From bean to batter: Enzymatic tailoring of faba bean protein for improved pound cakes

The poor solubility, emulsification, and gelling properties of faba bean protein isolate (FPI) limit its use as an egg replacement. This study enhanced FPI functionality through enzymatic modification using transglutaminase (TG) and Alcalase (AC), evaluating their performance in a pound cake model system. FPI dispersions were treated with TG (1–10 U/g protein) or AC (0.1–1.0 U/g protein) under optimised conditions and lyophilised. Morphology, structure, and degree of hydrolysis were analysed via SEM, SDS-PAGE, and free amino acid profiling. Functional properties including solubility, foaming, emulsifying stability, water/oil-holding capacity, and gelation were correlated with cake quality parameters. AC treatments markedly improved solubility (up to 61.58%) and foam capacity (108.84%), with ACH showing the highest DH (9.00%) but near-complete loss of gelation (G' < 1.5 Pa). TG induced protein crosslinking, enhancing gelation (G' up to 6693 Pa for TGL), although solubility decreased substantially (3.93–5.48%). WHC and OHC were highest in heat-treated blanks, reflecting heat-induced denaturation and freeze-drying effects on protein microstructure. TGH (10 U/g protein) achieved the highest specific volume among FPI-derived samples (1.80 ± 0.02 mL/g) and ACL (0.1 U/g protein) produced the softest crumb (hardness: 10.16 ± 0.52 N) and lowest separation rate (1.75 ± 0.21%/min), though none reached the CEP control (2.33 ± 0.03 mL/g). Emulsifying stability and gelation emerged as key determinants of cake quality. Enzymatic modification can selectively enhance FPI functional traits, though balancing enzyme type and concentration remains essential for optimal performance in complex food systems.