Diversidade genética, frutificação, atributos de qualidade e compostos bioativos em cambuizeiros diferenciados pela coloração do fruto

Abstract

Myrciaria floribunda (West ex Willd.) O. Berg is a tropical fruit tree native of Brazil. The fruits are small, succulent and have the potential for in natura and industrial consumption with functional properties to human health. To increase the knowledge about the variability of this species and to support its domestication, this study aimed to evaluate the genetic diversity, fructification, quality attributes and bioactive compounds in Myrciaria floribunda differentiated by fruit color. The plant material came from an in situ population located at the Experimental Field of Embrapa Coastal Tablelands, in the municipality of Itaporanga d’Ajuda, SE. Genetic diversity was estimated by 15 ISSR primers. The evaluation of the fruiting stages ‘green,’ ‘underripe’ and ‘ripe,’ was conducted from January to April 2018, and in March the fruits were harvested, which were evaluated according to the coloration. The characteristics evaluated were: weight, length and width; number of seeds; pH; soluble solids; titratable acidity and vitamin C content. In the extraction process of phenolic compounds of fruits and their antioxidant activity, the extraction method was used under atmospheric pressure (maceration) and pressurized liquid (PLE). The contents of total phenols, flavonoids and antioxidant activity were quantified by the DPPH method. No specific molecular mark that characterizes fruit coloration was found; however, high genetic diversity was observed among the evaluated individuals. There was heterogeneity in the maturation of both types of the tree. The highest ripening peak occurred at 63 DAA (83.2 % of the orange-colored fruits and 68.3 % of the purple-colored fruits). The purple fruits showed higher physical attributes; however the orange fruit pulp was distinguished by the higher titratable acidity content. The maceration extraction method showed a better overall yield of purple fruit extracts, with 47.83 %. All extracts analyzed showed excellent content of phenolic compounds, especially purple fruits (4212.96 ± 180.55 and 3870.37 ± 353.09 mg AGE/100 g obtained by maceration and PLE, respectively). The content of flavonoids was also quite considerable, the PLE obtained 693.16 ± 180.09 and 770.08 ± 103.62 mg RE/100 g in purple and orange fruit extracts, respectively. No difference was found between the phytochemical profiles of the extracts of Myrciaria floribunda of different stains, with most of the compounds identified by the UPLC-QTOF-MSE analysis derived from caffeic acid, ellagic acid, ellagic acid derivatives and ellagitannins. The extracts of purple fruits showed higher antioxidant activity (124.6 ± 9.52 μg/mL) when extracted by maceration.