TITLE:
Biochemical Changes of Cubiu Fruits (Solanum sessiliflorum Dunal, Solanaceae) According to Different Tissue Portions and Ripening Stages
AUTHORS:
Moacir Couto de Andrade Júnior, Jerusa Souza Andrade, Suely de Souza Costa
KEYWORDS:
Cocona, Fruit Placenta, Medicinal Plant, Pectinesterase Activity, Vitamin C
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.7 No.12,
October
31,
2016
ABSTRACT: Cubiu fruits (Solanum sessiliflorum Dunal, Solanaceae) are known for their high nutritional
value and low caloric content. This work aimed at evaluating biochemical
indices of cubiu fruits according to different tissues (peel, pulp and placenta) and ripening
stages (green, turning, ripe and fully ripe). The fruits were randomly harvested
to investigate sensory aspects (colorimetry, blanching effect, pigments) and
biochemical indices (moisture and dry matter, Total Soluble Solids (TSS), pH, Titratable
Acidity (TA), TSS/TA ratio, ascorbic acid, Alcohol-Insoluble Solids (AIS),
pectinesterase activity and pectin content). The analyses were performed at the laboratory
of Instituto Nacional de Pesquisas da Amazonia (INPA), Manaus, Brazil.
The blanching process preserved pulp colors at all ripening stages. Chlorophylls were
higher in green peels; flavonoids and carotenoids, in fully ripe peels. Anthocyanins
were entirely absent. Pulp (turning fruits) showed the highest moisture content
(91.05), followed by ripe pulp (90.70) and fully ripe pulp (90.62). Pulp TSS changed
little whereas placenta TSS declined and were associated with increased TA and pH
reduction (fully ripe fruits). Pulp pH and TA varied little whereas placenta pH was
notably low and TA was remarkably high (fully ripe fruits). Pulp TSS/TA ratio
showed predominance of TSS while in placenta, there was predominance of organic
acids. AIS, precursors of pectin, were stable during ripening. The statistical analysis
of dietary fiber content showed one modal value in the AIS. In pulp, pectinesterase
activity correlated inversely with pectin content. Cubiu fruits were significant sources
of bioactive compounds, e.g. chlorophylls, flavonoids and carotenoids, predominantly
in the peel and the pulp; soluble functional fibers, e.g. pectin (g/100 g fresh weight), particularly in the green peel (1.00) and the fully ripe pulp (1.12), and other
versatile molecules, e.g. ascorbic acid (mg/100 g fresh weight), especially in the fully
ripe peel (32.45) and placenta (24.84) and the turning placenta (21.27). Cubiu fruits
are rich in ascorbic acid and should be included in the human diet.