This study explores the extraction and application of Pithecellobium dulce seed protein isolate (PSPI) in chocolate compound coating formulations. PSPI was extracted via ultrasonication-assisted isoelectric precipitation under optimized conditions (solute-to-solvent ratio 1:30, pH 12, 10 min), yielding 23.64% with 38.28% recovery. PSPI exhibited high protein content (75.3%), low water activity (0.22), near-neutral pH (6.94), and favourable techno-functional properties, including high water (3.27 g/g) and oil holding capacities (4.81 g/g), improved solubility (↑21.3%), and superior thermal stability compared to skim milk powder (SMP). While in vitro digestibility was slightly lower than SMP (88.52% vs. 92.42%), PSPI outperformed other reported plant protein isolates such as Prosopis africana , conophor nut, and Moringa oleifera . PSPI was partially substituted for SMP in chocolate compound coatings. Among the formulations, PSPIC-2 (20% PSPI substitution) demonstrated the best balance of physicochemical, nutritional, rheological, and sensory properties, showing increased protein and ash content, reduced carbohydrates, higher TSS (↑0.9%) and Casson yield stress (↑4%), with only minor reductions in colour (↓7.9%) and pH (↓3.9%). Sensory analysis confirmed that taste and texture were comparable to the control. These findings support the use of PSPI as a sustainable, plant-based ingredient in functional chocolate compound coatings. • Developed protein-rich chocolate by replacing 10–50% skim milk powder (SMP) with P. dulce protein. • Optimised extraction gave 23.64% protein isolate with 75.3% protein and improved functionality. • Optimised chocolate had high sensory acceptability and matched the control in key quality parameters. • Enhanced emulsifying, solubility, and water-holding capacities improved the nutritional profile. • Chocolate met microbial safety standards and provided a sustainable alternative to SMP.
Fathima et al. (Sun,) studied this question.