Maria Cristina Dias Paes

Variabilidade de genótipos de milho quanto à composição de carotenoides nos grãos

O objetivo deste trabalho foi caracterizar e avaliar a variabilidade quanto ao teor e perfil de carotenoides nos graos de 134 genotipos de milho (Zea mays), com vistas a utilizacao em programas de biofortificacao. Os materiais foram provenientes dos campos experimentais e do Banco Ativo de Germoplasma da Embrapa Milho e Sorgo, Sete Lagoas, MG. Sao cultivares e hibridos comerciais, linhagens-elite e outros acessos escolhidos com base na coloracao amarelo-alaranjada do endosperma. A quantificacao do teor de carotenoides totais, carotenos e xantofilas mono-hidroxilada e di-hidroxilada dos graos foi realizada por metodo cromatografico-espectrofotometrico. As medias encontradas nos graos foram 22,34µ gg-1 de carotenoides totais, 2,55µ gg-1 de carotenos, 3,86µ gg-1 de xantofilas mono-hidroxiladas e 15,93µ gg-1 de xantofilas di-hidroxiladas. Os genotipos foram agrupados em 18 grupos pelo metodo de Tocher. O germoplasma da Embrapa possui potencial para ser usado em programas de desenvolvimento de linhagens de milho biofortificadas, quanto ao total de carotenoides pro-vitamina A.

Nutritional properties of cherry tomatoes harvested at different times and grown in an organic cropping

The physicochemical characteristics of the cherry tomato cultivated in organic and conventional production systems and harvested at either 30 or 45 days of cropping were evaluated using a randomized, 2x2 factorial design (2 cropping systems x 2 harvesting times) with five repetitions. The parameters analyzed were color, centesimal composition, total energetic value, carotenoids and bioactive amine content. Tomatoes harvested at 30 days had higher total soluble solid (TSS) content when grown conventionally, but when harvested at 45 days, both conventional and organic tomatoes had similar TSS values, probably due to increased N availability in the soil. Organic cherry tomatoes had higher contents of β-carotene, lycopene and bioactive amine. On the other hand, tomatoes from conventional cropping were more alkaline and brighter. In conclusion, organic tomatoes are more nutritious than conventional varieties, and if allowed to ripen for up to 45 days, contain higher levels of TSS, carotenoids and total bioactive amines.

Color of Corn Grains and Carotenoid Profile of Importance for Human Health

The increasing on the levels of carotenoids in staple foods of broad human consumption is one of the strategies of food biofortification programs, mainly due to the importance of these compounds to human health on the prevention of vitamin A deficiency. Maize is a major staple food due to its high consumption in regions where problems of Vitamin A deficiency are of great relevance. Maize biofortification programs have made progress in determining the amounts of carotenoids in grain of thousands of accesses. This work aimed at studying the influence of the color of the grains in the profile of carotenoids in four different Brazilian genotypes. The selection of ears within the same genotype was based on a color scale, considering the lighter (lightest yellow) in one group and the most colorful (darkest orange) in another group. Significant interactions (p 0.05) between the color of the grains and the genotypes for all the variables were detected in addition to genetic variability for both groups (lightest yellow and darkest orange). The colored ears of corn showed a high level of total carotenoids (TC) and fractions in RS 535 and RS 445, and the colorful ears of genotype RS 535 showed 300% more α + β carotenes (μg·g-1) in relation to lighter of this same material. The results of this study showed the influence of genotype on the grain color and content of carotenoids, indicating that breeders have the flexibility to make selection of some genotypes based on grain color, reducing cost and time compared to laboratory methods used for the screening of genetic materials.

Análise de trilha para carotenoides em milho

Path analysis for carotenoids in maize Although aspects of magnitude and significance are considered, the study of correlations between traits, alone, does not necessarily guarantee a cause and effect relationship between them. Therefore, the objective of this study was to use path analysis to allow the unfolding of correlations in direct and indirect effects, considering the carotenoids profile of maize genotypes. Data was obtained from the national assay of maize cultivars conducted by Embrapa Maize and Sorghum in the 2004/2005 growing season, with means of ten genotypes in five environments. The contents of total carotenoids (CT), alpha and -carotene, lutein, zeaxanthin and -criptoxantin were evaluated. Xanthophyll zeaxanthin provided the highest direct effect on -carotene. The high correlations between -carotene and total carotenoids and between -carotene and -criptoxanthin are due the indirect effect via zeaxanthin. The direct selection of genotypes with high levels of -carotene appears as a more effective alternative, but if other fractions of carotenoids were also considered, methods of simultaneous selection of characters using selection indices are more efficient in

Color and chemical composition and of green corn produced under organic and conventional conditions

The present study aimed to evaluate the chemical properties of green corn, grown in both organic and conventional farming systems, using a completely randomized factorial design. Four corn varieties (AG 1051, BR 106, SWB 551 and VIVI) of green corn kernels were evaluated for color, proximate composition, total calories, carotenoids and bioactive amines. The farming system affected some chemical and physical characteristics of green corn, but this effect was dependent upon variety. In general, organic green corn kernels were reddish (a* color component) and had higher levels of β-carotene compared to the conventional ones, suggesting that these characteristics are related. Moreover, organic green corn had higher levels of total carbohydrates and total energy compared to conventional varieties. On the other hand, crude fiber levels were higher in conventional grains - an unexpected result that deserves further investigation. Finally, the levels of cadaverine and spermine bioactive amines were not affected either by the corn variety or by the farming system.

Influence of the moisture at harvest and drying process of the grains on the level of carotenoids in maize (Zea mays)

Maize is considered a source of carotenoids; however, these compounds are highly unstable, degraded by high temperatures, exposure to light and presence of oxygen. The objective of this work was to evaluate the influence of the moisture and type of drying applied to grains on the level of carotenoids in yellow maize. The experiment was conducted in a completely randomized design (2 × 4 factorial), two levels of initial moisture at the harvest (22 and 19%) and three types of drying (in the sun; in the shade and in a dryer) and control (no drying). The samples of grains after drying with 12% of final moisture were analyzed by concentration of total carotenoids, carotenes (α-carotene + β-carotene), monohydroxilated carotenoids (β-cryptoxanthin), and xanthophylls (lutein + zeaxanthin). Initial moisture, type of drying and the interaction between moisture versus drying influence (p≤0.05) the levels of carotenoids in grains. This is the first report about the drying conditions and harvest’s initial moisture as influence on the profile and content of carotenoids in maize grains. Based on the results, this work suggested that the harvest be carried out preferably when the grains present 22% humidity, with drying in a dryer or in shade for further use or storage.

CAROTENOID RETENTION IN MINIMALLY PROCESSED BIOFORTIFIED GREEN CORN STORED UNDER RETAIL MARKETING CONDITIONS

Storing processed food products can cause alterations in their chemical compositions. Thus, the objective of this study was to evaluate carotenoid retention in the kernels of minimally processed normal and vitamin A precursor (proVA)-biofortified green corn ears that were packaged in polystyrene trays covered with commercial film or in multilayered polynylon packaging material and were stored. Throughout the storage period, the carotenoids were extracted from the corn kernels using organic solvents and were quantified using HPLC. A completely factorial design including three factors (cultivar, packaging and storage period) was applied for analysis. The green kernels of maize cultivars BRS1030 and BRS4104 exhibited similar carotenoid profiles, with zeaxanthin being the main carotenoid. Higher concentrations of the carotenoids lutein, b-cryptoxanthin, and b-carotene, the total carotenoids and the total vitamin A precursor carotenoids were detected in the green kernels of the biofortified BRS4104 maize. The packaging method did not affect carotenoid retention in the kernels of minimally processed green corn ears during the storage period.

Carotenoides em grãos de milho verde após a aplicação de herbicidas pós-emergentes

The objective of this work was to evaluate the efect of post-emergence herbicide application on carotenoid content in green corn grains. A completely randomized design was used, with five treatments - no application; foramsulfuron + iodosulfuron-methyl-sodium (40 g ha-1); nicosulfuron (20 g ha-1); mesotrione (120 g ha-1) and tembotrione (100 g ha-1) -, and two replicates. The grains were evaluated in terms of lutein, zeaxanthin, beta-cryptoxanthin, alpha-carotene and beta-carotene, pro-vitamin A carotenoids, total carotenoid contents, and percentage of lutein, zeaxanthin and pro-vitamin A carotenoids. Tembotrione and nicosulfuron herbicides did not cause deleterious effects on total carotenoids or fractions with pro-vitamin A activity.