Enzymatic protein hydrolysates from high pressure-pretreated isolated pea proteins have better antioxidant properties than similar hydrolysates produced from heat pretreatment

Pea Peptides and Heavy Metal Neurotoxicity: Exploring Mechanisms and Mitigation Strategies in PC12 Cells

Calsyntenin-1 (Clst1) is a sensitive indicator of lead (Pb) toxicity in neural tissue. This study was designed to investigate the impact of lead exposure on Clst1 expression in PC12 cells and the mitigating effect of pea peptide 4 (PP4) on lead-induced neurotoxicity. Data showed that lead exposure, at varying doses and durations, disrupted the mRNA expression and protein levels of Clstn1 in PC12 cells. However, immunofluorescence results showed that treatment with PP4 significantly increased Clstn1 protein expression in the Pb + PP4 and PP4 groups compared to the Pb groups (P < 0.05). Lead exposure activates the JNK and p38 pathways; at the same time, PP4 treatment enhances ERK pathway activation and reduces JNK and p38 activation.

Quality changes in high hydrostatic pressure treated enriched tomato sauce

BACKGROUND

Use of high hydrostatic pressure (HHP) with reduced processing times is gaining traction in the food industry as an alternative to conventional thermal treatment. In order to enhance functional benefits while minimizing processing losses, functionalized products are being developed with such novel techniques. In this study, changes in quality parameters for HHP treated enriched tomato sauce were evaluated, with the aim to assess its viability as an alternative to conventional thermal treatment methods.

RESULTS

HHP treatments at 500 MPa, 30 °C/50 °C significantly increased the total phenolic and lycopene content of the sauce samples, achieving 6.7% and 7.5% improvements over conventionally treated samples. The antioxidant capacity of the HHP-treated samples was also found to match or be better than conventionally treated samples. Furthermore, a T2 relaxation time study revealed that pressure-temperature processing treatments were effective in maintaining the structural integrity of water molecules. Microbiological analyses revealed that 500 MPa/50 °C 5 min treatment can offer 8 logs reduction colony formation, matching the results of conventional thermal treatment.

CONCLUSION

Combined pressure-temperature treatments improve results, reduce time consumption. 500 MPa/50 °C treatments provided retention of quality parameters and significant reduction in microbial activity. © 2024 The Author(s). Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Effects of preheat treatment and syringic acid binding on the physicochemical, antioxidant, and antibacterial properties of black soybean protein isolate before and after in vitro digestion

This study investigated the effects of preheat treatment (70-100 °C) and syringic acid (SA) grafting on the antioxidant, antibacterial, and physicochemical properties of black soybean protein isolate (BSPI) before and after in vitro digestion. The results revealed that both preheat treatment and SA grafting increased the digestibility and the absolute zeta potential value of BSPI. However, as the preheating temperature increased, the antioxidant ability of BSPI decreased, which was improved by SA grafting. During in vitro digestion, the absolute zeta potential and antioxidant activities of preheated BSPI and preheated BSPI-SA complex followed the order: intestine > gastric > before digestion. Compared with before digestion, preheated BSPI with its SA complex after in vitro digestion exhibited excellent antibacterial activities. Importantly, the preheated BSPI-SA complex enhanced the SA recovery rate during digestion and SA stability, with the highest recovery rate observed for the SA-grafted BSPI with preheat treatment at 100°C (BSPI100-SA). The principal component analysis sufficiently distinguished preheated BSPI and preheated BSPI-SA complexes. There were partitions between BSPI and BSPI-SA treated at different preheating temperatures. This study contributes to expanding the potential applications of BSPI with its SA complex in food products and offers guidance for designing SA delivery systems. PRACTICAL APPLICATION: Preheated BSPI-SA complexes could serve as functional ingredients in food or health products. Besides, preheated BSPI has application potential as a carrier for SA delivery.

Dry beans (Phaseolus vulgaris L.) modulate the kinetics of lipid digestion in vitro: Impact of the bean matrix and processing

The lipid-lowering effect of dry beans and their impact on lipid and cholesterol metabolism have been established. This study investigates the underlying mechanisms of this effect and explore how the structural integrity of processed beans influences their ability to modulate lipolysis using the INFOGEST static in vitro digestion model. Dietary fiber (DF) fractions were found to decrease lipolysis by increasing the digesta viscosity, leading to depletion-flocculation and/or coalescence of lipid droplets. Bean flours exhibited a more pronounced reduction in lipolysis compared to DF. Furthermore, different levels of bean structural integrity showed varying effects on modulating lipolysis, with medium-sized bean particles demonstrating a stronger reduction. Hydrothermal treatment compromised the ability of beans to modulate lipid digestion, while hydrostatic-pressure treatment (600 MPa/5min) enhanced the effect. These findings highlight that the lipid-lowering effect of beans is not solely attributed to DF but also to the overall bean matrix, which can be manipulated through processing techniques.

Enhancing activity of food protein-derived peptides: An overview of pretreatment, preparation, and modification methods

Food protein-derived peptides have garnered considerable attention due to their potential bioactivities and functional properties. However, the limited activity poses a challenge in effective utilization aspects. To overcome this hurdle, various methods have been explored to enhance the activity of these peptides. This comprehensive review offers an extensive overview of pretreatment, preparation methods, and modification strategies employed to augment the activity of food protein-derived peptides. Additionally, it encompasses a discussion on the current status and future prospects of bioactive peptide applications. The review also addresses the standardization of mass production processes and safety considerations for bioactive peptides while examining the future challenges and opportunities associated with these compounds. This comprehensive review serves as a valuable guide for researchers in the food industry, offering insights and recommendations to optimize the production process of bioactive peptides.

Effects of processing technologies on the antioxidant properties of common bean (Phaseolus vulgaris L.) and lentil (Lens culinaris) proteins and their hydrolysates

The effects of ultrasound (280 W, 5 min), heat treatment (75 °C and 90 °C for 10 min) and microfluidization (125 MPa, 4 cycles) as pre or post treatments and their combination with enzymatic hydrolysis on the antioxidant properties of common bean and lentil protein hydrolysates were investigated. In general, hydrolysis resulted in increases of antioxidant activity, both in the presence and absence of processing technologies. The increases reached maximum values of 158% (ABTS), 105% (DPPH), 279% (FRAP) and 107% (TAC) for the bean protein hydrolysates submitted to post-treatment with ultrasound (ABTS, FRAP and TAC) and pre-treatment with microfluidization (DPPH), compared to their respective controls (untreated samples). For lentil proteins, the increases reached 197% (ABTS), 170% (DPPH), 690% (FRAP) and 213% (TAC) for samples submitted to ultrasound post-treatment (ABTS), microfluidization pre-treatment (DPPH) and post-treatment (FRAP), and 75 °C pre-treatment (TAC) compared to their respective controls. Surface hydrophobicity and molecular weight profile by SEC-HPLC analysis indicated modifications in the structures of proteins in function of the different processing technologies. For both proteins, electrophoresis indicated a similar profile for all hydrolysates, regardless of the process applied as pre or post treatment. Solubility of bean and lentil protein concentrates was also improved. These results indicated that different processing technologies can be successfully used in association with enzymatic hydrolysis to improve the antioxidant properties of lentil and bean proteins.

Potential Application of High Hydrostatic Pressure on the Production of Hydrolyzed Proteins with Antioxidant and Antihypertensive Properties and Low Allergenicity: A Review

The high hydrostatic pressure (HHP) process has been studied for several applications in food technology and has been commercially implemented in several countries, mainly for non-thermal pasteurization and shelf-life extension of food products. HHP processing has been demonstrated to accelerate proteolytic hydrolysis at a specific combination of pressure and pressure-holding time for a given protein source and enzyme. The enzymatic hydrolysis of proteins is a well-known alternative to producing biologically active peptides, with antioxidant and antihypertensive capacity, from different food protein sources. However, some of these protein sources contain allergenic epitopes which are often not degraded by traditional hydrolysis. Moreover, the peptide profile and related biological activity of a hydrolysate depend on the protein source, the enzymes used, the parameters of the proteolysis process (pH, temperature, time of hydrolysis), and the use of other technologies such as HHP. The present review aims to provide an update on the use of HHP for improving enzymatic hydrolysis, with a particular focus on studies which evaluated hydrolysate antihypertensive and antioxidant capacity, as well as residual allergenicity. Overall, HHP has been shown to improve the biological properties of hydrolysates. While protein allergenicity can be reduced with traditional hydrolysis, HHP can further reduce the allergenicity. Compared with traditional hydrolysis methods, HHP-assisted protein hydrolysis offers a greater opportunity to add value to protein-rich products through conversion into high-end hydrolysate products with enhanced nutritional and functional properties.

Transformation of Seafood Side-Streams and Residuals into Valuable Products

Seafood processing creates enormous amounts of side-streams. This review deals with the use of seafood side-streams for transformation into valuable products and identifies suitable approaches for making use of it for different purposes. Starting at the stage of catching fish to its selling point, many of the fish parts, such as head, skin, tail, fillet cut-offs, and the viscera, are wasted. These parts are rich in proteins, enzymes, healthy fatty acids such as monounsaturated and polyunsaturated ones, gelatin, and collagen. The valuable biochemical composition makes it worth discussing paths through which seafood side-streams can be turned into valuable products. Drawbacks, as well as challenges of different aquacultures, demonstrate the importance of using the various side-streams to produce valuable compounds to improve economic performance efficiency and sustainability of aquaculture. In this review, conventional and novel utilization approaches, as well as a combination of both, have been identified, which will lead to the development of sustainable production chains and the emergence of new bio-based products in the future.

Acetylcholinesterase and butyrylcholinesterase inhibitory activities of antioxidant peptides obtained from enzymatic pea protein hydrolysates and their ultrafiltration peptide fractions

This study optimized the enzymatic hydrolysis of yellow field pea proteins using alcalase (ACH), chymotrypsin (CHH), flavourzyme (FZH), pancreatin (PCH), pepsin (PEH), and trypsin (TPH) to obtain hydrolysates and ultrafiltered fractions (<1, 1-3, 3-5 and 5-10 kDa) that possess antioxidant plus acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activities. The hydrolysates exhibited varying degrees of radical scavenging and inhibition of linoleic acid peroxidation, as well as cholinesterase inhibition activities but the potency generally improved by >10% after UF separation into peptide fractions. ACH, FZH, and PEH exhibited significantly (p < .05) higher (20%-30% increases) radical scavenging activities than the other hydrolysates. The 1 and 3 kDa UF fractions of ACH, FZH, and PEH inhibited ~20%-30% AChE activity, while ACH, PCH, TPH, and PEH inhibited ~20%-40% BuChE activity. We conclude that the pea protein hydrolysates and their peptide fractions possess multifunctional properties with potential use against neurodegenerative disorders. PRACTICAL APPLICATIONS: Alzheimer's disease (AD) has multiple pathological pathways in addition to the loss of acetylcholine (ACh) catalyzed by acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). The presence of severe oxidative stress triggered by lipid peroxidation and formation of free radicals is a common trait in AD patients. The concept of AChE and BuChE inhibition as an approach toward AD amelioration involves the use of compounds with a similar structure to ACh, the natural substrate. Peptides derived from food proteins consist of ester bonds with structural similarity to ACh and theoretically possess the ability to interact with AChE and BuChE. Results from the present study imply that pea protein-derived peptides are potential candidates for use as inhibitors of AChE and BuChE activities, with application in the prevention and management of AD.

Bioactive and health-promoting properties of enzymatic hydrolysates of legume proteins: a review

This study comprehensively reviewed the effect of controlled enzymatic hydrolysis on the bioactivity of pulse protein hydrolysates (PPHs). Proteolysis results in the partial structural unfolding of pulse proteins with an increase in buried hydrophobic groups of peptide sequences. The use of PPHs in a dose-dependent manner can enhance free radical scavenging and improve antioxidant activities regarding inhibition of lipid oxidation, ferric reducing power, metal ion chelation, and β-carotene bleaching inhibition. Ultrafiltered peptide fractions with low molecular weights imparted angiotensin-I converting enzyme (ACE) inhibitory effects during in vitro simulated gastrointestinal digestion and in vivo conditions. Ultrasonication, high-pressure pretreatments, and glycosylation as post-treatments can improve the antiradical, antioxidant, and ACE inhibitory activities of PPHs. The electrostatic attachment of pulse peptides to microbial cells can inhibit the growth and activity of bacteria and fungi. Bioactive pulse peptides can reduce serum cholesterol and triglycerides, and inhibit the formation of adipocyte lipid storage, allergenic factors, inflammatory markers, and arterial thrombus without cytotoxicity. The combination of germination and enzymatic hydrolysis can significantly increase the protein digestibility and bioavailability of essential amino acids. Moreover, the utilization and enrichment of bakery and meat products with functional PPHs ensure quality, safety, and health aspects of food products.

Effect of Hydrothermal Cooking Combined with High-Pressure Homogenization and Enzymatic Hydrolysis on the Solubility and Stability of Peanut Protein at Low pH

A novel method combining high-pressure homogenization with enzymatic hydrolysis and hydrothermal cooking (HTC) was applied in this study to modify the structure of peanut protein, thus improving its physicochemical properties. Results showed that after combined modification, the solubility of peanut protein at a pH range of 2–10 was significantly improved. Moreover, the Turbiscan stability index of modified protein in the acidic solution was significantly decreased, indicating its excellent stability in low pH. From SDS-PAGE (Sodium Dodecyl Sulfate PolyAcrylamide Gel Electrophoresis), the high molecular weight fractions in modified protein were dissociated and the low molecular weight fractions increased. The combined modification decreased the particle size of peanut protein from 74.82 to 21.74 μm and shifted the isoelectric point to a lower pH. The improvement of solubility was also confirmed from the decrease in surface hydrophobicity and changes in secondary structure. This study provides some references on the modification of plant protein as well as addresses the possibility of applying peanut protein to acidic beverages.

Effects of High Hydrostatic Pressure Pretreatment on the Functional and Structural Properties of Rice Bran Protein Hydrolysates

Rice bran protein (RBP) hydrolysis was conducted after high hydrostatic pressure (HHP) pretreatment. The structural and functional properties of HHP-pretreated rice bran protein hydrolysates (RBPH) were investigated. HHP pretreatments were conducted at 100, 200, and 300 MPa; then, enzymatic hydrolysis at atmospheric pressure was performed using trypsin. An RBPH sample that had not been pretreated by HHP was used as a control. Free sulfhydryl (SH) content, SDS-PAGE profiles, high-performance size exclusion chromatography (HPSEC), Fourier transform infrared (FTIR) spectrum, scanning electron microscopy (SEM), intrinsic fluorescence spectrum, solubility, and emulsifying and foaming properties were evaluated. Changes in particle size and ζ-potential were monitored. Compared with the control, the results of solubility, the emulsifying activity index (EAI) and the emulsifying stability index (ESI) increased significantly (p < 0.05) at 200 MPa. The content of free SH increased significantly (p < 0.05) at 100 MPa. FTIR spectrum and fluorescence analysis confirmed the changes in the secondary and tertiary structures. The experimental results indicated that the structural and functional properties of HHP-pretreated RBPH improved.

Steam Explosion-Assisted Extraction of Protein from Fish Backbones and Effect of Enzymatic Hydrolysis on the Extracts

The development of an efficient pretreatment, prior to enzymatic hydrolysis, is a good strategy for the sustainable use of refractory fish byproducts. This study compared hydrothermal pretreatments at 159 °C for 2 min, followed by water extraction (steam explosion-assisted extraction, SE) and 121 °C for 70 min (hot-pressure extraction, HPE), for the recovery of proteins from fish backbones. The effect of enzymatic hydrolysis on the properties of the obtained fish bone protein (FBP) was also evaluated. The results demonstrated that FBP had high contents of protein (81.09-84.88 g/100 g) and hydroxyproline (70-82 residues/1000 residues). After hydrolysis with Flavourzyme, for 3 h, the FBP hydrolysates that were pretreated with SE (SFBP-H) exhibited a better degree of hydrolysis (DH) and nitrogen recovery (NR), and a higher level of umami taste free amino acids (151.50 mg/100 mL), compared with the HPE-treated samples. The obtained SFBP-H mainly distributed below 3000 Da and had strong scavenging effects on 1,1-diphenyl-2-picrylhydrazy (DPPH) (IC₅₀ = 4.24 mg/mL) and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) (IC₅₀ = 1.93 mg/mL) radicals. Steam explosion-assisted extraction is a promising route for recovering proteins from native fish bone materials, and improving the flavor and antioxidant activity of the hydrolysates.

Application of preliminary high-pressure processing for improving bioactive characteristics and reducing antigenicity of whey protein hydrolysates

This study investigated the use of Novo Pro-D® (NPD) and Ficin (FC) as alternative proteases for the production of bioactive peptides with reduced allergenicity from whey protein concentrate (WPC). In addition, the use of high hydrostatic pressure processing as pre-treatment of WPC and its impact on the final characteristics of hydrolysates were also evaluated. NPD treatments generated hydrolysates with a 98% reduction of soluble proteins, greater in vitro antioxidant capacity, and less immunoreactivity when compared to FC ones. However, pre-treatment was an essential tool to improve WPC hydrolysis when FC was used, resulting in hydrolysates with less soluble proteins, enhanced antioxidant capacity, and less allergenicity compared with conventional hydrolysis. As for NPD, the pre-treatment of WPC improved the in vitro antioxidant capacity and resulted in a 100% reduction in immunoreactivity to β-lactoglobulin in a shorter processing time. Importantly, bioactive peptides generated by FC displayed an improved ability to induce in vitro arterial relaxation, compared with those obtained from NPD process. Therefore, this study provides innovative evidence regarding how the proteases used for production of whey hydrolysates can improve its biological effects, and discloses the use of high hydrostatic pressure combined with enzymatic hydrolysis as a promising alternative to produce hydrolysates with improved properties.

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.

Influence of Hydrolysis on the Bioactive Properties and Stability of Chickpea-Protein-Based O/W Emulsions

This study evaluated the effect of enzymatic hydrolysis on the emulsion microstructure and bioactive properties of oil-in-water emulsions generated using chickpea protein concentrate (CP) and its 10 and 210 min Alcalase CP hydrolysates (CPH₁₀ and CPH₂₁₀, respectively) at three pH values (2.5, 5.0, and 7.5). Chromatographic profiles demonstrated CP protein breakdown following hydrolysis. Increasing the degree of hydrolysis resulted in increased emulsion droplet size and decreased viscoelastic moduli. The antioxidant capacities of the emulsions generated with CPH₁₀ and CPH₂₁₀ increased significantly compared to those generated with CP and were pH-dependent. Both angiotensin-converting enzyme and dipeptidyl peptidase-IV inhibitory activities were significantly increased in emulsions stabilized with CPH₂₁₀; however, these results were also pH-dependent. In vitro gastrointestinal digestion of the emulsions resulted in a significant increase in all bioactivities. These results demonstrate the potential for enzymatic hydrolysis to beneficially modulate the emulsifying and bioactive properties of CP proteins.

Effect of inlet temperature on the physicochemical properties of spray-dried seed-watermelon seed protein powder

Here, we studied the effects of inlet temperature on the physicochemical properties of the hydrolyzed protein (seed-watermelon seed hydrolyzed protein [SWSP]) powder in seed-watermelon seeds. The inlet temperature of the study was in the range of 150 to 180 °C, and the remaining experimental parameters remained constant, that is, the feed flow rate was 0.2 L/hr, the concentration of maltodextrin was 30%, and the outlet temperature was 80 °C. We studied the water activity and moisture content, bulk density, flowability (Carr index and Hausner ratio), angle of repose, solubility, color, hygroscopicity, powder morphology, particle size, crystallinity, and odor of the sample. Inlet temperature of 170 to 180 °C reduced the moisture content and increased the particle size. It was found that the value of measured water activity was less than 0.5, which helped in maintaining stability of the sample. Powders produced at the temperatures showed smoother particle surfaces, whereas higher inlet temperature showed spherical particles with some shrinkage as analyzed by scanning electron microscope. The inlet temperature affected the color of the sample, thus at high temperature, the sample had a brighter color. The sample was approximately 18% crystalline. At a preparation temperature of 160 °C, the sample showed significant antioxidant activity (P < 0.05).

Advances on Food-Derived Peptidic Antioxidants-A Review

The oxidation process is considered to be the main reason behind human aging, human degenerative diseases and food quality degradation. Food-derived peptidic antioxidants (PAs) have wide sources and great activity, and have broad application prospects in removing excess reactive oxygen species in the body, anti-aging and preventing and treating diseases related to oxidative stress. On the other hand, PAs are expected to inhibit the lipid peroxidation of foods and increase the stability of the food system in the food industry. However, the production pathways and action mechanism of food-derived PAs are diverse, which makes it is difficult to evaluate the performance of PAs which is why the commercial application of PAs is still in its infancy. This article focuses on reviewing the preparation, purification, and characterization methods of food-derived PAs, and expounds the latest progress in performance evaluation and potential applications, in order to provide an effective reference for subsequent related research of PAs.

The health benefits, functional properties, modifications, and applications of pea (Pisum sativum L.) protein: Current status, challenges, and perspectives

In recent years, the development and application of plant proteins have drawn increasing scientific and industrial interests. Pea (Pisum sativum L.) is an important source of high-quality vegetable protein in the human diet. Its protein components are generally considered hypoallergenic, and many studies have highlighted the health benefits associated with the consumption of pea protein. Pea protein and its hydrolysates (pea protein hydrolysates [PPH]) possess health benefits such as antioxidant, antihypertensive, and modulating intestinal bacteria activities, as well as various functional properties, including solubility, water- and oil-holding capacities, and emulsifying, foaming, and gelling properties. However, the application of pea protein in the food system is limited due to its poor functional performances. Several frequently applied modification methods, including physical, chemical, enzymatic, and combined treatments, have been used for pea protein to improve its functional properties and expand its food applications. To date, different applications of pea protein in the food system have been extensively studied, for example, encapsulation for bioactive ingredients, edible films, extruded products and substitution for cereal flours, fats, and animal proteins. This article reviews the current status of the knowledge regarding pea protein, focusing on its health benefits, functional properties, and structural modifications, and comprehensively summarizes its potential applications in the food industry.

Effect of heating on the digestibility of isolated hempseed (Cannabis sativa L.) protein and bioactivity of its pepsin-pancreatin digests

The objective was to investigate the effects of heat pretreatment and simulated gastrointestinal digestion on potential antioxidant, anticancer and anti-inflammatory activities of hempseed (Cannabis sativa L.) proteins. Unheated isolated hempseed protein (IHP) and its heated counterparts (100 °C, 15 min and 30 min, termed as HP15D and HP30D) were hydrolyzed sequentially with pepsin and pancreatin and analyzed for digestibility and bioactivity (antioxidant, anti-proliferative and anti-inflammatory properties). Heat pretreatment led to an increase of low molecular weight proteins and degree of hydrolysis, and decrease of concentration of soluble protein, which means heat pretreated can significantly improve the digestibility of IHP. Pepsin-pancreatin digests released from heat pretreated IHP possessed less antioxidant, antiproliferative and anti-inflammatory properties than digests from unheated IHP. In conclusion, heat pre-treatment improved the digestibility of IHP but the resulting digests from heated IHP had lower bioactivity.

Effects of heating or ultrasound treatment on the enzymolysis and the structure characterization of hempseed protein isolates

The effects of heating (90 °C/30 min) or ultrasound (200/400/600 W) treatment on antioxidant and angiotensin-converting enzyme inhibitory (ACEI) activity of hydrolysates from hempseed protein isolates (HPI) were studied. The secondary structure, surface hydrophobicity, intrinsic fluorescence, scanning electron microscopy (SEM) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis of HPI treated by heating or ultrasound were measured. The results showed that hydrolysate from HPI treated with ultrasound at 200 W showed higher hydrolysis degree, proportion of lower molecular mass components (1.0-3.0 kDa), antioxidant and ACEI activity than those from heating or high-power treated. The changes in secondary structure, surface hydrophobicity and intrinsic fluorescence indicated the unfolding of HPI after ultrasound. The SEM results showed that HPI treated with ultrasound at 200 W exhibited decrease in particle size and deformation and further increased in power caused the aggregates of HPI. In conclusion, the ultrasound treatment at low-power was superior to 90 °C/30 min treatment in facilitating enzymatic release of antioxidant and ACEI peptides from HPI.

Pulsed electric fields treatment at different pH enhances the antioxidant and anti-inflammatory activity of ovomucin-depleted egg white

This research investigated the effects of pulsed electric fields (PEF) (1.4-1.7 kV/cm, 653-695 kJ/kg) and heating (60 and 80 °C for 10 min) at different pH (4, 5, 7, and 9) on the antioxidant and anti-inflammatory activity of ovomucin-depleted egg white (OdEW) after in vitro gastrointestinal hydrolysis. PEF and heating (80 °C for 10 min) at pH 4 enhanced the antioxidant activity of the whole hydrolysates, chemically determined using DPPH and ORAC assays. Furthermore, the anti-inflammatory activity of protein hydrolysates was assessed in lipopolysaccharide-stimulated HT-29 cells using ELISA assay. PEF and heating at pH 4 enhanced the anti-inflammatory activity of the whole hydrolysates dose-dependently. Hydrolysates at 1 mg/ml showed similar inhibition (35.5% and 35.9%) of interleukin-8 production, due to PEF treatment and heating (80 °C for 10 min), respectively. Results indicated that prior PEF treatment can analogously enhance both antioxidant and anti-inflammatory activity of OdEW hydrolysates to heating, with potentially reduced thermal input.

Functional properties of amaranth, quinoa and chia proteins and the biological activities of their hydrolyzates

Amaranth, quinoa and chia are non-conventional sources of proteins whose interest has increased in recent years due to their excellent nutritional value. Vegetable proteins can be used as food ingredients to replace animal proteins in human diet. The present article provides a comprehensive analysis of amaranth, quinoa and chia proteins and focuses on their solubility, superficial, gelling and textural properties as well as on the biological activities of enzymatic hydrolyzates.

Improving the enzymolysis efficiency of potato protein by simultaneous dual-frequency energy-gathered ultrasound pretreatment: Thermodynamics and kinetics

The thermodynamics and kinetics of traditional and simultaneous dual frequency energy-gathered ultrasound (SDFU) assisted enzymolysis of potato protein were investigated to get the knowledge of the mechanisms on the SDFU's promoting efficiency during enzymolysis. The concentration of potato protein hydrolysate and parameters of thermodynamic and kinetic during traditional and SDFU assisted enzymolysis were determined. The results showed that potato protein hydrolysate concentration of SDFU assisted enzymolysis was higher than traditional enzymolysis at the hydrolysis time of 60min (p<0.05) whereas not significantly different at 120min (p>0.05). In some cases, SDFU assisted enzymolysis took less hydrolysis time than traditional enzymolysis when the similar conversion rates of potato protein were obtained. The thermodynamic papameters including the energy of activation (E_a), enthalpy of activation (△H), entropy of activation (△S) were reduced by ultrasound pretreatment while Gibbs free energy of activation (△G) increased little (1.6%). Also, kinetic papameters including Michaelis constant (K_M) and catalytic rate constant (k_cat) decreased by ultrasound pretreatment. On the contrary, reaction rate constants (k) of SDFU assisted enzymolysis were higher than that of traditional enzymolysis (p<0.05). It was indicated that the efficiency of SDFU assisted enzymolysis was higher than traditional enzymolysis in a limited time. The higher efficiency of SDFU assisted enzymolysis was related with the decrease of E_a and K_M by lowering the energy barrier between ground and active state and increasing affinity between substrate and enzyme.

Characterization of peptides from common bean protein isolates and their potential to inhibit markers of type-2 diabetes, hypertension and oxidative stress

BACKGROUND

Diabetes and hypertension are diseases affecting a high proportion of the world population; the use of food-based products such as common bean peptides may contribute to reduce the risk of complications associated to chronic diseases. The aim was to produce and characterize peptides from common bean protein isolates and evaluate their potential to inhibit markers of type-2 diabetes, hypertension and oxidative stress.

RESULTS

Mexican black and Brazilian Carioca bean isolated proteins were characterized after pepsin/pancreatin digestion. Also, four synthesized pure peptides, originally found in these beans, were evaluated. Bean protein digests and pure peptides exerted dipeptidyl peptidase-IV (DPP-IV) inhibition (IC₅₀ = 0.03-0.87 mg dry weight (DW) mL^-1 ). Lineweaver-Burk plots and computational modeling showed competitive inhibition of DPP-IV. Angiotensin-converting enzyme (ACE) inhibition ranged from IC₅₀ = 0.09 to 0.99 mg DW mL^-1 , and α-glucosidase inhibition ranged from 36.3 to 50.1% mg^-1 DW. Carioca Perola bean digested proteins presented the highest antioxidant capacity (269.3 mmol L^-1 Trolox equivalent g^-1 DW) as the peptide KTYGL (P > 0.05) with the most potent DPP-IV and ACE inhibition.

CONCLUSION

Peptides from common bean have antidiabetic and antihypertensive potential regardless of their antioxidant capacity. © 2016 Society of Chemical Industry.

Effect of Low-Frequency Ultrasonic-Assisted Enzymolysis on the Physicochemical and Antioxidant Properties of Corn Protein Hydrolysates

The aim of this study was to investigate the effect of low-frequency ultrasound on the enzymolysis of corn protein. A L9(34) orthogonal design was used to optimize ultrasound pretreatment conditions. Degree hydrolysis (DH), conversion rate of protein (CR), and DPPH IC50were selected as analytical indicators. Under the optimal ultrasound conditions (5 W/L power, 2 s/2 s on/off time, 50°C temperature, and 25 min time), the DH, CR, and radical (DPPH∙,OH∙) scavenging capacities were significantly increased. Molecular weight distribution and amino acid profile analysis showed that ultrasound pretreatment enhanced the formation of short-chain peptides with molecular weight of 200–3000 Da, especially the peptides containing hydrophobic amino acids. Moreover, 40 potential antioxidant peptides were purified by C18 semipreparative column and identified by UPLC-ESI-MS. The results suggest that the optimal ultrasonic-assisted enzymolysis technology could be useful for preparation of antioxidant peptides from corn.

Pretreatment of flaxseed protein isolate by high hydrostatic pressure: Impacts on protein structure, enzymatic hydrolysis and final hydrolysate antioxidant capacities

The effect of high hydrostatic pressure (HHP) on flaxseed protein structure and peptide profiles, obtained after protein hydrolysis, was investigated. Isolated flaxseed protein (1%, m/v) was subjected to HHP (600MPa, 5min or 20min at 20°C) prior to hydrolysis with trypsin only and trypsin-pronase. The results demonstrated that HHP treatment induced dissociation of flaxseed proteins and generated higher molecular weight aggregates as a function of processing duration. Fluorescence spectroscopy showed that HHP treatment, as well as processing duration, had an impact on flaxseed protein structure since exposition of hydrophobic amino acid tyrosine was modified. Except for some specific peptides, the concentrations of which were modified, similar peptide profiles were obtained after hydrolysis of pressure-treated proteins using trypsin. Finally, hydrolysates obtained using trypsin-pronase had a greater antioxidant capacity (ORAC) than control samples; these results confirmed that HHP enhanced the generation of antioxidant peptides.

High-Pressure-Assisted Enzymatic Release of Peptides and Phenolics Increases Angiotensin Converting Enzyme I Inhibitory and Antioxidant Activities of Pinto Bean Hydrolysates

Pinto bean protein concentrate was hydrolyzed by subtilisins at 0.1, 100, and 200 MPa and 50 °C for 15 min. Alcalase hydrolysis at 100 MPa led to higher ACE inhibition, reducing power, and free radical scavenging activity of hydrolysates. However, hydrolysate obtained by Savinase at 200 MPa showed the best ACE-inhibitory and radical scavenging activities. Proteolysis by Savinase at 200 MPa was considered the most effective treatment to increase small peptides (<3 kDa), flavonoids, total phenolic compounds, and oxygen radical absorbance capacity in hydrolysates. In this hydrolysate, small phaseolin fragments with reported ACE-inhibitory and antioxidant sequences were identified. Catechin, pelargonidin 3-glucoside, and ferulic acid were the main phenolic compounds. Hihg-pressure-assisted hydrolysis of common bean protein concentrates would provide benefits in the production of functional hydrolysates providing higher functionality and added value to the resulting hydrolysate due to synergistic effects of bioactive peptides and soluble phenolics.