Effect of enzymatic hydrolysis on the physicochemical and emulsification properties of rice bran albumin and globulin fractions

Enhancing the physical and oxidative stability of hempseed protein emulsion via comparative enzymolysis with different proteases: Interfacial properties of the adsorption layer

Effects of enzymolysis by seven proteases (Alcalase, Bromelain, Flavourzyme, Papain, Pepsin, Protamex, and Trypsin) with distinct cleavage specificities on the emulsification performance of hempseed protein (HPI) and its correlation with the structural and interfacial characteristics were explored in this study. Upon enzymolysis, a remarkable decrease in α-helix and β-turn was observed in resultant hydrolysates (HPH), accompanied by a rise in β-sheet and random coil, notably by Alcalase, Bromelain, Papain, and Trypsin. Overall, proteolysis led to noticeable reductions in surface hydrophobicity and total sulfhydryls as well as a redshift in intrinsic fluorescence, with Papain showing the most pronounced effects, possibly due to its higher hydrolysis degree (4.00 %). Interestingly, among the seven HPHs, Papain-HPH with the highest solubility (67.4 %) and smallest molecular weight exhibited compromised interfacial activity, lowest emulsifying activity (EAI, 1.67 m2/g), and highest creaming index (CI, 64 %). Contrastively, Trypsin hydrolysis significantly improved the interfacial activity, albeit causing a notable decrease in interfacial viscoelasticity of the absorbed layers. Consequently, Trypsin yielded the best EAI (10.5 m2/g) and emulsion stability (CI, 4 %); yet, the smallest emulsion droplets with homogeneous distribution and high apparent viscosity were spotted. Additionally, the oxidative stability of emulsions was conspicuously enhanced, contingent upon the antioxidative capacity of HPHs.

Innovative insights into the enzymatic hydrolysis of salmon milt: Structural and functional analysis influenced by protease type and enzymolysis time

In this study, hydrolysates were obtained from salmon milts using four proteases (neutrase, papain, trypsin and novozym 11028). The effects of protease type and enzymolysis time (30, 60, 90, and 120 min) on the structural characteristics and functional properties of the hydrolysates were assessed. The fluorescence intensity of all hydrolysates increased as the extension of enzymolysis time, accompanied by an increase in solubility, emulsifying and foaming ability. Trypsin-hydrolysates showed the highest protein recovery and degree of hydrolysis (DH). The electrophoresis indicated that papain-hydrolysates contained more aggregates (>60 kDa), which was confirmed by larger particle size and lower DH. Neutrase-hydrolysate exhibited the smallest particle size and the highest emulsifying and foaming ability, while the highest emulsifying stability appeared in papain-hydrolysates. Neutrase-hydrolysate displayed the strongest antioxidant potential while papain-hydrolysate possessed the weakest. Results demonstrated that the salmon milt protein hydrolysates can be utilized as nutraceutical and functional food ingredients.

Tailoring soy protein/corn zein mixture by limited enzymatic hydrolysis to improve digestibility and functionality

This study aimed to modify plant protein mixture to improve their functionality and digestibility by limited hydrolysis. Soy protein isolate and corn zein were mixed at the ratio of 5:1 (w/w), followed by limited hydrolysis using papain from 15 to 30 min. The structural characteristics, in vitro digestibility, and functional properties were evaluated. Also, DPPH radical scavenging activity was determined. The results indicated that the molecular weight of different modified samples was largely reduced by limited hydrolysis, and the proportion of random coil was significantly increased. Furthermore, the solubility, foaming, emulsifying and water-holding capacity of hydrolyzed protein mixture were significantly improved, which were close to those of whey protein isolate. In vitro digestibility after 30-min limited hydrolysis was remarkably elevated. In addition, the hydrolyzed protein mixture exhibited a higher antioxidant activity than those of untreated proteins. Overall, limited hydrolysis of protein mixture led to improved digestibility, functionality and antioxidant activity.

In vitro digestion and functional properties of bovine β-casein: A comparison between adults and infants

Gastrointestinal digestibility behavior, structural and functional characteristics of bovine β-casein (β-CN) were studied in vitro under infant and adult conditions. This direct comparison helps reveal the effects of different physiological stages on the digestive behavior of β-CN. Not only was the degree of hydrolysis (DH) of β-CN analyzed, but also the changes in its digestive morphology, microstructure, and secondary structure during digestion were explored in depth. Meanwhile, we focused on the physicochemical properties of β-CN digesta, including solubility, emulsifying and foaming properties, as well as their functional properties, such as antimicrobial and antioxidant activities. Key results showed that β-CN underwent more extensive hydrolysis in the adult digestion model, with approximately twice the DH compared to the infant model. The adult model exhibited faster digestion kinetics, less protein flocculation, and a more loosened secondary structure, indicating a more efficient digestion process. Notably, the digesta from the adult model displayed significantly improved solubility and emulsifying properties, and also enhanced antioxidant capacities, with significantly better inhibition of two common pathogenic bacteria than the infant model, and an average increase in the diameter of the inhibition zone of approximately 2 mm. These findings underscore the differential digestive behavior and functional potential of β-CN across physiological stages. This comprehensive assessment approach contributes to a more comprehensive insight into the digestive behavior of β-CN. Therefore, we conclude that producing products from unmodified β-CN may be more suitable for the adult population, and that the digesta in the adult model exhibit higher functional properties.

Performance of Azolla pinnata fern protein hydrolysates as an emulsifier and nutraceutical ingredient in an O/W emulsion system and their effect on human gut microbiota and mammalian cells

This study investigated the dual potential of Azolla pinnata fern protein hydrolysates (AFPHs) as functional and nutraceutical ingredients in an oil/water emulsion system. The AFPH-stabilised emulsion (AFPH-E) displayed a small and uniform droplet distribution and was stable to aggregation and creaming over a wide range of pH (5-8), salt concentrations ≤ 100 mM, and heat treatment ≤ 70 °C. Besides, the AFPH-E possessed and maintained strong biological activities, including antihypertensive, antidiabetic, and antioxidant, under different food processing conditions (pH 5-8; NaCl: 50-150 mM, and heat treatment: 30-100 °C). Following in vitro gastrointestinal digestion, the antihypertensive and antioxidant activities were unchanged, while a notable increase of 8% was observed for DPPH. However, the antidiabetic activities were partially reduced in the range of 5-11%. Notably, AFPH-E modulated the gut microbiota and short-chain fatty acids (SCFAs), promoting the growth of beneficial bacteria, particularly Bifidobacteria and Lactobacilli, along with increased SCFA acetate, propionate, and butyrate. Also, AFPH-E up to 10 mg mL-1 did not affect the proliferation of the normal colon cells. In the current work, AFPH demonstrated dual functionality as a plant-based emulsifier with strong biological activities in an oil/water emulsion system and promoted healthy changes in the human gut microbiota.

Characterization of Yeast Protein Hydrolysate for Potential Application as a Feed Additive

Yeast protein can be a nutritionally suitable auxiliary protein source in livestock food. The breakdown of proteins and thereby generating high-quality peptide, typically provides nutritional benefits. Enzyme hydrolysis has been effectively uesed to generate peptides; however, studies on the potential applications of different types of enzymes to produce yeast protein hydrolysates remain limited. This study investigated the effects of endo- (alcalase and neutrase) and exotype (flavourzyme and prozyme 2000P) enzyme treatments on yeast protein. Endotype enzymes facilitate a higher hydrolysis efficiency in yeast proteins than exotype enzymes. The highest degree of hydrolysis was observed for the protein treated with neutrase, which was followed by alcalase, prozyme 2000P, and flavourzyme. Furthermore, endotype enzyme treated proteins exhibited higher solubility than their exotype counterparts. Notably, the more uniform particle size distribution was observed in endotype treated yeast protein. Moreover, compared with the original yeast protein, the enzymatic protein hydrolysates possessed a higher content of β-sheets structures, indicating their higher structural stability. Regardless of enzyme type, enzyme treated protein possessed a higher total free amino acid content including essential amino acids. Therefore, this study provides significant insights into the production of protein hydrolysates as an alternative protein material.

Non-covalent interaction between hemp seed globulin and two hemp seed phenolic compounds: Mechanism and effects on protein structure, bioactivity, and in vitro simulated digestion

This study focused on elucidating the non-covalent interactions between hemp seed globulin (GLB) and two hemp seed phenolic compounds, Cannabisin A (CA) and Cannabisin B (CB), and to explore these interactions on the protein's structure, conformation, and functionality. Fluorescence quenching and thermodynamic analysis revealed that static quenching governed non-covalent interaction processes, with hydrogen bonds and van der Waals forces functioning as major forces. This was further substantiated by molecular docking studies. The binding affinity order was CA > CB, indicating that the specific phenolic compound had a notable impact on the binding affinity. Furthermore, when complexed with CA, Tyr and Trp residues were exposed to a more hydrophilic environment than when complexed with CB. It was noted that the complexation with either CA or CB consistently affects GLB's secondary structure, particle size, and ζ-potential. GLB treated with the phenolic compounds exhibited enhanced ABTS and DPPH scavenging activities and improved digestibility compared to untreated GLB. Furthermore, the non-covalent interactions significantly increased CA's water solubility, highlighting GLB as a promising natural carrier for hydrophobic bioactive components. These findings hold potential implications for enhancing hemp seed protein applications within the food industry by positively influencing its functional properties and bioactivity.

Microfluidic Analysis for the Determination of Protein Content in Different Types of Plant-Based Drinks

The widespread consumption of plant-based drinks, driven by health and dietary reasons (including cow's milk allergy, lactose intolerance, milk protein intolerance, following a vegetarian or vegan diet) necessitates automated and accurate test methods. Our study demonstrates the simultaneous determination of protein components and total protein concentrations in plant-based milk alternatives using a rapid and reproducible microchip gel electrophoretic method. As expected, the electrophoretic profiles of each plant-based drink differed. Based on our analyses and statistical evaluation, it can be determined that the protein profiles of different plant-based beverages do not differ significantly between different manufacturers or different expiry dates. The measured total protein content was compared with the nominal values, i.e., the values stated on the beverage labels. As the number of consumers of functional and specialized plant-based milk alternatives continues to rise, it is important to prioritize methods that provide qualitative and quantitative information on protein composition and other nutrients.

Applications of Enzyme Technology to Enhance Transition to Plant Proteins: A Review

As the plant-based food market grows, demand for plant protein is also increasing. Proteins are a major component in foods and are key to developing desired structures and textures. Seed storage proteins are the main plant proteins in the human diet. They are abundant in, for example, legumes or defatted oilseeds, which makes them an excellent candidate to use in the development of novel plant-based foods. However, they often have low and inflexible functionalities, as in nature they are designed to remain densely packed and inert within cell walls until they are needed during germination. Enzymes are often used by the food industry, for example, in the production of cheese or beer, to modify ingredient properties. Although they currently have limited applications in plant proteins, interest in the area is exponentially increasing. The present review first considers the current state and potential of enzyme utilization related to plant proteins, including uses in protein extraction and post-extraction modifications. Then, relevant opportunities and challenges are critically discussed. The main challenges relate to the knowledge gap, the high cost of enzymes, and the complexity of plant proteins as substrates. The overall aim of this review is to increase awareness, highlight challenges, and explore ways to address them.

Functional Properties of Corn Byproduct-Based Emulsifier Prepared by Hydrothermal-Alkaline

As consumers' interest in nature-sourced additives has increased, zein has been treated hydrothermally under alkaline conditions to prepare a nature-sourced emulsifier. The effects of mild hydrothermal-alkaline treatment with different temperatures or alkaline concentrations on the emulsifying properties of zein were investigated. The emulsification activity and stability index of zein hydrolysates increased by 39% and 164%, respectively. The optimal simple stabilized emulsion was uniform and stable against heat treatment up to 90 °C, sodium chloride up to 200 mmol/L, and pH values ranging from 6 to 9. Moreover, it presented excellent storage stability compared to commonly used food emulsifiers. The surface hydrophobicity caused the depolymerization of the tertiary structure of zein and the dissociation of subunits along with exposure of hydrophilic groups. The amino acid composition and circular dichroism results reveal that the treatment dissociated protein subunits and transformed α-helices into anti-parallel β-sheets and random coil. In conclusion, mild hydrothermal-alkaline treatment may well contribute to the extended functional properties of zein as a nature-sourced emulsifier.

Fabrication of emulsions prepared by rice bran protein hydrolysate and ferulic acid covalent conjugate: Focus on ultrasonic emulsification

The aim of the paper was to investigate the effect of ultrasonic emulsification treatment on the fabrication mechanism and stability of the emulsion. The covalent conjugate made with rice bran protein hydrolysate (RBPH) and ferulic acid (FA) was used as the emulsifier. The effects of high intensity ultrasound (HIU) power with different level (0 W, 150 W, 300 W, 450 W and 600 W) on the stability of emulsion were evaluated. The results showed that ultrasonic emulsification can significantly improve the stability of the emulsions (p < 0.05). The emulsion gained better stability and emulsifying property at 300 W. It was able to fabricate emulsion with smaller particle size, more uniform distribution and higher interfacial protein content. It was confirmed by fluorescent microscopy and cryo-scanning electron microscopy (cryo-SEM) furtherly. And it was also proved that the emulsion treated by proper HIU treatment at 300 W had better storage stability. Excessive HIU treatment (450 W, 600 W) had negative effects on the stability of emulsion. The stability of emulsion (300 W) against different environmental stresses was further explored, which established a theoretical basis for the industrial application of emulsion in food industry.