Variabilities of Tetrapleura tetraptera (Schumach & Thonn.) taub. and Aframomum citratum (C. Pereira) K.Schum from three Agro-ecologic zones in Cameroon and effect of extraction methods on the phenolic compounds recovery

Abstract

The fruits of Tetrapleura tetraptera and Aframomum citratum were identified among the most commonly used and available spices in Cameroonian cities. They are mainly collected in the bimodal forest (Zone V), unimodal forest (Zone IV) and the highlands (Zone III)2 zones. They are part of the traditional pharmacopeia in Central and West African countries. The aim of this study was to characterize fruit samples harvested on the three agroecological zones (AEZ) and to examine few traditional extraction methods for the phenolic compounds recovery in a domestic food consumption situation. Tetrapleura tetraptera fruits were harvested in twelve villages spread over three AEZ (Zones V, IV, III) and Aframomum citratum fruits were selected in nine villages spread over two AEZ (Zones V, IV). Various analysis (dry matter, ash,total fat, crude proteins, total sugars, crude fibre contents; energy, water activity and pH; Fe, Ca, Mg and K contents; total polyphenols and flavonoids contents) using standard analytical, colorimetric, spectroscopy and spectrophotometric procedures were used. For both extraction methods investigated (Maceration, infusion, decoction), an extraction ratio of 1/5 was used. Statistical analysis and Principal Component Analysis (PCA) were performed. The results showed that concerning Tetrapleura tetraptera samples, crude fibre content is significantly (p<0.05) high on samples from Zones IV and III while samples from Zone V possess more sugars, calories, minerals and phenolic compounds. About Aframomum citratum, samples from Zone IV are the most sweet and the ones from Zone V contain more protein, fibre, phenolic and minerals (especially samples from the East region) contents. For both species, decoction was the most efficiency extraction method. The result gives a graphic representation of the studied characteristics which can serve as a decision-making tool (for sampling) to guide the various stakeholders involved in the valuation and exploitation of these fruits