Effects of degree of hydrolysis (DH) on the functional properties of egg yolk hydrolysate with alcalase

Identifying the potential of ovalbumin and its' hydrolysates to be used in a liquid food system to develop functional beverages

Ready-to-drink protein beverages have gained attention in the functional beverage market. This study examined the possibility of using ovalbumin and its hydrolysates to develop functional protein beverages. Lyophilized ovalbumin (5%, w/v) was dissolved in distilled water (pH 10) with sugar, salt, and vanilla and pasteurized at 56.7°C for 3.5 min to prepare a basal ovalbumin beverage (OVA). The beverages were sequentially hydrolyzed using pepsin (pH 2.5, 37°C for 3 h) first, then with protease (pH 6.5, 37°C for 3 h), or protease (pH 6.5, 37°C for 3 h) followed by trypsin (pH 7.8, 37°C for 3 h) combinations. Three beverages (OVA, PrTr, and PePr) were tested for physical, functional, and quality characteristics. Complete hydrolysis by enzyme combinations was ensured using 15% SDS-PAGE. Enzymatic hydrolysis caused an increase in the solubility of ovalbumin in water. The beverages showed antioxidant activity, and hydrolyzed drinks showed antimicrobial activity. No significant difference in acidity, but a reduction in pH, an increase in TSS, and alterations in viscosity were observed among the drinks with storage. A significant difference (p < 0.05) in titratable acidity was identified between the two hydrolyzed drinks, but no difference (p > 0.05) within a treatment was observed until Day 14. In conclusion, ovalbumin and its hydrolysates have the potential for preparing functional protein beverages with a shelf-life of up to 7 days.

Preparation of microgel particles from egg yolk components by combining phospholipase A2 with high-pressure homogenization: Physicochemical, structural properties and their effects on foaming, processing stability of egg white protein

In this study, two types of microgel particles from egg yolk components were prepared by combining enzymatic hydrolysis with high-pressure homogenization (HPH), and their differences in physicochemical properties, foaming properties, and microstructure were compared. Results showed that the particle size of both types of microgel particles had decreased from 2744.07 ± 408.26 nm (egg yolk, EY) to 144.97 ± 3.19 nm (PLA2 hydrolyzed egg yolk microgel particles, PYM) and 535.07 ± 46.07 nm (egg yolk microgel particles hydrolyzed by PLA2, YMP), from 736.24 ± 34.61 nm (EG) to 182.76 ± 4.12 nm (PLA2 hydrolyzed egg yolk granules microgel particles, PGM) and 443.98 ± 27.09 nm (egg yolk granules microgel particles hydrolyzed by PLA2, GMP). Besides, their interfacial adsorption abilities were significantly improved, reflected in the increase values in overrun, from161.90 % ± 9.84 % (EY) to 269.64 % ± 16.73 % (PMY) and 307.20 % ± 16.09 % (YMP), from 189.21 % ± 5.02 % (EG) to 280.38 % ± 36.05 % (PGM) and 261.91 % ± 34.03 % (GMP). Their structural properties showed higher stabilities after treatments. When the microgel particles are applied to cakes, the specific volume was increased from 2.05 ± 0.1 mL/g (EY) to 2.25 ± 0.13 mL/g (PYM) and 2.45 ± 0.03 mL/g (YPM), and from 2.00 ± 0.09 mL/g (EG) to 2.51 ± 0.13 mL/g (PGM) and 2.75 ± 0.21 mL/g (GMP), respectively. The hardness and chewiness were reduced with both types of microgel particles from egg yolk components, which indicated their potential value as edible foam stabilizers in the baking industry.

Direct hydrolysis of einkorn whole grain flour proteins for the generation of bioactive peptides using various proteases

In this study, it was aimed to investigate the direct release of BAPs from einkorn flour in one-step process. Thus, the protein extraction step was eliminated, thereby reducing processing cost. Commercial proteases (Alcalase, Flavourzyme, Neutrase, and Trypsin), and crude enzyme from Bacillus mojavensis sp. EBTA7 were used for hydrolyzing einkorn flour (30 %, w/v) solutions at 50-60 °C. The supernatants after centrifugation were used for bioactivity and techno-functionality tests. All hydrolysates demonstrated significant antioxidant capacities, with values ranging from 17.7 to 33.0 μmol TE/g for DPPH, 107 to 190 μmol TE/g for ABTS, and 0.09 to 3.08 mg EDTA/g for ion-chelating activities. Alcalase and Flavourzyme hydrolysis had the highest DPPH activities, while Bacillus mojavensis sp. EBTA7 enzyme yielded relatively high ABTS and ion-chelating activities. Notably, Bacillus mojavensis sp. EBTA7 crude enzyme hydrolysates demonstrated higher oil absorption capacity (2.94 g oil/g hydrolysate), robust emulsion (227 min), and foam stability (94 %) compared to commercial enzymes. FTIR spectroscopy confirmed variations in the secondary structure of peptides. All hydrolysates exhibited negative zeta potentials. The SDS-PAGE showcased MW ranged from 14 to 70 kDa, which was influenced by both the enzyme type and the degree of hydrolysis. Overall, Bacillus mojavensis sp. EBTA7 hydrolysates revealed considerable bio and techno-functional characteristics.

Insight into the solubilization mechanism of wheat gluten by protease modification from conformational change and molecular interaction perspective

The low solubility limits the utilization of other functional characteristics of wheat gluten (WG). This study effectively improved the solubility of WG through protease modification and explored the potential mechanism of protease modification to enhance the solubility of WG, further stimulating the potential application of WG in the food industry. Solubility of WG modified with alkaline protease, complex protease, and neutral protease was enhanced by 98.99%, 54.59%, and 51.68%, respectively. Notably, the content of β-sheet was reduced while the combined effect of hydrogen bond and ionic bond were increased after protease modification. Meanwhile, the reduced molecular size and viscoelasticity as well as the elevated surface hydrophobicity, thermostability, water absorption capacity, and crystallinity were observed in modified WG. Moreover, molecular docking indicated that protease was specifically bound to the amino acid residues of WG through hydrogen bonding, hydrophobic interaction, and salt bridge.

Assessment of functional efficacy of sheep plasma protein hydrolysates and their utilization in mutton sausage

The present study examines the bioactive potential of sheep plasma protein hydrolysates (SPPH) produced by in-vitro gastrointestinal digestion as antioxidants, antimicrobials, anti-obesity agents, and inhibitors of lipid oxidation in sausage to address the oxidative stability and shelf-life issues of mutton. The antioxidant and antimicrobial activities, indicate a positive relationship between the degree of hydrolysis and digestion duration. The study finds that SPPH has a potent inhibitory effect on pancreatic lipase and cholesterol esterase. It has higher oil holding capacity than sheep plasma protein, observed at one hour of hydrolysis time. SPPH exhibit an improved behavior in foaming properties along alkaline pH and digestion time while display lower emulsifying activity and stability with hydrolysis advancement. The SPPH act as a natural preservative in developing functional mutton sausage by inhibiting lipid-oxidation. This study showed that the recovery of SPPH can be a cost-effective and sustainable strategy for generating available ingredients for enhanced shelf-life of meat products.

Effect of high-hydrostatic pressure on the digestibility of egg yolk and granule

The impact of high hydrostatic pressure (HHP) on protein digestibility of egg yolk and egg yolk granule was evaluated by static in vitro digestion using the standardized INFOGEST 2.0 method. The degree of hydrolysis (DH) and the phospholipid content were determined during digestion, and the protein and peptide profiles were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and reverse phase-high pressure liquid chromatography (RP-HPLC). The results showed that HHP induced protein aggregation in egg yolk and granule, mainly by disulfide bridges, which were not disrupted in the oral phase. Proteolysis during the gastric phase improved egg yolk and granule protein solubility, regardless of whether HHP was applied. However, the extent of the samples' digestibility was not affected, with DH values ranging from 15% to 20%. During the intestinal phase, the DH of egg yolk protein (∼40%) was higher than that of the granule (∼25%), probably due to the denser structure of the granule reducing the accessibility of intestinal enzymes. The DH, peptide, and protein profiles of control and HHP-treated egg yolk showed similar protein digestion behaviors for both gastric and intestinal phases. Among the different proteins, only the digestibility of β-phosvitin in HHP-treated granule was enhanced. Consequently, applying HHP to granules represents an interesting process that improves the digestibility of phosvitin with the potential to generate bioactive phosvitin-derived phosphopeptides. PRACTICAL APPLICATION: High hydrostatic pressure, mainly used as a preservation process, did not impair the nutritional quality of the egg yolk and granule proteins but improved the susceptibility of phosvitin (protein contained in egg yolk) proteolysis to produce bioactive phosphopeptides. Consequently, applying HHP to granules represents an interesting process that improves the digestibility of phosvitin.

Egg Yolk as a New Source of Peptides with Antioxidant and Antimicrobial Properties

A significant increase in interest in food-derived peptides obtained mostly through enzymatic reactions has been observed in the past few years. One of the best sources of bioactive peptides are defatted egg yolk proteins, which can potentially find application as high-quality nutritional supplements for infants with cow's milk protein intolerance and as natural preservatives. The aim of this study was to obtain peptides from defatted egg yolk protein, to study their antioxidant and antimicrobial properties, and to identify peptides with bioactive properties To control the course of the process, MALDI-TOF/MS (matrix-assisted laser desorption/ionization time-of flight/mass spectrometry) spectra were also examined. The peptide mixture obtained through enzyme digestion was tested for its antioxidant properties by measuring the scavenging activity in 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•), 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical cation decolorization (ABTS•+), and ferric reducing activity (FRAP) assays. Antimicrobial activity was also studied. The peptide mixture exhibited significant antioxidant activity: DPPH-1776.66 ± 32.99, ABTS-390.43 ± 8.92, and FRAP-16.45 ± 0.19. The inhibition of bacterial growth by two concentrations of the peptide mixture was examined. The best result was obtained in Bacillus cereus, with an inhibition zone of 20.0 ± 1.0 and 10.7 ± 0.6 mm at the concentrations of 50 and 25 mg/mL, respectively. The results of the study suggest that the mixture of egg yolk peptides may exhibit a number of health-promoting properties.

Technological, nutritional, and biological properties of apricot kernel protein hydrolyzates affected by various commercial proteases

The effect of enzymatic hydrolysis of apricot kernel protein with different proteases (Alcalase, pancreatin, pepsin, and trypsin) on the amino acid content, degree of hydrolysis (DH), antioxidant, and antibacterial characteristics of the resulting hydrolyzates was investigated in this study. The composition of amino acids (hydrophobic: ~35%; antioxidant: ~13%), EAA/TAA ratio (~34%), and PER index (~1.85) indicates the ability of the hydrolyzate as a source of nutrients and antioxidants with high digestibility. Enzymatic hydrolysis with increasing DH (from 3.1 to a maximum of 37.9%) led to improved solubility (especially in the isoelectric range) and changes in water- and oil-holding capacity. The highest free radical scavenging activity of DPPH (83.3%), ABTS (88.1%), TEAC (2.38 mM), OH (72.5%), NO (65.7%), antioxidant activity in emulsion and formation of TBARS (0.36 mg MDA/L), total antioxidant (1.61), reducing power (1.17), chelation of iron (87.7%), copper (34.8%) ions, and inhibition of the growth of Escherichia coli (16.3 mm) and Bacillus cereus (15.4 mm) were affected by the type of enzymes (especially Alcalase). This research showed that apricot kernel hydrolyzate could serve as a nutrient source, emulsifier, stabilizer, antioxidant, and natural antibacterial agent in functional food formulations.

Kinetics of Egg-Yolk Protein Hydrolysis and Properties of Hydrolysates

Lecithin-free egg yolk (LFEY) is a byproduct of the extraction of egg-yolk phospholipids, which contain approximately 46% egg yolk proteins (EYPs) and 48% lipids. The enzymatic proteolysis is the alternative to increase the commercial value of LFEY. The kinetics of proteolysis in full-fat and defatted LFEY with Alcalase 2.4 L was analyzed in terms of the Weibull and Michaelis-Menten models. A product inhibition effect was also studied in the full-fat and defatted substrate hydrolysis. The molecular weight profile of hydrolysates was analyzed by gel filtration chromatography. Results pointed out that the defatting process did not importantly affect the maximum degree of hydrolysis (DH_max) in the reaction but rather the time at which DH_max is attained. The maximum rate of hydrolysis (V_max) and the Michaelis-Menten constant K_M were higher in the hydrolysis of the defatted LFEY. The defatting process might have induced conformational changes in the EYP molecules, and this affected their interaction with the enzyme. Consequently, the enzymatic reaction mechanism of hydrolysis and the molecular weight profile of peptides were influenced by defatting. A product inhibition effect was observed when adding 1% hydrolysates containing peptides lower than 3 kDa at the beginning of the reaction with both substrates.

The dynamic change in the degradation and in vitro digestive properties of porcine myofibrillar protein during freezing storage

The myofibrillar protein (MP) degradation and in vitro digestive properties of porcine longissimus during freezing at -8, -18, -25 and - 40 °C for 1, 3, 6, 9 and 12 months were investigated. As the freezing temperature and duration of frozen storage increased, the amino nitrogen and TCA (trichloroacetic acid)-soluble peptides of the samples were significantly increased, while the total sulfhydryl content and band intensity of myosin heavy chain, actin, troponin T, tropomyosin were significantly decreased (P < 0.05). At higher freezing storage temperatures and durations, the particle size of MP samples and the green fluorescent spots detected using a laser particle size analyzer and confocal laser scanning microscopy became large. After 12 months of freezing, the digestibility and the degree of hydrolysis of the trypsin digestion solution of the samples frozen at -8 °C were significantly decreased by 15.02 % and 14.28 %, respectively, when compared to fresh samples, whereas, the mean surface diameter (d_3,2) and mean volume diameter (d_4,3) were significantly increased by 14.97 % and 21.53 %, respectively. Therefore, frozen storage induced protein degradation and impaired the ability of digestion in the pork proteins. This phenomenon was more evident as the samples were frozen at high temperatures over a long storage period.

The Impact of Processing and Extraction Methods on the Allergenicity of Targeted Protein Quantification as Well as Bioactive Peptides Derived from Egg

This review article discusses advanced extraction methods to enhance the functionality of egg-derived peptides while reducing their allergenicity. While eggs are considered a nutrient-dense food, some proteins can cause allergic reactions in susceptible individuals. Therefore, various methods have been developed to reduce the allergenicity of egg-derived proteins, such as enzymatic hydrolysis, heat treatment, and glycosylation. In addition to reducing allergenicity, advanced extraction methods can enhance the functionality of egg-derived peptides. Techniques such as membrane separation, chromatography, and electrodialysis can isolate and purify specific egg-derived peptides with desired functional properties, improving their bioactivity. Further, enzymatic hydrolysis can also break down polypeptide sequences and produce bioactive peptides with various health benefits. While liquid chromatography is the most commonly used method to obtain individual proteins for developing novel food products, several challenges are associated with optimizing extraction conditions to maximize functionality and allergenicity reduction. The article also highlights the challenges and future perspectives, including optimizing extraction conditions to maximize functionality and allergenicity reduction. The review concludes by highlighting the potential for future research in this area to improve the safety and efficacy of egg-derived peptides more broadly.

Flavor substances of low-valued red swamp crayfish (Procambarus clarkii) hydrolysates derived from double enzymatic systems

To make better use of low-valued crayfish (Procambarus clarkii), double enzymatic systems containing endopeptidase and Flavourzyme® were applied to investigate their effect on the physicochemical properties and volatile substances of low-valued crayfish. The results demonstrated that the double enzymatic hydrolysis had a positive effect on reduced bitterness and increased umami. Among them, the highest degree of hydrolysis (31.67 %) was obtained using trypsin and Flavourzyme® (TF), which showed 96.32 % of peptides with molecular weight < 0.5 kDa and 101.99 mg/g of free amino acids. The quality and quantity analysis showed that the types and relative contents of volatile compounds especially benzaldehyde, 1-octen-3-ol, nonanal, hexanal, 2-nonanone, 2-undecanonewere increased in the double enzymatic hydrolysis. In addition, the increase of esters and pyrazines was also found in gas chromatography-ion mobility spectrometry (GC-IMS). The results indicated that different enzymatic systems could be performed to enhance the flavor substances of low-valued crayfish. In conclusion, double enzymatic hydrolysis may be used as an advisable technique to promote the high-value utilization of low-valued crayfish and provides valuable information for the shrimp products requiring enzymatic hydrolysis.

Nutritional Quality, Techno-Functional Characteristics, and Safety of Biomass Powder and Protein Isolate Produced from Penicillium maximae

This study investigated the suitability of Penicillium maximae biomass powder and protein isolate as a food product or food ingredient. The biomass powder is rich in proteins (34.8%) and insoluble fiber (36.2%) but poor in lipids (3.1%). Strong water hydration (8.3 g/g, 8.5 g/g) and oil holding (6.9 g/g, 16.3 g/g) capacity were observed in the biomass powder and protein isolate, respectively, besides 100% emulsion stability, indicating multiple applications in the food industry. No locomotor impairment was induced in Drosophila melanogaster flies after consuming extracts of P. maximae biomass powder. Furthermore, decreased production of reactive oxygen species and preservation of survival, viability, and fertility parameters were observed in the nematode Caenorhabditis elegans, which reinforces the potential of P. maximae biomass for human and animal consumption. Together, the results show the vast food applicability of P. maximae biomass and protein isolate as protein substitutes with several health and environmental benefits.

Study on functional improvement of freeze-thaw egg yolk pellet by enzymatic hydrolysis

Freeze-thaw egg yolk pellet (FYP) could be produced as a by-product in the process of egg yolk immunoglobulin (IgY) extraction. The FYP contained many superior nutritional components like fresh egg yolk, but it has poor functionalities because of protein denaturation resulted from freezing treatment during IgY extraction. For the purpose of comprehensive utilization of egg yolk resources, FYP was subjected to enzymatic hydrolysis with alcalase to produce FYP hydrolysates (FYPh) with four enzyme concentrations of 250, 500, 1000 and 2000 U/g for improved functional properties. And then FYPh was spray dried to obtain hydrolyzed egg yolk pellet powder (HYP). Solubility, emulsifying property and surface hydrophobicity of HYP were investigated. The results showed that enzymatic hydrolysis could lead to noticeable changes in surface hydrophobicity, microstructure, solubility and emulsifying properties of HYP compared with the control group without enzymatic hydrolysis treatment. Solubility and emulsification stability index generally increased from 19 g/100 g, 12.33 to 87 g/100 g, 76.63 with increasing degree of hydrolyze, respectively. This study demonstrated that the functional properties of FYP could be effectively improved when the enzyme addition amount reached 1000 U/g. HYP prepared under this condition owes desirable solubility and emulsification, and has the potential of application in food industry.

Co-fermented cow milk protein by Lactobacillus helveticus KLDS 1.8701 and Lactobacillus plantarum KLDS 1.0386 attenuates its allergic immune response in Balb/c mice

Milk protein is one of the major food allergens. As an effective processing method, fermentation may reduce the potential allergenicity of allergens. This study aimed to evaluate the therapeutic potential of co-fermented milk protein using Lactobacillus helveticus KLDS 1.8701 and Lactobacillus plantarum KLDS 1.0386 in cow milk protein allergy (CMPA) management. This study determined the secondary and tertiary structures of the fermented versus unfermented proteins by Fourier-transform infrared spectroscopy and surface hydrophobicity to evaluate its conformational changes. Our results showed that different fermentation methods have significantly altered the conformational structures of the cow milk protein, especially the tertiary structure. Further, the potential allergenicity of the fermented cow milk protein was assessed in Balb/c mice, and mice treated with the unfermented milk and phosphate-buffered saline were used as a control. We observed a significant reduction in allergenicity via the results of the spleen index, serum total IgE, specific IgE, histamine, and mouse mast cell protease 1 in the mice treated with the co-fermented milk protein. In addition, we analyzed the cytokines and transcription factors expression levels of spleen and jejunum and confirmed that co-fermentation could effectively reduce the sensitization of cow milk protein by regulating the imbalance of T helper (Th1/Th2 and Treg/Th17). This study suggested that changes of conformational structure could reduce the potential sensitization of cow milk protein; thus, fermentation may be a promising strategy for developing a method of hypoallergenic dairy products.

Improved effect of ultrasound-assisted enzymolysis on egg yolk powder: Structural properties, hydration properties and stability characteristics

Preparation of egg yolk powder (EYP) with excellent hydration properties and dissolution stability is important for the efficient utilization of its functional properties and nutritional properties in food. In this work, a new method utilizing ultrasound-assisted enzymolysis (UP-EM) was investigated to obtain EYP. Compared to enzymolysis-alone treated (EM), ultrasonic pre-treatment (UP) significantly increased the enzymatic hydrolysis rate by 106.28%. In particular, the UP 60 W 20 min-EM group obtained the desired solubility and coefficient of stability. The observed microstructure of EYP showed that the egg yolk particles obtained by UP-EM were more uniformly distributed and smaller in particle size. The protein structure was confirmed by Fourier transform infrared spectrum, which showed that UP enhanced the hydrogen bonding force between egg yolk proteins. Therefore, it can be believed that UP-EM can significantly improve the hydration properties and dispersion stability of EYP, laying the foundation for its wide applications in food industry.

Texture and viscoelastic characteristics of silver carp (Hypophthalmichthys molitrix) surimi affected by combination of washing regimes and hydrogen peroxide

This study aimed to apply H₂ O₂ at different concentrations in combination with mince:water (M:W) ratios and different washing cycles (WC) in order to produce surimi gel from silver carp without compromising its quality characteristics. Color, texture, microstructure and rheological properties of surimi gels were investigated. Water holding capacity, texture profile and gel strength, showed a greater dependency on number of washing cycles than the M:W ratios and percentage of H₂ O₂ (p<0.05), i.e., higher washing cycles, firmer surimi gel. Accordingly, T2 (one WC, 2% H₂ O₂ , 1:3), T10 (two WC, 1% H₂ O₂ , 1:2) and T16 (three WC, 1% H₂ O₂ , 1:2) treatments resulted the most cohesive and resilient surimi compared to the rest (p<0.05), confirmed by SEM images. However, all treated fish mince samples with H₂ O₂ , resulted in a surimi gel with lower texture quality compared to the control surimi prepared by conventional washing process without H₂ O₂ (p<0.05). A temperature sweep test was conducted based on the LVR stress and frequency values and the aforementioned surimi gels exhibited an obvious valley shape pattern at temperature range of 48-62°C. In the creep-recovery test, the Burgers model satisfactorily described the internal structure of the surimi gel samples as the lowest deformation belonged to the control samples followed by T2. However, after 300s strain, neither of surimi gels were fully recovered their original shape. Altogether, further studies are needed to clarify the effects of H₂ O₂ in reduction of washing cycles, without significantly affecting the textural and rheological properties of resultant surimi gel.

The effects of different protease treatments on the techno-functional, structural, and bioactive properties of bovine casein

In this study, bovine sodium caseinate (NaCas) was hydrolyzed with four proteases, alcalase, savinase, subtilisin A, and flavourzyme. In addition to the structural changes occurred through the enzymatic hydrolysis, the solubility, oil binding capacity, zeta potential, emulsification properties, and in vitro antioxidant capacity, anti-carcinogenic and antidiabetic properties of hydrolysates were determined. FTIR combined with hierarchical cluster analysis (HCA) made in Amide I region enable to classification of the samples based on the changes of the secondary structure depending on the enzyme type and degree of fragmentation. Technological properties of NaCas were enhanced through the enzymatic hydrolysis, and those were more prominent in serine-type enzymes, regardless of the enzyme type, all hydrolysates showed high antioxidant capacities. All hydrolysates, specifically those produced by savinase and alcalase, reduced the viability of the carcinogenic Caco-2 cells in a dose-dependent manner and showed a very low level of cytotoxicity against healthy HEK-293 cells. The hydrolysis treatment made a significant contribution to the antidiabetic activity of NaCas. Particularly alcalase and savinase hydrolysates suppressed the activity of α- amylase and α- glucosidase. Therefore, the generated milk protein hydrolysates could be used in functional food developments for specific dietary purposes.

Mechanistic insights into the improved properties of mayonnaise from the changes in protein structures of enzymatic modification-treated egg yolk

Heat treatment is an important step in mayonnaise production but can affect the quality of mayonnaise because thermal treatment can accelerate oil droplet coalescence. To resolve this issue, in this study, enzymatically modified egg yolks were applied to produce mayonnaise. Egg yolk hydrolyzed with 0.2% neutral protease could effectively produce mayonnaise with superior heat stability, and this effect was attributed to enzymatic modifications that increased the degree of amino acid ionization, the overall hydrophilicity and the ability to adsorb proteins. Moreover, electrophoresis and FT-IR results showed that the enzymatically modified egg yolk proteins had a smaller molecular weight and more flexible structure, which could also favor the improved properties. The study elucidated why mayonnaise prepared by enzymatic modification-treated egg yolk has better thermal stability.

Heat treatment is an important step in mayonnaise production but can affect the quality of mayonnaise because thermal treatment can accelerate oil droplet coalescence.

Cow and camel milk-derived whey and casein protein hydrolysates demonstrated effective antifungal properties against selected Candida species

Bioactive peptides derived from milk proteins are widely known to possess antibacterial activities. Even though the antibacterial effects of milk-derived peptides are widely characterized, not much focus is given to their antifungal characterization. Therefore, in this study, we investigated the antifungal properties of camel and cow whey and casein hydrolysates against various species of pathogenic Candida. The hydrolysates were produced using 2 enzymes (alcalase and protease) at differing hydrolysis durations (2, 4, and 6 h) and tested for their antifungal properties. The results showed that intact cow whey and casein proteins did not display any anti-Candida albicans properties, whereas the alcalase-derived 2 h camel casein hydrolysate (CA-C-A2) displayed a higher percentage of inhibition against Candida albicans (93.69 ± 0.26%) followed by the cow casein hydrolysate generated by protease-6 h (Co-C-P6; 81.66 ± 0.99%), which were significantly higher than that of fluconazole, a conventional antifungal agent (76.92 ± 4.72%). Interestingly, when tested again Candida krusei, camel casein alcalase 2 and 4 h (CA-C-A2 and CA-C-A4), and cow whey alcalase-6 h (CO-W-A6) hydrolysates showed higher antifungal potency than fluconazole. However, for Candida parapsilosis only camel casein alcalase-4 h (Ca-C-A4) and cow casein protease-6 h (Co-C-P6) hydrolysates were able to inhibit the growth of C. parapsilosis by 19.31 ± 0.84% and 23.82 ± 4.14%, respectively, which was lower than that shown by fluconazole (29.86 ± 1.11%). Overall, hydrolysis of milk proteins from both cow and camel enhanced their antifungal properties. Camel milk protein hydrolysates were more potent in inhibiting pathogenic Candida species as compared with cow milk protein hydrolysates. This is the first study that highlights the antifungal properties of camel milk protein hydrolysates.

Effect of Drying Techniques on the Physical, Functional, and Rheological Attributes of Isolated Sunflower Protein and Its Hydrolysate

The influence of freeze and convection (at 40 and 50 °C) drying on the physical, functional, and rheological attributes of sunflower protein (SP) and its hydrolysate (SPH) was investigated. Compared with convectively-dried samples, the lightness, turbidity, bulk density, and particle size values of the freeze-dried SP and SPH were substantially higher, but the browning index was lower (p < 0.05). Additionally, freeze-dried samples exhibited good solubility and foaming characteristics, whereas lower emulsion properties with the most pH values were observed. Furthermore, SPHs possessed higher solubility as well as foamability over SPs under varying pH values (2.0–10.0), whilst reduction in the emulsion activity index was clearly observed (p < 0.05). Convectively-dried powders exhibited greater viscosity and consistency coefficient; and significantly lower flow behavior index of dispersions, relative to the respective freeze-dried preparations, indicating that dehydration methods influenced the flow behavior of the investigated samples. From a molecular weight analysis, convectively-dried samples at various temperatures were characterized with high proportion of small-sized particles at ≤1 kDa fractions over the respective powders obtained by freeze drying. The observations made, thus, would benefit food processors and manufacturers in electing better dehydration technique based on the desired traits of SP and SPH powders for successful application in food product formulations.

Enzymatic Hydrolysis of Broken Rice Protein: Antioxidant Activities by Chemical and Cellular Antioxidant Methods

Excessive reactive oxygen species (ROS) is an important cause of aging, and supplementing antioxidants through diet is one of the important ways to delay aging. Some studies have confirmed that rice protease hydrolysate has antioxidant activity, but was rarely been investigated on cells. Thus, commercial enzymes, alkaline enzyme, neutral enzyme, pepsin, chymotrypsin, and trypsin were selected to hydrolyze broken rice protein (BRP) to obtain the corresponding hydrolysates, which were A-broken rice protein hydrolysate (BRPH), N-BRPH, P-BRPH, C-BRPH, and T-BRPH, respectively. Then the antioxidant properties of BRPHs were evaluated by different chemical and cellular antioxidation. Molecular weight, peptide length distribution, and amino acid sequence were detected to insight into the antioxidant properties. Among BRPHs, the A-BRPH displayed the strongest hydroxyl radical scavenging activity (IC50 = 1.159 mg/ml) and metal ion-chelating activities (IC50 = 0.391 mg/ml). Furthermore, cellular antioxidation confirmed that A-BRPH significantly increased cell viability and inhibited the intracellular ROS release in both aging cells and cell-aging processes. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) results revealed that peptides with molecular weight <14.5 KDa were produced by enzymatic hydrolysis. Additionally, A-BRPH rich in low molecular weight (<3 kDa) and short-length peptides with some specific amino acids, such as aromatic and hydrophobic amino acids, contributes to the antioxidant properties. This study provided theoretical to the utilization of broken rice and confirmed that A-BRPH could be used in new anti-aging food and health products for human consumption.

A review on recent advances of egg byproducts: Preparation, functional properties, biological activities and food applications

The rapid development of egg industries produced vast byproducts that have not been effectively used. In this paper, the comprehensive utilization of egg byproducts was reviewed. Protein extraction and enzymatic hydrolysis were the main used ways for recycle of egg byproducts. The fact that eggshell membrane could accelerate would healing and improve facial skin of healthy people for 12 weeks was found. However, salted egg white had poor functional properties owing to high salt and ultrafiltration was an effective technology to remove 92.93% of salt. Moreover, Defatted yolk protein had the great potential to be used as food additives and functional foods. Other egg byproducts such as egg inhibitor and eggshells also were discussed. The novel applications of egg byproducts in the food field included food additives, feeds, food packaging materials and nutraceuticals based on current knowledge, but the proportion needed to be improved. This paper would provide a new insight for comprehensive utilization of egg byproducts.

Degree of hydrolysis, functional and antioxidant properties of protein hydrolysates from Grass Turtle (Chinemys reevesii) as influenced by enzymatic hydrolysis conditions

Grass turtle muscle was hydrolyzed with papain enzyme to produce protein hydrolysate (PH) and the degree of hydrolysis (DH) was determined. Under optimal conditions, the highest DH was 19.52% and the yield was recorded as 17.26%. Protein content of the hydrolysates was ranged from 73.35% to 76.63%. Total amino acids were more than 96.77% for each PH. The PH obtained at DH 19.52% achieved excellent solubility and emulsifying activity which were 95.56% and 108.76 m2/g, respectively at pH 6. Foam capacity amounted 100% in PH of DH 19.52% at pH 2, and water-holding capacity was 4.38 g/g. The antioxidant activity showed the strongest hydroxyl radical scavenging activity (95.25%), ABTS (84.88%), DPPH (75.89%), iron chelating (63.25%), and cupper chelating (66.90%) at DH 11.96%, whereas reducing power (0.88) at DH 19.52%. Thus, the findings indicated that utilization of grass turtle muscle protein hydrolysate is a potential alternative protein resource to improve the nutritional and functional properties in food ingredients and product formulations.

Emerging Emulsifiers: Conceptual Basis for the Identification and Rational Design of Peptides with Surface Activity

Emulsifiers are gradually evolving from synthetic molecules of petrochemical origin to biomolecules mainly due to health and environmental concerns. Peptides represent a type of biomolecules whose molecular structure is composed of a sequence of amino acids that can be easily tailored to have specific properties. However, the lack of knowledge about emulsifier behavior, structure-performance relationships, and the implementation of different design routes have limited the application of these peptides. Some computational and experimental approaches have tried to close this knowledge gap, but restrictions in understanding the fundamental phenomena and the limited property data availability have made the performance prediction for emulsifier peptides an area of intensive research. This study provides the concepts necessary to understand the emulsifying behavior of peptides. Additionally, a straightforward description is given of how the molecular structure and conditions of the system directly impact the peptides' ability to stabilize emulsion droplets. Moreover, the routes to design and discover novel peptides with interfacial and emulsifying activity are also discussed, along with the strategies to address some of their major pitfalls and challenges. Finally, this contribution reviews methodologies to build and use data sets containing standard properties of emulsifying peptides by looking at successful applications in different fields.

Biofunctionality of Enzymatically Derived Peptides from Codfish (Gadus morhua) Frame: Bulk In Vitro Properties, Quantitative Proteomics, and Bioinformatic Prediction

Protein hydrolysates show great promise as bioactive food and feed ingredients and for valorization of side-streams from e.g., the fish processing industry. We present a novel approach for hydrolysate characterization that utilizes proteomics data for calculation of weighted mean peptide properties (length, molecular weight, and charge) and peptide-level abundance estimation. Using a novel bioinformatic approach for subsequent prediction of biofunctional properties of identified peptides, we are able to provide an unprecedented, in-depth characterization. The study further characterizes bulk emulsifying, foaming, and in vitro antioxidative properties of enzymatic hydrolysates derived from cod frame by application of Alcalase and Neutrase, individually and sequentially, as well as the influence of heat pre-treatment. All hydrolysates displayed comparable or higher emulsifying activity and stability than sodium caseinate. Heat-treatment significantly increased stability but showed a negative effect on the activity and degree of hydrolysis. Lower degrees of hydrolysis resulted in significantly higher chelating activity, while the opposite was observed for radical scavenging activity. Combining peptide abundance with bioinformatic prediction, we identified several peptides that are likely linked to the observed differences in bulk emulsifying properties. The study highlights the prospects of applying proteomics and bioinformatics for hydrolysate characterization and in food protein science.

Functionality of Cricket and Mealworm Hydrolysates Generated after Pretreatment of Meals with High Hydrostatic Pressures

The low consumer acceptance to entomophagy in Western society remains the strongest barrier of this practice, despite these numerous advantages. More positively, it was demonstrated that the attractiveness of edible insects can be enhanced by the use of insect ingredients. Currently, insect ingredients are mainly used as filler agents due to their poor functional properties. Nevertheless, new research on insect ingredient functionalities is emerging to overcome these issues. Recently, high hydrostatic pressure processing has been used to improve the functional properties of proteins. The study described here evaluates the functional properties of two commercial insect meals (Gryllodes sigillatus and Tenebrio molitor) and their respective hydrolysates generated by Alcalase®, conventionally and after pressurization pretreatment of the insect meals. Regardless of the insect species and treatments, water binding capacity, foaming and gelation properties did not improve after enzymatic hydrolysis. The low emulsion properties after enzymatic hydrolysis were due to rapid instability of emulsion. The pretreatment of mealworm meal with pressurization probably induced protein denaturation and aggregation phenomena which lowered the degree of hydrolysis. As expected, enzymatic digestion (with and without pressurization) increased the solubility, reaching values close to 100%. The pretreatment of mealworm meal with pressure further improved its solubility compared to control hydrolysate, while pressurization pretreatment decreased the solubility of cricket meal. These results may be related to the impact of pressurization on protein structure and therefore to the generation of different peptide compositions and profiles. The oil binding capacity also improved after enzymatic hydrolysis, but further for pressure-treated mealworm hydrolysate. Despite the moderate effect of pretreatment by high hydrostatic pressures, insect protein hydrolysates demonstrated interesting functional properties which could potentially facilitate their use in the food industry.

Use of Alcalase in the production of bioactive peptides: A review

This review aims to cover the uses of the commercially available protease Alcalase in the production of biologically active peptides since 2010. Immobilization of Alcalase has also been reviewed, as immobilization of the enzyme may improve the final reaction design enabling the use of more drastic conditions and the reuse of the biocatalyst. That way, this review presents the production, via Alcalase hydrolysis of different proteins, of peptides with antioxidant, angiotensin I-converting enzyme inhibitory, metal binding, antidiabetic, anti-inflammatory and antimicrobial activities (among other bioactivities) and peptides that improve the functional, sensory and nutritional properties of foods. Alcalase has proved to be among the most efficient proteases for this goal, using different protein sources, being especially interesting the use of the protein residues from food industry as feedstock, as this also solves nature pollution problems. Very interestingly, the bioactivities of the protein hydrolysates further improved when Alcalase is used in a combined way with other proteases both in a sequential way or in a simultaneous hydrolysis (something that could be related to the concept of combi-enzymes), as the combination of proteases with different selectivities and specificities enable the production of a larger amount of peptides and of a smaller size.

Physicochemical properties of soy protein hydrolysate and its formulation and stability with encapsulated probiotic under in vitro gastrointestinal environment

The objective of this study was to prepare protein isolate from defatted soybean and identify an optimal hydrolysis protocol to create improved hydrolysates and ascertain the optimum encapsulation technique for probiotics. Soy protein isolate (SPI) was prepared using an alkaline extraction procedure for solubility within a neutral, beverage-specific pH range. The soy protein hydrolysate (SPH) was prepared from aqueous extracted SPI using pepsin. The physicochemical properties of the SPH were investigated by solubility, degree of hydrolysis (DH), surface hydrophobicity, and electrophoresis. Hydrolysates from 2, 2.5, and 3 hr of hydrolysis time achieved the suitable DH between 2.5% to 5.0%. The 2.5 to 3 hr hydrolysates were also significantly more soluble than SPI at all pH levels from 85% to 95% solubility. Surface hydrophobicity of the hydrolysates ranged from 15 to 20 S0 values. Alginate (1%), resistant starch (2%), and probiotic culture (0.1%) were used as an encapsulation agent to protect probiotics. Alginate microcapsules were observed to be 1 mm in size using environmental scanning electron microscopy. The dried SPH and encapsulated probiotics with alginate in a dry powder formulation were tested for its gastrointestinal resistance and probiotic viability under in vitro simulated digestion. Approximately 1-log decrease was observed for all experimental groups after simulated digestion (final log colony forming units [CFU]/mL range: 6.55 to 6.19) with free probiotics having the lowest log CFU/mL (6.10 ± 0.10) value. No significant difference was observed among experimental groups for probiotic viability (P = 0.445). The findings of this research will provide an understanding of formulation for easily digestible protein and encapsulated probiotics. PRACTICAL APPLICATION: The findings of this research provide an understanding of improved formulation for more suitable soy protein hydrolysate and viability of encapsulated probiotics in gastrointestinal environment. Probiotics with the prebiotics in an encapsulated environment provide a technology for the enhancement of probiotics viability and for applications in suitable products for health and wellness.