Caracterização e avaliação do potencial antioxidante de mangas (Mangifera indica L.) cultivadas no Estado de Minas Gerais

• Main Author: Ribeiro, Sônia Machado Rocha
• Publication Date: 2006
• Format: Doctoral thesis
• Language: por
• Source: LOCUS Repositório Institucional da UFV
• Download full: http://locus.ufv.br/handle/123456789/288
• topic: Mangifera indica; Potencial antioxidante; Mangiferina; Quercetina; Mangifera indica; Antioxidant potential; Mangiferin; Quercetin; CNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS::CIENCIA DE ALIMENTOS::QUIMICA, FISICA, FISICO-QUIMICA E BIOQUIMICA DOS ALIM. E DAS MAT.-PRIMAS ALIMENTARES

Mango culture is an important economic activity both at national and international level. Mango agro-industry is also a growing sector in domestic and foreign markets, and producers expectation is of expanding the consuming market. Diffusion of information concerning mango nutritional and functional values, therefore, can add value to the fruit and byproducts, resulting in increased consumption and market competitiveness. Mango pulp has potential for becoming an excellent dietary antioxidant source, having in its composition molecules with biological antioxidant activities such as carotenoids, ascorbic acid and phenolic compounds. Also, mango agro-industrial residues, peel and seed, have the same phenolic compounds making them antioxidant sources for a range of uses. However, there is lack of works in the literature on the antioxidant potential of pulp and residues from mangos cultivated in Brazil. This work investigated the antioxidant potential of pulp of four commercial mango cultivars cultivated in Minas Gerais and the agro-industrial residues from cultivar Ubá. The study was carried out through the quantification of antioxidant compounds (ascorbic acid, total carotenoids, β-carotene, total phenolics), in vitro antioxidant activity tests, and biological assays using Wistar rats. Ripe fruits, characterized by pulp firmness, total soluble solids and color, were used for the assays. It was found that the levels of ascorbic acid in pulp were 15.69; 9.79; 10.54 and 77.71 mL per 100 g of pulp for varieties Haden, Tommy Atkins, Palmer and Ubá, respectively. There was no significant difference between varieties Haden and Tommy Atkins for ascorbic acid content, while the other varieties were statistically different for this parameter. Total carotenoids varied from 1.91 to 2.63 µg per 100 g, with no significant difference among varieties Tommy Atkins, Palmer and Ubá; variety Haden gave total carotenoids content significantly lower than the others. The β-carotene contents were significantly different among the four varieties, with values of 888; 608.39; 661.27 and 2,221 µg per 100 g for varieties Haden, Tommy Atkins, Palmer and Ubá, respectively. Total phenolics differed among the four varieties with values of 62.1; 48.4; 128.2 and 208.7 mg of gallic acid equivalent per 100 g of pulp for varieties Haden, Tommy Atkins, Palmer and Ubá, respectively. Zinc contents ranged from 0.249 to 0.33 mg per 100 g of pulp, with no significant differences among the four varieties. There were no significant differences among iron contents, ranging from 0.121 to 0.298 mg per 100 g of pulp. Copper contents ranged from 0.081 to 0.097 µg per 100 g of pulp, with no significant differences between Palmer and Ubá (0.083 and 0.081 µg per 100 g of pulp, respectively); Haden gave higher level (0.097 µg per 100 g of pulp) and Tommy Atkins gave significant lower level (0.077 µg per 100 g). All the four varieties showed antioxidant potential in the chemical tests, but there was significant difference among varieties, with variety Ubá being superior. There was difference regarding the contents of quercetin, mangiferin and kaempherol. Mangiferin was detected in pulp of varieties Ubá, Haden and Tommy Atkins; quercetin was only detected in varieties Ubá and Haden; and kaempherol only in variety Ubá. Biological assays showed that supplementation of commercial ration for wistar rats with lyophilized mango pulp at 10% resulted in increase of lipid peroxidation marker, evaluated by the thiobarbituric acid reactive substances (TBARS) test, both in the absence and the presence of oxidative stress induced by diclofenac, suggesting the occurrence of pro-oxidant effect. The biological assays with supplementation of AIN-G ration with lyophilized mango pulp at 3% showed reduction in lipid peroxidation, demonstrating the antioxidant effect, in the absence and the presence of oxidative stress induced by paracetamol. Total phenolics of agroindustry residues of variety Ubá were 48.95 mg gallic acid equivalent/kg DM (kilogram of dry matter) in skin and 68.45 mg gallic acid equivalent per kg DM in seed. Skin and seed contain mangiferin in the concentration of 270.5 mg kg-1 DM and 46.5 mg kg-1 DM, respectively. The skin contains quercetin at 785.3 mg kg-1 DM and kaempherol at 35.3 mg kg-1 DM. Hydroalcoholic extracts of residues showed antioxidant potential comparable to butylhydroxianisol (BHA) and gallic acid.