CHEMOMETRIC STRATEGY FOR OPTIMIZATION OF AN ACID DECOMPOSITION METHOD TO DETERMINE THE MINERAL COMPOSITION IN ALMOND PULP (Terminalia catappa Linn.)

Abstract

In this work, multivariate optimization techniques were applied to develop an acid digestion procedure in digester block using “cold finger” as reflux system to determine minerals in almond pulp samples by inductively coupled plasma optical emission spectrometry. Two-level full factorial design and Box-Behnken design were applied to evaluate and optimize the factors involved in the acid digestion process. In both experimental designs, Function D and Function MR multiple responses were used to establish the method condition for all analytes and with greater digestion efficiency. Two apple and spinach leaves certified reference materials were analyzed to confirm the proposed method accuracy. The digestion efficiency was evaluated by residual carbon content which showed 1.32-1.77% range. The concentration values found for each element in almond pulp collected in Salvador, Bahia, Brazil in mg 100 g-1 were: 3.08 (Ca), 0.209 (Cu), 0.407 (Fe), 356 (K), 21.5 (Mg), 0.096 (Mn), 34.4 (P) and 0.289 (Zn). The developed method was simple and efficient for almond pulp mineral composition evaluation. This unconventional fruit has nutritional relevance with future application for new food recipes and pharmaceutical products formulation.