pH-shifting Treatment Research Articles

Improving the emulsification characteristics of rapeseed protein isolate by ultrasonication assisted pH shift treatment.

Rapeseed protein isolate (RPI) is an important nutrimental macronutrient in human diet due to its abundance in amino acids. However the poor emulsifying attributes of RPI limits its application in food industry, which needs to be overcome for its application in food industry. Ultrasonication-aided pH shift (UpHS) treatment is an efficient method for enhancing the functionality of plant/ food protein. In this work, the emulsification characteristics of RPI modified by UpHS technique under different solubility levels were studied. Results showed that the emulsifying activity and stability of modified RPI were significantly improved by 168.46 % (sample with high solubility treated by Ultrasonication-aided pH 12.5, HSpH 12.5) and 134.5 % (sample with high solubility treated by Ultrasonication-aided pH 1.5, HSpH 1.5), respectively compared with the native sample (P < 0.05), and the emulsifying activity was positively correlated (P < 0.05) with solubility. The emulsification stability under acidic condition was higher than that under alkaline condition (HSpH 12.5 increased by 83.5 %). In addition, the adsorption capacity and zeta potential of RPI were increased to 93.74 % and 13.83 % respectively, whereas the particle size and surface tension were reduced to 41.04 % and 23.63 % respectively. This indicates the changes in the molecular structure of modified rapeseed protein, which improved the emulsifying activity of RPI. Moreover, the interfacial film of emulsions formed by the modified protein had stronger compressive resistance, contributing to the enhanced emulsifying stability of the RPI. These results show that UpHS treatment can effectively improve the emulsification properties of proteins, and can be widely used in food industry.

Effect of pH-Shift Treatment on IgE-Binding Capacity and Conformational Structures of Peanut Protein

Hypoallergenic processing is an area worthy of continued exploration. In the treatment of the peanut protein (PP), pH shift was applied by acidic (pH 1.0–4.0) and alkaline (pH 9.0–12.0) treatment, after which the pH was adjusted to 7.0. Following pH-shift treatment, PP showed a larger particle size than in neutral solutions. SDS-PAGE, CD analysis, intrinsic fluorescence, UV spectra, and surface hydrophobicity indicated the protein conformation was unfolded with the exposure of more buried hydrophobic residues. Additionally, the IgE-binding capacity of PP decreased after pH-shift treatment on both sides. Label-free LC–MS/MS results demonstrated that the pH-shift treatment induced the structural changes on allergens, which altered the abundance of peptides after tryptic digestion. Less linear IgE-binding epitopes were detected in PP with pH-shift treatment. Our results suggested the pH-shift treatment is a promising alternative approach in the peanut hypoallergenic processing. This study also provides a theoretical basis for the development of hypoallergenic food processing.

PH-shifting treatment improved the emulsifying ability of gelatin under low-energy emulsification

The effects of pH-shifting treatments (pH 3, 5, 7, 9, and 11) on the stability of gelatin emulsions made by low-energy stirring were investigated. pH-shifting treatments significantly enhanced the ESI and EAI of the emulsion (P < 0.05) and reduced its particle size (P < 0.05) under low-energy emulsifying conditions. The pH11–7 shifting treatment significantly increased the degree of depolymerization and the level of ordered structure of gelatin (P < 0.05). These transformations resulted in a significant increase in the exposure of hydrophobic and negatively charged residues (P < 0.05) on the surface of gelatin, facilitating a faster adsorption rate of gelatin onto the oil-water interface as well as an increase in the amount of gelatin adsorbed at the interface. Moreover, the alkali-shifting treatment promoted the formation of a thin viscoelastic interfacial film, which contributed to the enhanced stability of the emulsion.

Structural changes and functional characteristics of common vetch isolate proteins altered by different pH-shifting treatments

To investigate protein structure and functional changes, common vetch protein isolate (CVPI) during pH-shifting were performed. Results showed secondary and tertiary structures of CVPI were improved during these treatments compared with the pH 7.0. Scanning electron microscopy showed the microstructure was changed from lamellar to spherical granular and rod-like structure during pH - shifting. Under 8 pH treatments (pH 2.0, 3.0, 12.0, 2.0 → 7.0, 3.0 → 7.0, 12.0 → 7.0, 11.0 → 9.0 and 11.0 → 7.0), the average particle sizes were smaller and from 82 to 146 nm. Under 8 pH treatments (pH 2.0, 3.0, 11.0, 12.0, 11.0 → 9.0, 11.0 → 7.0,12.0 → 9.0 and 12.0 → 7.0), the protein solubility was higher and from 63 to 86 %. Under 3 pH treatments (pH 2.0, 11.0 and 12.0), the emulsion activity index and emulsion stability index was higher and from 40 to 60 m2/g and from 54 to 97 min. Under 5 pH treatments (pH 2.0, 12.0, 11.0 → 9.0, 12.0 → 9.0 and 12.0 → 7.0), the foaming capacity and foaming stability was higher and from 145 to 185 % and from 67 to 82 %. Therefore, the pH – shifting treatment gave the CVPI improved characteristics in structural and functional properties.

Effect of ultrasound-assisted pH-shifting treatment on the physicochemical properties of melon seed protein

Melon seeds have received considerable attention in recent years because of their high protein content, but they have not yet been fully used. The modification of melon seed protein (MSP) using ultrasound-assisted pH-shifting treatment was investigated in this study by analyzing structural characteristics and functional properties. The particle size, free sulfhydryl content, surface hydrophobicity, solubility, secondary structure, water-holding capacity, oil-holding capacity, emulsification activity index, and emulsification stability index of MSP were determined. MSP treated with ultrasound-assisted, pH-shifting had a smaller particle size, lower free sulfhydryl content, higher surface hydrophobicity, and solubility increased from 43.67 % to 89.12 %. The secondary structure of MSP was affected by ultrasonic treatment, manifesting as an α-helix increase and β-helix, β-turn, and random coil content decrease, which may be the reason why the protein structure became more compact after treatment. The water and oil holding capacities of MSP increased from 2.74 g/g and 3.14 g/g in untreated samples to 3.19 g/g and 3.97 g/g for ultrasound-treated samples, and further increased to 3.97 g/g and 5.02 g/g for ultrasound-assisted, pH-shifting treatment at pH 9.0, respectively. The emulsification activity index of MSP was 21.11 m2/g before treatment and reached a maximum of 32.34 m2/g after ultrasound-assisted, pH-shifting treatment at pH 9.0. The emulsification stability of MSP was maximized by ultrasonic treatment at pH 7.0. Ultrasound-assisted, pH-shifting treatment can effectively improve the functional properties of MSP by modifying the protein structure, which improves the potential application of melon seed protein in the food industry.

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.

Effects of combined hot alkaline and pH-shift treatments on structure and functionality of legume protein-EGCG conjugates: Soybean-, pea-, and chickpea protein-EGCG systems

Legume proteins are appealing in the food industry for their nutrition and sustainability, but their low solubility due to the compact structure makes their applications in food industry limited. In this study, three commonly used legume proteins in food industry were selected as samples to be tested: soy protein (SP), pea protein (PP), and chickpea protein (CP). This study aims to improve the structural properties of these three proteins, so that it could promote effective grafting with epigallocatechin gallate (EGCG) through a combined hot alkaline and pH-shift treatments. Legume protein solutions were adjusted to pH 12 and heated at 80 °C for 30 min, resulting to a 13%–19% increase in free thiol content and a 59%–610% increase in surface hydrophobicity. This kind of change in structure leads to a 19%–46% increase in EGCG grafting degree. Treated protein-EGCG conjugates exhibited smaller and more uniform particle sizes, improved emulsification activity by 27%–218%, and additionally enhanced solubility, thermal stability, and antioxidant activity. Among all the tested proteins, pre-treated SP-EGCG conjugates showed the best solubility, emulsification, and thermal stability due to their highest surface hydrophobicity, highest EGCG grafting degree, and loose structure. These results indicate that combined hot alkaline and pH-shift treatment enhances the functional properties of legume proteins, expanding their potential applications as functional ingredients in the food industry.

Properties of Myofibrillar Protein in Frozen Pork Improved through pH-Shifting Treatments: The Impact of Magnetic Field.

The present study demonstrates the effects of pH-shifting treatments and magnetic field-assisted pH-shifting treatments on the properties of myofibrillar protein (MP) in frozen meat. The solubility results indicate that the pH-shifting treatments increased the solubility of MP from 16.8% to a maximum of 21.0% (pH 9). The values of surface hydrophobicity and protein particle size distribution indicate that the pH-shifting treatment effectively inhibited protein aggregation through electrostatic interactions. However, under higher pH conditions (pH 10, 11), the treatments assisted by the magnetic field increased the degree of aggregation. The total thiol content and SDS-PAGE results further suggest that the magnetic field-assisted pH-shifting treatment accelerated the formation of covalent bonds among MPs under the alkaline environment. The results of the Differential Scanning Calorimetry (DSC) and protein secondary structure analysis indicate that the magnetic field promoted the unfolding of protein structures in an alkaline environment, markedly reducing the effective pH levels of pH-shifting. Electron paramagnetic resonance (EPR) data indicate that the phenomenon might be associated with the increased concentration of free radicals caused by the magnetic field treatment. In summary, the application of magnetic field-assisted pH-shifting treatments could emerge as a potent and promising strategy to improve the protein properties in frozen meat.

Preparation of a curcumin oil bodies delivery system based on pH-Shift treatment: Physicochemical properties, protein structure, and digestive properties

Curcumin (Cur) was encapsulated in oil bodies (OBs) using pH-shift treatment. The physicochemical properties, surface protein structure, stability, and in vitro digestion of the prepared composite emulsion (COB) were characterized. The results showed a fading of Cur crystallization peak in COB. Besides, the highest encapsulation rate, largest particle size and zeta potential were observed at pH 0.5. Compared to OBs, the hydrophilic groups of COB surface proteins were unfolded and the central hydrophobic region remained relatively stable, with reduced COB storage stability and good oxidative stability. In vitro simulated digestion revealed that Cur was released in a sustained manner. The highest bioaccessibility (57.5%) and stability (67.3%) of COB were observed at pH 0.5. The present study suggested that pH-shift treatment is a viable method for the preparation of COB carriers. This information may provide new ideas for the preparation of lipophilic polyphenol delivery systems such as Cur, which can contribute to the application of OBs in a variety of food processing applications, including plant-based milk, fortified foods, etc.

Emulsifying and interfacial properties of glutenin processed by pH-shifting treatment

Modifying and improving protein functionality is crucial for expanding the application of proteins in the food industry. The aim of this study was to investigate the effect of pH-shift treatments on the emulsifying and interfacial properties of glutenin (Glu). Glu was exposed to acidic (pH 1–3) and basic (pH 10–13) pH values for 4 h and subsequently neutralized for refolding. The pH-shifting treatments significantly improved Glu surface wettability with three-phase contact angle from 66.21 ± 2.31° to 91.4 ± 0.88°. The alkali shift treatment resulted in samples with larger Kdiff values. The treated samples also showed amplitude and frequency dependence in their E, Ev, and Ed values, with higher E and Ed values indicating an elastic membrane at the interface. Emulsions prepared from Glu treated with alkali shift treatment exhibited smaller particle size, larger ζ-potential, and more stable storage properties. The rheological results indicated higher viscosity, thixotropy and creep of emulsions prepared from alkali shift treated Glu. In conclusion, treatment of Glu with alkali shift resulted in significant improvements in emulsifying and interfacial properties, suggesting that Glu may be a more promising ingredient for use in food.

Improvement of processable properties of plant-based high internal phase emulsions by mung bean protein isolate based on pH shift treatment.

High internal phase emulsions (HIPEs) are unique emulsion systems that transform liquid oil into solid-like fats, thus avoiding the use of saturated fat and leading to a healthier and more sustainable food system for consumers. HIPEs with oil volume fraction (ϕ) of 75-85% were fabricated with mung bean protein isolate (MPI) under different pH shift treatments at 1.0% concentration through the one-step method. In the present study, we investigated the physical properties, microstructures, processing properties, storage stability and rheological properties of HIPEs. The results suggested that the properties of MPI under different pH shift treatments were improved to different degrees, stabilizing HIPEs (ϕ = 75-85%) with various processability to meet food processing needs. Under alkali shift treatment conditions, the particle size of MPI was significantly reduced with better solubility. Moreover, the exposure of hydrophobic groups increased the surface hydrophobicity of MPI, awarding MPI better emulsifying properties, which could stabilize the HIPEs with higher oil phase fraction. In addition, the MPI under pH 12 shift treatment (MPI-12) had the best oil-carrying ability to form the stable HIPEs with oil volume fraction (ϕ) up to 85%, which was the highest oil phase in preparing the HIPEs using plant protein solely at a low concentration under neutral conditions. A series of stable HIPEs with different processing properties was simply and feasibly fabricated and these are of great potential in applying edible HIPEs. © 2024 Society of Chemical Industry.

Improving the textural and functional properties of soy protein isolate using dielectric barrier discharge (DBD) plasma-assisted pH-shifting

This study aimed to improve the textural and functional properties of soy protein isolate (SPI) through a plasma-assisted pH-shifting method to create an alternative to meat products. The SPI was treated with DBD plasma for 0, 5, 10, and 15 min and then subjected to pH-shifting of 10 and 12 for 48 h before being adjusted to a neutral pH. The changes in the secondary structure of protein were evaluated using FTIR spectroscopy, free sulfhydryl measurement, and scanning electron microscopy (SEM). Heating the pH-shifted suspensions resulted in the formation of SPI gels with a densely cross-linked polymer-like network. Rheological and textural properties indicated that the pH-shifting treatment of SPI led to the production of stiff gels, so that the gel hardness increased from ∼6.75 to ∼13.28 N after 15 min plasma treatment at pH 12-shifting. The DBD plasma pretreatment negatively affected the functional properties of the SPI and decreased the solubility about 12 and 8% after 10 min plasma treatment at pH-shifting 10 and 12, respectively. The plasma-assisted pH-shifting offered a new approach for preparing SPI gel with enhanced water holding capacity, potentially expanding the range of applications for SPI in food formulations that require gelling and texturizing functions.

Enhancing the functionalities of chickpea protein isolate through a combined strategy with pH-shifting and cold plasma treatment

This study investigated the impact of combining pH-shifting and cold plasma (CP) treatment on chickpea protein isolate (CPI) functionality. Compared with pH-shifting treatment alone, the functional properties of CPI were significantly improved when the pH was shifted under acidic (pH = 2) or alkaline (pH = 12) conditions, followed by a 30 s CP treatment before neutralization at pH 7. Particularly, the method conducted at pH 12 followed by 30 s CP treatment proved most efficient, significantly improving solubility (from 65.51 ± 1.07% to 73.01 ± 0.65%), gel strength (from 27.19 ± 1.51 g to 66.57 ± 1.69 g), fat absorption capacity (from 2.39 ± 0.02 g/g to 4.22 ± 0.05 g/g), emulsifying activity (from 57.47 ± 0.06 m2/g to 71.95 ± 0.19 m2/g), foaming capacity (from 58.33 ± 2.36% to 123 ± 5.1%), and in vitro protein digestibility (from 47.49 ± 0.44% to 55.78 ± 0.8%). These improvements were attributed to reduced protein aggregates, increased solubility, and enhanced surface hydrophobicity. Furthermore, alterations in the secondary and tertiary protein structure following these treatments positively impacted CPI's functional properties, offering important implications for protein modification with improved functional profiles.

Docosahexaenoic acid–mediated milk protein treated by ultrasound-assisted pH shifting for enhanced astaxanthin delivery and processed cheese application

Whey protein isolate (WPI)-based nanodelivery systems have recently attracted an increasing amount of attention. Despite this, research focusing on milk protein concentrate (MPC) and micellar casein (MCC) as carriers loaded in hydrophobic compounds is lacking. This study investigated the mediated effect of docosahexaenoic acid (DHA) in 3 different milk proteins for the embedding of astaxanthin (ASTA) after ultrasound-assisted pH-shifting treatment. We then evaluated the application of milk protein carriers in cheese processing by comparing MPC, MCC, and WPI. The particle size, polydispersity index, and zeta potential results of the milk protein-DHA complex suggested that the addition of 0.36 μmol/mL DHA optimized the delivery of milk protein to ASTA. All 3 DHA-mediated milk proteins induced an improvement in encapsulation efficiency and antioxidant properties of ASTA. Furthermore, the DHA-mediated MPC and MCC played a stronger role in improving the bioaccessibility, thermal and storage stability of ASTA than those without DHA. Tests conducted to examine the application in cheese production indicated that MCC carrier had a positive effect on the texture of cheeses. However, the delivery effect was dependent on the milk protein variety, in which MCC exhibited the best protection ability of ASTA, followed by MPC and WPI. The simulated digestion and storage stability results of cheese further confirmed that the protein encapsulation mediated by DHA was more conducive to ASTA absorption. These findings suggested that the DHA-mediated milk protein complexes studied here may be suitable hydrophilic delivery carriers for the hydrophobic nutrient ASTA, potentially playing different roles in regulating the storage stability and bioaccessibility.

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.

Oil-water interfacial behavior of zein-soy protein composite nanoparticles in high internal phase Pickering emulsion

We investigated the interfacial properties of zein-soy protein isolate (SPI) composite particles (ZSCPs) at the oil-water (O/W) interface through pH-shift treatment, along with the preparation and stability of high internal phase Pickering emulsions (HIPPEs). Fourier transform infrared spectroscopy (FTIR), three-dimensional fluorescence, and scanning electron microscopy (SEM) revealed hydrogen bonds and hydrophobic interactions within ZSCPs, altering their structure based on mass ratios. Increasing SPI content in ZSCPs decreased particle size, dynamic interfacial tension (γ), and molecular entanglement, promoting diffusion, penetration, and rearrangement processes. Zein particles (ZPs) exhibited fast diffusion and penetration rates due to higher surface hydrophobicity (H0) and lower zeta potential, while rearrangement was hindered. ZSCPs formed viscoelastic films at the O/W interface, strengthened by SPI. Protein films displayed strain softening during extension in the dilatational measurement under relatively large amplitude (>20%). However, during compression at large amplitude, the protein particle with zein to SPI mass ratios of 10:0 and 7:3 interface films showed strain hardening, while 5:5, 3:7 and 0:10 strain softening. HIPPEs stabilized by ZSCPs showed enhanced interface performance, ensuring long-term stability (upto 30 days). These findings offer new prospects for ZSCP applications in food emulsions, while enhancing our understanding of protein particle adsorption at the O/W interface.

Ultrasound-assisted pH shift-induced interfacial remodeling for enhancing soluble yeast protein content: Effects on structure and interfacial properties of proteins under different treatment conditions

Solubility is a necessary condition for proteins to exert their functional properties. To expand the application of yeast protein (YP) in food production, the action of ultrasound-assisted pH shift on the solubility of YP was investigated. The solubility of YP increased significantly with ultrasound-assisted pH-shift treatment, especially the protein yield reached 83.82 ± 3.08% for the sample with an ultrasound power of 60% and an ultrasound time of 30 min (U60-pH12-30). In contrast, the yield and solubility of soluble YP showed less improvement with alkaline shift or ultrasound alone. Ultrasound-assisted pH shift treatment significantly increased the content of β-sheet, free sulfhydryl groups, and disulfide bonds, and the samples had a loose and disordered microstructure compared to the treatment alone. In addition, the combined treatment considerably minimized the particle size of the protein and increased the solubility, foaming properties, and surface hydrophobicity (H0) value, especially the H0 of U60-pH12-30, which showed the highest value (451.70 ± 25.66). In summary, ultrasound-assisted pH shift treatment could significantly enhance protein solubility, thereby increasing the amount of soluble protein and improving protein processing properties.

Fabrication of water-in-oil-in-gel emulsion gel based on pH-shifting soybean lipophilic protein and carboxymethyl chitosan: Gel performance, physicochemical properties and digestive characteristics

In this study, Soybean lipophilic protein (LP) was modified by pH-shifting treatment and the modified LP was cross-linked with carboxymethyl chitosan (CMCS) to form an interpenetrating network structure to prepare water-in-oli-in-gel emulsion gels (W/O/G). The effects of the variation of phase ratio and addition of cross-linking agent (genipin) on the physicochemical properties and digestive characteristics of W/O/G were investigated. FT-IR and intermolecular force analysis showed that pH-shifting treatment exposed more hydrophobic groups in LP, and promoted the increase of intermolecular hydrophobic interaction and hydrogen bonding force. With the increase of GP addition and W1/O ratio, the swelling rate, water-holding capacity and UV stability of W/O/G gradually increased. While the porosity, encapsulation efficiency and in vitro degradation rate kept decreasing. W/O/G exhibited thixotropy in rheological tests and withstood a maximum compressive force of 1870 mN at a strain of 40%. Additionally, CMCS confered a certain pH response capability to W/O/G, which both maintained the gel network during pH changes and enabled the slow-release of the encapsulated bioactive in simulated in vitro digestion and improves bioaccessibility up to 80.63%. This study provided a theoretical basis for the cross-linking of modified LP and CMCS to form interpenetrating networks and enriched the gelation treatment of W/O/W emulsions.

Enhancement of emulsion stability and functional properties of hemp protein‐based dairy alternative by different treatments after cellulase hydrolysis

SummaryHemp milk is a plant‐based beverage emerging as a sustainable dairy alternative and it is essential to improve the emulsification properties and stability of hemp protein for increasing acceptability. This study demonstrates the preparation of protein‐rich hemp milk with enhanced emulsion stability and functional properties through cellulase hydrolysis of fibre components in hemp protein. The emulsions were prepared using the hemp dispersions obtained after cellulase treatment followed by mechanical treatment (ME) and in combination with either enzymatic (trypsin) (EE) or mild chemical (pH‐shift) treatment (PE). The influences of these treatments on the particle size distribution, zeta potential, flow behaviour, microstructure, flocculation, and coalescence properties of the emulsions are investigated. The emulsions (EE/PE) prepared with dispersions processed through tryptic or pH shift treatments showed improved stability as indicated by reduced flocculation and coalescence indices (8.9% and 10.8%, for EE and 11.8% and 13.2% for PE) as compared to only mechanically treated emulsion (ME) (37.5% and 15.3%). Furthermore, the enhanced stability of EE and PE samples is attributed to a reduction in particle size and enhanced zeta potential (EE: 45.1 mV &gt; PE: 38.7 mV &gt; ME: 34.1 mV).