High-pressure Homogenization Treatment Research Articles

Effects of High-Pressure Homogenization on the Structure and Functional Properties of Solenaia oleivora Proteins.

Solenaia oleivora, a rare freshwater shellfish with high protein quality, is unique to China. However, the poor hydrosolubility and functional properties of Solenaia oleivora proteins hinder their utilization in food products. Herein, the alkaline dissolution-isoelectric precipitation method was used for the extraction of Solenaia oleivora proteins. Furthermore, the impact of high-pressure homogenization (HPH) treatment varying from 0 to 100 MPa on the structure and functional properties of Solenaia oleivora proteins was investigated. The obtained results indicated that HPH treatment decreased the α-helix content and enhanced the β-sheet and random coil content. Furthermore, the HPH caused the unfolding of protein structure, exposing aromatic amino acids, increasing the free thiol group content, and enhancing surface hydrophobicity. As the homogenization pressure increased from 0 to 100 MPa, the particle size of Solenaia oleivora proteins decreased from 899 to 197 nm with the polymer dispersity index (PDI) value decreased from 0.418 to 0.151, the ζ-potential increased from -22.82 to -43.26 mV, and the solubility increased from 9.54% to 89.96%. Owing to the significant changes in protein structure and solubility, the emulsifying, foaming, and digestive properties of Solenaia oleivora proteins have been significantly improved after treatment with HPH.

Exploring the emulsifying properties of biopolymers from Ulva lactuca in stabilizing high internal phase emulsions

Seaweed is a promising raw material for food emulsion stabilizers due to its abundance, low cost, and rich content of various natural biological macromolecules. This study explores the potential of using Ulva lactuca (UL) to stabilize emulsions by employing high-pressure homogenization (HPH) to release its interfacial active components. The results demonstrate that UL extract (ULE) with emulsifying activity was gradually extracted as the HPH pressure increased from 100 to 800 MPa. Concentrating the macromolecular components, specifically polysaccharides and proteins, in the ULE via membrane filtration resulted in a concentrated fraction, referred to as ULER, which exhibited enhanced emulsification performance. By optimizing the oil volume fraction (φ) and pH, it was found that high internal phase emulsions (φ = 0.7–0.8) showed superior viscoelasticity and stability at pH 3–7. In terms of stability, it was observed that the emulsions stabilized by ULER maintained their structure over extended periods without significant phase separation. The strong interaction between exogenous Ca2⁺ and ULER increased the apparent viscosity and viscoelasticity of the emulsion. However, the addition of Ca2⁺ did not significantly enhance the stability of the ULER-stabilized emulsions and, in some cases, even led to a decrease in emulsion stability. This effect may be probably due to the specific interactions between the Ca2⁺ ions and the polysaccharides and proteins in the ULER, which can affect the network structure of the emulsion. Overall, this study highlights the potential of HPH treatment in processing UL to transform it into an effective emulsion stabilizer for applications in the food industry.

Molecular motion behaviors of starch affect starch-polyphenol inclusion complex and digestibility among different stilbenes polyphenol structures

Starch-polyphenol V-type inclusion complex has become a hot topic due to its anti-digestibility and nutritional function. This paper aimed to explore the molecular motion behavior of starch affects starch-polyphenol inclusion complex and digestibility among different stilbene polyphenol structures (resveratrol (RA), pterostilbene (PB) and polydatin (PD) via the high-pressure homogenization (HPH) and heat moisture treatment (HMT) processes), which represented the fully extended and limited molecular motion behavior of starch, respectively. These results revealed distinct trends in complex formation among different stilbenes polyphenol structures, highlighting RA as particularly conducive to increasing single helix and V-type crystalline structures with the highest resistant starch (RS) content of 28.11 % due to its smaller steric hindrance. Novelty, in HPH environments with extended molecular motion behavior, the steric hindrance and hydrophobicity/CH-π interactions of polyphenols influence complex formation in the order of RA > PB > PD. Conversely, in HMT systems with limited molecular motion behavior, the limited movement of molecules emphasized the importance of hydrogen bond interactions between polyphenols and starch. Thus, the glucoside in PD enhanced its interaction with starch compared to methoxy-modified PB, leading to increased formation of inclusion complex with RS content of 18.61 %. Overall, these findings deepen the understanding of starch-polyphenol interactions.

Tailoring pea proteins gelling properties by high-pressure homogenization for the formulation of a model spreadable plant-based product

This study investigated the impact of high-pressure homogenization (HPH) at varying intensities on the gelling properties of a commercial pea protein concentrate for the formulation of emulsion-filled gels as a model spreadable plant-based product. As a preliminary characterization, pea protein dispersions (10%-15%–20% w/w) underwent HPH treatments, 60 and 150 MPa for 5 cycles. Mechanical characteristics of heat-set gels were evaluated through rheological measurements. Emulsion-filled gels were then produced, starting from a common primary emulsion, incorporating either native or treated pea protein suspensions, and characterized with frequency and amplitude sweep tests, back extrusion, texture profile analysis (TPA) and confocal laser scanning microscopy (CLSM). Results revealed that HPH treatments had a significant influence on the aggregation state of protein suspensions reducing residue size, but inducing the formation of new, albeit smaller, agglomerates, with a direct impact on gel network formation. Treatment at 150 MPa consistently produced a stiffer, compact, and elastic gel structure, as confirmed by frequency sweep, back extrusion and TPA tests. Additionally, when this structure was disrupted, it exhibited creamy-viscous characteristics, as verified by amplitude sweep analyses. CLSM micrographs showed the formation of a more structured and compact gel matrix with the increase of the pressure applied.

A natural protein-lipid co-assembly as efficient Pickering emulsifier from egg yolk sphere microgel prepared via high-pressure homogenization

Egg yolk sphere is a kind of natural colloidal histological structure formed by the co-assembly of a large number of proteins and lipids, which has the dual functions of hydrophilic and lipophilic for application in emulsion. In this study, egg yolk sphere microgels (EYSMs) were prepared by high pressure homogenization (HPH) technique at various pressures (0–90 MPa) and used as Pickering emulsifiers for emulsification to obtain oil-in-water emulsions with an oil-water ratio of 11:9. The microscopic morphology, structure, and physicochemical properties of EYSMs were analyzed. The results showed that EYSMs obtained at 60 MPa (60-EYSMs) exhibited superior emulsifying properties with an emulsifying activity index (EAI) of 2.8 m2/g and an emulsifying stability index (ESI) of 356.6 min, resulting in enhanced storage stability of the emulsion for 30 d. The HPH treatment decreased the lipid content in EYSMs while creating a more homogeneous protein-lipid arrangement, which provided EYSMs with balanced hydrophilic and hydrophobic sites to improve emulsifying properties. Furthermore, the free sulfhydryl groups and hydrophobic moieties exposed by HPH promoted -S-S- formation on the EYSMs surface, promoting the increase in surface hydrophobicity and emulsifying ability. The confocal laser scanning microscopy (CLSM) and cryogenic scanning electron microscopy (cryo-SEM) revealed that the EYSMs adsorbed at oil-water interface and formed an intercross-linked spatial three-dimensional network structure, which worked as a physical barrier to the stable emulsion formation. This study introduces a novel research concept and delves into the emulsification mechanism of protein-lipid composite particles, offering a fresh insight for the development and utilization of emulsifiers.

Soluble hemp protein-xylose conjugates fabricated by high-pressure homogenization and pH-shifting treatments.

The process of Maillard conjugation occurs with plant proteins and sugars and can be influenced by several factors, such as processing time, pH, and shear force. By utilizing cavitation processes such as high-pressure homogenization (HPH) and pH-shifting, it is possible to regulate the degree of grafting, functional characteristics, and structural changes in the formation of conjugates. The present study aimed to improve the hemp protein concentrate (HPC) through two different conjugation techniques: HPH and pH-shifting-assisted processes. The best conjugation conditions for the conventional method were identified as a 1:2 HPC to xylose ratio, a pH of 10, and 3 h of treatment at 70 °C. The use of HPH and pH 12-shifting methods resulted in a remarkable 2.5-fold increase in grafting degree, requiring less processing time. Fourier transform infrared spectra confirmed the formation of conjugates. Conjugates produced through HPH with pH 12-shifting (MPHX) transformed into soluble glycoproteins with a particle size of 74 nm. MPHX solubility increased by 5.7-fold than HPC, reaching 85.7%, with a more negatively charged surface at -32.4 mV. Microimages showed cracked and sharp forms for conjugated proteins compared to untreated HPC. Additionally, MPHX conjugates demonstrated superior properties in emulsion stability, foaming capacity, and antioxidant activity compared to HPC and classical conjugates. The use of HPH and pH-shifting-assisted Maillard conjugation was highly effective in enhancing the functional attributes of hemp protein conjugates. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Set yogurt incorporated with insoluble dietary fiber maintains non-sedimentation: Combined alkaline hydrogen peroxide modification and high-pressure homogenization process

Insoluble dietary fiber (IDF) settles in set yogurt due to its water insolubility. Making IDF non-settling in set yogurt without thickeners is the current objective. This study attempted to modify IDF with alkaline hydrogen peroxide (AHP) and combine it with a high-pressure homogenization (HPH) process to resolve the settling of IDF in set yogurt. The results showed that AHP-treated IDF (IDF-AHP) altered the structure of IDF, enhanced hydration properties, and had no hydrogen peroxide residue. Set yogurt incorporated with 1, 3, and 5% (w/w) IDF-AHP underwent a HPH process, resulting in non-settling IDF-AHP. The water retention, firmness, and cohesion of yogurt were improved, and the storage modulus (G′) increased during 28-day refrigeration. and the casein gel properties were improved. These results show that combining AHP with HPH treatment prevented the settling of IDF in yogurt and improved its texture. Further studies revealed that AHP and HPH were necessary to prevent IDF from settling in yogurt. This study confirms the applicability of the method and provides new ideas for the commercial production of IDF yogurt.

Application of high-pressure homogenization-assisted pH-shift to enhance techno-functional and interfacial properties of lentil protein isolate

High-pressure homogenization (HPH) is a promising physical non-thermal approach to improve protein techno-functionality. This study aims to examine the effects of HPH on the lentil proteins through the perspective of the interfacial adsorption mechanism. The impact of HPH treatment on lentil protein isolate (LPI) at varying pressure levels (0–150 MPa) was determined using several analytical techniques, including SDS-PAGE, FTIR, solubility, and techno-functional properties (foaming and emulsifying properties), alongside analyses of interfacial tension and interfacial shear rheology at the o/w and a/w interfaces for two pH values (2.0 and 4.5). Results reveal that HPH treatment up to 100 MPa effectively unfolds lentil proteins by disrupting disulfide-bonded subunits into lower molecular weight fractions and unfolding highly-ordered secondary structures into random coils. LPI's capacity to produce emulsions and foams was found to be enhanced concurrently with these physicochemical changes, particularly at pressures up to 50 MPa. The findings aligned with the interfacial tension and shear rheology analyses, which show that proteins can form interfacial viscoelastic films on both o/w and a/w interfaces. Furthermore, the interfacial behavior of LPI and the effect of HPH on the interfacial behavior were found to be pH-dependent. The lower interfacial tension and the higher interfacial viscoelastic moduli (G′ and G″) were recorded at 50 MPa and 0 MPa at pH 2.0 and 4.5, respectively. These results stated that the effects of the HPH on the technofunctionality of LPI can be further enlightened by investigating the interfacial adsorption kinetics.

Advancing soy protein isolate-ulvan film physicochemical properties and antioxidant activities through strategic high-pressure homogenization technique

Soy protein-based films often exhibit poor properties, including limited mechanical strength, stability, and bioactivity, which hinder their extensive application in the food industry, particularly in edible packaging. To enhance the properties of soy protein-based films, we employed high-pressure homogenization (HPH) to modify the soybean protein isolate (SPI) molecules and sought to cross-link SPI with ulvan polysaccharide, which possesses distinctive bioactivities. The results confirmed that soluble ulvan polysaccharides were incorporated into the cross-linking system through hydrogen bonding. Results indicated that HPH treatment enhanced SPI's solubility and surface hydrophobicity (H0), promoting hydrogen bonding and hydrophobic interactions between SPI and ulvan, as evidenced by ζ-potential and turbidity measurements. Structural and microstructural analyses of both individual SPI and composite films, using FT-IR, XRD, CD and SEM, demonstrated a high compatibility between HPH-treated SPI and ulvan. The incorporation of ulvan reduced the films' tensile strength (TS), but higher pressure significantly improved it (p < 0.05). Post-HPH modification, the films exhibited increased contact angle and swelling capacity (p < 0.05), indicating enhanced hydrophobicity. Higher pressure treatments resulted in more opaque and yellowish films, thereby diminishing ultraviolet light transmission. Thermal stability analyses, via TGA-DSC, showed that U-HSPI films had improved thermal stability compared to pure SPI films. Moreover, ulvan inclusion boosted the antioxidant capacity of SPI films, especially after HPH treatment. Overall, this study confirms that HPH modification substantially influences the properties and activities of SPI-based films, and the complex films based on SPI and ulvan with improved physicochemical and antioxidant properties exhibit a great potential in the food packaging field.

Enhancing Cutin Extraction Efficiency from Industrially Derived Tomato Processing Residues by High-Pressure Homogenization.

This study primarily aimed to enhance the extraction of cutin from industrial tomato peel residues. Initially, the conventional extraction process was optimized using response surface methodology (RSM). Subsequently, high-pressure homogenization (HPH) was introduced to improve extraction efficiency and sustainability. The optimization process focused on determining the optimal conditions for conventional extraction via chemical hydrolysis, including temperature (100-130 °C), time (15-120 min), and NaOH concentration (1-3%). The optimized conditions, determined as 130 °C, 120 min, and 3% NaOH solution, yielded a maximum cutin extraction of 32.5%. Furthermore, the results indicated that applying HPH pre-treatment to tomato peels before alkaline hydrolysis significantly increased the cutin extraction yield, reaching 46.1%. This represents an approximately 42% increase compared to the conventional process. Importantly, HPH pre-treatment enabled cutin extraction under milder conditions using a 2% NaOH solution, reducing NaOH usage by 33%, while still achieving a substantial cutin yield of 45.6%. FT-IR analysis confirmed that cutin obtained via both conventional and HPH-assisted extraction exhibited similar chemical structures, indicating that the main chemical groups and structure of cutin remained unaltered by HPH treatment. Furthermore, cutin extracts from both conventional and HPH-assisted extraction demonstrated thermal stability up to approximately 200 °C, with less than 5% weight loss according to TGA analysis. These findings underscore the potential of HPH technology to significantly enhance cutin extraction yield from tomato peel residues while utilizing milder chemical hydrolysis conditions, thereby promoting a more sustainable and efficient cutin extraction process.

Insight into the mechanism of synergy of ultrasound and high pressure homogenization on the emulsion stability and interfacial behaviors of α-lactalbumin with mogroside V

Due to uneven distribution amino acid residues of α-lactalbumin (αLA) at oil-water interface, some measurement should be adopted to improve its interfacial behavior and emulsion stability. Therefore, this study focused on the mechanism of synergy of ultrasound and high pressure homogenization on the emulsion stability and interfacial behaviors of α-lactalbumin with mogroside V (MGV). Four treatments were adopted: ultrasound (US), high pressure homogenization (HPH) and combined treatment (US-HPH and HPH-US). Primarily, emulsion stability of αLA/MGV was analyzed. US-HPH or HPH-US exhibited better emulsion stability than US or HPH. Especially, HPH-US-αLA/MGV emulsion was not stratified at the given time (45 d), which was the most stable emulsion. Moreover, the micromorphology of emulsion showed that MGV and UH/HPH treatment suppressed the aggregation of αLA emulsion droplet. In addition, interfacial adsorption mass and viscoelasticity of physical treated αLA was improved with MGV in the order of HPH-US > US-HPH > US > HPH, specifically, frequency shift (ΔF) and dissipation shift (ΔD) of HPH-US-αLA/MGV was 42.2% and 32.5% higher than that without MGV. This finding may provide a potential approach for obtaining natural and high-efficient protein-based emulsifier in food industry.

Development and characterization of pH-sensing films based on red pitaya (Hylocereus polyrhizus) peel treated by high-pressure homogenization for monitoring fish freshness

High pressure homogenization (HPH) was used to physically modify red pitaya (Hylocereus polyrhizus) peel (RPP) dispersions to develop pH-sensing films for monitoring fish freshness. Effects of HPH treatment at various pressures of 0 (control), 10, 20, 30, 40, 60 and 80 MPa on microstructure and properties of RPP film-forming dispersions (FFDs) and their resultant films were systematically investigated. Results showed that due to the structure destructing effect of HPH, the mean particle size of RPP dispersion treated at 80 MPa decreased significantly from 129.17 to 37.41 μm and its total soluble solids content increased from 7.64 to 8.62 °Bx. Rheological analysis manifested that all FFDs exhibited a shear thinning behavior with higher apparent viscosities as well as storage modulus and loss modulus with increasing HPH pressure. Besides, the HPH treated FFDs had a higher total betacyanins content and showed an obvious color response to pH variation. Consequently, the resultant films had not only smoother surfaces and more transparent appearance, but also better water vapor barrier and mechanical properties than the control. Particularly, film obtained from RPP treated at 60 MPa showed a highest tensile strength of 21.87 MPa and elongation at break of 22.09%, together with a lowest water vapor permeability of 11.41 g⋅mm⋅m−2⋅d−1⋅kPa−1. Notably, this film also exhibited high sensitivity to volatile ammonia and showed a remarkable color variation when applied for monitoring fish spoilage at 25 °C. Thus, the pH-sensing films developed from HPH treated RPP had desirable properties to be potentially used in intelligent food packaging.

Physicochemical and rheological properties of soybean oil body fermented milk: Impacts of high pressure homogenization

In the present research, the impacts of high-pressure homogenization (HPH) (20, 60, 90, 120 and 150 MPa) on the physicochemical, rheological and sensory properties of soybean oil body (SOB) fermented milks were explored. Experimental results showed that with the increase of HPH pressure, acidity and water-holding capacity (WHC) of SOB fermented milk significantly increased, while its pH, peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) significantly decreased. The SOB fermented milk was found to be pseudoplastic fluids and the SOB fermented milk at 150 MPa had the highest apparent viscosity. Meanwhile, the SOB fermented milk of 150 MPa possessed the highest sensory score. Finally, principal component analysis (PCA) and heatmap showed that SOB fermented milk had the best characteristics after HPH treatment at 150 MPa. Therefore, HPH pressure could observably improve sensory, textural and rheological properties of SOB fermented milk. These results provide theoretical reference for HPH treatment to develop high-quality fermented dairy products.

Effects of high-pressure homogenization and ultrasound on the composition, structure, and physicochemical properties of proteins extracted from Nannochloropsis Oceania

This study examined the effects of high-pressure homogenization (HPH) and ultrasonication pre-treatment on the structural and physicochemical properties of proteins extracted from defatted Nannochloropsis Oceania biomass (DNOB). HPH treatment was found to enhance the solubility of protein extracted from DNOB compared to ultrasound, where samples pretreated with three passes (3P) of HPH exhibited lower solubility than two passes (2P). The morphology of extracted samples was visualized by scanning electron microscopy, which HPH pre-treatment, especially with more passes, were able to breakdown DNOB into fragments. Alternatively, more holes were displayed on the surface of the extracts pretreated with ultrasound especially when higher amplitude applied. The particle size of extracts from HPH3P (129.5 µm) significant dropped from HPH2P (314.25 µm), where samples pretreated with ultrasound at 20 % amplitude (US20) also decreased in particle size compared to 40 % amplitude (US40), from 115.25 µm to 78.22 µm. Protein flexibility of DNOB extracts were enhanced by both HPH2P and HPH3P but decreased for ultrasound samples. β-sheets were found to be the most abundant protein secondary structure for all samples, where samples treated with HPH3P contained the highest percentage of β-sheets (72 %) than control, HPH2P, ultrasonication at 20 and 40 % amplitude (52–62 %). The high percentage of β-sheets found in HPH3P sample also contributed to its outstanding emulsifying properties which stood out among all, especially at concentrations over 1 mg/ml. Results obtained from this study helped to direct the application of DNOB extracts as functional food ingredient for future food innovation.

Phytochemical composition and in-vitro bioaccessibility of phenolics in different varieties of tamarillo (Solanum betaceum) fruits: Effect of the high-pressure homogenization and ultrasonication

The phytochemical composition in three different varieties of tamarillo (yellow, red, and purple) cultivated in Northeast India was analysed. The pulp showed good amount of protein, fat, and crude fiber, and the pH and TSS of the tamarillos ranged from 3.70 to 3.94 and 9.6–10.2 °Brix, respectively. Vitamin C was highest in purple tamarillo and all were rich in potassium. Anthocyanins were majorly found in purple tamarillo (0.35 mg C3G/g), while carotenoids were maximum in yellow tamarillo (0.63 mg βCE/100 g). However, both anthocyanins and carotenoids pigments were found in purple and red tamarillo varieties. Through HPLC analyses, six phenolic acids were identified and among them, gallic, chlorogenic, ferulic and rosmarinic acids were the major ones. Pelargonidin-3-O-rutinoside was the major anthocyanin in purple (86.22 µg/g) and red (9.88 µg/g) tamarillo. Three different carotenoids viz. zeaxanthin, β-cryptoxanthin and β-carotene were present in all the varieties of tamarillo. High pressure homogenization and ultrasonication treatments had significant impact on the phytochemical composition. High pressure homogenization at 750 bar and ultrasound for 10 min showed higher phenolics, anthocyanins and carotenoids in the tamarillo varieties and these techniques are recommended for processing of tamarillos. The treated pulp rich in phytochemicals can be used for novel product development.

Tailoring Nanostructured Cellulose for Efficient Pickering Emulsions Stabilization

AbstractNanostructured celluloses, nanofibrils (CNFs) and nanocrystals (CNCs), are prepared through TEMPO‐mediated oxidation by controlling the intensity of the process modulated by catalyst concentration and processing time. These nanomaterials are evaluated as stabilizers for Pickering emulsions, fabricated using high‐pressure homogenization (HPH). Both CNFs and CNCs exhibit efficient steric and electrostatic stabilization of oil‐in‐water (O/W) emulsions. CNFs display strong inter‐droplet interactions, leading to the formation of a 3D fibrous network emulsion with higher viscosity compared to CNCs‐stabilized emulsions. However, CNFs also show a higher tendency toward flocculation, due to fibrils’ entanglement in the continuous phase. Interestingly, the HPH treatment has a notable impact on the CNFs’ interfacial layer, enhancing the emulsifying ability of CNFs and improving stability against coalescence. Conversely, CNCs‐stabilized emulsions exhibit lower viscosity but demonstrate higher interfacial activity and stabilization capability. Remarkably, no phase separation during 10 months of refrigerated storage, indicating excellent long‐term stability. Importantly, the HPH treatment does not significantly change the emulsifying ability of CNCs. In conclusion, this study highlights the possibility of obtaining nanocelluloses (NCs) with tailored emulsifying properties by regulating the intensity of TEMPO‐mediated oxidation applied to pulp cellulose. These findings open up new opportunities for the development of innovative ingredients for the food and cosmetic industries.

Foaming and structural properties of egg yolk components microgel particles and their adsorption characteristics at the air-water interface

In this study, microgel particles of egg yolk and its components were constructed by inducing and modifying their structure via the high-pressure homogenization (HPH). In order to compare their structural characterization and reveal their adsorption mechanism at the air-water interface, yolk components were also combined with egg white protein (EWP) to achieve their microgels for investigation. Results suggested that after HPH, foam stabilities of egg yolk protein microgel (EYM) and egg yolk plasma microgel (EPM) were significantly improved, whereas no significance occurred on egg yolk granules microgel (EGM). Interestingly, after HPH, the adsorption capacity of the microgels from combination of yolk components and EWP exhibited a significant increasing trend. However, their interfacial adsorption stability was poor. Fluorescence spectrum and surface tension revealed that more hydrophilic groups and lower surface tension would occur on EY and EP after HPH, whilst no significant effects would happen on EG, which was consistent with the results of foaming characteristics. SDS-PAGE exhibited that there was no obvious change in the protein bands of egg yolk and its components, indicating that egg yolk and component proteins did not undergo covalent crosslinking or degradation with HPH treatment. In summary, our study prepares for the first time of the microgel particles from egg yolk components for stabilizing the air-water interface. In addition, we have revealed the relationship between the physicochemical properties, microstructures and interfacial adsorption properties of the microgel particles from egg yolk components, and have explored their mechanisms in depth.

Unraveling the effect of combined heat and high-pressure homogenization treatment on the improvement of chickpea protein solubility from the perspectives of colloidal state change and structural characteristic modification

Chickpea protein (CP) is a promising plant protein ingredient, but the poor solubility has limited its broad application. In this study, heating followed by high-pressure homogenization (HPH) was used to improve the solubility of CP. The results showed that combined heat (80℃, 30 min) and HPH (80 MPa, 2 cycles) treatment exhibited an additive effect in improving the solubility of CP. This improvement could be attributed to the dissociation and the rearrangement of large insoluble protein aggregates into small-sized soluble protein aggregates, the increased exposure of hydrophobic residues and reactive sulfhydryl groups, the transformation of α-helices to β-sheets and β-turns. Moreover, the 11S subunits of CP could form reinforced disulfide covalent cross-links under heating + HPH, which may provide steric hindrance preventing the reassembly of large protein bodies. This work proposes an interesting approach to enhance the physicochemical properties of CP for tailoring techno-functional plant protein ingredients in food formulations.

Improving the solubility and interfacial absorption of hempseed protein via a novel high pressure homogenization-assisted pH-shift strategy

A pH shift treatment aided by high pressure homogenization (HPH) with various pressures (0–120 MPa) was employed to structurally modify hempseed protein isolate (HPI). Compared with individual pH shift or HPH treatment, HPH-assisted pH shift improved the structural flexibility of HPI, as revealed by the increased random coil in protein secondary structure. With the incorporation of HPH into pH shift, the intrinsic fluorescence intensity was remarkably attenuated and redshifted, whereas the surface hydrophobicity was pronouncedly boosted, indicating the extensive unfolding of protein structure. Moreover, the cotreated HPI exhibited a smaller and more homogenous particle size, notably at a higher pressure. Consequently, the solubility was drastically raised by the cooperated treatments, to the maximum value (62.8 %) at 120 MPa. These physicochemical changes in the cotreated HPI facilitated a consolidated interfacial activity. Moreover, the cooperated treatment, especially highly pressured (120 MPa), facilitated the penetration and rearrangement of proteins at the oil–water interface.

Characterization of yeast protein isolates extracted via high-pressure homogenization and pH shift: A promising protein source enriched with essential amino acids and branched-chain amino acids.

In the global food industry, plant-based protein isolates are gaining prominence as an alternative to animal-based counterparts. However, their nutritional value often falters due to insufficient essential amino acids. To address this issue, our study introduces a sustainable protein isolate derived from yeast cells, achieved through high-pressure homogenization (HPH) and alkali pH-shifting treatment. Subjected to HPH pressures ranging from 60 to 120MPa and 1 to 10 cycles, higher pressure and cycle numbers resulted in enhanced disruption of yeast cells. Combining HPH with alkali pH-shifting treatment significantly augmented protein extraction. Four cycles of HPH at 100MPa yielded the optimized protein content, resulting in a yeast protein isolate (YPI) with 75.3g protein per 100g powder, including 30.0g of essential amino acids and 18.4g of branched-chain amino acids per 100g protein. YPI exhibited superior water and oil-holding capacities compared to pea protein isolate, whey protein isolate (WPI), and soy protein isolate. Although YPI exhibited lower emulsifying ability than WPI, it excelled in stabilizing protein-stabilized emulsions. For foaming, YPI outperformed others in both foaming ability and stabilizing protein-based foam. In conclusion, YPI surpasses numerous plant-based protein alternatives in essential amino acids and branched-chain amino acids contents, positioning it as an excellent candidate for widespread utilization as a sustainable protein source in the food industry, owing to its exceptional nutritional advantages, as well as emulsifying and foaming properties. PRACTICAL APPLICATION: This study introduces a sustainable protein isolate derived from yeast cells. YPI exhibited considerable promise as a protein source. Nutritionally, YPI notably surpassed plant-based protein isolates in EAA and BCAA contents. Functionally, YPI demonstrated superior water-holding and oil-holding capacities, as well as an effective emulsion and foam stabilizer.