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Yeast, identified as a microorganism, boasts a considerable protein content, positioning yeast protein as a highly promising alternative in the quest for sustainable protein sources. The primary aim of this study is to evaluate the protein quality of yeast protein and compare it with animal proteins (whey concentrate/isolate proteins) and plant proteins (soy, wheat, pea proteins). Notably, yeast protein exhibits the highest ratio of indispensable/dispensable amino acids (IAAs/DAAs, 0.91). However, in both in vivo and in vitro digestion experiments, yeast protein demonstrated lower true protein digestibility (TPD) and true ileal digestibility (TID) compared to other proteins. Despite this, the yeast protein's amino acid score (AAS, 1.37 for >3 years), protein digestibility-corrected amino acid score (PDCAAS, 100 % for >3 years), and digestibility-corrected amino acid score (DIAAS, 82.42 % for >3 years) of yeast protein surpassed those of plant proteins, yet remained lower than animal proteins primarily due to its lower digestibility. [Display omitted] • The protein and amino acid digestibility were measured based on growing rats and in vitro method using the INFOGEST protocol. • The protein quality of yeast protein was compared with common dietary animal and plant proteins. • Yeast protein possessed balanced amino acid composition and low digestibility. • Yeast can serve as a candidate for balancing the amino acid profile of plant-based foods. [ABSTRACT FROM AUTHOR]

This study aimed to unravel the peptide profiles of six distinct yeast protein samples and identify novel umami peptides within them. Peptide characteristics analysis support the proposition that yeast protein peptide pools represent exceptional reservoirs of umami peptides. Nine potential umami peptides were screened using the iUmami_SCM, UMPred-FRL, Umami_YYDS, Umami-MRNN, Innovagen, Expasy-ProtParam, and ToxinPred tools. Peptides AGVEDVY, LFEQHPEYRK, AFDVQ, GPTVEEVD, NVVAGSDLR, ATNGSR, and VEVVALND (1 mg/mL) were confirmed to possess umami taste, and the first five peptides exhibited significant umami-enhancing effects on 0.35 % monosodium glutamate. Molecular docking indicated that peptide residues His, Arg, Tyr, Asp, Gln, Thr, Ser, and Glu primarily bound to His71, Ser107/109/148, Asp147/218, and Arg277 of T1R1 and Ser104/146, His145, Asp216, Tyr218, and Ala302 of T1R3 through hydrogen bonds. This study enriches the umami peptide repository for potential food additive use and establishes a theoretical foundation for exploring taste compounds in yeast proteins and their broader applications. • Peptidomics analysis of six yeast proteins was conducted using nano-LC-MS/MS. • Seven of the nine virtually screened peptides exhibited a confirmed umami taste. • AGVEDVY, LFEQHPEYRK, AFDVQ, GPTVEEVD, and NVVAGSDLR had umami-enhancing effects. • Peptide residues H, R, Y, D, Q, T, S, E are mainly bound to receptors via H-bonds. • Residues H, S, D, R, Y in T1R1/3 are particularly vital for umami taste perception. [ABSTRACT FROM AUTHOR]

• This is the first study of producing meat analogues with yeast protein. • Yeast protein can improve the fibrous structure of meat analogues. • Yeast protein makes meat analogues brighter and whiter. • The β-sheet structure content is the highest with 40 g/100 g yeast protein content. In this study, yeast and soy protein at different ratios (0:1, 1:9, 2:8, 3:7, 4:6, and 5:5) were used to produce meat analogues (MA) via high-moisture extrusion. According to color analysis, the addition of yeast protein (YP) increased the lightness of MA from 43.12 ± 0.26 (the control) to 50.37 ± 0.46 (50 g/100 g, dry basis). Textural results indicated that when the YP content was 40 g/100 g (dry basis), the hardness, chewiness, and fibrous degree of MA reached the maximum (523.94 ± 11.91 N, 724.55 ± 22.89 N, and 2.06 ± 0.15, respectively), which were higher than the control (419.63 ± 7.52 N, 618.02 ± 14.82 N, and 1.43 ± 0.03, respectively). Furthermore, YP increased the free water ratio, S S bond, and total β-sheets structure content, while reducing the β-turn structure content and thermal stability of MA. Overall, YP is a promising protein source for preparing high-quality MA. [ABSTRACT FROM AUTHOR]