Carotenoides e compostos bioativos : relação com propriedades anti-radical livre e corante em frutas tropicais / Carotenoids and bioactive compounds : relationship between free radical scavenger properties and color in tropical fruits

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The increased demand for high life quality has been associated to healthy food, increasing the industry interest for functional foods, which are defined as any food or bioactive compounds with potential to be benefic for the consumer health. The bioactive compounds found in foods, such as carotenoids, phenolic compounds and ascorbic acid (AA) are involved with these benefic actions. Firstly, some carotenoid standards in different concentrations were evaluated regarding not only their radical scavenger activity, but also their color parameters (CIELAB), since these pigments are responsible for the color of many foods. The results showed that the number of conjugated double bonds, presence of carbonyl group and concentration influenced both the radical scavenger activity and the color parameters. After that, the radical scavenger activity of complex extracts were determined, by ABTS assay, obtained from pulps extracts prepared in the laboratory from 18 tropical fruit applying Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) to characterize and grouped the 18 extracts, as well as to correlate radical scavenger and the bioactive compounds, such as AA, phenolic compounds, flavonoids and total carotenoids. The fruits were divided into five groups, following Hierarchical Cluster Analysis (HCA). Principal Component Analysis (PCA) indicated that antioxidant activity showed high correlation to total phenolic compounds (r= 0.99) and flavonoids (r= 0.86); however, correlation was found to be very poor with AA (r= 0.02) and total carotenoid levels (r= 0.08). The cashew-apple was specially evaluated since the processing of juice from the cashew-apple fruit generates a pomace that constitutes a rich source of phenolic compounds, AA and carotenoids. Considering that this pomace can be processed into functional ingredients, the cashew-apple clone CCP-076, from Estação Experimental de Paraipaba (CE) at Embrapa Agroindústria Tropical, was pressed and than the pomace formed was humidified and pressed again until exhaustion (retentado), followed by filtration (raw extract) and concentration (concentrated extract). The retentado presented significantly higher total phenol and total carotenoid contents, higher free radical scavenger activity, as well as higher yellow color intensity, indicated by higher b* and chroma (C*) values. On the other hand, the concentrated extract showed the highest AA content. The major carotenoids identified in both retentado and extracts were all-trans-b-cryptoxanthin and all-trans-b-carotene. These results showed that the retentado has a good potential to be applied as a functional ingredient. Another fruit also specially analyzed was the papaya fruit (Carica papaya cv. Golden) that has a great export demand to North American and Europe markets; however, since it is a climacteric fruit, it is susceptible to postharvest losses. The papaya fruits were divided into three groups: control (without treatment), ethylene (treated with ethylene) and 1-methylcyclopropene (1-MCP) (treated with 1-MCP). In all groups, carotenoid composition, carried out by HPLC, and color parameters were evaluated during ripening. The treatment with ethylene and 1-MCP decreased carotenoid accumulation and enhanced acyclic carotenoid biosynthesis. Although the gas treated fruits presented lower carotenoid content as compared to the control, the color values (a*, b*) were similar in treated and non-treated fruits during ripening

ASSUNTO(S)

free-radical scavenger color frutas tropicais tropical fruits atividade anti-radical livre compostos bioativos bioactive compounds carotenoids carotenoides cor

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