Emulsifying Activity Research Articles

Impact of a Dual Treatment on Resistant Starch Level and Techno‐Functional Properties of Pea and Faba Bean Flours

AbstractStarch‐rich pulses’ flours, which are rich in fiber and resistant starch (RS), can be an interesting gluten‐free ingredient for the development of novel healthy foods. The study aims to increase the RS content of protein‐reduced fraction of legume flours (pea [P] and faba bean [FB]) by the application of thermal (autoclaving‐cooling) and dual (thermal plus high‐hydrostatic pressure) treatments. Both treatments enhance the RS contents, reaching 6.8% in P flour after dual treatment. The techno‐functional properties are dependent both on the type of flour and the treatment applied. A loss of water solubility (WS) and an increase in water binding capacity are observed. The WS index and emulsion activity remained unchanged or slightly changed, but emulsion stability decreased significantly. The viscosity of the samples is modified according mainly to the flour type. P flour is more affected by the dual treatment than FB flour, which is evidenced by the greater changes shown in RS, WS, and pasting properties.

Unveiling a novel exopolysaccharide produced by Pseudomonas alcaligenes Med1 isolated from a Chilean hot spring as biotechnological additive

Exopolysaccharides (EPSs), a constitutive part of bacterial biofilm, act as a protecting sheath to the extremophilic bacteria and are of high industrial value. In this study, we elucidate a new EPS produced by thermotolerant (growth from 34–44 °C) strain Pseudomonas alcaligenes Med1 from Medano hot spring (39.1 °C surface temperature, pH 7.1) located in the Central Andean Mountains of Chile. Bacterial growth was screened for temperature tolerance (10–60 °C) to confirm the thermotolerance behaviour. Physicochemical properties of the EPS were characterized by different techniques: Scanning Electron Microscopy- Energy Dispersive X-ray Spectroscopy (SEM-EDS), Atomic Force Microscopy (AFM), High-Performance Liquid Chromatography (HPLC), Gel permeation chromatography (GPC), Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR), and Thermogravimetric analysis (TGA). Whole genome of P. alcaligenes Med1 has also been studied in detail to correlate the structural and functional characteristics with genomic insight. The EPS demonstrated amorphous surface roughness composed of evenly distributed macromolecular lumps composed of mainly carbon and oxygen. The monosaccharide analysis has shown the presence of glucose, galactose, and mannose sugars at different ratios. TGA revealed the high thermal stability (315.3 °C) of the polysaccharide. The GPC has shown that Med1 is a low molecular weight polysaccharide (34.8 kDa) with low PI. The 2D-NMR linkage analysis suggests a diverse array of glycosidic bonds within the exopolysaccharide structure. The functional properties of the EPS were evaluated for food industry applications, specifically for antioxidant (DPPH, FRAP an H2O2). Extracted Med1 EPS revealed significant emulsification activity against different food grade vegetative oils (Coconut oil, Corn oil, Canola oil, Avocado oil, Sunflower oil, Olive oil, and Sesame oil). The highest 33.9% flocculation activity was observed with 60 mg L−1 EPS concentration. It showed water-holding (WHC) of 107.6% and oil-holding (OHC) capacity of 110.8%. The functional EPS produced by Pseudomonas alcaligenes Med1 from Central Andean Chilean hot spring of central Chile can be a useful additive for the food-processing industry.

Advances in Research on the Improvement of Low-Salt Meat Product Through Ultrasound Technology: Quality, Myofibrillar Proteins, and Gelation Properties.

The high sodium content in meat products poses health risks to consumers and does not align with modern green and healthy living standards. Current strategies for directly reducing the sodium content in meat products are limited by their negative impact on the sensory or quality attributes of the products. In recent years, there has been great interest in applying ultrasound technology to reduce sodium content. This paper discusses the advantages and disadvantages of current mainstream strategies for reducing the sodium content in meat products, as well as the potential mechanisms by which ultrasound-assisted marination improves the quality of low-salt meat products. The main findings indicate that ultrasound, through its cavitation and mechanical effects, facilitates the transition of proteins from stable insoluble aggregates to stable soluble complexes, exposing more hydrophilic groups and, thus, enhancing protein solubility. At the same time, ultrasound promotes a greater number of proteins to participate in the formation of interfacial layers, thereby increasing emulsifying activity. Furthermore, ultrasound treatment promotes the interaction between proteins and water, leading to partial unfolding of protein chains, which allows polar residues to more readily capture water in the gel, thereby improving the water-holding capacity of the gel. These effects will contribute to the formation of high-quality low-salt meat products. However, variations in the frequency, intensity, and duration of ultrasound treatment can lead to differing effects on the quality improvement of low-salt meat products.

A New Bacterial Strain Producing Both of the Surfactin and Fengycin Lipopeptide Biosurfactant with Strong Emulsifications on Crude Oil.

A new lipopeptide-producing strain Cytobacillus sp. R3-1 was isolated from the production water of the Daqing oilfield in China and identified based on 16S rRNA gene sequence analyses. The strain R3-1 is capable of simultaneously producing both of the surfactin and fengycin, the two major families of the lipopeptide biosurfactant. The chemical structures of the surfactin and fengycin were confirmed by a combination of the ESI-MS, FT-IR, and amino acid analyses, and the impact of various temperatures, pH, and NaCl concentrations on the emulsifying activity (E24) was investigated. The lipopeptide biosurfactant produced by the strain R3-1 exhibited strong emulsifying activity with E24 value over 60% on crude oil and different hydrocarbons, including the cyclohexane, hexadecane, benzene, toluene, kerosene, diesel oil, and liquid paraffin. Meanwhile, it showed excellent emulsifying activity across a broad range of conditions of the temperature up to 60 °C, NaCl tolerance up to 100 g/L, and pH values between 5 and 9, which suggests that the strain R3-1 is a valuable microbial candidate for the simultaneous production of the surfactin and fengycin lipopeptide biosurfactant with strong emulsifying properties and stability under diverse environmental conditions and is a potential application in environmental bioremediation and enhanced oil recovery.

Mechanism study on the improvement of egg white emulsifying characteristic by ultrasound synergized citral: Physicochemical properties, molecular flexibility, protein structure

As a natural emulsifier, egg white protein (EWP) has great interfacial characteristics and high security, and has broad development prospects. This study explored the impact of ultrasound synergized citral (CI) treatment on the microstructure, molecular flexibility and emulsifying property of EWP, and predicted the interaction between CI and ovalbumin (the main protein in EWP) through molecular docking. The decrease in free amino content and the growth in molecular weight of EWP suggested that CI and proteins were successfully grafted. The results of physicochemical properties revealed that UCEWP (ultrasound synergized citral-treated EWP) had smaller particle size and larger ζ-potential absolute value, which meant that the stability of UCEWP system was enhanced. From the perspective of interfacial characteristics, UCEWP had lower interfacial tension, which remarkably improved its emulsifying property. The emulsifying activity index (EAI) and emulsifying stability index (ESI) of UCEWP were 1.99 times and 3.19 times higher than that of natural EWP (NEWP). Analysis of Fourier transform infrared spectroscopy (FT-IR) and fluorescence spectroscopy illustrated that the secondary and tertiary structures of UCEWP were more disordered and stretched than those of EWPs. Protein microstructure demonstrated that UCEWP presented loose small particle distribution, and correlation analysis reflected that the improvement of molecular flexibility was positively correlated with the enhancement of emulsifying property. These results elucidated that ultrasound synergized CI treatment is an effective mean to improve the molecular flexibility and emulsifying property of EWP, which provides a valuable reference for further application of EWP.

TECHNO-FUNCTIONAL PROPERTIES OF CHICKPEA PROTEIN ISOLATE-TREATED ACIDIC AND BASIC PH-CYCLING

This study examined the impact of extreme pH-cycling treatments on chickpea protein isolate (CPI). Untreated CPI, along with samples shifted to pH 2 (pH2) and pH 12 (pH12), displayed solubilities of 60.25%, 25.01%, and 75.48%, respectively. Both treatments significantly improved water and oil absorption capacities. Emulsion activity and stability for CPI at pH2 and pH12 were 125 m2/g and 110 m2/g, respectively, versus 75 m2/g for the untreated sample. Notably, the foaming capacity and stability of pH12-treated CPI increased by 3.5 and 8.8 times, respectively, compared to the untreated protein. pH12-treated CPI also demonstrated the lowest gelling concentration at 10%, compared to 14% and 18% for untreated and pH2-treated CPI, respectively. Microstructural analysis revealed partial disintegration of CPI under pH-cycling, underscoring that alkaline pH12-shifting notably enhances functional properties of CPI.

Impact of dehulling, germination and fermentation on the bioactive and functional properties of grey pea flour.

Grey pea is a largely overlooked legume in the Nordic countries, and its potential uses in various food products remain unexplored. It is a nutrient-rich crop with low environmental impact, making it an attractive option for sustainable and nutritious plant-based alternatives. To investigate the impact of dehulling, germination, and fermentation on the bioactive (polyphenol content and antioxidant capacity) and functional characteristics (water absorption index, water solubility index, water and oil binding capacity, emulsifying properties and gelation concentration) of grey pea flour. Additionally, protein content and pasting properties (temperature, peak viscosity, trough viscosity, breakdown, final viscosity, and setback) were measured. Dehulling was performed using a runner disk sheller. Germination was carried out for 24 and 48 h at ambient temperature, and fermentation was conducted for 8 h at 43°C using a starter culture. The results indicate that dehulling did not significantly affect functional properties and gelling capacity (p = 0.297 for oil absorption capacity, p = 0.5 for emulsion activity, and p = 0.607 for emulsion stability), but it resulted in a notable decrease in total polyphenol content (TPC) and antioxidant capacity (TAC). Conversely, 48 h of germination increased TAC measured by two methods: FRAP (19%) and DPPH (30%). This process increased through viscosity by 1.2-fold, while it did not significantly affect the water absorption index (WAI), water solubility index (WSI), or the emulsifying properties of grey pea flour. Fermentation significantly improved TPC (p < 0.001 for whole grey peas and p = 0.004 for dehulled grey peas), with a TPC increase of up to 67% in fermented dehulled pea flour. TAC measured by both methods, showed significant increases, ranging from 35 to 104%. However, fermentation reduced emulsifying and pasting properties, as indicated by the peak, through and final viscosity, which may be desirable only for certain food products. Further, germination and fermentation showed significant increases in protein content, by 4 and 8%, respectively. Fermented grey pea flour exhibited enhanced bioactive characteristics, while 48-h germination positively impacted pasting properties. Overall, these processes led to changes in both the bioactive and functional properties of grey pea flour, creating opportunities for the use of these flours in a wide array of food products.

Thermal stability of γ-PGA modified fish gelatin emulsion.

Emulsions are thermally unstable systems. This research aimed to investigate the thermal stability of fish gelatin (FG) oil-in-water emulsions in the presence of poly-γ-glutamic acid (γ-PGA) as an additive after heat treatment. The study assessed how γ-PGA influences the thermal stability of FG emulsions over time, focusing on their properties, structure, and food application potential. The incorporation of γ-PGA significantly enhanced the thermal stability of FG emulsions, preserving their morphology after heating. Emulsions containing 0.1% γ-PGA showed no significant changes after 24 h at 90 °C, while emulsions without γ-PGA experienced noticeable delamination. Rheological evaluations revealed that the energy storage modulus and loss modulus of FG-γ-PGA emulsions remained consistently higher than those of FG emulsions, regardless of heating duration. Particle size analysis indicated minimal changes for FG-γ-PGA emulsions (413 nm after 24 h) compared to a substantial increase for FG emulsions (1598 nm). After heating, FG-γ-PGA emulsions demonstrated significantly higher emulsifying activity index (EAI) (74 m2 g-1 versus 22.7 m2 g-1) and emulsifying stability index (ESI) (97% versus 76%). Additionally, the texture properties of meat mince formulated with FG-γ-PGA emulsions were comparable to those containing fat, showcasing their potential as a fat replacement. The study concludes that γ-PGA enhances the thermal stability of FG emulsions, maintaining their integrity and improving functional properties under heat treatment. These findings offer valuable insights for the formulation of thermally stable emulsions, presenting promising opportunities for innovative applications in the food industry. © 2024 Society of Chemical Industry.

Spray dried protein concentrates from white button and oyster mushrooms produced by ultrasound-assisted alkaline extraction and isoelectric precipitation.

In the present study, the optimization of ultrasound-assisted alkaline extraction (UAAE) and isoelectric precipitation (IEP) was applied to white button (WBM) and oyster (OYM) mushroom flours to produce functional spray dried mushroom protein concentrates. Solid-to-liquid ratio (5-15% w/v), ultrasound power (0-900 W) and type of acid [HCl or acetic acid (AcOH)] were evaluated for their effect on the extraction and protein yields from mushroom flours submitted to UAAE-IEP protein extraction. Prioritized conditions with maximized protein yield (5% w/v, 900 W, AcOH, for WBM; 5% w/v, 900 W, HCl for OYM) were used to produce spray dried protein concentrates from white button (WBM-PC) and oyster (OYM-PC) mushrooms with high solids recovery (62.3-65.8%). WBM-PC and OYM-PC had high protein content (5.19-5.81 g kg-1), in addition to remarkable foaming capacity (82.5-235.0%) and foam stability (7.0-162.5%), as well as antioxidant phenolics. Highly pH-dependent behavior was observed for solubility (> 90%, at pH 10) and emulsifying properties (emulsification activity index: > 50 m2 g-1, emulsion stability index: > 65%, at pH 10). UAAE-IEP followed by spray drying increased surface hydrophobicity and free sulfhydryl groups by up to 196.5% and 117.5%, respectively, which improved oil holding capacity (359.9-421.0%) and least gelation concentration (6.0-8.0%) of spray dried mushroom protein concentrates. Overall, the present study showed that optimized UAAE-IEP coupled with spray drying is an efficient strategy to produce novel mushroom protein concentrates with enhanced functional attributes for multiple food applications. © 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.

Yeast cell wall-derived proteins: Identification and characterization as food emulsifiers

Emulsification activity has been identified in the cell wall mannoproteins of Saccharomyces cerevisiae—which is widely utilized in food products—and their applications have been explored. However, apart from Gas proteins, no other emulsifying cell wall proteins have been identified. A comprehensive understanding of the cell wall proteins involved in emulsification is crucial for advancing their applications. Herein, emulsifying proteins easily released from the cell wall, unlike Gas proteins that are covalently attached, were purified and characterized. Consequently, fructose 1,6-bisphosphate aldolase 1 (Fba1), Enolase (Eno) 1, and Eno2 showed emulsifying activity, and Fba1 had the highest activity. These are glycolytic proteins localized in the cytoplasm and cell wall. Because Triose-phosphate dehydrogenase (glyceraldehyde-3-phosphate dehydrogenase) 2 (Tdh2)—another glycolytic protein—is also localized in the cell wall, its emulsifying ability was investigated. Results indicated that Tdh2 also had strong activity and was comparable to the activity of casein, an emulsifier. Moreover, Tdh2 displayed higher emulsifying activity with 14 and 16 carbon hydrocarbons and stabilized emulsions in soybean oil. Tdh2—with a smaller molecular weight and nearly absent sugar chains compared to Gas proteins—holds promise for investigating the relationship between protein structure and emulsification. This study identified new emulsifying proteins localized to the cell wall through mechanisms other than covalent bonding. In addition, these proteins have potential applications as yeast-derived emulsifiers.

Enhancement of mono-acylated MEL-D production in an acyltransferase gene-deleted strain of Pseudozyma tsukubaensis by supplementation with di-acylated MEL-B in culture medium

Mannosylerythritol lipids (MELs) are glycolipid biosurfactants produced by various yeasts. MEL producers produce mainly di-acylated MELs (consisting of two fatty acid chains). Among them, Pseudozyma tsukubaensis is a di-acylated MEL-B (d-MEL-B) producer. In a previous study, we generated an acyltransferase-deleted strain of P. tsukubaensis (ΔPtMAC2), which selectively produced mono-acylated MEL-D (m-MEL-D, consisting of one fatty acid chain), but not d-MEL-B. However, m-MEL-D productivity in ΔPtMAC2 was low, and oil consumption was significantly reduced compared to the parent strain. Based on these findings, we hypothesized that the d-MEL-B produced by the parent strain may act as an emulsifier in the culture medium, leading to easier utilization of the oil. By contrast, the m-MEL-D produced by ΔPtMAC2 may not have the ability to emulsify oil, thus the oil is used inefficiently and productivity of m-MEL-D is low. Therefore, we expected that adding d-MEL-B to the culture medium during ΔPtMAC2 cultivation would increase m-MEL-D production. To enhance the oil consumption and m-MEL-D production of ΔPtMAC2, d-MEL-B and chemical surfactants were added to the culture medium as emulsifiers during ΔPtMAC2 cultivation. Adding d-MEL-B enhanced both the oil consumption and m-MEL-D production of ΔPtMAC2; Tween 20 and Triton X-100 also showed enhancement effects. As expected, d-MEL-B, Tween20 and TritonX-100, showed marked olive oil emulsification activity, whereas m-MEL-D did not. These results strongly support our hypothesis and significantly improve m-MEL-D productivity.

Maillard reacted wheat gluten and polydextrose complex enhances the emulsifying properties and stability of Pickering emulsion

This study aims to explore the characteristics and stability of Pickering emulsion based on the Maillard reaction products of polydextrose (PDX) and gluten. The effects of the PDX:gluten ratio (from 0.0:1 P0.0G1 to 2.4:1 P2.4G1) during Maillard reaction on Pickering emulsion quality were examined. The degree of PDX grafting to gluten increased from 0.51%±0.05% to 18.99%±0.98% when the PDX:gluten ratio increased from 0.2:1 to 2.2:1. Scanning electron microscopy and infrared spectroscopy confirmed the structural change and covalent interaction of PDX–gluten conjugate. The P2.2G1 conjugate showed a higher emulsification activity (1.82±0.04 m2/g) compared with P0.0G1 (0.97±0.05 m2/g). The particle size, ζ-potential value and confocal laser scanning microscopic image of PDX–gluten conjugate-based emulsion were compared with those of gluten-based emulsion to illustrate the stability role of PDX–gluten conjugate in the interfacial layer of Pickering emulsion. This study demonstrated that the Maillard reacted gluten–PDX conjugate was a potential stabilizer for Pickering emulsions. These findings provided a foundation knowledge for the construction of Pickering emulsion based on PDX–gluten conjugates.

Modulating the techno-functional properties of quinoa (Chenopodium quinoa Wild) protein concentrate using high-pressure technologies and their impact on in vitro digestibility: A comparative study

High hydrostatic pressure (HHP; 200–600 MPa at 24 °C for 20 min) and dynamic high pressure (DHP; 50–180 MPa) were applied to modulate the techno-functional properties of quinoa protein concentrate (QPC) produced from non-defatted flour using a lab-scale extraction. QPC's unique composition, with 74.6 % protein and significant levels of unsaturated fatty acids, influenced the effects of HHP and DHP. HHP significantly (P < 0.05) enhanced hydration properties, peaking at 400 and 500 MPa (on average 4.34 g/g), while DHP reduced the oil absorption capacity from 2.5 to 1.8 g/g. Both processing techniques decreased QPC protein solubility. This reduction corresponded to decreased foaming capacity and emulsifying properties in HHP-processed QPC. DHP increased emulsifying activity and stability indices, with optimized improvements at 100 MPa of 39.4 and 414.4 %, respectively. These modifications in QPC's properties occurred without noticeable loss in in vitro protein digestibility (IVPDaverage = 86.1 %). The findings support the potential of high-pressure technologies to uniquely modulate different techno-functional properties of QPC, produced from non-defatted flour, while maintaining high digestibility, thereby offering greater versatility in its use. Industrial relevanceQuinoa is a strategic choice for diversifying plant protein sources, with the use of non-defatted flour in QPC production offering new insights into its composition and properties, reducing both costs and environmental impact. In this study, HHP and DHP, recognized as “green” physical processing technologies, demonstrated advantageous potential to develop innovative quinoa protein ingredients with added value and clean-label appeal, while maintaining their high nutritional value. The distinctive effects of high-pressure technologies and varying pressure levels on modulating QPC's techno-functional properties underscore the creation of multifunctional QPC and the optimization of key properties, addressing the urgent demands of the plant-based food segment.

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.

Having their cake and eat it too: Effects of different cations in reduced-salt myofibrillar protein microgel pickering emulsion under high-intensity ultrasound

Health concerns have increased the demand for low-salt emulsified meat products emulsions; however, salt-soluble myofibrillar proteins (MP) are less than optimal emulsifiers under low-salt conditions. In this study, four different cations (Na+, K+, Ca2+, and Mg2+) were added to a Pickering emulsion and high-intensity ultrasound (HIU, 20 kHz, 600 W) was used to determine the quality of the final emulsion. The divalent cation group was found to significantly (P < 0.05) improve the emulsification performance of the emulsion; in particular, the emulsion activity index and emulsion stability index of Mg2+-H group increased to 16.24 ± 1.22 m2/g and 89.66 ± 3.01%, respectively. Measurements of the particle size and zeta potential confirmed that the emulsion particle size of the Mg2+-H group decreased, and the electrostatic repulsion force increased. Based on the surface hydrophobicity and endogenous tryptophan spectra, the particle structure of the MP microgel was determined to be a more stable emulsifier. What's more, the divalent cations promoted the droplets to become evenly dispersed under high-intensity ultrasound. The micrograph confirmed this result: the divalent cation group emulsion was more uniform and stable than the monovalent cation group emulsion. Divalent cations are more suitable than monovalent cations for improving the quality of reduced-salt Pickering emulsions.

Hofmeister ion effects induced by different acidifiers and alkalizers improve the techno-functional properties of complex rapeseed protein during pH-driven self-assembly

pH-driven method is an effective strategy to prepare complex protein. This study provides guidance on how to select acidifiers and alkalizers from view of Hofmeister ion effects. Cations and anions regulated the molecular structure (particle size, surface charge, protein folding/unfolding, structural orderliness) of complex rapeseed proteins (CRPs) mainly via electrostatic and hydrogen bond. No evident changes were found in the molecular weight distribution, but their distribution on oil/air-water interface varied greatly. Various techno-functional properties of CRPs were synergistically improved: Citrate3− and Na+ increased the emulsifying activity index of CRPs from 80 to 102.21 m2/g; Citrate3−, K+ and Na+ made the foaming stability of CRPs close to 80 % after 60 min of storage. Moreover, the oil/water-holding and gel properties of CRPs were regulated effectively. These findings demonstrate the key role of Hofmeister ion effects in improving CRPs properties, contributing to develop, select, and apply novel acidifiers and alkalizers during pH-driven treatment.

Characterization and functional properties of muskmelon seed meal and oil

Muskmelon seeds, often discarded as waste, are rich sources of protein and healthy oil, making them excellent alternate sources of fat and protein. Muskmelon seeds of hybrid cultivars were assessed for their physico-chemical and functional properties. Fat and protein content of endosperm varied from 38.77–42.74 % and 22.6–35.17 %, respectively. Muskmelon seed oil showed desired characteristics as per WHO norms with high saponification value of 190.28–197.65. Linoleic acid (60.5–65.6 %) and palmitic acid (8.3–9.5 %) were the major constituent of melon seed oil. Defatted muskmelon seed meals (DSMs) contained 36.45–48.12 % proteins and minerals like potassium, phosphorous, magnesium and calcium. The total polyphenol content of the various DSMs ranged from 11.94 to 15.503 mg GAE/g, and the antioxidant activity quantified as IC50 value, ranged from 24.75–32.97 mg/ml. Chloroform and methanol extract of seeds showed anti-proliferative activity, with IC 50 value varied from 75.07–141.3 µg/ml. Solvent retention capacity of defatted seed meals ranged from 60.94 to 104.5 % (water), 86.87–137.39 % (sodium carbonate), 95.09–123.11 % (lactic acid) and 89.27–138 % (sucrose). WAC and OAC varied from 1.64–2.35 g/g and 1.97–2.13 g/g respectively. Solubility of DSMs varied from 20–35 %, maximal at alkaline pH. Likewise, emulsion activity and solubility also followed classic U-shaped curve and were highest at alkaline pH. The study concluded that muskmelon seeds being rich in protein and oil can be unconventional, sustainable, environmentally friendly and vegan sources of high quality protein and PUFA rich oil.

Enzymatic Hydrolysis as an Effective Method for Obtaining Wheat Gluten Hydrolysates Combining Beneficial Functional Properties with Health-Promoting Potential.

The byproduct from wheat starch production contains approximately 70% gluten (WG) and is an inexpensive but demanding protein raw material for the food industry. This study attempted to determine the optimal hydrolysis conditions for such raw material to obtain peptides combining beneficial functional characteristics with health-promoting activity. The proteases Bromelain, Alcalase, Flavourzyme, and a protease from A. saitoi were used for hydrolysis. It was shown that the tested proteases differ both in terms of the effective hydrolysis conditions of gluten and the profile of the released hydrolysates. Bromelain was particularly effective in converting gluten into peptides, combining beneficial health and functional properties. It achieved maximum activity (189 U/g) against WG at pH 6 and 60 °C, and the best-balanced peptides in terms of desired properties were released at a dose of 2.5 U/g. These peptides were free from most allergenic epitopes, effectively inhibited ACE, and, at 0.34 g, were equivalent to the approved dose of BHT. Their emulsifying activity was higher than that of gluten, and the foaming formation and stabilization potential exceeded that of ovalbumin by 10% and 19%, respectively. It seems that Bromelain-released WG hydrolysates are a promising candidate for a safe fat stabilizer and egg white substitute.

The functional attributes of protein hydrolysates from horsegram (Macrotyloma uniflorum)

SummaryThe functional attributes of enzymatically derived horsegram protein hydrolysates from dehulled horsegram were investigated in this study. Hydrolysates were produced using commercial proteases, namely Alcalase® 2.4L and Protex 6L, at varying degrees of hydrolysis (DH) – specifically, 5%, 8%, and 10%. Maximum DH reached 11% with Alcalase® 2.4L and 11.5% with Protex 6L. Optimal hydrolysis conditions entailed a dehulled horsegram concentration of 2.5% (w/v), an enzyme–substrate ratio (E/S) of 0.001% for Alcalase® 2.4L and 0.002% for Protex 6L, at 55 °C and 60 °C, respectively, for 5 h, maintaining a pH of 7.5. Enhanced solubility was observed across a wide pH range (2–10), with HG‐PH exhibiting an increase from 21% to 56%. Analysis of functional properties revealed a significant elevation (P &lt; 0.05) in both water holding and oil holding capacities with increasing DH. Emulsion activity decreased from 0.5 to 0.1 in proportion to DH increase. Conversely, foaming capacity (FC) showed a positive correlation with the hydrolysis extent, rising from 24% to 98%. However, foam stability decreased across all samples, declining from 84% to 12%. These findings underscore the potential of incorporating these hydrolysates into diverse food applications, capitalising on their heightened solubility, water and oil holding capacities, and foam‐forming characteristics. The comprehensive array of functional properties exhibited by HG‐PH renders it a promising ingredient for integration into food product formulations.

Covalent interaction of ovalbumin with proanthocyanidins improves its thermal stability and antioxidant and emulsifying activity.

The structure of proanthocyanidins (PC) contains a large number of active phenolic hydroxyl groups, which makes it have strong antioxidant capacity. This study investigated the structural and functional properties of ovalbumin (OVA) modified by its interaction with PC. It was found that on increasing the concentration ratio of PC to OVA from 10:1 to 40:1, the free amino and total sulfhydryl contents of OVA decreased from 470.59 ± 38.77 and 29.81 ± 0.31 nmol mg-1 to 96.61 ± 4.55 and 21.22 ± 0.78 nmol mg-1, respectively, and the free sulfhydryl content increased from 7.65 ± 0.41 to 9.48 ± 0.58 nmol mg-1. These results indicated that CN and CS bonds were formed and PC was covalently linked with OVA. The PC content in the OVA-PC conjugates increased from 281.93 ± 12.92 to 828.81 ± 46.09 nmol mg-1 on increasing the concentration ratio of PC to OVA from 10:1 to 40:1. The contents of α-helix and β-turn of OVA decreased, and the contents of β-sheet and random coil increased, confirmed by circular dichroism. The tertiary structure of OVA was also altered according to the results of fluorescence and ultraviolet absorption spectra. The surface hydrophobicity of OVA-PC conjugates decreased with increasing bound polyphenol content. The conjugation of OVA to PC significantly improved its emulsification and antioxidant activity and denaturation temperature. This study may provide valuable information for improving OVA's functional properties and its PC conjugates for applications in the food industry. © 2024 Society of Chemical Industry.