Production and biological activity of ß-1,3-xylo-oligosaccharides using xylanase from Caulerpa lentillifera.

In this study, ß-1,3-xylanase (Xyl3088) was designed and prepared by constructing the expression vector plasmid and expressing and purifying the fusion protein. ß-1,3-xylo-oligosaccharides were obtained through the specific enzymatic degradation of ß-1, 3-xylan from Caulerpa lentillifera. The enzymolysis conditions were established and optimized as follows: Tris-HCl solution 0.05 mol/L, temperature of 37 °C, enzyme amount of 250 µL, and enzymolysis time of 24 h. The oligosaccharides' compositions and structural characterization were identified by thin-layer chromatography (TLC), ion chromatography (IC) and liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS). The IC50 values for scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2-azino-bis-3-ethyl-benzothiazoline-p-sulfonic acid (ABTS+), and superoxide anion radical (•O2-) were 13.108, 1.258, and 65.926 mg/mL for ß-1,3-xylo-oligosaccharides, respectively, and 27.588, 373.048, and 269.12 mg/mL for ß-1,4-xylo-oligosaccharides, respectively. Compared with ß-1,4-xylo-oligosaccharides, ß-1,3-xylo-oligosaccharides had substantial antioxidant activity and their antioxidant effects were concentration dependent. ß-1,3-xylo-oligosaccharides also possessed a stronger anti-inflammatory effect on RAW 264.7 cells stimulated by lipopolysaccharide (LPS) than ß-1,4-xylo-oligosaccharides. At a working concentration of 100 µg/mL, ß-1,3-xylo-oligosaccharides inhibited the release of NO and affected the expression of IL-1ß, TNF-α, and other proteins secreted by cells, effectively promoting the release of pro-inflammatory mediators by immune cells in response to external stimuli and achieving anti-inflammatory effects. Therefore, ß-1,3-xylo-oligosaccharides are valuable products in food and pharmaceutical industries.

Highly Efficient Production of Cellulosic Ethanol from Poplar Using an Optimal C6/C5 Co-Fermentation Strain of Saccharomyces cerevisiae.

Cellulosic ethanol is the key technology to alleviate the pressure of energy supply and climate change. However, the ethanol production process, which is close to industrial production and has a high saccharification rate and ethanol yield, still needs to be developed. This study demonstrates the effective conversion of poplar wood waste into fuel-grade ethanol. By employing a two-step pretreatment using sodium chlorite (SC)-dilute sulfuric acid (DSA), the raw material achieved a sugar conversion rate exceeding 85% of the theoretical value. Under optimized conditions, brewing yeast co-utilizing C6/C5 enabled a yield of 35 g/L ethanol from 10% solid loading delignified poplar hydrolysate. We increased the solid loading to enhance the final ethanol concentration and optimized both the hydrolysis and fermentation stages. With 20% solid loading delignified poplar hydrolysate, the final ethanol concentration reached 60 g/L, a 71.4% increase from the 10% solid loading. Our work incorporates the pretreatment, enzymatic hydrolysis, and fermentation stages to establish a simple, crude poplar waste fuel ethanol process, expanding the range of feedstocks for second-generation fuel ethanol production.

Comparison of different drying pretreatment combined with ultrasonic-assisted enzymolysis extraction of anthocyanins from Lycium ruthenicum Murr.

Extraction of anthocyanins from Lycium ruthenicum Murr. (L. ruthenicum) is a notable challenge in food production, requiring methods that balance efficiency and safety. In this study, we conducted a comparative analysis the extraction of anthocyanins by natural air drying (NAD), vacuum freeze drying (VFD), hot air drying (HAD), and vacuum microwave drying (MVD) combined with ultrasonic-assisted enzymolysis extraction (UAEE). The results demonstrated that the extraction yield and antioxidant activity of anthocyanins were significantly higher in VFD. This phenomenon can be attributed to the modification of raw material's microstructure, leading to an increased extraction yield of specific anthocyanins such as Cyanidin-3-galactoside, Delphinidin chloride, Cyanidin, and Petunidin. According to the pretreatment results, the extraction process of anthocyanins was further optimized. The highest yield (3.16 g/100 g) was obtained in following conditions: 0.24 % pectinase, 48 °C, solid:liquid = 1:21, and 21 min ultrasonic time. This study improves the commercial value and potential application of L. ruthenicum in food industry.

Investigating the Mechanism of Microwave-Assisted Enzymolysis Synergized with Magnetic Bead Adsorption for Reducing Ovalbumin Allergenicity through Biomass Spectrometry Analysis.

This study found that, after microwave treatment at 560 W for 30 s, alkaline protease enzymolysis significantly reduced the allergenicity of ovalbumin (OVA). Furthermore, specific adsorption of allergenic anti-enzyme hydrolyzed peptides in the enzymatic products by immunoglobulin G (IgG) bound to magnetic bead further decreased the allergenicity of OVA. The results indicated that microwave treatment disrupts the structure of OVA, increasing the accessibility of OVA to the alkaline protease. A comparison between 17 IgG-binding epitopes identified through high-performance liquid chromatography-higher energy collisional dissociation-tandem mass spectrometry and previously reported immunoglobulin E (IgE)-binding epitopes revealed a complete overlap in binding epitopes at amino acids (AA)125-135, AA151-158, AA357-366, and AA373-381. Additionally, partial overlap was observed at positions AA41-59, AA243-252, and AA320-340. Consequently, these binding epitopes were likely pivotal in eliciting the allergic reaction to OVA, warranting specific attention in future studies. In conclusion, microwave-assisted enzymolysis synergized with magnetic bead adsorption provides an effective method to reduce the allergenicity of OVA.

Study on the effect of enzymolysis combined fermentation on reducing the off-flavor of egg white powder.

BACKGROUND: The application of egg white powder (EWP) was subject to its off-flavor. In the present study, flavourzyme and lactic acid bacteria were used to treat egg white powder (EWP) and the mechanism effects of enzymolysis-fermentation were explored. RESULTS: Compared with the control group, enzymolysis combined with fermentation treatment group (EW-EF) reduced the four-representative off-flavor compounds (geranyl acetone, 1-octen-3-ol, octanal and nonanal) by more than 62.66%. Fermentation produced esters with good flavor, and enzymolysis produced fresh amino acids. Characterization of protein structure indicated that fermentation decreased both fluorescence intensity and surface negative charges, accelerating the aggregation of proteins; enzymolysis promoted aggregation and degradation, improving the stability of the egg white proteins. Meanwhile, enzymolysis broke down the hydrophobic cavities bound to off-flavor compounds, releasing protein-bound off-flavor compounds and removing them through fermentation. CONCLUSION: EW-EF had the best effect of off-flavor removal on EWP. The results of the present study could provide a green and effective method for improving the flavor of EWP. © 2024 Society of Chemical Industry.

Enzymatically green-produced bacterial cellulose nanoparticle-stabilized Pickering emulsion for enhancing anthocyanin colorimetric performance of versatile films.

To enhance the colorimetric performance of anthocyanin (Ant), a konjac glucomannan (KGM)-based multifunctional pH-responsive indicator film was fabricated by introducing enzymatically prepared bacterial nanocellulose (EBNC) stabilized camellia oil/camellia essential oil Pickering emulsion (BCCE). Specifically, optimized enzymatic hydrolysis time (36 h) was determined based on the particle size and microstructure. Then BCCE (containing 0.4% EBNC) was incorporated into Ant-containing KGM, and the novel active indicator film (KGM-Ant-BCCE) was constructed. Films with varying BCCE concentrations (3%-11%) exhibited enhanced UV shielding, thermal stability, mechanical strength, water vapor and oxygen permeability, hydrophobicity, and antioxidant performance. The pronounced color change of KGM-Ant-BCCE indicated its potential for visually detecting shrimp freshness. Moreover, the biodegradability (25 days) confirmed the environmentally benign property of the film. In summary, incorporating green-produced EBNC nanoparticle-stabilized BCCE offers an innovative pathway to improve the color indication capability of polysaccharide-based smart packaging.

Simultaneous extraction of five heavy metal ions from root vegetables via dual-frequency ultrasound-assisted enzymatic digestion.

The dual-frequency ultrasound-assisted enzymatic digestion (DUED) technique was developed for synchronous green extraction of five heavy metal ions in root vegetables. The combination of α-amylase, cellulase, and papain showed significant advantageous in extracting heavy metal ions. Under optimized dual-frequency ultrasonic conditions, the extraction rates of Cr, As, Cd, Pb, and Hg in carrots reached 99.04%, 105.88%, 104.65%, 104.10%, and 103.13% respectively. And the extraction process is highly efficient, completing in just 15 min. Compared to conventional microwave-assisted acid hydrolysis method, this technique eliminates the need for high-temperature concentrated acid, enhancing its environmental sustainability while maintaining mild reaction conditions, making it ideal for biosensors application. Additionally, simultaneous extraction and detection of four heavy metals in lotus roots were successfully achieved by using DUED and a fluorescent paper-based microfluidic chip. The obtained results are consistent with those obtained using conventional methods.

Conformation-Activity Mechanism of Alcalase Hydrolysis for Reducing In Vitro Allergenicity of Instant Soy Milk Powder.

Effective reduction of the allergenicity of instant soy milk powder (ISMP) is practically valuable for expanding its applications. This study optimized the enzymolysis technology of ISMP using single-factor experiments and response surface methodology, combined serological analysis, cellular immunological models, bioinformatics tools, and multiple spectroscopy techniques to investigate the effects of alcalase hydrolysis on allergenicity, spatial conformation, and linear epitopes of ISMP. Under the optimal process, special IgE and IgG1 binding abilities and allergenic activity to induce cell degranulation of alcalase-hydrolyzed ISMP were reduced by (64.72 ± 1.76)%, (56.79 ± 3.72)%, and (73.3 ± 1.19)%, respectively (P < 0.05). Moreover, the spatial conformation of instant soy milk powder hydrolysates (ISMPH) changed, including decreased surface hydrophobicity, a weaker peak of amide II band, lower contents of α-helix and ß-sheet, and an enhanced content of random coil. Furthermore, the linear epitopes of major soy allergens, 9 from glycinin and 13 from ß-conglycinin, could be directionally disrupted by alcalase hydrolysis. Overall, the structure-activity mechanism of alcalase hydrolysis to reduce ISMP allergenicity in vitro was preliminarily clarified. It provided a new research direction for the breakthrough in the desensitization of ISMP and a theoretical basis for revealing the potential mechanism of alcalase enzymolysis to reduce the allergenicity of ISMP.

Industrial Distillation Fractions of Garlic Essential Oil, Design, Synthesis, and Antifungal Activity Evaluation of Aliphatic Substituted Trisulfide Derivatives.

Garlic oil has a wide range of biological activities, and its broad-spectrum activity against phytopathogenic fungi still has the potential to be explored. In this study, enzymatic treatment of garlic resulted in an increase of approximately 50 % in the yield of essential oil, a feasible GC-MS analytical program for garlic oil was provided. Vacuum fractionation of the volatile oil and determination of its inhibitory activity against 10 fungi demonstrated that garlic oil has good antifungal activity. The antifungal activity levels were ranked as diallyl trisulfide (S-3)>diallyl disulfide (S-2)>diallyl monosulfide (S-1), with an EC50 value of S-3 against Botrytis cinerea reached 8.16 mg/L. Following the structural modification of compound S-3, a series of derivatives, including compounds S-4~7, were synthesized and screened for their antifungal activity. The findings unequivocally demonstrated that the compound dimethyl trisulfide (S-4) exhibited exceptional antifungal activity. The EC50 of S-4 against Sclerotinia sclerotiorum reached 6.83 mg/L. SEM, In vivo experiments, and changes in mycelial nucleic acids, soluble proteins and soluble sugar leakage further confirmed its antifungal activity. The study indicated that the trisulfide bond structure was the key to good antifungal activity, which can be developed into a new type of green plant-derived fungicide for plant protection.

Effect of degraded flaxseed meals on the growth performance, nutrient digestibility, and health status of broilers.

OBJECTIVE: The present study evaluated the effect of flaxseed meal degraded by a protease, Lactobacillus plantarum, or both on the growth performance, nutrient digestibility, and health status of broilers. METHODS: There were four diets containing flaxseed meals in its non-degraded form (control, CON), degraded with 3,000 U/kg of protease (enzymatic, ELM), 1.0×109 CFU/kg of Lactobacillus plantarum (fermented, FLM), or both (dual-degraded, DLM). Each form of flaxseed meals was added at 15% of diet. A total of 480 yellow-feathered broilers at 22 d of age were distributed into 4 groups with 6 replicates of 20 chickens each. The feeding trial lasted for 42 d. Growth performance, apparent fecal digestibility (dry matter, energy, crude protein, and ash), and serum immunoglobins and antioxidases were determined at 42 and 63 d of age. RESULTS: Results showed that ELM, FLM, and DLM increased (p<0.001) the contents of peptides and decreased (p<0.001) cyanogenic glycosides, compared to CON. The diets with degraded flaxseed meals increased (p<0.05) feed intake and body weight gain throughout the feeding trial, and the digestibility of energy, crude protein, and ash at the end of feeding trial. Furthermore, all degraded groups enhanced (p<0.05) broiler health status by increasing serum immunoglobulins A and G. Additinally, DLM showed more pronounced effects (p<0.05) on these parameters than ELM or FLM. CONCLUSION: Flaxseed meals degraded by enzymolysis, fermentation, or both had improved nutrition and application in broilers.

Wheat gliadin hydrolysates based nano-micelles for hydrophobic naringin: Structure characterization, interaction, and in vivo digestion.

In this study, enzymatic hydrolysis was used to fabricate wheat gliadin hydrolysates (WGHs) for the encapsulation and protection of naringin. The exposure of hydrophilic amino acids decreased the critical micelle concentration (from 0.53 ± 0.02 mg/mL to 0.35 ± 0.03 mg/mL) and improved solubility, which provided amphiphilic conditions for the delivery of naringin. The hydrolysates with a degree of hydrolysis (DH) of 9 % had the strongest binding affinity with naringin, and exhibited the smallest particle size (113.7 ± 1.1 nm) and the highest encapsulation rate (83.2 ± 1.3 %). The storage, heat and photochemical stability of naringin were improved via the encapsulation of micelles. Furthermore, the micelles made up of hydrolysates with a DH of 12 % significantly enhanced the bioavailability of naringin (from 19.4 ± 4.3 % to 46.8 ± 1.4 %). Our experiment provides theoretical support for the utilization of delivery systems based on water-insoluble proteins.

Study on the structure-activity relationship of rice immunopeptides based on molecular docking.

Research on food-derived immunoregulatory peptides has attracted increasing attention of scientists worldwide. However, the structure-activity relationship of rice immunopeptides was not clearly. Herein, 114 rice immunopeptides were obtained by simulating the enzymatic hydrolysis of rice proteins and were further analyzed by NetMHCIipan-4.0. Subsequently, the molecular docking was used to simulate the binding of immunoreactive peptides to major histocompatibility complex class II (MHC-II) molecules. Results show that S, R, D, E, and T amino acid could easily form hydrogen bonds with MHC-II molecules, thus enhancing innate and adaptive immunity. Finally, glucose-modified rice immunopeptides were to investigate the binding of the peptides with MHC-II molecules after glycosylation modification; this provided a theoretical basis for the targeted modification of the generated immunopeptides. All in all, the present study provides a theoretical foundation to further utilize rice processing byproducts and other food products to enhance immunity.

Structural characterization, molecular dynamic simulation, and conformational visualization of a water-soluble glucan with high molecular weight from Gastrodia elata Blume.

Polysaccharides have been widely used in the development of natural drugs and health food. However, polysaccharide characterization lags due to inherently complicated features and the limitations of existing detection approaches. We aimed to provide new insight into the fine structure and conformational visualization of polysaccharides from Gastrodia elata Blume, a medicinal and edible plant. A water-soluble polysaccharide (GEP2-6) with the high molecular weight of 2.7 × 106 Da was first obtained, and its purity reached 99.2 %. Chemical and spectroscopic analyses jointly revealed that GEP2-6 was a glucan linked by α-(1 â†’ 4) and α-(1 â†’ 6) glycosidic bonds. After enzymolysis, the local structure of GEP2-6 included α-1,4-Glcp, α-1,6-Glcp, α-1,4,6-Glcp, and α-1-Glcp at a molar ratio of 31.27∶1.32∶1.08∶0.93. The glycosidic linkage pattern of repeating units was further simulated by a glycan database and spatial examination software. The good dissolution performance was interpreted by dynamics simulation and practical molecular characteristics. Spherical flexible chains and the porous stable conformation were corroborated using atomic force microscopy. In addition, GEP2-6 could effectively scavenge DPPH and hydroxyl radicals as a promising natural antioxidant. These efforts will contribute to the expansion of clinical applications of this G. elata polysaccharide and the structural elucidation for macromolecular polysaccharides combined with traditional and modern analysis techniques.

First-in-human validation of enzymolysis clearance strategy for decreasing renal radioactivity using modified [68Ga]Ga-HER2 Affibody.

PURPOSE: Enzymolysis clearance strategy, characterized by releasing the non-reabsorbable radioactive fragment under the specific cleavage of enzymes, is confirmed to be a safe and effective way to reduce the renal radioactivity accumulation in mice. However, the effectiveness of this strategy in humans remains unknown. Human epidermal growth factor receptor 2 (HER2) is overexpressed in various types of tumors, and radiolabeled HER2 Affibody is believed to be an attractive tool for HER2-targeted theranostics. However, its wide application is limited by the high and persistent renal uptake. In this study, we intend to validate the effectiveness of enzymolysis clearance strategy in reducing renal accumulation by using a modified HER2 Affibody. MATERIALS AND METHODS: A new HER2 Affibody ligand, NOTA-MVK-ZHER2:2891, containing a cleavable Met-Val-Lys (MVK) linker was synthesized and labeled with 68Ga. The microPET imaging study was performed in SKOV-3 tumor mice to assess the uptakes of the control ligand and the MVK one in tumors and kidneys. Seven healthy volunteers were included for biodistribution and dosimetric studies with both the control and MVK ligands performed 1 week apart. Urine and blood samples from healthy volunteers were collected for in vivo metabolism study of the two ligands. Four HER2-positive and two HER2-negative patients were recruited for [68Ga]Ga-NOTA-MVK-ZHER2:2891 PET/CT imaging at 2 and 4 h post-injection (p.i.). RESULTS: [68Ga]Ga-NOTA-MVK-ZHER2:2891 was stable both in PBS and in mouse serum. MicroPET images showed that the tumor uptake of [68Ga]Ga-NOTA-MVK-ZHER2:2891 was comparable to that of [68Ga]Ga-NOTA-ZHER2:2891 at all the time points, while the kidney uptake was significantly reduced 40 min p.i. (P < 0.05). The biodistribution study in healthy volunteers showed that the kidney uptake of MVK ligand was significantly lower than that of the control ligand at 1 h p.i. (P < 0.05), with the SUVmean of 34.3 and 45.8, respectively, while the uptakes of the two ligands in the other organs showed negligible difference. The effective doses of the MVK ligand and the control one were 26.1 and 28.7 µSv/MBq, respectively. The enzymolysis fragment of [68Ga]Ga-NOTA-Met-OH was observed in the urine samples of healthy volunteers injected with the MVK ligand, indicating that the enzymolysis clearance strategy worked in humans. The PET/CT study of patients showed that the range of SUVmax of HER2-positive lesions was 9.4-21, while that of HER2-negative lesions was 2.7-6.2, which suggested that the MVK modification did not affect the ability of ZHER2:2891 structure to bind with HER2. CONCLUSION: We for the first time demonstrated that enzymolysis clearance strategy can effectively reduce renal radioactivity accumulation in humans. This strategy is expected to decrease renal radiation dose of peptide and small protein-based radiotracers, especially in the field of radionuclide therapy.

Debittering of Emblica (Phyllanthus emblica L.) fruit powder: Preparation and biological activity.

Emblica, also known as Phyllanthus emblica L., is a drug homologous food that is rich in polyphenols with various biological activities. However, its bitterness and astringency pose a significant challenge to its utilization in food products. In this study, we aimed to identify the optimal conditions for debittering Emblica. Our findings revealed that the best debittering conditions were: temperature = 50 °C, pH = 4, α-l-rhamnosidase concentration 200 U/g, and time = 5 h. High-performance liquid chromatography (HPLC) and molecular docking analysis revealed that enzymatic hydrolysis partially removed bitterness compounds. The results of antioxidant activity, xanthine oxidase, and α-glucosidase inhibitory activity assays confirmed that the Emblica fruit powder still exhibited good biological activity after enzymatic debitterization. Moreover, gastric fluids treatment might contribute to the above enhancing effect of enzymatic hydrolysates of Emblica. This study provided a theoretical basis for promoting the processing and utilization of Emblica fruit powder, as well as understanding its biological activity.

Resource utilization of wastepaper and bentonite: Cu(II) removal in the aqueous environment.

Contamination of heavy metals has always been a pressing concern. The dry-wet alternately treated carboxymethylcellulose bentonite (DW-CB) was successfully prepared by intercalating bentonite (BT) with carboxymethyl cellulose (CMC) obtained by solvent processes using enzymatically digested wastepaper as cellulosic raw material, and the adsorption capacity of Cu2+ on DW-CB in aqueous solution was investigated. A 98.18 ± 2.31 % removal efficiency was achieved by 4 g/L of DW-CB after 8 h in a solution containing 100 mg/L of Cu2+, which were 4.1 times and 1.5 times of that of BT and adsorbent prepared without alternating dry-wet process, respectively. The introduction of -COOH groups during the preparation of DW-CB enhanced the electrostatic interaction between DW-CB and Cu2+, which was the main driving force for Cu2+ removal. The pseudo-first-order kinetic model and Langmuir model better described the adsorption process and adsorption capacity of Cu2+ on DW-CB. DW-CB still showed high removal of Cu2+ (19.61 ± 0.99 mg/g) in the presence of multiple metal ions, while exhibiting the potential for removal of Zn2+, Mg2+ and K+, especially Mg2+ (22.69 ± 1.48 mg/g). However, the interactions of organics with Cu2+ severely affected the removal of Cu2+ by DW-CB (removal efficiency: 17.90 ± 4.17 % - 95.33 ± 0.27 %). In this study, an adsorbent with high targeted adsorption of Cu2+ was prepared by utilizing wastepaper and BT, which broadened the way of wastepaper resource utilization and had good economic and social benefits.

Quality improvement of soybean meal by yeast fermentation based on the degradation of anti-nutritional factors and accumulation of beneficial metabolites.

BACKGROUND: Soybean meal (SBM) is the main protein source for animal diets but its anti-nutritional constituents affect animal growth and immunity. The yeast culture of soybean meal (SBM-YC) that fermented with yeast and hydrolyzed by protease simultaneously could reduce anti-nutritional factors effectively and accumulate beneficial metabolites. RESULTS: The crude protein and acid-soluble protein content of SBM-YC reached 542.5 g kg-1 and 117.2 g kg-1 , respectively, and the essential amino acid content increased by 17.9%. Raffinose and stachyose decreased over 95.0%, and the organic acid content such as acetic acid, butyric acid, citric acid, lactic acid, succinic acid, and propionic acid produced by fermentation reached 6.1, 3.8, 3.6, 2.5, 1.2, and 0.4 g kg-1 , respectively. As biomarkers of yeast culture, nucleosides and their precursors reached 1.7 g kg-1 ; in particular, the inosine content increased from 0 to 0.3 g kg-1 . The total antioxidant capacity, 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) free radical activity, metal chelating ability, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging ability were increased by 50.3%, 46.1%, 43.9%, and 20.6%, respectively. CONCLUSION: This study established a diversified evaluation index, which could lay the foundations for the production and quality control of SBM-YC in the future. © 2023 Society of Chemical Industry.

Effects of enzymolysis and fermentation of Chinese herbal medicines on serum component, egg production, and hormone receptor expression in laying hens.

OBJECTIVE: In the present study, we aimed to investigate the effects of enzymolysis fermentation of Chinese herbal medicines (CHMs) on egg production performance, egg quality, lipid metabolism, serum reproductive hormone levels, and the mRNA expression of the ovarian hormone receptor of laying hens in the late-laying stage. METHODS: A total of 360 Hy-Line Brown laying hens (age, 390 days) were randomly categorized into four groups. Hens in the control (C) group were fed a basic diet devoid of CHMs, the crushed CHM (CT), fermented CHM (FC), and enzymatically fermented CHM (EFT) groups received diets containing 2% crushed CHM, 2% fermented CHM, and 2% enzymatically fermented CHM, respectively. RESULTS: Compared with crushed CHM, the acid detergent fiber, total flavonoids, and total saponins contents of fermented CHM showed improvement (p<0.05); furthermore, the neutral and acid detergent fiber, total flavonoids, and total saponins contents of enzymatically fermented CHM improved (p<0.05). At 5 to 8 weeks, hens in the FC and EFT groups showed increased laying rates, haugh unit, albumin height, yolk color, shell thickness, and shell strength compared with those in the C group (p<0.05). Compared with the FC group, the laying rate, albumin height, and Shell thickness in the EFT group was increased (p<0.05). Compared with the C, CT, and FC groups, the EFT group showed reduced serum total cholesterol and increased serum luteinizing hormone levels and mRNA expressions of follicle stimulating hormone receptor and luteinizing hormone receptor (p<0.05). CONCLUSION: These results indicated that the ETF group improved the laying rate and egg quality and regulated the lipid metabolism in aged hens. The mechanism underlying this effect was likely related to cell wall degradation of CHM and increased serum levels of luteinizing hormone and mRNA expression of the ovarian hormone receptor.

Effect of enzymolysis combined with Maillard reaction treatment on functional and structural properties of gluten protein.

In this work, the modified gluten was prepared by enzymolysis combined with Maillard reaction (MEG), and its functional and structural properties were investigated. The result showed that the maximum foamability of MEG was 19.58 m2/g, the foam stability was increased by 1.8 times compared with gluten, and the solubility and degree of graft were increased to 44.4 % and 28.1 % at 100 °C, whereas the content of sulfhydryl group decreased to 0.81 µmol/g. The scavenging ability on ABTS+radical and DPPH radical of MEG was positively correlated with reaction temperature, and the maximum values were 86.57 % and 71.71 % at 140 °C, respectively. Furthermore, the fluorescence quenching effect of tryptophan and tyrosine residues was enhanced, while the fluorescence intensity decreased with the temperature increase. Scanning electron microscopy revealed that the surface of enzymatically hydrolyzed-gluten became smooth and the cross section became straightened, while MEG turned smaller and irregular approaching a circular structure. FT-IR spectroscopy showed that enzymatic hydrolysis promoted the occurrence of more carbonyl ammonia reactions and the formation of precursors of advanced glycosylation end products. These results provide a feasible method for improving the structure and functional properties of gluten protein.

Enzymolysis kinetics of corn straw by impeded Michaelis model and Box-Behnken design.

Enzymatic hydrolysis is an essential step in the lignocellulosic biorefining process. In this paper, Box-Behnken was used to optimize the enzymatic hydrolysis process of corn stalk, and the promotion effect of three typical surfactants on the enzymatic hydrolysis process was investigated. The experimental results showed that the total reducing sugar yield reached 67.6% under the best-predicted conditions. When the concentration of Tween 80 is 0.1%, it could be increased to 80.2%. In addition, the Impeded Michaels Model (IMM) is introduced in this study to describe the enzymatic hydrolysis process of corn stalks. Finally, the initial contact coefficient between the enzyme and cellulose (Kobs,0) and the gradual loss coefficient of enzyme activity (ki) caused by reaction obstruction were obtained by fitting data, which successfully verified the rationality of the model.