Most proteins for human consumption are animal-derivated sources; however, due to its environmental impact (soil erosion, gas emissions, water footprint) and increasing demand, different plant-based sources are necessary. The purpose of this work is to use amaranth crop biomass for protein concentrates production. The effect of processing (extraction and drying) on the structure and some functional properties of biomass protein concentrates are evaluated for food applications. Thermal and acid precipitation was used for extraction of soluble proteins and lyophilization, vacuum convection, and spray-drying methods for protein concentrates production. Protein structure analyses were gel electrophoresis (SDS-PAGE), isoelectric point (zeta potential), spectrometry (FTIR), calorimetry (DSC), and amino acids profile. The functionality was evaluated by solubility (UV-VIS), rheological and emulsifying properties at different pH values. The most preserved protein structure was the precipitated by acidification and dried by spraying, which showed the highest solubility values (> 90 %), and desired rheological properties. Lyophilization enhanced the emulsifying activity (~95 %) and stability to gravity (~63 %) and heat (~79 %). The essential amino acids content (49 %) was higher than FAO recommendations for children (36 %), and protein composition was in agreement with the Codex Alimentarius for plant protein consumption. This research approaches the use of highly available biomass from amaranth crop as a sustainable source of proteins. Mostly protein isolation uses expensive technologies, which increases the final product cost. Herein, a simple method was adequate to obtain high nutritional quality, and food functionality protein concentrates for food-related applications.