Jasmin S. Yang

While the bioactivity of pulse protein hydrolysates is widely studied, the holistic impact of unit operations from flour to final powder remains unexamined. This study produced black bean hydrolysate powders using enzyme‐assisted extraction, direct steam injection (low temperature, LT: 130°C/15 s, or high temperature, HT: 145°C/4 s) and spray‐drying to evaluate their effects on bioactivity. Overall, the structural and physicochemical properties of the LT and HT samples were similar, with evidence of denaturation and aggregation through decreased intrinsic fluorescence intensity, increased surface hydrophobicity, and decreased surface charge at pH 4 compared to a non‐thermally treated, freeze‐dried control. Despite structural changes, protein solubility was similar (50%–51% at pH 4, 86%–94% at pH 7), as aggregates remained soluble in neutral conditions. Trypsin inhibitor activity was unaffected by thermal treatment (165–167 trypsin units inhibited/mg protein), but the in vitro protein digestibility of the LT (81%) and HT (83%) samples was significantly higher than the control (51%). Total phenolic content (58–63 mg GAE/g protein), antioxidant activities (ABTS/ORAC) (0.83–1.02 mg GAE/g protein), and antidiabetic activity (α‐glucosidase inhibition, 18%–19%) were mostly retained following direct steam injection and spray‐drying, but ACE‐inhibition activity decreased for HT (70% vs. 89%–93% for LT and control), signifying that antihypertensive peptides may have been degraded or irreversibly aggregated at higher processing temperatures. The results demonstrate that enzyme‐assisted extraction followed by industrially relevant thermal processing and drying is an effective method to generate bioactive black bean hydrolysate powders, supporting future commercialization of functional pulse ingredients for nutraceutical applications.

Pulses have become important feedstocks for the production of plant-based protein ingredients. While solvent-free dry fractionation technologies have been developed, wet fractionation methods (aqueous extraction) remain prevalent in the food industry as they typically yield protein isolates of superior purity. Pulse protein processing involves extraction (i.e., separation of proteins into the aqueous extraction media), recovery (i.e., isolation of the proteins from other soluble components), and drying (i.e., removal of water for improved microbial stability and subsequent food formulation). The conditions of each of these unit operations can have significant effects on protein yield and the quality of the final product due to the sensitivity of pulse proteins to pH, heat, and other processing conditions. This review aims to synthesize existing literature exploring the impacts of incumbent and novel extraction, recovery, and drying methods on pulse protein yields, functionality, and biological properties, while highlighting studies that take a more holistic approach to guide process optimization. This review also emphasizes the potential applications of pulse protein processing co-products, including the insoluble starch/fiber fraction and the whey fraction (supernatant) obtained following isoelectric precipitation, to enhance overall process sustainability and profitability from an industrial perspective.

This work explores the aqueous and enzyme-assisted extraction of black bean proteins with a focus on extraction yields, kinetics, protein functionality, and in vitro protein digestibility.

Lentil proteins are gaining popularity as food ingredients, serving both functional and nutritional purposes. To better understand the properties of lentil proteins extracted using commercially relevant methods (alkaline and enzymatic), sequential fractionation by solubility (Osborne fractionation) was performed and the physicochemical, thermal, and functional properties of the extracts were characterized. Fractionation revealed that 43% of lentil proteins were water‐soluble (ALB, albumin‐rich), 37% salt‐soluble (GLO, globulin‐rich), 14% alkaline‐soluble (GLU, glutelin‐rich), and 3% ethanol‐soluble (PRO, prolamin‐rich). Protein extraction yields of 81% and 87% were achieved by alkaline (pH 9.0, 50 °C, 1:10 solids‐to‐liquid ratio, 60 min) and enzymatic extraction (same conditions with 0.5% (w/w) Alkaline Protease), respectively. Proteomic analysis allowed for the identification of 129 proteins among all extracts, and the ALB and GLO fractions exhibited similar protein profiles as the alkaline‐extracted proteins. The secondary structure of the protein fractions was dominated by β‐sheets (20%–35%) and unordered structures (45%–48%). Surface hydrophobicity and absolute zeta potential were negatively correlated ( R ² = 0.82, p < 0.05). ALB and GLO fractions had higher denaturation temperatures than the alkaline/enzymatically‐extracted proteins, potentially due to partial denaturation. ALB and GLO fractions also had the highest solubility and emulsification capacities. Under acidic conditions, enzymatically‐extracted proteins exhibited better solubility (58 vs. 33%), emulsification (499 vs. 403 g oil/g dry sample), and similar foaming capacity (57%–69%) compared to alkaline‐extracted proteins. This study showed that alkaline and enzymatically extracted lentil proteins share physicochemical and functional characteristics with water‐ and salt‐extracted proteins, demonstrating the efficacy of these single‐stage extraction strategies in achieving high yields and desirable functionality.