Optimizing protein quality: synergies and comparisons of single and combined alternative proteins from diverse sources

The global shift towards plant-based diets underlines the critical need to thoroughly evaluate the nutritional value of alternative proteins to meet dietary requirements. To effectively assess the protein quality, it is crucial to understand its composition and digestibility. Through this study, the protein quality assessment of a panel of proteins deriving from emerging plants (i.e., legumes and cereals) and microalgae sources (n = 8) was conducted. Protein digestibility, analyzed using two different methods and expressed in three different ways, showed a high discrepancy. This suggests that relying on two quantification methods and different ways of result expression can give a broader insight into understanding the protein digestibility of alternative proteins compared to a unilateral approach. The amino acid profiles and digestibility scores of individual proteins revealed that all sources contained limiting amino acids and that none met the dietary requirements. Based on the individual amino acid scores, we conducted theoretical calculations to explore potential protein blends. The optimal blend identified contained no limiting amino acids and included pea protein isolates and corn protein concentrates as the primary components, supplemented with barley protein concentrates, Spirulina, or Nannochloropsis oceanica. These results underscore the importance of protein versatility, demonstrating that strategically blending cereals, legumes, and microalgae can significantly enhance nutritional quality.