a natural carotenoid biosynthesis pathway for CSR.…”