Enhanced solubility of yeast protein via high-pressure homogenization-assisted limited enzymatic hydrolysis: mechanisms of structural modification and implications for functionality and nutrition.
Oct 2026· Food Research International· Vol 242 Pt 4, pp.
120065
· 0 citations· 79 references
Medicine
Abstract
Yeast protein (YP) is recognized as a sustainable and hypoallergenic microbial protein source, yet its low solubility (typically <22%) severely restricts its utilization in food formulations. Improving solubility is therefore a key step toward broader industrial application of YP. This study investigated a synergistic treatment combining high-pressure homogenization and restriction enzymatic hydrolysis (HPH-neu) to improve the solubility of yeast protein (YP). The HPH-neu treatment significantly enhanced solubility to 81.58 ± 0.29%. In contrast, the individual application of either high-pressure homogenization (HPH) or restriction enzymatic hydrolysis (neu) was less effective in improving solubility than the combined approach. Structural analysis indicated that HPH-neu processing notably increased the contents of α-helix and random coil, and scanning electron microscopy (SEM) revealed a corresponding looser and more disordered microstructure. Furthermore, the combined treatment significantly reduced particle size (242.8 ± 5.59 nm), free sulfhydryl group content (2.20 ± 0.01 μ mol/g), and surface hydrophobicity (H0, 14123.67 ± 257.85).At the same time, it improved functional properties including the emulsifying activity index (40.51 ± 2.86 m2/g), foaming capacity (146.67 ± 2.89%), and in vitro digestibility (90.64 ± 0.33%). The HPH-neu process also yielded high scores for PDCAAS and SRC, reaching 65.96 and 73.11, respectively. In summary, the integrated HPH-neu strategy not only effectively enhanced the solubility of YP but also improved its multifaceted functional properties and digestibility. This strategy offers a promising route for protein valorization and the development of high-quality, nutritious protein ingredients.
Limited redispersibility constrains commercial yeast-protein ingredients. This study compared preparation efficiency, structure, and function of yeast protein prepared by alkaline extraction-acid precipitation (ASAP) and high-pressure homogenization-assisted pH shift (HPHS). ASAP achieved higher product yield (69.23% ± 1.42%) and protein recovery (57.81% ± 2.42%) than HPHS. ASAP-YP exhibited dense sheet-like morphology, higher β-turn content (55.71%), and preserved reactive groups, whereas HPHS-YP formed porous aggregates with higher α-helix content and lower sulfhydryl availability. Under tested conditions, ASAP-YP showed higher solubility (pH 3-13), water absorption (17.99 ± 0.62 g/g), oil absorption (7.98 ± 0.12 g/g), emulsifying activity (59.88 ± 2.58 m2/g), and foaming capacity (124.00% ± 2.00%). Multivariate analysis indicated β-turn content, surface hydrophobicity, and reactive-group content were positively associated with selected functional properties. These findings support ASAP as a promising route, while validation across additional raw materials remains necessary.
Lin Li, Xiaoyu Ma, Dan Huang et al.· Food Chemistry· 0 citations
Mycoprotein, with a balanced amino acid profile and potential benefits for muscle maintenance, is a promising protein source for elderly-friendly high-protein foods. Yet, rigid fungal cell walls and entangled hyphal networks enclosing intracellular proteins may restrict enzymatic accessibility under elderly digestive conditions. In this study, high-pressure homogenization (HPH) was applied as a food-grade structural regulation strategy to improve the digestive adaptability of mycoprotein. Native mycoprotein (MYC), HPH-treated mycoprotein (HMYC), pork (PORK), and commercial plant-based meat (PLANT) were evaluated using a static in vitro oral-gastric-intestinal digestion model simulating elderly physiological conditions. Structural disintegration, hydrolysis behavior, free amino acid release, multiple light scattering, and microrheological properties were analyzed to elucidate digestive adaptation mechanisms. HPH markedly disrupted the cell-wall-associated and hypha-entangled structure of mycoprotein without significantly altering its major nutrient composition, thereby improving enzyme accessibility and digestion-induced disintegration. During gastric and intestinal digestion, the particle size D[4,3] of HMYC decreased by over 80%, indicating enhanced structural breakdown efficiency. HMYC exhibited a significantly higher hydrolysis degree than MYC, while its free amino acid release approached that of PORK and exceeded those of both MYC and PLANT. Multiple light scattering revealed improved enzyme-substrate interaction and greater physical structural transformation after HPH treatment. Microrheological analysis further confirmed improved restructuring behavior and reduced structural resistance during digestion. Overall, HPH effectively improved the digestive adaptability of mycoprotein under elderly digestive conditions, making its digestive behavior closer to that of PORK, while the distinct digestion behavior of PLANT was mainly associated with matrix effects from added lipids and hydrocolloids, supporting the development of elderly-friendly mycoprotein-based foods.
Yifei Gao, Chengpu Chen, Dan Yang et al.· Food & Function· 0 citations
The textural properties of food colloidal systems are highly dependent on the gelling characteristics of animal-derived proteins (such as egg protein, EP) and polysaccharides (such as starch, pectin, and gums). The development of plant-based protein alternatives faces challenges such as insufficient gel strength and poor structural stability. This study focused on purified Chlorella protein extract (PCPE). To address the insufficient gel performance of PCPE, a synergistic optimization strategy of "modification combined with calcium ion regulation" was proposed. Results revealed that alkali treatment strengthened ionic interactions while weakening hydrogen bonds and hydrophobic interactions, promoting protein molecular rearrangement and resulting in a narrower and more concentrated particle-size distribution. This increased the initial storage modulus to 136 Pa, comparable to that of EP. TGase treatment catalyzed protein-protein and protein-polysaccharide covalent cross-linking, forming a dense network structure and significantly increasing gel hardness to approximately 1.5 times that of EP. Furthermore, the addition of calcium ions synergistically enhanced gel strength via salt bridge formation, further elevating the initial storage modulus to 297 Pa. However, a high calcium concentration (25 mM) led to an approximately 20% reduction in water-holding capacity for TGase-treated PCPE gels. This study elucidates the multidimensional regulatory mechanisms underlying enhanced plant-protein gelation and provides a strategy for developing sustainable plant-based gelled foods.
Hao Chen, Qun Gao, Ruoyu Wu et al.· International Journal of Bio...· 0 citations
Pea protein offers valuable nutritional and environmental advantages, yet its application in food emulsions is hindered by poor solubility and emulsifying capacity—a consequence of its inherently aggregated and rigid structure. To address this limitation, the present study developed a dual modification strategy combining controlled enzymatic hydrolysis (DH 3%) with heat assisted pH shifting. PPI was first hydrolyzed with either trypsin or pepsin, then subjected to pH 3 or pH 9 at 70°C. Trypsin hydrolysis proved markedly more effective than pepsin treatment, generating fragments with enhanced surface hydrophobicity, reduced aggregate size (~280 nm), and improved solubility, dispersibility, and emulsifying performance—benefits attributable to the stringent cleavage specificity of trypsin for lysine and arginine residues. Subsequent alkaline pH shifting (pH 9) with heating further exploited electrostatic repulsion to dissociate the aggregates to ~160 nm, yielding additional functional gains. In contrast, acidic pH shifting (pH 3) under the same heating conditions promoted extensive protein reaggregation and conferred no functional benefit. The optimally modified PPI—obtained by combining trypsin hydrolysis with alkaline pH shifting—enabled formulation of submicron sized oil in water emulsions (D_4,3=0.607±0.001 μm). These emulsions withstood 30 days of storage (D_4,3=0.837±0.003 μm) and heating at 95°C for 60 min (D_4,3=1.18±0.05 μm) with only modest droplet size increases, demonstrating notable stability. This work establishes that the synergy between enzymatic digestion and alkaline pH shifting effectively dissociates protein aggregates while avoiding the generation of excessively small peptides that would compromise emulsion stability. The dual strategy thus transforms pea protein into an efficient molecular emulsifier, offering a promising route for developing advanced plant based ingredients.
Kai Zhang, Yue Ding, Xinshuai Zhang et al.· Chiang Mai Journal of Scienc...· 0 citations
Pea protein is increasingly used in food formulations due to its nutritional value and sustainability. However, its limited solubility, weak interfacial properties, and undesirable off-flavors remain major constraints for broader application. In this study, pea protein isolate (PPI) was subjected to multi-stage high-pressure homogenization (HPH) at pressures ranging from 100/1000 psi to 500/5000 psi with various pass numbers (1, 2, and 3) to examine how processing intensity affects its structural, functional, and volatile properties. SDS-PAGE showed no detectable changes in molecular weight distribution, whereas FTIR, particle size distribution, and zeta potential analyses collectively indicated that HPH induced subtle physicochemical modifications in PPI. These modifications improved functional properties, particularly solubility, which increased from 83.18% in the untreated sample to 88.14% under optimized conditions. Enhancements in foaming capacity and emulsifying activity were also observed, most prominently at 500/5000 psi, although excessive processing resulted in a slight decline in foaming performance. In contrast, emulsifying stability remained largely unchanged across conditions. Furthermore, GC-MS was used to evaluate the changes in the volatile profile of PPI after HPH treatment. Seven major compounds dominated by lipid oxidation products were identified. Their relative abundances varied with homogenization conditions with pressure exerting a more pronounced influence than pass number. Overall, HPH effectively tailored the properties of PPI by reducing particle size, improving solubility and interfacial properties, and altering its volatile profile, although at higher homogenization pressures the potential trade-off between functionality and oxidative flavor stability needs to be considered.
Muxin Zhao, Jiajia Rao, Bingcan Chen· International Journal of Bio...· 0 citations
Antibiotic resistance of Staphylococcus aureus threatens public health. Plant by-product protein hydrolysates contain antibacterial peptides as antibiotic alternatives, but compact native protein structures restrict hydrolysis efficiency and antibacterial fragment release. This study applied high hydrostatic pressure (HHP) to assist papain hydrolysis of chili pepper seed protein (PSP) to improve hydrolysis efficiency and antibacterial activity. Pressurisation (100–500 MPa) enhanced PSP hydrolysis degree by 4.48–28.84%. Hydrolysis at 100 MPa gave rise to hydrolysate optimal antibacterial activity with 18.90% and 10.25% higher inhibition rates and zones. Structural and physicochemical analysis indicated that hydrolysis at 100 MPa increased the α-helix content by 23.15%, surface hydrophobicity by 20.50%, < 3 kDa peptides by 284.07%, and improved solubility and dispersion. These variations strengthen hydrolysate capacity on membrane binding and disruption, and form a favorable antibacterial microenvironment. These results provide an effective strategy to optimize enzymatic hydrolysis and high-value utilization of chili pepper seeds.
Sidi Liu, Yue Han, Yiyi He et al.· Food Chemistry: X· 0 citations