Hemp Protein Isolate Research Articles

Hemp Protein Isolate-Based Natural Thermal-Reversible Hydrogel as a Novel Wound Dressing Material.

Hydrogels, due to their excellent microstructure and mechanical strength, have become a novel biomaterial in wound dressing. However, plant proteins have never been considered because of their poor original gelling performances and insufficient rheological properties. Here, we reported the fabrication of a plant protein-based thermal-reversible gel using a reverse micelle-extracted hemp protein isolate (HPI). A systematic study was conducted to fully reveal their microstructure, rheological properties, and anti-inflammatory effect to lay a foundation for this newly developed plant protein hydrogel as a potential natural wound dressing. By modulating protein concentration (4% HPI) and temperature (85 °C), a thermal-reversible HPI gel appeared as a filament structure with the major molecular driving force of hydrophobic interactions and hydrogen bonds. By characterizing the rheological properties, lower gel strength and wider linear viscoelastic regime were determined in the thermal-reversible HPI gel compared with a thermal-irreversible HPI gel. Besides, large amplitude oscillatory shear data identified the thermal-reversible gel as a soft gel which demonstrated intracycle strain stiffening and shear thinning behavior. Moreover, the thermal-reversible HPI gel is nontoxic and has benefits in neutrophil growth with injectability and perfect wound coverage. This study opens a novel means to form a natural thermal-reversible hydrogel that can be a new material source for wound dressing.

Hemp (Cannabis sativa L.) protein: Impact of extraction method and cultivar on structure, function, and nutritional quality

Hemp (Cannabis sativa L.) is increasingly gaining traction as a novel and sustainable source of plant protein. Accordingly, the aim of this study was to investigate the effectiveness of two protein extraction methods, alkaline extraction coupled with isoelectric precipitation (AE-IEP) and salt extraction coupled with ultrafiltration (SE-UF) in producing hemp protein isolates (pH-HPI and salt-HPI) with high purity and yield. Structural characterization as impacted by extraction method and cultivar was performed and related to functional performance and nutritional quality. Both extraction methods, with carefully selected parameters, resulted in HPI with high purity (86.6–88.1% protein) and protein extraction yields (81.6–87.3%). All HPI samples had poor solubility (∼9–20%) at neutral pH compared to commercial soy protein and pea protein isolates (cSPI, cPPI). A relatively high surface hydrophobicity and low surface charge contributed to such poor solubility of HPI. However, HPI demonstrated similar solubility at acidic pH (50–67%) and comparable gel strength (up to 24 N) to cSPI. Comparing experimental amino acid composition to the theoretical amino acid distribution in hemp protein provided insights to the functional performance of the protein isolates. While pH-HPI demonstrated better functionality than salt-HPI, minimal structural, functional, and nutritional differences were noted among the pH-HPI samples extracted from four different cultivars. Overall, results from this work could be used to guide future attempts to further develop successful protein extraction processes, and to provide valuable insights to propel breeding efforts that target enhanced hemp protein characteristics for food applications.

Manothermosonication, high-pressure homogenization, and their combinations with pH-shifting improve the techno-functionality and digestibility of hemp protein

The growing interest in plant-based proteins, particularly hemp protein, has driven the exploration of new methods to address the limitations of its industrial utilization, such as its poor functional properties. This study examined how manothermosonication (MTS) and high-pressure homogenization (HPH) techniques, along with pH-shifting, could enhance the techno-functionality of hemp protein isolate (HPI) and produce functionalized hemp protein nanoaggregates. Optimal processing conditions of MTS were 50 °C, 200 kPa, and 90 s, as determined by response surface methodology. The pH-shifting + MTS and pH-shifting + HPH treatments reduced the size of hemp protein nanoaggregates by 3.2- and 1.9-fold, respectively, compared to the untreated HPI. The changes in secondary (FTIR, CD), tertiary (SH group, fluorescence intensity), and 3D structures (XRD) confirmed modifications of treated hemp proteins. The XRD patterns showed an increase in the %crystallinity values from 21% to 29% upon the pH-shifting + MTS treatment. The combination of pH-shifting + MTS resulted in the highest solubility and digestibility, 2.1- and 1.3-fold higher than the untreated HPI, respectively, followed by the MTS-alone and HPH treatments. In addition, the emulsion properties (emulsion activity, stability, creaming index, and droplet sizes) exhibited the highest values in HPI treated by pH-shifting + MTS and + HPH. The MTS and HPH technologies provide a promising viewpoint for producing protein nanoaggregates with enhanced functional properties for microencapsulation, edible film, and other applications.

Microfluidized hemp protein isolate: an effective stabilizer for high-internal-phase emulsions with improved oxidative stability.

Hemp protein isolates (HPIs), which provide a well-balanced profile of essential amino acids comparable to other high-quality proteins, have recently garnered significant attention. However, the underutilized functional attributes of HPIs have constrained their potential commercial applications within the food and agriculture field. This study advocates the utilization of dynamic-high-pressure-microfluidization (DHPM) for the production of stable high-internal-phase emulsions (HIPEs), offering an efficient approach to fully exploit the potential of HPI resources. The findings underscore the effectiveness of DHPM in producing HPI as a stabilizing agent for HIPEs with augmented antioxidant activity. Microfluidized HPI exhibited consistent adsorption and anchoring at the oil-water interface, resulting in the formation of a dense and compact layer. Concurrently, the compression of droplets within HIPEs gave rise to a polyhedral framework, conferring viscoelastic properties and a quasi-solid behavior to the emulsion. Remarkably, HIPEs stabilized by microfluidized HPI demonstrated superior oxidative and storage stability, attributable to the establishment of an antioxidative barrier by microfluidized HPI particles. This study presents an appealing approach for transforming liquid oils into solid-like fats using HPI particles, all without the need for surfactants. HIPEs stabilized by microfluidized HPI particles hold promise as emerging food ingredients for the development of emulsion-based formulations with enhanced oxidative stability, thereby finding application in the food and agricultural industries. © 2023 Society of Chemical Industry.

Production and identification of immunomodulatory peptides in intestine cells obtained from hemp industrial by-products

Hemp seeds have attracted the interest of the food industry recently, to be employed as functional food, considering their nutritional composition, highlighting the high content and quality of the proteins. In this study, ten hemp protein hydrolysates (HPHs) were obtained by enzymatic hydrolysis with two food-grade proteases from a hemp protein isolate and the inflammatory properties were evaluated in Caco-2 cell line. To this end, the gene expression and the release of proinflammatory and anti-inflammatory cytokines by Caco-2 cells stimulated with bacterial lipopolysaccharide and treated with HPHs at concentrations of 50 and 100 μg/mL were analyzed. The peptides contained in each HPH were identified and those with higher quality of the match in the spectrum were subjected to in silico analyses to determine which peptides were bioactive and contributing to the immunomodulatory activity of the hydrolysates. The results suggest that the immunomodulatory properties of these HPHs could have a beneficial effect at the level of the intestinal epithelium. The HPH20A and HPH60A + 15F exerted high immunomodulatory properties based on the cytokine levels release. The oligopeptides MAEKEGFEWVSF and GLHLPSYTNTPQLVYIVK were proposed as the most active ones. The potential of these peptides as nutraceuticals to prevent or pretreat intestinal inflammation is promising, though requires validation by in vivo assays.

Hemp protein hydrolysates’ ability to inhibit ice recrystallization is influenced by the dispersing medium and succinylation

Freezing damage to foods can occur due to the formation of large ice crystals in the microstructure of foods, leading to unfavorable changes in the quality. The objective of this study was to determine the ice recrystallization inhibition (IRI) activity of hemp protein isolate (HPI) as affected by enzymatic hydrolysis and modification by succinylation. The IRI activity was evaluated using splat assay in phosphate buffer saline (PBS) and 10 mM NaCl. Enzymatic hydrolysis did not result in the production of IRI active hydrolysates when evaluated in PBS. Succinylation at 0.25:1 molar ratio of bromelain and trypsin hydrolysates resulted in the most IRI active hemp protein hydrolysates in PBS, having a 49% and 46% increase in IRI activity. When evaluated at 10 mM NaCl, both unmodified and modified HPI hydrolysates are IRI active. The unmodified hydrolysates were all significantly more IRI active in 10 mM NaCl, the hydrolysate produced by bromelain hydrolysis for 60 min had increased activity by 42% in the medium compared to PBS. Our results show that the ability of HPI hydrolysates to inhibit growth of ice crystal is influenced by the dispersing medium used during splat assay and succinylation.

Structural and Functional Characteristics of Hemp Protein Isolate–Pullulan Polysaccharide Glycosylation Conjugate in an Aqueous Model System

Hemp protein, with its important nutritional and industrial value, has trickled into the aisles of protein demand; however, its poor functional properties have largely limited its implementation in food. Herein, we aimed to modify hemp protein isolate (HPI) via glycosylation coupling with pullulan polysaccharide, and we subsequently characterized its structural and functional properties. The conjugation variables were HPI to pullulan ratio (i.e., 3:1, 2:1, 1:1, 1:2, and 1:3 w/w), incubation temperature (i.e., 50, 60, 70, 80, and 90 °C), and incubation time (i.e., 3, 6, 12, 24, and 48 h). Native HPI was used as a control for comparison purposes. We found that DG tended to decrease when the pullulan to HPI ratio was greater than 1:1 and when the temperature exceeded 80 °C. SDS-PAGE analysis shows that when the DG is increased, wider and heavier molecular weight bands emerge near the top of the running gel, while such observations were absent in the control. Further, glycosylation could loosen the HPI's secondary and tertiary structures, as well as increase surface hydrophobicity. The solubility of HPI after glycosylation significantly increased (p < 0.05) at pH 7.0 compared to HPI without glycosylation. Emulsifying activity improved significantly (p < 0.05), with glycosylation with HPI-pullulan at a ratio of 1:3 showing maximum emulsifying activity of 118.78 ± 4.48 m2/g (HPI alone: 32.38 ± 3.65 m2/g). Moreover, the HPI-pullulan glycosylation time of 24 h showed maximum foaming activity (23.04 ± 0.95%) compared to HPI alone (14.20 ± 1.23%). The foaming stability of HPI (79.61 ± 3.33%) increased to 97.78 ± 3.85% when HPI-pullulan was conjugated using a glycosylation temperature of 80 °C. Compared with the un-glycated HPI, HPI-pullulan also increased WHC (4.41 ± 0.73 versus 9.59 ± 0.36 g/g) and OHC (8.48 ± 0.51 versus 13.73 ± 0.59 g/g). Intriguingly, correlation analysis showed that protein functional characteristics were significantly and positively correlated with DG. Overall, our findings support the notion that pullulan conjugation provides further functional attributes to the HPI, thereby broadening its potential implementation in complicated food systems.

Nutritional composition, ultrastructural characterization, and peptidome profile of antioxidant hemp protein hydrolysates

Hemp is the term commonly used to refer to the variety of Cannabis sativa L. cultivated for industrial purposes. The seeds have gained interest in recent years as functional foods due to their nutritional composition and high content of protein and bioactive compounds. In this study, ten hemp protein hydrolysates (HPHs) were obtained by enzymatic hydrolysis with Alcalase and Flavourzyme from hemp protein isolate (HPI) and their antioxidant properties (DPPH radical scavenging activity, beta-carotene activity and ferric ion reducing antioxidant power (FRAP)) were evaluated. Shorter peptide sequences, mainly obtained with Flavourzyme, were found to react with free radicals more easily. The peptidome of all the hydrolysates was characterized, identifying, and quantifying the peptides. Furthermore, 19 unique peptides were assessed by in silico tools to hypothesize those that could be responsible of the bioactivity reported for the hydrolysates. From the identified peptides, based on the molecular features and the predictions, the peptides KNAIYTPH, EERPGHF, and KNGMMAPH, among others, are proposed to be highly contributing to the antioxidant activity of the hydrolysates.

Reverse micelles extraction of hemp protein isolate: Impact of defatting process on protein structure, functionality, and aromatic profile

Hempseed is becoming an emerging crop because of the potential utilization of its multifunctional constituents particularly hemp proteins in commercial products. Recently, reverse micelles (RMs) extraction technology has been introduced into protein extraction because of its convenience and low-cost nature. The current study aims to investigate the influence of the defatting process on the extraction performance, chemical compositions, physicochemical properties, and aromatic profile of hemp protein isolate (HPI) extracted via RMs extraction. Our results suggest that defatting is not a necessary step for RMs to extract protein from hemp flours in terms of extraction performance. HPIs obtained from non-defatted hemp flour (ND-HF) and defatted hemp flour (D-HF) exhibited great similarities in proximate composition and protein subunits, and functional properties (isoelectric point, solubility, emulsifying, foaming, and thermal stability). Meanwhile, a higher percentage of β-sheet and a greater surface hydrophobicity were observed in HPI obtained from ND-HF. In addition, the gel formed by HPI from ND-HF displayed a higher least gelling concentration (4% w/v) with yellowish color and stronger gel strength as compared to D-HF HPI. Concerning aroma profile, HPI from ND-HF yielded a higher number and content of aromatic compounds than the counterpart. The current research implies that RMs could be applied to directly extract HPI from non-defatted hemp flours without largely impacting the functionality of the protein, thus giving a great potential of the eco-friendly way for protein extraction.

Encapsulation of essential oils using hemp protein isolate–gum Arabic complex coacervates and evaluation of the capsules

Complex coacervates of hemp protein isolate and gum Arabic were prepared. These complex coacervates were used to encapsulate essential oils (EOs). The nature of the EO affected the physical properties, structure and bioactives of capsules.

Production of hemp protein isolate-polyphenol conjugates through ultrasound and alkali treatment methods and their characterization

Two easy-to-implement methods, i.e., ultrasound and alkali treatment, were used to produce conjugates of hemp protein isolate (HPI) and polyphenols (gallic acid and catechin). The effect of these two methods of conjugation on the degree of conjugation (free amino and sulfhydryl group contents), particle size, charge tensity, secondary and tertiary structures, surface hydrophobicity, solubility and emulsifying properties, antioxidant activities of the resulting conjugates were determined. The effect of conjugation on the storage, temperature, and salt stability was evaluated. The results showed that alkali treatment induced more polyphenols to conjugate with HPI than ultrasound treatment. The conjugation significantly improved the solubility, emulsifying properties of HPI, especially in the case of HPI-gallic acid conjugate prepared through ultrasound treatment. The improvement in technofunctional properties correlated with unfolding of molecules, reduced particle size, surface hydrophobicity, interfacial tension, and increased charge intensity. The conjugation of HPI with polyphenols improved its antioxidant activities. Emulsions stabilized by conjugates also exhibited higher storage, temperature and salt stability. These findings indicate that these two easy-to-implement conjugation methods can be readily used to develop HPI-polyphenol conjugates and use them as new class of emulsifier.

Hemp protein isolate-polysaccharide complex coacervates and their application as emulsifiers in oil-in-water emulsions

Complex coacervates of hemp protein isolate (HPI) and three different polysaccharides (gum Arabic, sodium alginate and pectin) were prepared and used as the emulsifiers in three different oils (hemp, essential and coconut oils) to produce oil-in-water (O/W) emulsions. The effects of polysaccharide and oil types and the methods of applying these complex coacervates as emulsifiers (in-situ and ex-situ) on the stability of emulsion were investigated in terms of storage time and temperature and the presence of salt. The results showed that the characteristics of emulsions, especially their stability, were affected by the type of polysaccharides, type of oil and the way these complex coacervates were applied as emulsifiers during the preparation of emulsions. The emulsion of hemp oil prepared using HPI-gum Arabic complex coacervate as emulsifier had the best storage stability. The emulsion prepared by in-situ method had better storage stability when stored at 4 °C. The emulsion stabilized by the ex-situ method was less sensitive to temperature and ionic strengths.

Hemp Seed Oil Extraction and Stable Emulsion Formulation with Hemp Protein Isolates

Industrial hemp (Cannabis sativa L.) is traditionally processed for its high fibre content in the textile industry, but in recent years, it has come to constitute a new raw material in the food industry. Hemp seeds, but also the seed meal, are rich in protein (25%) and oil (30%), the latter consisting of 80–90% of unsaturated fatty acids; they represent a rich and balanced nutritional source to replace the classic animal sources, and they are used in the food industry to supply new food trends. In this work, the hemp oil extraction process was studied, taking advantage of the supercritical CO2 and ultrasounds, and comparing it with the exhaustive Soxhlet technique. The residual cake from extraction is a protein-rich waste that can be used for food formulations. From this perspective, the hemp oil extracted was used to formulate emulsions with the consistency of vegetable drinks, enriched with standard hemp protein isolate and stabilized with the addition of 0.05% w/w of thickening polysaccharides (Gellan gum). The formulated emulsion is stable, and this can encourage the process improvement and the use of the waste from hemp seed extraction for the valorisation of by-products and waste to obtain complete food products with high nutritional value.

Structural, functional properties, and volatile profile of hemp protein isolate as affected by extraction method: Alkaline extraction–isoelectric precipitation vs salt extraction

The utilization of industrial hemp in food is gaining popularity. This study aimed to comprehensively investigate the impact of alkaline extraction–isoelectric precipitation (AE-IEP) and salt extraction (SE) dialysis on structural, functional properties and the volatile profile of hemp protein isolate (HPI). A higher protein content (97.21%) in SE extracted HPI (SE-HPI) was obtained than the AE-IEP extracted HPI (93.37%). In particular, protein subunit composition, structural properties were strongly influenced by the extraction methods. For example, SE-HPI exhibited a larger percentage of albumin (46.53%) and a lower amount of β-sheet (52.65%) than its counterpart (albumin 20.92%, β-sheet 54.46%). Consequently, SE-HPI showed the higher solubility, emulsion activity, and thermal stability. Interestingly, the volatile profile of the proteins showed that SE-HPI exhibited a lower number (21) of volatile compounds when compared to its counterpart (25). This study highlights the importance of establishing the relationships between extraction methods and functional attributes of HPI.

Regional differentiation based on volatile compounds via HS-SPME/GC–MS and chemical compositions comparison of hemp (Cannabis sativa L.) seeds

Cannabis sativa L., has gained increasing attention due to its potential applications in various fields. However, the compositions of hemp seeds from different producing regions are quite different, significantly affects resource utilization. This work conducted the regional differentiation of hemp seeds from Dongbei, Guangxi, Inner Mongolia and Shanxi in China based on the headspace solid phase micro-extraction coupled with gas chromatography-mass spectrometry (HS-SPME/GC–MS) and multivariate analysis. Moreover, the chemical composition, amino acid and fatty acid profiles of hemp seeds and antioxidant activities of hemp protein isolate were evaluated from above four producing regions. The results showed that hemp seeds had large amounts of fat (24.30–34.65%) and protein (21.87–23.40%) with ideal amino acid and fatty acid profiles and large amounts of volatiles. More than 300 volatile compounds were detected, and 35 key contributors to the unique aroma were finally identified out of 110 volatile compounds with odor activity values (OAVs), including 14 aldehydes, 2 ketones, 4 alcohols, 2 esters, 1 acid, 3 aromatics, 5 terpenes and 4 other compounds. The content of alcohols in all hemp seeds was highest and 16 unique volatiles only found in hemp seeds from Shanxi. Meanwhile, the VIP scores indicated that acetic acid, hexanal, hexan-1-ol and eucalyptol contributed the most to the difference among groups. According to the results of fuzzy comprehensive evaluation, the hemp seeds from Shanxi seemed to have the better quality. Therefore, multivariate analysis combined with HS-SPME/GC–MS could effectively distinguish hemp seeds from different producing regions, and thus decipher the geographical characteristics of raw materials.

Hemp protein isolate – gum Arabic complex coacervates as a means for oregano essential oil encapsulation. Comparison with whey protein isolate – gum Arabic system

The potential of hemp protein isolate-gum Arabic complex (HPI-GA) coacervates to encapsulate Origanum vulgare L. subsp. hirtum essential oil (OEO) was evaluated in comparison to the well-studied whey protein isolate-GA encapsulating system. Different biopolymer (1 or 2% w/w) and OEO (0.5 or 1%) concentrations were tested and the formed OEO microcapsules were characterized in terms of encapsulation yield and efficiency, as well as structural, morphological, moisture sorption, antioxidant, and antimicrobial properties. Gas chromatography was applied to determine possible ensuing changes to oil's composition. OEO was successfully encapsulated in both protein-polysaccharide systems as demonstrated by encapsulation yield and efficiency results and confirmed by FTIR spectroscopy, while its major volatile constituents (carvacrol and thymol) were highly preserved. Biopolymer concentration increase and low OEO's addition levels positively affected the encapsulation parameters (e.g., ∼90% encapsulation efficiency for the HPI-GA) due to the more complete droplets' surface coverage and enhancement of proteins-GA interactions at the interface. SEM analysis showed the typical, uneven, irregular morphology of freeze-dried powders, being denser and more aggregated upon OEO content increase. The sorption characteristics of coacervates exhibited the type II isotherm and the GAB model accurately described the obtained curves revealing lower monolayer moisture content in the case of HPI. The implementation of disc diffusion method showed that encapsulation acted protectively on OEO's antimicrobial activity, while DPPH and CUPRAC assays revealed the preservation of EO's antioxidant activity. These features provide evidence that HPI-GA can be used as alternative wall materials to encapsulate EOs by the complex coacervation method.

Nutritional Quality, Chemical, and Functional Characteristics of Hemp (Cannabis sativa ssp. sativa) Protein Isolate.

(1) Background: Hemp seeds are a source of plant-based protein, making them an appropriate supplement to a plant-based diet. The current work was focused on the preparation of the protein isolate from the hemp seeds with eco-friendly and cheap technology. Moreover, it evaluated the physicochemical and functional properties of hemp protein isolate for its potential application in food manufacturing. (2) Methods: The protein content of hemp seeds has been isolated through two main steps: (1) extraction of the protein content of an alkaline pH (10-12); (2) precipitation of the extracted protein on an acidic pH as an isoelectric point (pH = 4.5). (3) Results: The edastin protein is the most predominant protein in the protein profile with a molecular weight of 58.1 KDa beside albumin with a molecular weight of 31.5 KDa. The FTIR spectrum detected the absorption peaks of the amide I at 1750 and 1600 cm-1, which pointed to C=O stretching while N-H stretching at 1650-1580 cm-1. The peak at 3250 is found to be related to N-H stretching of the aliphatic primary amine (3400-3300 cm-1) and the N-H stretching for the secondary (II) amine appeared at 3350-3310 cm-1. The Hemp protein isolate (HPI) showed a high content of arginine (15.52 g/100 g), phenylalanine + tyrosine (9.63 g/100 g), methionine + cysteine (5.49 g/100 g), leucine + isoleucine (5.21 g/100 g), and valine (4.53 g/100 g). It contains a moderate level of threonine (3.29 g/100 g) and lysine (2.50 g/100 g) with tryptophan as the limiting amino acid (0.22 g/100 g). The HPI showed an appropriate water-and-oil holding capacity (4.5 ± 2.95 and 2.33 ± 1.88 mL/g, respectively). The foaming capacity of the HPI was increased with increasing the pH values to reach the maximum value at pH 11 (67.23 ± 3.20%). The highest emulsion ability index of the HPI was noted at pH 9 (91.3 ± 2.57 m2/g) with low stability (19.15 ± 2.03). (4) Conclusions: A strong positive correlation (r = 0.623) was shown between protein concentration and solubility. The current easy-to-use, cheap, and eco-friendly technology provides the industrial sector with a cheap protein isolate for manufacturing protein-rich diet and beverages. The HPI showed a good nutritional quality and functional properties that might be helpful in utilizing it in different food products such as beverages and bakery products.

Physicochemical and Antioxidant Properties of Industrial Hemp Seed Protein Isolate Treated by High-Intensity Ultrasound.

Ultrasound is one of the non-thermal, green, and novel technologies used to functionalize plant proteins. We recently determined the optimum conditions of high-intensity ultrasound (HIUS) treatment for maximum solubility and investigated the functional properties of hemp seed protein isolate (HSPI) under the optimal conditions. In this study, we analyzed changes in primary, secondary, and tertiary structures, physical microstructures, thermal stability, and antioxidant capacity of ultrasound-applied hemp protein isolate (HSPI-HIUS). The free SH group content (+59%) and zeta potential (+25%) increased upon ultrasound treatment. The electrophoretic protein patterns of HSPI showed no significant change after HIUS treatment. The FTIR spectrum revealed the wavenumber shifts in Amid 1 and 2 regions of protein. The denaturation temperature and the ratio of β-structure increased after sonication. Antioxidant properties of hemp seed protein isolates were increased by 38% by ultrasound treatment. The obtained data in this study showed that HIUS treatment would be promising for improving the functional, physicochemical, and antioxidant properties of HSPI.

Application of ultrasound treatment to improve the technofunctional properties of hemp protein isolate

The hemp seed protein isolate (HPI) was extracted from defatted hemp seed meal using alkaline extraction (pH = 10.0) acid precipitation (pH = 4.3) method. The effects of ultrasound treatment on its solubility, emulsifying properties, particle size, microstructure, molecular subunits, secondary and tertiary structures, and surface hydrophobicity were determined. Solubility and emulsifying properties of HPI were significantly improved after ultrasound treatment (20 kHz) at 400 W for 12 min. The solubility, emulsion activity, and emulsion stability indices increased by 3.7- 1.7- and 1.5-fold, respectively. The improvement in functional properties correlated with reduced particle size, increased surface hydrophobicity and the alteration in secondary and tertiary structure of HPI. The solubility and emulsifying properties of the ultrasound treated HPI were better than native pea protein isolate but still not as good as those of native soy protein isolate for which further research is needed.

Effect of Soybean Phosphatidyl Ethanolamine on the Formation and Properties of Pickering Emulsion Stabilized by Hemp Protein Isolate

This paper studied the effect of soybean cephalin on hemp protein isolated Pickering emulsion properties. The emulsifying activity index, the microstructure, droplet size, Zeta potential, the influence of rheological properties and storage stability were measured. It was critical to explore the influence mechanism of hemp protein isolated Pickering. The results showed that the stability of Pickering emulsion was improved after the addition of cephalin. The optimum indexes of the Pickering emulsion were obtained when the amount of cephalin was 30%, with an emulsion activity index of 4.63 m2⁄g and a dispersion index of 0.23. The droplet size was 125 nm, and the Zeta potential was -27.12 mV. The apparent viscosity of the emulsion was small. There was no obvious droplet aggregation and oil leakage phenomenon after 7 days storage, therefore the storage stability was good. This study provided a theoretical basis for improving the stability of hemp protein isolate Pickering emulsion, which could also expand the application field of soybean cephalin.