Abstract

ORDONEZ, Elizabeth S; LEON-AREVALO, Aurelia; RIVERA-ROJAS, Humberto  and  VARGAS, Evil. Quantification of total polyphenols and antioxidant capacity in skins and seeds from cacao (Theobroma cacao L.), tuna (Opuntia ficus indica Mill), grape (Vitis Vinífera) and uvilla (Pourouma cecropiifolia). Scientia Agropecuaria [online]. 2019, vol.10, n.2, pp.175-183. ISSN 2077-9917.  http://dx.doi.org/10.17268/sci.agropecu.2019.02.02.

The objectives were to quantify the total polyphenols and the antioxidant capacity by inhibiting the DPPH and ABTSº+ radicals in skins/peel and seed of tuna, cocoa, grape and uvilla. The samples were dried at 60 °C/12 h and ground; an extract water/methanol (v/v) was prepared; it was macerated for 24 hours and then centrifuged at 10000 rpm/10 min/4 ºC. The results were analyzed using the completely randomized design (CRD; DCA - acronym in Spanish) and a multivariate analysis. The content of the polyphenols varied between 9.07 and 1.78 gEAG/100g. The antioxidant capacity against the DPPH free radical had the following order: grape seed, cape gooseberry skin and seed > grape skin and cacao skin > cacao hull > purple prickly pear peel > yellow prickly pear seed > yellow prickly pea r skin > yellow prickly pear peel > purple prickly pear skin > purple prickly pear seed. The correlation between total polyphenols and the antioxidant activity (DPPH) efficiency was r2 = 0.934. The greatest antioxidant capacity against the ABTSº+ free radical was found in the cape gooseberry skin and seed and the grape seed; the least was found in the yellow prickly pear peel. According to the principal component analysis, the best treatments were the cape gooseberry skin and seed and the grape seed .

Keywords : Skin; seed; polyphenols; natural antioxidants.

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