PLANT-BASED BEAN PROTEIN INGREDIENTS: AMINO ACID PROFILE AND IN VITRO DIGESTIBILITY

The global demand for healthier diets and the replacement of animal proteins with plant-based alternatives has increased substantially. However, this trend also raises concerns regarding the nutritional quality of plant protein sources. Therefore, this study aimed to evaluate the amino acid profile and in vitro protein digestibility of selected plant protein sources. The samples comprised two protein flours obtained from carioca beans by dry fractionation, BPF1 (51.32% protein) and BPF2 (35.83% protein), as well as a commercial rice protein concentrate (RPC, 80.40% protein) and a sunflower protein concentrate (SPC, 57.73% protein). Protein digestibility was additionally assessed for two binary blends: BPRP (60% BPF2 and 40% RPC; 50.37% protein) and BPSP (40% BPF2 and 60% SPC; 47.38% protein). The amino acid profile was determined by reverse-phase HPLC after pre-column derivatization. In vitro gastrointestinal digestion was performed according to the INFOGEST 2.0 protocol, and protein digestibility was calculated from the protein content determined by the Kjeldahl method after digestion. Amino acid profile analysis demonstrated that samples BPF1 and BPF2 presented amino acid scores (AAS) higher than 1.0 for all quantified essential amino acids, with the lowest AAS value observed for the Met+Cys pair (1.3), indicating an adequate amino acid composition according to FAO recommendations for adults. In contrast, lysine was identified as the limiting amino acid in RPC (AAS = 0.7) and SPC (AAS = 0.9). The combination of BPF2 with RPC or SPC has the potential to improve amino acid balance through the complementary contribution of sulfur-containing amino acids and lysine. Regarding protein digestibility, BPF1 (66.75%), BPF2 (63.41%), SPC (62.33%), and the BPSP blend (60.79%) showed the highest digestibility values, which are comparable to those reported for plant protein ingredients. Conversely, RPC (34.54%) and the BPRP blend (41.57%) presented lower digestibility, which may be associated with antinutritional compounds, limited protein solubility, and intrinsic characteristics of the food matrix. Overall, BPF1, BPF2, and SPC demonstrated suitable nutritional quality and higher protein digestibility, highlighting their potential as ingredients for nutritionally balanced plant-based food formulations. 
Acknowledgements: FAPESP 2020/07015-7; 2022/11541-1 ; 2024/02262-7; and 2024/13419-4.