Studies relating the consumption of food and their nutritional properties have a great contribution in the field of health. Intake of bioactive compounds, such as proteins, vitamins, minerals and other molecules present in foods can also present substances considered antinutritives or toxic, such as cyanide, polyphenols, nitrate, saponins, protease inhibitors and lectins. The tubers are rich in carbohydrates, proteins, vitamins, organic acids, anthocyanins, phytosterols, glycolipids, antioxidants, besides presenting low lipid content. Experimental analyzes of dioscorine, the main protein present in several varieties of yams (Dioscorea spp.) has been performed over the years, demonstrating several biological activities. The present study aims to isolate the protein fraction dioscorine present in tubers of Dioscorea cayennensis and to perform its phytochemical characterization by determining the presence of secondary compounds. The tubers underwent the process of separating the mucilage and obtaining the ultrafine flour, the protein extraction was performed in buffer solution: Tris HCl 0.05M pH 8.3, the total extract was submitted to protein precipitation with ammonium sulfate in the fraction 45-75% (F_45-75). The material underwent dialysis with molecular exclusion cutoff of 8 kDa, and lyophilization for sample concentration. Phytochemical determination was performed using specific techniques such as: saponins (foam-stirring test); tannins (reaction with ferric chloride/lead acetate/gelatin); carbohydrates (Molisch test); starch (iodine test); anthocyanins, anthocyanidins and flavonoids (pH variation test/heating); catechins (reaction with hydrochloric acid/heating), flavonols and xanthones (reaction with granulated magnesium/hydrochloric acid/heating). The chemical compounds identified in the total extract were: tannins, carbohydrates, saponins, flavones, flavonols and xanthones, the protein fraction did not show any phytochemical compound. Therefore, the isolated protein fraction of tubers of D. cayennensis showed no influence of secondary metabolites on their biological activities, being a target for the synthesis of natural products, considering their biotechnological and pharmaceutical importance.