Degree Of Hydrolysis Research Articles

Human milk vs. Infant formula digestive fate: In vitro dynamic digestion and in vivo mini-piglet models lead to similar conclusions

Infant formula (IF), the only nutritionally adequate substitute for human milk (HM), still needs to be improved to be more biomimetic with HM, including in terms of digestive fate. The latter can be explored using different digestion models. The present study aimed to compare IF and HM digestion using in vivo (mini-piglet) and in vitro (dynamic system, DIDGI®) models. Fresh mature HM was collected and compared with a standard bovine IF. In vivo, 18 Yucatan mini-piglets (24-day-old) received HM or IF and were euthanized 30 min after the last meal. The entire digestive content was collected from the stomach to the colon. In vitro, the same meals were fed to an in vitro dynamic digestion model simulating the term infant at four weeks of age. Digesta were sampled regularly in the gastric and intestinal compartments. Structure (confocal microscopy and laser light scattering) and proteolysis (SDS-PAGE for residual intact proteins, OPA for hydrolysis degree, LC-MS/MS for peptides) were investigated along digestion. The digesta microstructure differed between HM and IF in a similar way between in vitro and in vivo digestion. In vitro gastric proteolysis of caseins and α-lactalbumin was significantly slower for HM than for IF, such as for the early intestinal proteolysis degree. In vitro bioaccessibility of free AAs explained only 30 % of the true ileal digestibility of AAs. Peptide mapping of caseins differed between HM and IF along their digestion. The relative peptide mapping data over six proteins from HM and IF were highly correlated between in vitro and in vivo digestion, particularly at 80 and 120 min of in vitro gastric digestion vs. in vivo stomach data and at 20 and 40 min of in vitro intestinal digestion vs. in vivo proximal jejunum data (r = 0.7–0.9, p < 0.0001, n = 1604). 40 to 50 % of the bioactive peptides identified in vivo were also found in vitro, with a good correlation of their abundances (r = 0.5, p < 0.0001, n = 61). Overall, in vitro and in vivo digestion were in good agreement, both indicating a different digestive fate for HM and IF.

Effects of papain hydrolysate of Pseudosciaena crocea roe on the physical and oxidative stability of water-in-oil emulsions

This study investigates the effects of hydrolysates from Pseudosciaena crocea roe on the physical and oxidative stability of oil-in-water emulsions, emphasizing the structure-activity relationship between peptide structure and emulsifying properties. The results showed that, compared to other proteases, hydrolysates prepared with papain (PCRHs) at moderate degrees of hydrolysis (DH 4.68% and 6.8%) exhibited superior emulsifying activity index (EAI) and emulsifying stability index (ESI). PCRHs with DH of 4.68%, 6.8% formed smaller particle sizes (89.8 ± 3.52 nm, 112 ± 2.65 nm) and more stable emulsions. EAI and ESI of PCRHs were significantly negatively correlated with emulsion particle size and significantly positively correlated with surface hydrophobicity, amino acid composition, relative molecular mass, random coil content and total sulfhydryl groups. Additionally, although PCRHs with DH of 4.68% produced smaller and more stable emulsion particles, PCRHs with DH of 6.8% significantly inhibited primary and secondary lipid oxidation products formation. Correlation analysis revealed that emulsions with smaller particle sizes exhibited poorer oxidative stability, and secondary volatile oxidation products better reflected the oxidative stability of emulsions. Therefore, hydrolysates from Pseudosciaena crocea roe protein with moderate hydrolysis, particularly PCRHs with DH of 6.8%, demonstrate potential as natural emulsifiers to maintain the physical and oxidative stability of oil-in-water emulsions.

Unravelling the Influence of Extraction Techniques on Protein Yield and Nutritional Value in Lesser Mealworm Larvae.

In the present work, chemical and enzymatic assisted techniques were compared for protein extraction from lesser mealworm larvae (LM, Alphitobius diaperinus), recently approved as a novel food in the European Union. All extracts showed appreciable nutritional quality, with quantities of essential amino acids above the reference standard. Conventional alkali extraction allowed the isolation of only 73% of the protein, preserving the amino acid composition but potentially causing denaturation or racemisation. The "stepwise" method, following the Osborne fractionation, improved protein recovery to 91% by isolating four fractions with different solubility properties. Additionally, enzymatic hydrolysis using Bacillus licheniformis proteases was also tested, and it provided hydrolysates with an average degree of hydrolysis of 14%, making them a potential hypoallergenic solution. Overall, these findings indicate the ability to tailor the composition of LM protein to meet specific needs, offering promising prospects for the use of insect protein ingredients in various applications.

Effect of ultrasound treatment on quality parameters and health promoting activity of fish protein hydrolysates extracted from side streams of Atlantic mackerel (Scomber scombrus).

Fish protein hydrolysates (FPH) obtained by enzymatic hydrolysis allows for smart valorization of fish side streams. However, further treatments are normally needed to enhance bioactive and functional properties of the obtained FPH. At present, the commonly used methods to improve functional properties of FPH include chemical and enzymatic modification. Chemical treatments often cause environmental problems, while the enzymatic modification method requires the use of quite expensive enzymes. In recent years, emerging technologies such as ultrasound treatment (US-treatment) have shown great potential in protein modification with high efficiency and safety, low energy consumption, and low nutritional destructiveness. In this study, high-power ultrasound treatments were applied to fish protein hydrolysates (FPH) extracted from Atlantic mackerel (Scomber scombrus) side streams to improve their quality parameters. The effect of three different treatments of 300 W, 450 W and 600 W at the operating frequency of 20 kHz for 10 min on the physicochemical, structural, and functional characteristics of FPH, were examined. The results have shown that with an increase in ultrasound power, the protein solubility of FPH increased linearly, and the changes were significant for all US-treated samples compared to control (untreated) samples. US-treatment significantly increased the degree of hydrolysis of FPH samples treated with 450 W and 600 W compared to control samples. The carbonyl content of FPH increased (significantly for 450 W and 600 W), while thiol groups decreased (significantly for 300 W and 450 W). This indicated that some US-treatments induced oxidation of FPH, however the values of the protein oxidation were low. Amino acid composition of FPH revealed that US-treatment increased the proportion of essential amino acids in the sample treated with 300 W and 450 W, but the increase was not significant. After the US-treatment, all FPH samples became lighter and less yellowish and reddish, which suggest potentially higher attractiveness to consumers. In addition, the in vitro antioxidant activity was assessed using the DPPH, FRAP, and ABTS assays and the cell-free dipeptidyl peptidase IV (DPP-IV) inhibitory activity was also measured. Moreover, these biological activities were measured at cellular level utilizing human intestinal Caco-2 cells. Specifically, the FPH capacity to lower H2O2-induced reactive oxygen species (ROS) and lipid peroxidation levels was used to measure its antioxidant activity. The findings suggest that Scomber scombrus hydrolysates could find use as ingredients for promoting health.

Influence of enzymatic hydrolysis conditions on the degree of hydrolysis of protein hydrolysate obtained from cocoa pod husk (Theobroma cacao L.)

Influence of enzymatic hydrolysis conditions on the degree of hydrolysis of protein hydrolysate obtained from cocoa pod husk (Theobroma cacao L.)

Screening and characterization of umami peptides from enzymatic and fermented products of wheat gluten using machine learning

To explore the umami peptides from wheat gluten hydrolysates (WGHs) with different degrees of hydrolysis (DH) after Corynebacterium glutamicum (C. glutamicum) fermentation, a high-throughput screening method for umami peptides was established based on machine learning. The results showed fermented WGHs with high DHs exhibited more favourable taste profile after 4 days of fermentation and produced more small molecule peptides. Fermentation increased the number of characteristic peptides in WGHs with DH10, DH15, and DH20. Among, fermented WGHs with DH15 were the important source of potential umami peptides. Six potential umami peptides were screened (QQLPQFEE, LSFE, EELR, YTCE, YTTD, EEDQ) and were demonstrated to form stable complex with the T1R1/T1R3 receptor through hydrogen bonding interactions, electrostatic interactions, and hydrophobic interactions forces. The affinity of peptides and receptor were in the range of −6.3 to −8.1 kcal/mol. GLU735, GLY755, SER734, SER757 and THR227 were the critical binding sites. Sensory evaluation and electronic tongue showed that six peptides exhibited umami profile and had the capacity to enhance umami and saltiness taste. EEDQ presented the strongest intensity of umami taste and QQLPQFEE had the lowest umami thresholds. This study provides reliable methods for effectively screening new microbial-derived umami peptides.

Peptidomics profiling and biological activities of grape pomace protein hydrolysates

Grape pomace protein isolate was hydrolysed by Alcalase, Flavourzyme and Protease either individually or in combination to produce hydrolysates with antihypertensive and antimicrobial properties. The degree of hydrolysis (DH) ranged between 22 and 52 % for Protease and Flavourzyme, respectively. Among all treatments, hydrolysates prepared using Flavourzyme exhibited the highest angiotensin-converting enzyme inhibitory (ACEi) activity, with an IC50 value of 91 μg/mL. The peptidomics analysis revealed that the peptides identified in Flavourzyme hydrolysate presented molecular features compatible with its bioactivity, like a high density of ACEi sequences per peptide. The hydrolysates were also able to inhibit the growth of Escherichia coli in a range between 9 and 54 % for Alcalase and Alcalase + Flavourzyme, respectively. Peptides in the most active hydrolysate evidenced a high occurrence of proline residues, which is a structural feature of some antimicrobial peptides.

Acid Hydrolysis of Quinoa Starch to Stabilize High Internal Phase Emulsion Gels.

Starch nanocrystals (SNCs) to stabilize high internal phase emulsions (HIPEs) always suffer low production efficiency from acid hydrolysis. Due to its small granule size, Quinoa starch (QS) was selected to produce SNCs as a function of acid hydrolysis time (0-4 days), and their structural changes and potential application as HIPEs' stabilizers were further explored. With increasing the acid hydrolysis time from 1 day to 4 days, the yield of QS nanocrystals decreased from 30.4% to 10.8%, with the corresponding degree of hydrolysis increasing from 51.2% to 87.8%. The occurrence of QS nanocrystals was evidenced from the Tyndall effect and scanning electron microscopy with particle size distribution. The relative crystallinity of QS subjected to different hydrolysis times (0-4 days) increased from 22.27% to 26.18%. When the acid hydrolysis time of QS was 3 and 4 days, their HIPEs showed self-standing after inversion, known as high internal phase emulsion gels (HIPE gels), closely related to their densely packed interfacial architecture around oil droplets, seen on an optical microscope, and relatively high apparent viscosity. This study could provide a theoretical guidance for the efficient production and novel emulsification of SNCs from QS to HIPE gels.

Formation of self-assembled fibril aggregates of trypsin-controllably hydrolyzed soy protein and its regulation on stability of high internal phase Pickering emulsions

The mechanisms of trypsin hydrolysis time on the structure of soy protein hydrolysate fibril aggregates (SPHFAs) and the stability of SPHFAs-high internal phase Pickering emulsions (HIPPEs) were investigated. SPHFAs were prepared using soy protein hydrolysate (SPH) with different trypsin hydrolysis time (0 min–120 min) to stabilize SPHFAs-HIPPEs. The results showed that moderate trypsin hydrolysis (30 min, hydrolysis degree of 2.31 %) induced SPH unfolding and increased the surface hydrophobicity of SPH, thereby promoting the formation of flexible SPHFAs with maximal thioflavin T intensity and ζ-potential. Moreover, moderate trypsin hydrolysis improved the viscoelasticity of SPHFAs-HIPPEs, and SPHFAs-HIPPEs remained stable after storage at 25 °C for 80 d and heating at 100 °C for 1 h. Excessive trypsin hydrolysis (> 30 min) decreased the stability of SPHFAs-HIPPEs. In conclusion, moderate trypsin hydrolysis promoted the formation of flexible SPHFAs with high surface charge by inducing SPH unfolding, thereby promoting the stability of SPHFAs-HIPPEs.

Characterization of some physicochemical, textural, and antioxidant properties of muffins fortified with hydrolyzed whey protein.

Whey protein hydrolysates, derived from enzymatic hydrolysis of whey protein isolates or concentrates, offer enhanced bioavailability and solubility compared to intact whey protein. In this study, whey protein hydrolysates (WPHs) having different hydrolysis degrees (5%, 10%, and 15%) were produced and muffin cakes were enriched with the addition of WPHs. In general, the addition of WPHs showed a significant effect on oil and protein content while the emulsion activity was improved with the increased hydrolysis degree (HD). The degree of hydrolysis increment resulted in a significant increase in both antioxidant power and antiradical activity of the WPHs. Ferric-reducing antioxidant power and ABTS radical scavenging activity ranged between 18.83-87.27 mg TE/100 g and 211.8-5063.1 mg TE/100 g, respectively. The highest FRAP and ABTS values were recorded for the 15% HD while the lowest was for the native whey protein isolate (WPI). The induction periods giving a clear information for the oxidative stability were 1593 min for the control muffins, and it was 1654for the muffin added with WPI. Rheological data revealed that all cake batter samples including WPHs showed viscoelastic behavior. WPHs could be efficiently used in muffin formulation to increase the biofunctional effects of the final products.

The impact of hot-air oven drying combined with Bacillus subtilis K[sbnd]C3 inoculation on quality characteristics and microbial profiles of salted shrimp paste

This study used hot-air oven drying with Bacillus subtilis KC3 inoculation to improve shrimp paste production. The fermentation rate, quality characteristics, as well as microbial profiles, were compared to those produced using sun-drying with/without inoculation. B. subtilis inoculation increased the degree of hydrolysis of shrimp paste (22.3–32.1 %) during fermentation, compared to those without inoculation (12.7–25.4 %), regardless of different drying methods (p < 0.05). The result corresponded to the faster development of shrimp paste characteristics, particularly color and browning intensity of inoculated samples when fermented for the same duration. More abundant halophilic, proteolytic, and lipolytic bacteria (p < 0.05) were also obtained in inoculated samples, confirming accelerated fermentation. Interestingly, there was no difference in proximate composition, pH, and aw among samples (p > 0.05), which were still in the range regulated by the product's standard. However, the protein and lipid degradation products such as nitrogen contents, 5′-nucleotides, free fatty acids or TBARS values, varied among samples, potentially influencing the release of desirable flavor precursors to a certain extent. The inoculation increased microbial richness and evenness/uniformity, according to next-generation sequencing analysis on microbiota profiles. Pearson's correlation also revealed that these microbiota profiles were correlated with several desirable quality characteristics to varying degrees. Thus, combining the inoculation with B. subtilis KC3 can enhance shrimp paste fermentation and quality when produced using an alternative hot-air oven while maintaining quality characteristics. The findings suggested the possibility of achieving a more efficient and consistent production process for shrimp paste.

Chewing characteristics of rice and reasons for differences between three rice types with different amylose contents

This study investigated the physicochemical structural changes in different types of rice (japonica rice [JR], indica rice [IR], and waxy rice [WR]) during oral digestion and explored the reasons for differences in oral digestion between the three different types. The results showed that, compared with JR (42.41 ± 3.06 mg/g) and WR (26.82 ± 0.67 mg/g), IR had the highest amylose content (49.95 ± 3.33 mg/g) and, related to this, hydrolysis rate. A correlation analysis showed that, the higher the amylose content, the harder the texture of rice, leading to longer chewing times and, as a result, a greater degree of hydrolysis. In addition, the higher the amylose content, the lower the exudate content and viscosity of rice, which affects chewing time and frequency, thereby affecting the degree of hydrolysis. Both X-ray computed tomography and scanning electron microscopy indicated that cooked IR had the loosest structure and the most pores, that were conducive to chewing and crushing and therefore contributed to the high hydrolysis rate. Analysis of the exudate structure showed that the amount of exudate affected rice pores. More exudates lead to pore coverage and a tight structure.

Enhancement of β-galactosidase catalytic activity and stability through covalent immobilization onto alginate/tea waste beads and evaluating its impact on the quality of some dairy products

The current study aimed to evaluate the hydrolysis of whole fat milk (WFM) and sweet whey (SW) using β-galactosidase (β-gal) after covalent immobilization onto activated alginate/tea waste (Alg/TW) beads as a novel carrier. The optimum temperature for free and Alg/TW/β-gal was 40 °C and the ideal pH was 7.0. However, Alg/TW/β-gal displayed better stabilities at high temperatures and a wide pH range. Additionally, the value of Km and Vmax for Alg/TW/β-gal was higher than the free enzyme. The Alg/TW/β-gal showed better residual activity (78.6 %) after 90 storage days at 4 °C. The reusability of Alg/TW/β-gal was very good as it conserved its full activity after 15 consecutive cycles and conserved 93 % of its initial activity after 10 cycles with ONPG (O-nitrophenyl-β-D-galactopyranoside) and lactose as a substrate, respectively. The impact of Alg/TW/β-gal on WFM and SW using HPLC analysis revealed a remarkable decrease in lactose concentration and increase of glucose and galactose concentrations. The SW exhibited higher degree of lactose hydrolysis (97.3 %) compared to WFM (62.4 %). Besides, SW had a prominent increase in total phenolic content (96.8 mg/L) compared to WFM (54.3 mg/L). The antioxidant activity had increased after enzyme treatment in both WFM and SW. The GC–MS analysis for volatile compounds identified twenty-five flavour constituents. Finally, Alg/TW/β-gal has a potential application for obtaining healthy, acceptable, and commercial dairy products of low lactose.

Antithrombotic and anticariogenic activity of peptide fractions from cowpea (Vigna unguiculata) protein hydrolysates.

Protein-derived peptide fractions can play a key role in the physiological and metabolic regulation and modulation of the body, which suggests that they could be used as functional ingredients to improve health and to reduce the risk of disease. This work aimed to evaluate the in vitro antithrombotic and anticariogenic bioactivity of hydrolysates and protein fractions obtained from cowpea (Vigna unguiculata) by biocatalysis. Cowpea protein concentrate was hydrolyzed by sequential action with two enzyme systems, Pepsin-Pancreatin or Alcalase-Flavourzyme. There was extensive enzymatic hydrolysis, with degrees of hydrolysis of 34.94% and 81.43% for Pepsin-Pancreatin and Alcalase-Flavourzyme, respectively. The degree of hydrolysis for the control treatments, without the addition of the enzymes Pepsin-Pancreatin and Alcalase-Flavourzyme was 1.1% and 1.2%, respectively. The hydrolysates were subjected to fractionation by ultrafiltration, with five cut-off points according to molecular weight (<1, 1-3, 3-5, 5-10 and >10 kDa). The Alcalase-Flavourzyme hydrolysate led to 100% inhibition of platelet aggregation, while the Pepsin-Pancreatin hydrolysate showed 77.41% inhibition, but this was approximately 100% in the ultrafiltered fractions. The highest anticariogenic activity was obtained with the Pepsin-Pancreatin system, with 61.55% and 56.07% for calcium and phosphorus demineralization, respectively. Hydrolysates and their peptide fractions from Vigna unguiculata exhibited inhibition of platelet aggregation and protection of tooth enamel and have the potential for use in the development of functional products with beneficial health effects. © 2024 Society of Chemical Industry.

Effect of concentration on PVA solutions and its usage in recycling carbon fiber/polyamide 12 prepregs

Abstract Polyvinyl alcohol (PVA) is a biodegradable synthetic polymer with high chemical resistance and excellent mechanical and oxygen barrier properties. Besides these superior properties, it is water-soluble, which provides its wide usage. However, its solubility depends on some factors. Although the temperature is one of these factors and increasing temperature could promote solubility, there is a solubility limit according to hydrolysis degree. In this study, PVA solutions at various concentrations were obtained by mixing fully hydrolyzed PVA1500 and water. Solutions were characterized by density, surface contact angle and dynamic viscosity measurements. Then, solvent casting was used to obtain films, and physical and mechanical properties were determined. Tensile test results showed optimum values at 10–12.5 wt.% PVA concentration. Also, vacuum drying changed the mechanical behavior of films significantly at all concentrations. While ultimate tensile stress values almost doubled and modulus values increased approximately three times, elongations critically decreased. Solutions were also subjected to waste carbon fiber (CF)/polyamide 12 (PA12) prepregs for recycling purposes. Lay-up and compression molding processes were applied to produce CF/PA12 composites. It was seen that mechanical results were significantly increased with increasing PVA concentration.

Impact of hydrolysis on the quantification of sulfonated acrylamide copolymers by size exclusion chromatography with UV detection

AbstractSize exclusion chromatography with UV detection (SEC‐UV) is a precise method for quantifying polyacrylamides in water. However, its accuracy can be compromised in complex matrices due to chemical degradation of the polymer. This study focuses on the impact of hydrolysis on quantifying sulfonated polyacrylamide copolymers (PAM‐AMPS) via SEC‐UV, analyzing key influencing factors. Using controlled hydrolysis, hydrolyzed copolymer (HPAM‐AMPS) standards with varying hydrolysis degree (HD) (HD = 7%–33%) were prepared without significant changes in polymer chain size. SEC‐UV analysis revealed that quantification accuracy is highly dependent on hydrolysis extent. Errors are minimal for HD up to 10%, but significantly higher for HDs of 22%–33%. Furthermore, this effect is modulated by polymer concentration. Our findings indicate that there are two compensating factors for the decrease in molar absorptivity due to amide‐to‐carboxylate substitution: the sulfonate group acting as an additional chromophore, and a redshift in absorption spectra due to hydrogen bonding at higher concentrations. This interplay between HD and concentration in this type of sulfonated polyacrylamide can help reduce quantification errors in complex aqueous samples prone to chemical degradation, like those found in environmental and subsurface applications.

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

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

Effects and optimization of hydrolysis conditions on the diameter distance ratio for metatitanic acid

Controlling and predicting the narrow particle size distribution of metatitanic acid could help to improve pigment and application performances of TiO2. To prepare metatitanic acid with narrow particle size distribution, the hydrolysis conditions of industrial TiOSO4 solution were optimized by using the response surface methodology of Box-Behnken design method. The effects of hydrolysis conditions such as TiO2 concentration, aging time and hydrolysis time on the diameter distance ratio and structure of metatitanic acid were investigated. The prediction model including the hydrolysis variables with good fitting result was established to predict the diameter distance ratio or optimize the hydrolysis variable values. The regression equation model was significant and reliable with actual correlation coefficient R2 of 0.9989. The hydrolysis conditions greatly influenced the quality and quantity of hydrolysis induced crystal nucleus, hydrolysis rate, completeness degree of hydrolysis, crystallization growth and aggregation rate, and eventually affected the particle size distribution of metatitanic acid. The synergistic interaction for TiO2 concentration and hydrolysis time was very significant. The verification experiments confirmed that the diameter distance ratio could reach the average value of 1.100 under the optimal conditions. The prepared metatitanic acid had anatase TiO2 phase structure, with average particle size of 1.621–1.819 µm. And this helped to improve the high quality and green development of the titanium dioxide industry.

Impact assessment of polymer, cross-linker, and nanoparticles on gelation kinetics and properties of silica nanocomposite hydrogel for water shut-off treatment in harsh reservoir conditions

The study presented the impacts of various parameters like compositional combinations of PHPA (partially hydrolyzed polyacrylamide), organic cross-linker (hydroquinone-HQ and hexamethylenetetramine-HX), and silica nanoparticles (SNP) in addition to the degree of hydrolysis and molecular weight of PHPA on the efficacy of hydrogel for water shut-off jobs. The investigation indicated that the gelation time, gel strength of the gel, tolerance against salinity, and temperature were tuned as required by the field conditions by changing the variables mentioned above. The gelation time was found to vary inversely with the concentration of polymer, cross-linkers, and silica nanoparticles, whereas the gel strength and temperature tolerance followed the reverse trend. SNP was observed to control the gel properties significantly, even at the lower polymer and cross-linker compositions, as evidenced by the stronger network in FESEM, rheological, and other related properties. The hydrogels prepared with the PHPA-LM (low molecular wt) and PHPA-HM (high molecular wt) polymers and HX-HQ cross-linkers showed improved temperature tolerance from 126.49 °C to 131.78 °C and 99.88 °C to 164.34 °C, respectively when improvised with SNP. The gel’s microstructure (FE-SEM image) exhibited significant silica nanoparticle aggregation and evenly distributed compact three-dimensional network structure. The prepared nanohydrogel with optimized composition maintained its stability even at a salinity of 60000 ppm and 120 °C for more than two years. Sand-pack flooding with the nanohydrogel proved very effective, with a permeability reduction of ∼ 90 %. Thus, the prepared nano-hydrogel could be effectively used for high temperature and high salinity conditions with preferred resistance to water flow.

Ultrasonication assisted enzymatic hydrolysis for generation of pulses protein hydrolysate having antioxidant and ACE-inhibitory activity

The main objective of this work was to investigate the impact of ultrasonication assisted enzymatic treatment on the physicochemical and bioactive properties of broad bean (BBP), lentil bean (LBP), and mung bean (MBP) protein isolates. The protein was extracted using alkaline acid precipitation method, ultrasonicated at a frequency of 20 kHz, temperature 20–30 °C and then hydrolysed using alcalase enzyme (1 % w/w, pH 8.5, 30 min, 55 οC). The generated hydrolysates were characterized by degree of hydrolysis (DH), SDS, FTIR, surface hydrophobicity, amino acid composition, antioxidant and antihypertensive properties. Results showed that the degree of hydrolysis was found to increase in ultrasonicated protein hydrolysate (18.9 to 40.71 %) in comparison to non- ultrasonicated protein hydrolysate (11 to 16.3 %). SDS-PAGE results showed significant changes in protein molecular weight profiles (100–11kDa) in comparison to their natives. However, no substantial change was found in ultrasonicated and non-ultrasonicated protein hydrolysates. The FTIR spectrum showed structural alterations in ultrasonicated and non-ultrasonicated protein hydrolysates, suggesting modifications in secondary structure such as amide A, amide I and amide II regions. The essential amino acid content varied in the range of 60.09 mg/g to 73.77 mg/g and 28.73 to 50.26 mg/g in case of ultrasonicated and non-ultrasonicated protein hydrolysates, and non-essential content varied in the range of 49.42 to 65.93 mg/g and 43.12 to 47.12 mg/g. Both antioxidant and antihypertensive activities were found to increase significantly in ultrasonicated and non-ultrasonicated protein hydrolysates in comparison to their native counterparts, highlighting their potential as functional ingredients for management of hypertension. It was concluded that ultrasonication assisted enzymatic hydrolysis is an efficient approach for production of bioactive pulse protein hydrolysates with enhanced nutracutical properties, thus offering promising avenues for their utilization in the food industry and beyond.