Natural sources with high antioxidant capacity represent an interesting potential to prevent or minimize the oxidative stress that causes many chronic diseases. The antioxidant capacity of red fruits (strawberry and cherry) was evaluated by miniaturized spectrophotometric methods 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and nitroblue tetrazolium (NBT). ABTS and DPPH colorimetric methods are based on the ability of antioxidants to scavenge synthetic free radicals produced in vitro, which have a different chemical structure from the natural reactive oxygen species generated in the human body. In this respect, the NBT method stands up because it is based on O 2 •scavenging which is generated in vitro by enzymatic reaction systems. The spectrophotometric assays adapted on microtiter plates allowed a rapid, inexpensive and simultaneous analysis. Larger amounts of lipophilic and hydrophilic antioxidants were obtained from strawberry fruit, which showed the lowest 50% signal inhibition concentration (IC 50) values. The fruit analyzed showed promising sources of bioactive compounds with high antioxidant properties.

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The proximate compositions, mineral contents, antioxidant capacity and bioactive compounds of 7 native Amazon fruits were chemically evaluated. The majority of the fruits showed high moisture contents (> 63.02%), and ash, total crude protein and total carbohydrate contents in the ranges of 0.22–2.07%, 0.17–2.44% and 7.17–41.71%, respectively. High levels of total lipids were found in uxi (23.25%) and monguba (18.67%). A wide range of mineral contents was detected and the highest levels were found in the samples of monguba seeds (Ca, Cu, Mg, and Zn), uxi pulp (Fe, and Mn) and pajurá pulp (Na). All the fruits showed antioxidant capacity, but the pajurá revealed the highest potential, statistically similar to that of acerola (p < 0.05). The highest vitamin C contents were found in bacuri and cupuaçu and the highest phenolic compound contents in monguba and pajurá fruits, but flavonoids were only detected in pajurá. A statistical correlation between the Na content and antioxidant capacity was also observed. Based on the results obtained, the fruits analyzed are suitable for use in the human diet, in the food and cosmetics industries as well as in pharmaceutical compositions.

The bromatological composition, mineral content, bioactive compounds, and antioxidant capacity of three native Amazon Arecaceae fruits (buriti, açaí, and inajá) were chemically evaluated. These fruits showed high moisture contents (> 55%), and levels of ash values, total crude protein, and total carbohydrates in the range of 0.68-1.28%, 0.49-2.14%, and 6.10-26.51%, respectively. High levels of total lipids were found in buriti (21.0%). A wide range of mineral content was detected and the highest levels were found in the pulps of buriti (Ca, Cu, Fe, and Mg), inajá (Na and Zn) and açaí (Mn). All three fruits showed antioxidant activity with important levels of phenolic compounds and good or rich content of vitamin C. This study provides new data on the antioxidant activity and the nutritional composition of native Amazonian fruits. Based on this study, these fruits are suitable for use in the food and cosmetics industries, as well as in pharmaceutical compositions.