Impact of encapsulants and drying methods on in-vitro protein digestibility of koro bean (Canavalia ensiformis) tempeh protein hydrolysates

Tempeh, a traditional plant-based fermented food, is prone to nutrient degradation during storage, particularly protein loss, which affects its digestibility and bioavailability. While fermentation and hydrolysis can enhance protein absorption, practical strategies to maintain the structural integrity of tempeh protein hydrolysates are still underexplored. This study investigated the impact of spray-drying (SD) and freeze-drying (FD) on encapsulating koro bean (Canavalia ensiformis) tempeh (KBT) protein hydrolysates using maltodextrin (MD), gum Arabic (GA), whey protein concentrate (WPC), and their combinations. The GA-FD treatment yielded the highest protein content (11.15% dry basis), exceptional in-vitro digestibility (99.15%), and encapsulation efficiency (95.79%). Analyses such as Fourier-transform infrared spectroscopy (FTIR) and SDS-PAGE confirmed the preservation of vital amide bonds and peptides, indicating minimal denaturation and improved enzymatic accessibility, which enhances protein bioavailability. GA’s ability to form a stable, hydrophilic matrix during freeze-drying was key in maintaining protein solubility and integrity. These findings highlight the importance of selecting suitable encapsulants and low-temperature drying methods to create high-quality, protein-rich ingredients. This research paves the way for innovative applications in nutrient-fortified food formulations, enhancing dietary options and health outcomes.