This work aims to characterize a novel system for thyme essential oil delivery based on the combination of natural emulsifiers (soy protein and soy lecithin) and alginate, produced using the ...extrusion technique. The formulations are optimized concerning alginate and soy protein concentrations (both 1 to 1.5 wt.%), and consequently lecithin amount, in order to achieve spherical beads in the range 2.0 to 2.3 mm and 1.2 to 1.4 mm, wet and dry, respectively. Fourier‐transform infrared analysis was performed, proving that there are interactions between all components. Lecithin–soy protein synergistic combination improved entrapment efficiency of total polyphenols (for nearly 12%) and decreased thymol release in a simulated gastric solution for nearly 35%, in comparison with beads without lecithin. The addition of lecithin enhances the thermal properties of the polysaccharide–protein systems at 50 °C after 3 hr of heating. The mechanical stability of the biopolymer carriers is improved with lecithin addition and the elastic modulus varied from 80.06 to 123.7 kPa, depending on the formulation. Alginate/soy protein/lecithin are effective carriers for the encapsulation, protection, and controlled release of thyme essential oil.
Practical Application
There is unfortunately growing human resistance to antibiotics. This work offers a novel system for effective protection and controlled release of thyme essential oil in the small intestine. The mechanical and thermal properties of the carrier were estimated as they indicate how the beads will be able to resist stress during their incorporation into food (i.e. cookies‐mixing, baking). The proposed approach offers ‘‘green advantage’’ as arises from all‐natural materials.
Two anthraquinonic dyes, C.I. Acid Blue 225 and C.I. Acid Violet 109, were used as models to explore the feasibility of using the horseradish peroxidase enzyme (HRP) in the practical decolorization ...of anthraquinonic dyes in wastewater. The influence of process parameters such as enzyme concentration, hydrogen peroxide concentration, temperature, dye concentration, and pH was examined. The pH and temperature activity profiles were similar for decolorization of both dyes. Under the optimal conditions, 94.7% of C.I. Acid Violet 109 from aqueous solution was decolorized (treatment time 15 min, enzyme concentration 0.15 IU/mL, hydrogen peroxide concentration 0.4 mM, dye concentration 30 mg/L, pH 4, and temperature 24°C) and 89.36% of C.I. Acid Blue 225 (32 min, enzyme concentration 0.15 IU/mL, hydrogen peroxide concentration 0.04 mM, dye concentration 30 mg/L, pH 5, and temperature 24°C). The mechanism of both reactions has been proven to follow the two substrate ping-pong mechanism with substrate inhibition, revealing the formation of a nonproductive or dead-end complex between dye and HRP or between H2O2 and the oxidized form of the enzyme. Both chemical oxygen demand and total organic carbon values showed that there was a reduction in toxicity after the enzymatic treatment. This study verifies the viability of use of horseradish peroxidase for the wastewaters treatment of similar anthraquinonic dyes.
The objective of this research was to investigate the impact of high-intensity ultrasound (HIU) generated by a probe-type sonicator (frequency 20 ± 0.2 kHz and an amplitude of 40%) for 2–20 min on ...the selected functional and structural properties of egg white proteins (EWPs) and their susceptibility to hydrolysis by alcalase. The protein solubility, foaming, and emulsifying properties were studied as a function of ultrasonication time and related to protein particle and structural properties. The length of ultrasonication exhibited important effect on EWP particle size, uniformity, and charge, affecting also the protein conformation and susceptibility to alcalase hydrolysis and determining functional properties. There was a linear correlation between the particle size decrease and the solubility while a two-step linear correlation between the foam capacity (FC)/foam stability (FS) and particle size was apparent. Specifically, FC and FS sharply increased with decreasing particle size for range from ∼370 to ∼260 nm, and below this range from 260.6 to 68.4 nm, the changes were not that substantial. Besides, the solubility, FC, and FS were directly and linearly related with the absolute value of the particle zeta potential. The overall emulsifying properties were also improved with an increase of sonication time, through both the decrease of the mean particle diameter and the increase of zeta potential, but there was no direct correlation between the emulsion activity/stability index and protein particle size and/or charge. Analysis of EWP structure by Raman spectroscopy revealed that the HIU leads to changes in the secondary structure, while heat and ultrasound generated by the ultrasound bath were not sufficient to exhibit this effect.
Graphical abstract
Immobilized lipase from
Candida antarctica
(Novozyme 435) was tested for the synthesis of various phenolic acid esters (ethyl and
n
-butyl cinnamate, ethyl
p
-coumarate and
n
-butyl
p
...-methoxycinnamate). The second-order kinetic model was used to mathematically describe the reaction kinetics and to compare present processes quantitatively. It was found that the model agreed well with the experimental data. Further, the effect of alcohol type on the esterification of cinnamic acid was investigated. The immobilized lipase showed more ability to catalyze the synthesis of butyl cinnamate. Therefore, the process was optimized for the synthesis of butyl cinnamate as a function of solvent polarity (log
P
) and amount of biocatalyst. The highest ester yield of 60.7 % was obtained for the highest enzyme concentration tested (3 %
w
/
w
), but the productivity was for 34 % lower than the corresponding value obtained for the enzyme concentration of 1 % (
w
/
w
). The synthesized esters were purified, identified, and screened for antioxidant activities. Both DPPH assay and cyclic voltammetry measurement have shown that cinnamic acid esters have better antioxidant properties than cinnamic acid itself.
Recovery of protein from soy grit, its functional properties and possibility for the reduction of time of conventional alkaline extraction by the assistance of enzymes were studied. Enzymatic ...treatment was performed by commercial preparations of cellulase (NS22086), xylanase (NS22083) and pectinase (Vinozym) (applied separately or in combination) as well as by commercial carbohydrases cocktail (Enzyme complex, NS22119). Three different extractions were investigated - alkaline (at pH 8 for 1 h, 2 h or 3 h), enzyme-assisted aqueous (at pH 5.5 for 3 h) and enzyme-assisted alkaline extractions (enzymatic extraction for 1 h followed by alkaline extraction for 1 h or 2 h) at 50 °C and solid:liquid ratio 1:10 (w/v). The highest enhancement of recovery of protein was achieved by pretreatment of soy grit with enzyme cocktails. Treatment with Enzyme complex followed by 1 h alkaline extraction increased protein yield for 21% compared to 2 h alkaline extraction. Treatment by combination of individual cellulase, xylanase and pectinase followed by 2 h alkaline extraction enhanced protein yield for 13% in comparison to 3 h alkaline extraction. So, reduced time of alkaline extraction was attained by the assistance of carbohydrases cocktails with even positive effect on protein yield. In addition, protein from enzyme-assisted alkaline extraction exhibited ameliorated solubility, emulsifying and whipping properties compared to alkaline extracted protein.
•Recovery of protein from soy grit was enhanced by carbohydrases-assisted alkaline extraction.•Reduced time of alkaline extraction was attained by enzymatic pretreatment.•Functional properties of protein from enzyme-assisted alkaline extraction were improved.
The objective of this study was to investigate the effects of different ultrasound pretreatment on enzymatic hydrolysis of egg white proteins (EWPs) by Alcalase as well as evaluating some functional ...and antioxidant properties of hydrolysates obtained by various proteases treatment and ultrasound technology. The effects of chosen ultrasound pretreatment parameters including frequency of ultrasonic waves (35 and 40 kHz), temperature (25 and 55 °C), time of pretreatment (15–60 min) and pH of egg white solution (7.00–10.00) were examined. It appeared that controlled ultrasound treatment can improved the hydrolysis process compared with untreated samples, but optimization of the power and length of sonication was important. The optimal ultrasound pretreatment at calorimetric power of 21.3 W and frequency of 40 kHz for 15 min at 25 °C and with naturally basic egg white (pH 9.25) resulted in increased initial rate and equilibrium degree of Alcalase hydrolysis by about 139.8 and 13.86 % compared with the control, respectively. EWP hydrolysates with ≈27.0 % degree of hydrolysis obtained with heat pretreatment and ultrasound pretreatments under optimal conditions were further separated by sequential ultrafiltration into 4 hydrolysate fractions (<1, 1–10, 10–30 and >30 kDa) which were investigated for protein content, peptide yield and antioxidant activity. The hydrolysis after heat pretreatment generated more peptides <1 kDa (19.04 ± 1.02 %) than ultrasound pretreatment did (11.90 ± 0.53 %), whereas the proportion of peptides <10 kDa were higher in the second case (28.80 ± 0.07 vs. 20.46 ± 0.39 %). The fraction obtained by the ultrasound pretreatment containing peptides with a molecular weight between 1 and 10 kDa demonstrated the strongest ABTS radical scavenging efficacy among the fractions (97.54 ± 0.30) with IC
50
value of 4.31 mg/mL. Compared with single-enzyme processes, the two-stage enzymatic processes did not significantly improve both antioxidant and functional hydrolysates’ properties.
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•Little work has been performed on bioactive peptides from wheat gluten.•Impeller geometry and agitation speed affect the reaction rate of gluten hydrolysis.•Optimization of ...antioxidant activity was achieved by using response surface methodology.•DPPH and ABTS scavenging activities are differently affected by degree of hydrolysis.•The peptide fraction of 3–10 kDa seems to be responsible for both scavenging activities.
The aim of the study was to find the optimal operational and process parameters for the enzymatic hydrolysis of wheat gluten in a batch stirred bioreactor regarding both degree of hydrolysis and antioxidant capacity of the obtained hydrolysates. It appeared that impeller geometry and agitation speed influenced the mass transfer resulting in enhanced gluten hydrolysis. The highest initial reaction rate (0.83 ± 0.02 min−1) and degree of hydrolysis (30.47%) were achieved with the pitched four-bladed impeller and agitation speed of 350–450 rpm, conditions which provided proper balance between requirements for adequate mass/heat transfer and low shear stress. The impact of other process conditions including gluten concentration, temperature, pH and enzyme-gluten (E/S) ratio on the enzymatic reaction was investigated by applying a Box-Behnken experimental design from the viewpoint of the degree of hydrolysis (DH) and antioxidant activity. Three models obtained allowed calculation of the hydrolysis degree, and both 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ABTS (2,2′-azino-bis (3-ethylbenzothiazoline-6-sulpfonic acid) radical scavenging activity from a given set of reaction conditions with good predictability. The statistical analysis showed that each variable had a significant effect on degree of hydrolysis and the antioxidant capacity of both tested systems. Hydrolysis up to around DH 15% improved DPPH radical scavenging activity, while excessive hydrolysis worsened it. The ABTS activity of the hydrolysates was not associated with the DPPH activity nor with the DH, revealing that it was not possible to fulfill all desirable quality requirements (maximum degree of hydrolysis and protein yield, maximum DPPH and ABTS scavenging activities) by using the same reaction conditions. Overall, the study might contribute to approve wheat gluten, a by-product of wheat starch industry, as an accessible and cheap source of bioactive compounds for the development of novel nutraceuticals, cosmetics and drugs.
Ethyl cinnamate, an ester known as flavor and fragrance compound, has been synthesized using two immobilized bioreactor systems, batch and fluidized bed bioreactors. The enzyme used for this ...synthesis is a commercial lipase B preparation, Novozyme 435. Initial kinetic studies were conducted in both employed bioreactor configurations, and kinetic constants were obtained. Several models were tried for fitting of experimental data, but the best fit, for both bioreactors, was obtained when the ping-pong bi-bi mechanism was used. Interestingly enough, ethanol inhibition occurred in batch bioreactor, but it did not exist in the fluidized bed bioreactor. Solid–liquid mass transfer coefficients were calculated for both bioreactors to determine whether mass transfer limitations existed in either of these systems. The calculation of Damköhler numbers and Thiele modulus confirmed that mass transfer limitations had no effect on the overall reaction in both bioreactors.
•Nanoparticles were produced by heat treatment from pumpkin leaf white protein.•Heat treatment induced changes in secondary structure and surface hydrophobicity.•High quenching constant of β-carotene ...for protein and nanoparticles from conventional recovery protocol.•Low binding ability of β-carotene for protein from green protocol increased almost 100 times upon heat treatment.
Nanoparticles prepared by heat treatment of protein from pumpkin leaves were evaluated as potential carriers of β-carotene. White protein fraction was recovered from green juice produced by pressing the leaves, with the step of enzyme-assisted extraction (green protocol) or without it (conventional protocol). Heat treatment of white protein fractions from conventional and green protocols at 90 °C and pH 9.3 during 20 min induced formation of nanoparticles with peak diameter 18 nm and 21 nm, respectively. Due to heating, portion of β-sheets in nanoparticles from both native protein fractions decreased by approximately 15 %, associated with an increase in surface hydrophobicity-to-area ratio. Quenching constant of β-carotene for nanoparticles was increased nearly 100 times by heating the white protein fraction recovered in green protocol. Native white protein fraction from conventional protocol and corresponding nanoparticles exhibited high ability to bind β-carotene, with quenching constant 3 × 105 L/mol and 3.3 × 105 L/mol, respectively. White protein fraction from pumpkin leaves appeared to be a suitable substrate for the fabrication of nanoparticles by heat treatment, with potential application as β-carotene nanocarriers in food matrices.
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► Covalently stablized and highly active
Candida rugosa lipase was used for statistical modeling of geranyl butyrate synthesis. ► Optimized reaction conditions enabled high-yielding ...production of targeted ester. ► Using the same catalyst, geranyl butyrate synthesis was optimized in fluidized bed reactor, as one being potentially used in industry. ► Optimized synthesis in fluidized bed reactor enabled high yielding, stable and kinetically improved ester production.
Three commercially available polymers (Sepabeads
® EC-EP, Sepabeads
® EC-HA and Purolite
® A-109) were tested for potential application as supports for covalent immobilization of lipase from
Candida rugosa by analyzing some critical properties of immobilized enzymes such as enzyme loading, activity and activity immobilization yield. Among them, lipase covalently immobilized on Sepabeads
® EC-EP via epoxy groups appeared to show the best performance in a standard hydrolytic reaction. Therefore, it was selected and assayed in the esterification of butyric acid and geraniol to produce geranyl butyrate, first in a batch system followed by continuous geranyl butyrate synthesis in a fluidized bed reactor, as one being potentially applicable for large-scale production.
Based on statistical analysis, optimal conditions for the production of geranyl butyrate by selected, immobilized lipase in the batch system are recommended as: temperature at 25–30
°C, water concentration at 3.6% (v/v) and acid/alcohol molar ratio at 2.5. A set of optimal conditions for the ester synthesis in a fluidized bed reactor system has also been determined, specifically, flow rate at 10
mL
min
−1, temperature at 35
°C, water concentration at 2% (v/v), substrate concentration at 0.1
M and acid/alcohol ratio at 2.0. Implementation of the optimized parameters in a batch system and in a fluidized bed reactor enabled production of target ester with high molar conversion, at > 99.9% for 48
h in the batch process, and 78.9% for 10
h in fluidized bed reactor. Although when assayed at their optimal conditions, lower molar conversion was achieved in the fluidized bed reactor system compared to the batch system, the volumetric productivity in fluidized bed reactor was more than five fold higher than that obtained in the batch system.
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