Optimal Hydrolysis Conditions Research Articles

Enzymatic Hydrolysis Optimization for Preparation of Sea Cucumber (Holothuria scabra) Hydrolysate with an Antiproliferative Effect on the HepG2 Liver Cancer Cell Line and Antioxidant Properties.

The sea cucumber body wall was subjected to enzymatic hydrolysis using papain. The relationship between the enzyme concentration (1-5% w/w protein weight) and hydrolysis time (60-360 min) and the degree of hydrolysis (DH), yield, antioxidant activities, and antiproliferative activity in a HepG2 liver cancer cell line was determined. The surface response methodology showed that the optimum conditions for the enzymatic hydrolysis of sea cucumber were a hydrolysis time of 360 min and 4.3% papain. Under these conditions, a 12.1% yield, 74.52% DH, 89.74% DPPH scavenging activity, 74.92% ABTS scavenging activity, 39.42% H2O2 scavenging activity, 88.71% hydroxyl radical scavenging activity, and 9.89% HepG2 liver cancer cell viability were obtained. The hydrolysate was produced under optimum conditions and characterized in terms of its antiproliferative effect on the HepG2 liver cancer cell line.

Optimization of enzymatic hydrolysis condition of edible bird’s nest crumbs by response surface methodology and determination of biochemical characteristics of the hydrolysate

Edible bird's nest (EBN) crumbs are the by-product of the bird's nest industry. Despite having lower economic value compared to the original material, EBN crumbs still maintain high protein and carbohydrate content. Therefore, this study aimed to determine the optimal hydrolysis condition for EBN crumbs using protease to achieve the maximum degree of hydrolysis (DH). Plackett Burman design was employed to identify the important factors. The results showed that enzyme loading, temperature and hydrolysis time had the strongest effect on the DH. These factors were subsequently subjected to the optimization study using central composite design (CCD) of response surface methodology (RSM). The optimized conditions for the enzymatic hydrolysis of EBN crumbs were at an enzyme loading of 4%, temperature of 51ºC, and hydrolysis time of 90 min. The experimental DH obtained at the optimized condition (63.5%) was close to the predicted DH (64.1%). The enzymatic hydrolysate prepared at the optimal condition showed relatively high amino acid concentration (151.6 ± 1.29 µg/mL) and radical scavenging activity (64.97 ± 0.79%) compared to the boiled sample with values of only 50.1 ± 2.43 µg/mL and 18.36 ± 0.17%, respectively. The resultant hydrolysate had no effect on some of the microorganisms employed in this study. The EBN crumbs hydrolysate inhibited tyrosinase activity with an IC50 of 70.22 µg/mL, greater than that of boiled EBN (IC50= 108.9 µg/mL). The results indicated that the EBN crumbs hydrolysate could be further applied in the cosmetic industry as a rich source of nutrients and bioactive compounds for the formulation of beauty products.

Guamara and Cocuixtle: Source of Proteases for the Transformation of Shrimp By-Products into Hydrolysates with Potential Application.

Since the fruits of Bromelia pinguin and Bromelia karatas are rich in proteases, the aim of this research was to optimize the hydrolysis process of cooked white shrimp by-products due to the effect of these proteases. A robust Taguchi L16' design was used to optimize the hydrolysis process. Similarly, the amino acid profile by GC-MS and antioxidant capacity (ABTS and FRAP) were determined. The optimal conditions for hydrolysis of cooked shrimp by-products were pH 8.0, 30 °C, 0.5 h, 1 g of substrate and 100 µg/mL of B. karatas, pH 7.5, 40 °C, 0.5 h, 0.5 g substrate and 100 µg/mL enzyme extract from B. pinguin and pH 7.0, 37 °C, 1 h, 1.5 g substrate and 100 µg/mL enzyme bromelain. The optimized hydrolyzates of B. karatas B. pinguin and bromelain had 8 essential amino acids in their composition. The evaluation of the antioxidant capacity of the hydrolyzates under optimal conditions showed more than 80% inhibition of in ABTS radical, B. karatas hydrolyzates had better higher ferric ion reduction capacity with 10.09 ± 0.02 mM TE/mL. Finally, the use of proteolytic extracts from B. pinguin and B. karatas to optimize hydrolysis process allowed obtaining hydrolyzates of cooked shrimp by-products with potential antioxidant capacity.

Experimental study on the continuous production of velvet bean-based bioactive peptides in a membrane reactor and bioactivity mapping

This study investigates the continuous production of bioactive peptides from fermented velvet bean (Mucuna pruriens) using a cost-effective enzymatic membrane reactor. The optimal operating conditions for continuous hydrolysis were residence time of 9 h, enzyme-to-substrate ratio of 10%, and the use of a 5-kDa PES membrane for separation. The resulting permeate exhibited notable antioxidant activity with DPPH and FRAP assay values of 0.28 and 0.12 mg AEAC/mL, respectively, and an angiotensin-converting enzyme (ACE) inhibition of 83.28%. Further fractionation of the permeate with a 2-kDa membrane led to increased antioxidant activity and ACE inhibition, with resulting half maximal inhibitory concentration (IC50) values of 7.6 and 0.6 μg protein/mL, respectively. Liquid chromatography-mass spectrometry was used to identify peptide sequences from the <2-kDa fraction, which were matched with the BIOPEP-UWM™ database. The results revealed that the fermented velvet bean peptides were predominantly dipeptidyl peptidase (DPP)-4 inhibitors and ACE inhibitors. Industrial relevanceThe combination of a stirred tank reactor and membrane separation has the potential to enable the continuous production of bioactive peptides from velvet bean through the use of a freely suspended enzyme system. This reactor design offers an alternative solution to the existing delay in commercializing bioactive peptides, by (i) simplifying the industrial process development for continuous bioactive peptide production, (ii) eliminating the need for enzyme immobilization, and (iii) eliminating batch-to-batch variability in product quality and unproductive time associated with batch-wise production.

Peptide extraction from silver carp (Hypophthalmichthys molitrix) scales via enzymatic hydrolysis and membrane filtration

In this work, peptides were extracted from Silver carp (SC) scales via protease hydrolysis and separated using two membranes (M1 and M2). The results revealed that the water: SC scale ratios of 50.6 mL/g, alkaline protease 1 (AP1) dose of 2313.6 U/mL, and pH of 8.14 were the optimal hydrolysis conditions, and the peptide yield reached 88.77 ± 0.32%. The optimal conditions of peptide separation were clarified: the operating pressure of the M1 (M2) was 0.25 (0.4) MPa, the liquid temperature was 30°C, and the operation time was 65 min. In this case, the permeability of the M1 (M2) reached 91.73 ± 96% (79.83 ± 7.23%), and the average molecular weight of the peptides was 758 Da (576 Da). Compared with M1 peptides, M2 peptides contained more acidic and aromatic amino acids exhibiting free-radical scavenging and tyrosinase inhibition properties. It might provide a way to utilize SC scales as a promising material to produce bioactive peptides.

Optimization and scale up of the enzymatic hydrolysis of Californian red worm protein (Eiseniafoetida)

Although the best-known use of the different species of earthworm is the production of organic fertilizer, they can also be considered a rich source of biologically and pharmacologically-active compounds, for use in the treatment of various diseases. In recent decades, with the development of biochemical technologies, research on the pharmaceutical effects of compounds extracted from different species of earthworms has begun. Enzymatic hydrolysis is the most common and widely used technique for producing bioactive hydrolysates, because it uses moderate operating conditions, with a certain specificity for the substrate. In the present study, the objective was to optimize and scale up the enzymatic hydrolysis of Eisenia foetida protein to obtain peptides with biological activity. The substrate characterization was carried out according to AOAC, a response surface design was performed for the optimization of the enzymatic hydrolysis and then the scaling was performed by means of dimensional analysis. The results show that the major component of the paste is protein, 65% of which is albumin, and the absence of pathogenic microorganisms was also found. Regarding optimization, it was found that the optimal hydrolysis conditions are achieved with pH = 8.5; temperature = 45 °C; amount of substrate = 125 g and volume of enzyme = 1245μL. For the scaling, 4 dimensionless pi-numbers were calculated which describe the process with no statistically significant differences between the model and the prototype; it can be concluded that the enzymatic hydrolysate of Eisenia foetida presents high values of antioxidant activity evaluated by different methodologies.

75 Development of a rapid screening assay for monitoring the relative nutritional value of pasture samples

Pasture with a high biodiversity has the potential to provide a balanced diet and year-round forage availability for grazing equids. Monitoring the influence of biotic and abiotic factors on the relative proportions of key nutrients in pasture could help to inform grazing strategies. Traditional wet chemistry forage analytical methods are labor-intensive and require large sample amounts, thereby limiting their usefulness for high sample throughput. To develop a high throughput screening assay, 3 different hydrolysis methods were compared, each allowing the simultaneous extraction of total hydrolyzable carbohydrates (THC), protein, and phenolics for subsequent spectrophotometric quantification using established microassays. Three pasture samples were collected from mixed species grassland plots (3m x 2m, SRUC Aberdeen, UK). These samples represented a diverse range of THC, protein, and phenolic contents and included high- and low-sugar perennial ryegrass and forage herbs plots (collected in June 2021) and a herbal ley plot (collected in August 2021). Freeze-dried and milled samples were extracted in triplicate and subjected to a range of hydrolysis conditions (Method 1: 2.4% H2SO4, 2 h at 100°C; Method 2: 3M HCl, 14 h at 100°C; Method 3: 2M HCl, 0.5 h at 95°C) before spectrophotometric quantification (Lever assay for reducing sugars,Ninhydrin assay for proteins, Fast Blue assay for phenolics). Solvent-matched calibration curves of Bovine serum albumin (BSA), gallic acid, and glucose/fructose standards were used to quantify analytes and evaluate optimal hydrolysis conditions for each analyte to maximize yield. Extractions were repeated across 3 consecutive days to assess reproducibility of each hydrolysis method. All 3 hydrolysis methods demonstrated a reproducibility and reliability > 99% for THC and phenolics across all samples. ANOVA (using SPSS: significance level set at P < 0.05) showed significant differences between the means of phenolics and THC concentrations for method 2 vs. method 1 (P = < 0.001) and method 2 vs. method 3 (P = 0.015). Method 3 was identified as most optimal for the quantification of THC and phenolics, resulting in analyte concentrations reflective of the expected seasonal and grass species differences in the samples. However, the short hydrolysis time of this method was not sufficient for optimal protein quantification as achieved by Method 2. Therefore, a combination of Method 2 and 3 was subsequently established and is undergoing further optimization to evaluate performance in a greater range of pasture samples.

Enzymatic hydrolysis and detection of 3‐monochloropropane‐1,2‐diol esters

AbstractThere are more and more studies on the detection method of 3‐chloro‐1,2‐propanediol fatty acid esters (3‐MCPD esters) at present, by comparing these methods for the determination of 3‐MCPD esters. Indirect methods, which determine total amount of 3‐MCPD after hydrolysis of the esters, have an advantage over direct methods. The existing indirect methods, however, may yield unreliable results or require long hours of alkaline methanolysis. In contrast, the indirect enzymatic hydrolysis method has mild conditions and more accurate results. In this study, we developed a reliable and rapid indirect method for determination of 3‐MCPD esters. 3‐MCPD esters were enzymolysis to 3‐MCPD by indirect enzymatic hydrolysis method, and the conditions of enzymatic hydrolysis were optimized, the content of 3‐MCPD after enzymatic hydrolysis was detected by gas chromatography–mass spectrometry (GC–MS) and the yield was calculated. Finally, the optimum conditions for enzymatic hydrolysis of 3‐MCPD esters were determined. According to the optimal enzymatic hydrolysis condition, the contents of 3‐MCPD esters in four food oils were determined. The method is simple and sensitive and can meet the requirement of 3‐MCPD esters detection in general oils.

Biotechnological enhancement of lactic acid conversion from pretreated palm kernel cake hydrolysate by Actinobacillus succinogenes 130Z

The aim of this study was to establish an improved pretreatment and fermentation method i.e. immobilized cells for high recovery of fermentable sugars from palm kernel cake (PKC) and its effects on fermentability performance by Actinobacillus succinogenes 130Z in the conversion of the fermentable sugar to lactic acid. The effects of oxalic acid concentrations (1–6% w/v) and residence times (1–5 h) on the sugar recovery were initially investigated and it was found that the highest mannose concentration was 25.1 g/L at the optimum hydrolysis conditions of 4 h and 3% (w/v) oxalic acid. The subsequent enzymatic saccharification of the pretreated PKC afforded the highest enzymatic digestibility with the recovered sugars amounting to 25.18 g/L and 9.14 g/L of mannose and glucose, respectively. Subsequently, the fermentability performance of PKC hydrolysate was evaluated and compared in terms of cultivation phases (i.e. mono and dual-phases), carbonate loadings (i.e. magnesium and sodium carbonates), and types of sugars (i.e. glucose and mannose). The highest titer of 19.4 g/L lactic acid was obtained from the fermentation involving A. succinogenes 130Z in dual-phase cultivation supplemented with 30 g/L of magnesium carbonate. Lactic acid production was further enhanced by using immobilized cells with coconut shell-activated carbon (CSAC) of different sizes (A, B, C, and D) in the repeated batch cultivation of dual-phase fermentation producing 31.64 g/L of lactic acid. This work sheds light on the possibilities to enhance the utilization of PKC for lactic acid production via immobilized A. succinogenes 130Z.

Silver Carp (Hypophthalmichthys molitrix) Scales Collagen Peptides (SCPs): Preparation, Whitening Activity Screening and Characterization

This study involves the preparation of scale collagen peptides (SCPs) with whitening activity from silver carp (Hypophthalmichthys molitrix) and their characterization and peptide sequence identification. In this article, scanning electron microscopy (SEM) was used to observe structure changes of sliver carp scales; enzymatic hydrolysis was optimized through protease screening and response surface optimization. The ultrafiltration was used to separate SCPs and the whitening activity was comprehensively evaluated using radical scavenging rate and tyrosinase-inhibiting activity, among others. An optimal component was characterized and identified using various modern spectral analysis techniques. The results showed that the surface of silver carp scales after decalcification was smooth and clear. The pepsin had the highest peptide yield and tyrosinase-inhibiting activity (90.01% and 82.25%, respectively). The optimal enzymatic hydrolysis conditions were an enzyme dosage of 16.1%, a solid-liquid ratio of 1:15.6 and a time of 4.9 h. The proportions of hydrophobic and basic amino acids in the peptide composition were 32.15% and 13.12%, respectively. Compared with SCPs2, SCPs1 (6096.68-9513.70 Da) showed better ·OH scavenging ability, tyrosinase-inhibiting activity and moisture absorption. SCPs1 was a macromolecular fragment of type I collagen with a triple helix structure, containing three peptide sequences with the potential for tyrosinase activity inhibition (AGPPGADGQTGQRGE, SGPAGIAGPAGPRGPAGPNGPPGKD and KRGSTGEQGSTGPLGMRGPRGAA). These results show that SCPs1 is a collagen peptide product with whitening potential.

The Preparation and Physiochemical Characterization of Tenebrio molitor Chitin Using Alcalase.

Chitin is mostly produced from crustaceans, but it is difficult to supply raw materials due to marine pollution, and the commonly used chemical chitin extraction method is not environmentally friendly. Therefore, this study aims to establish a chitin extraction process using enzymes and to develop edible insect-derived chitin as an eco-friendly new material. The response surface methodology (RSM) was used to determine the optimal conditions for enzymatic hydrolysis. The optimal conditions for enzymatic hydrolysis by RSM were determined to be the substrate concentration (7.5%), enzyme concentration (80 μL/g), and reaction time (24 h). The solubility and DDA of the mealworm chitosan were 45% and 37%, respectively, and those of the commercial chitosan were 61% and 57%, respectively. In regard to the thermodynamic properties, the exothermic peak of mealworm chitin was similar to that of commercial chitin. In the FT-IR spectrum, a band was observed in mealworm chitin corresponding to the C=O of the NHCOCH3 group at 1645 cm-1, but this band showed low-intensity C=O in the mealworm chitosan due to deacetylation. Collectively, mealworm chitosan shows almost similar physical and chemical properties to commercial chitosan. Therefore, it is shown that an eco-friendly process can be introduced into chitosan production by using enzyme-extracted mealworms for chitin/chitosan production.

Optimization of hydrolysis conditions of crop straw and its effect in Chlorellasorokiniana culture.

Taking straws of corn, wheat, and millet as raw materials, we pretreated them with alkaline hydrogen peroxide, and then hydrolyzed by cellulase and xylanase. We selected the total sugar content in the hydrolysate as the indicator to evaluate the hydrolysis of the straws from three crop species, and further optimized the conditions. Then, the hydrolysates of three types of crop straws were used as carbon source for Chlorella sorokiniana culture to assess their effects on microalgal cultivation. The results showed that the optimal hydrolysis conditions for the three crop straws were identified as solid-liquid ratio of 1:15, temperature of 30 ℃, and treatment time of 12 h. Under such optimal condition, the total sugar contents increased up to 1.677, 1.412, and 1.211 g·L-1 in the corn, millet and wheat straw hydrolysate, respectively. The hydrolysates from the three crop straw could significantly increase both algal biomass and lipid content of C. sorokiniana. Corn straw hydrolysate had the best effect, with high levels of algal biomass (1.801 g·L-1) and lipid content (30.1%). Therefore, we concluded that crop straw hydrolysates as carbon source could significantly promote microalgal biomass and lipid enrichment. The results could lay the foundation for the efficient conversion and utilization of straw lignocellulose raw materials, provide new knowledge for the resource utilization of agricultural wastes, as well as the theoretical basis for the efficient cultivation of microalgae using crop straw hydrolysates.

Enzymatic hydrolysis as a valorization strategy of bovine lungs: Optimization of process variables and study of antioxidant capacity

Background The increase in meat production would also imply an increase in the generation of by-products or edible offal. These by-products can be used, due to their high protein content, as a substrate to obtain hydrolysates with functional activities. This study aimed to valorize bovine lungs by producing hydrolysates with antioxidant capacity. Results A response surface methodology study was carried out using a central composite design in which factors were temperature (43.2–76.8°C), enzyme/substrate ratio [ES: 0.65–4.85% (w/w)] using Alcalase 2.4 L/Flavourzyme (1:1) and pH (5.8–9.2). The antioxidant capacity of the obtained BLH (bovine lung hydrolysates) was evaluated by the ABTS, DPPH, and FRAP methods. The maximum antioxidant capacity was achieved at 53.°C, ES ratio of 2.3% (w/w), and pH of 8.2. Under optimal hydrolysis conditions, the antioxidant capacity increased rapidly from the beginning of the reaction to 30 min, reaching a maximum at 120 min; then, it decreased until the end (180 min). The degree of hydrolysis increased as hydrolysis occurred up to a maximum of 45%. Molecular weight distribution of BLH evaluated by Tricine-SDS-PAGE and SEC-FPLC showed that bovine lung proteins hydrolyzed for 120 min presented low molecular weight peptides (<5 kDa), which are absent in the non-hydrolyzed sample. Conclusion In this work, we optimized the variables for producing BLH with antioxidant capacity using commercial proteases in a short reaction time, making it a worthwhile strategy for the recovery of by-products from the meat industry.

Identification and preparation of selenium-containing peptides from selenium-enriched Pleurotus eryngii and their protective effect on lead-induced oxidative damage in NCTC1469 hepatocytes.

Lead (Pb) is a highly toxic and persistent substance that easily accumulates in living organisms, eliciting cellular toxicity and oxidative stress. Some selenium-containing proteins and peptides prepared from plant extracts are beneficial for protecting the body's health and resisting external disturbances. In the present study, selenium-containing peptide species were prepared from selenium-enriched Pleurotus eryngii protein hydrolysates and to evaluate the benefits of selenium-containing peptides on Pb-induced oxidative stress in NCTC1469 hepatocytes. Trypsin was selected as primary enzyme to hydrolyze the selenium-enriched protein (SPH). The optimal hydrolysis conditions were: hydrolysis time, 1.5h; initial pH 8.0. The SPH was digested by trypsin and then purified by ultrafiltration, gel filtration chromatography and reversed-phase HPLC to obtain the selenium-containing peptides SPH-I-2. Furthermore, SPH-I-2 was analyzed and a number of total 12 selenium-containing peptides were identified by liquid chromatography-tandem mass spectroscopy. The NCTC1469 cell culture study showed that selenium-containing peptides were capable of reducing reactive oxygen species levels and regulating the Keap1/Nrf2 pathway by upregulating Nrf2, HO-1, GCLC, GCLM and NQO1 genes and downregulating Keap1 genes. Moreover, selenium-containing peptides were also able to suppress Pb-induced elevated levels of nitric oxide (NO), lactate dehydrogenase (LDH), malondialdehyde (MDA), increase antioxidant enzyme activity and alleviate cell apoptosis. The present study indicated that the selenium-containing peptides could protect cells from Pb2+ -induced oxidative stress. © 2023 Society of Chemical Industry.

Recovery of TiO&lt;sub&gt;2&lt;/sub&gt; from spent SCR catalyst by acidolysis and additional crystal seeds-hydrolysis method

In this study, a rapid and efficient method of recovering TiO&lt;sub&gt;2&lt;/sub&gt; from spent SCR (selective catalytic reduction) catalyst supplied by a coal-fired power plant in Shanghai was developed. The acid leaching and sodium roasting-water leaching residues (titanium slag) from spent SCR catalyst were employed as the raw material. First, titanium slag was dissolved into H2SO4 solution under different conditions. The optimal acidolysis conditions were 85 wt% H&lt;sub&gt;2&lt;/sub&gt;SO&lt;sub&gt;4&lt;/sub&gt;, 5.0 g/g acid-residues ratio, 90℃ acidolysis temperature and 2.0 h acidolysis time. Simultaneously, the highest acidolysis efficiency can reach 92.02%. The acidolysis solution was collected and concentrated to 200 g/L (measured by TiO&lt;sub&gt;2&lt;/sub&gt; concentration). Then, acidolysis solution was adjusted to pH 0.52-9.15, followed by adding 0-40 mL additional crystal seeds and reacting under certain conditions to obtain the hydrolysis product. The optimal hydrolysis conditions were 25 mL additional crystal seeds, pH 7.46, 120℃ hydrolysis temperature and 3.0 h hydrolysis time. Finally, the recovered product was obtained by roasting hydrolysis product at 700℃ for 2.0 h. The results of hydrolysis stability test indicated that this method can make the hydrolysis efficiency of acidolysis solution stabilize at approximately 90% under optimal conditions. The main component of recovered product was anatase TiO&lt;sub&gt;2&lt;/sub&gt; with the purity of 86.88%.

Preparation and activity evaluation of angiotensin-I converting enzyme inhibitory peptides from protein hydrolysate of mulberry leaf.

Angiotensin-I converting enzyme (ACE) inhibitory peptides drew wide attention in the food industry because of their natural reliability, non-toxicity, and safety. However, the characteristics of ACE inhibitory peptides obtained from protein hydrolysate of mulberry leaf prepared by Flavourzyme were still unclear. Based on the single-factor test, the Plackett-Burman test and response surface test were used to determine the key factors affecting the ACE inhibition rate in mulberry leaf protein hydrolysate and the optimum conditions of enzymatic hydrolysis. The results showed that the optimum technical parameters were as follows: the ratio of material to liquid is 1: 25 (w / v, g/mL), the Flavourzyme to substrate ratio was 3,000 U/g, the temperature of enzymatic hydrolysis was 50°C, pH was 6.3, and the time of enzymatic hydrolysis was 2.9 h. The ACE inhibitory peptides in the mulberry leaf protein hydrolysates were purified by ultrafiltration and gel filtration, aiming to obtain the highest active component. The 12 peptide sequences were identified by reverse liquid chromatography-mass spectrometry, and then, they were docked to the crystal structure of human angiotensin-I converting enzyme (1O8A), and the interaction mechanisms of 12 peptide sequences and 1O8A were analyzed. The docking results showed that among the 12 peptide sequences, ERFNVE (792.37 Da), TELVLK (351.72 Da), MELVLK (366.72 Da), and FDDKLD (376.67 Da), all had the lowest docking energy, and inhibition constant. The chemosynthetic ERFNVE (IC50: 2.65 mg/mL), TELVLK (IC50: 0.98 mg/mL), MELVLK (IC50:1.90 mg/mL) and FDDKLD (IC50:0.70 mg/mL) demonstrated high ACE-inhibitory activity with competitive inhibition mode. These results indicated that the ACE-inhibiting peptides from mulberry leaf protein hydrolyzed (FHMP) had the potential activities to inhibit ACE and could be used as functional food or drugs to inhibit ACE. This work provides positive support for mining the biological activity of mulberry leaves in the treatment of hypertension.

Optimization of cell wall breaking process of the microalgae Haematococcus pluvialis.

Haematococcus pluvialis can synthesize and accumulate astaxanthin, and is regarded as the organism with the highest content of astaxanthin in the current nature. However, only when Haematococcus pluvialis cell wall is broken can the astaxanthin be effectively extracted. Therefore, the breaking of the hard cell wall of Haematococcus pluvialis becomes the key difficulty hindering the extraction of astaxanthin. In this study, the cell wall was broken using enzyme digestion and mechanical action and the response surface methodology was used to optimize the cell wall breaking process. Taking the cell wall breaking rate of Haematococcus pluvialis as the index, the single factor experiment was used to calculate the effects of solid-liquid ratio, enzyme type and dosage, digestion temperature, digestion pH and hydrolysis time on the cell wall breaking rate. When the ultrasonic power is 175 W and the ultrasonic time is 2 min, the highest wall breaking rate is 68.8%. The high pass tissue grinder has the best wall breaking efficiency of 70.3% in 6 min and 70 Hz. In combination with single factor analysis and response surface analysis, the optimum enzyme digestion conditions were determined as follows: the ratio of material to liquid was 1:150, the amount of enzyme was 1%, the ratio of Pectinase to cellulase was 1:1, and the optimum hydrolysis conditions were as follows: hydrolysis time 5 h, hydrolysis temperature 55 °C, pH 5.5; and the amount of enzyme was 1%. The theoretical wall breaking rate is 77.2%, the actual extraction rate is 75.4%, and the relative error is 2.2%. In conclusion, the method of using combined enzyme to break the wall of Haematococcus pluvialis is simple, mild, green and efficient. It can be used in the processing of broken wall.

Impact of Enzymatic Hydrolysis on Antioxidant Activity of Snakehead Fish (&lt;I&gt;Channa striata&lt;/I&gt;) Head Protein Hydrolysate

Highlight Research Snakehead fish head possess high protein content and potential to be used as materials for protein hydrolysate Snakehead fish head protein hydrolysis optimum condition were determined Snakehead fish head hydrolysate protein antioxidant activity were analyzed Snakehead fish head is potential to be used as materials for fish protein hydrolysate Abstract There is concern regarding the use of synthetic antioxidants which spurred the yearly increase of natural antioxidants to substitute synthetic ones. Fish protein hydrolysate (FPH), which has been reported to have potent antioxidant properties, could be utilized to solve this problem. This study aimed to utilize the by-product of snakehead fish (head) and determine the optimum hydrolysis conditions to obtain FPH with antioxidant activity. Two parameters were tested during the hydrolysis process: enzyme concentration (papain enzyme) and hydrolysis time. The optimum condition was evaluated by measuring dissolved protein, hydrolysis degree (DH), and antioxidant activity, including DPPH, ABTS, and FRAP. The optimal hydrolysis conditions were 5% enzyme concentration and 6 h of hydrolysis time at 55°C and pH 7.0. The DPPH, ABTS, and FRAP antioxidant activities were 50.70%, 66.67%, and 1.35 M Tr/mg, respectively. Based on the antioxidant activity, Snakehead fish head has the potential as a source of natural antioxidants.

Screw electromechanical hydrolyzer for processing poultry by-products

The use of keratin-containing products in various industries, including agriculture, cosmetics, and biomedicine requires solving the urgent problem of improving the methods and means of hydrothermal hydrolysis of keratin waste. The purpose of this work was to study the screw electromechanical hydrolyzer to provide modes of efficient conversion of keratin waste into a useful product with added value. The research was based on the basic principles of electrodynamics, heat and mass transfer, mathematical modeling by the finite element method, and experimental verification of the multiphysical parameters of the electromechanical hydrolyzer. The experimental model of the electromechanical hydrolyzer was used to determine the optimal conditions for hydrothermal hydrolysis of keratin waste in terms of thermal conditions, raw material transportation, pressure, and magnetic field effects. As a result of the processing, bulk hydrolyzed brown feather flour with a specific odor was obtained. According to the size of the electromagnetic system of the experimental sample, a mathematical model for studying thermal and electromagnetic processes was built. The regularities of the spatial distribution of magnetic induction for the cross-section, axial distribution on the surface of the screw, and the upper faces of the screw winding of an electromechanical hydrolyzer were determined. Three-dimensional images of the heating of the screw and the screw electromechanical hydrolyzer itself were obtained. By comparing the results of mathematical modeling and empirical studies, the adequacy of the mathematical model was confirmed. The results of the research can find application in the field of animal husbandry in the production of feed additives of increased digestibility for the needs of feeding agricultural animals and poultry

Optimization of an Innovative Hydrothermal Processing on Prebiotic Properties of Eucheuma denticulatum, a Tropical Red Seaweed

Seaweed is a sustainable source of marine oligosaccharides that potentially could be used as a prebiotic ingredient for functional food development. The study aims to optimize the oligosaccharide preparation through thermal hydrolysis of an under-utilized red seaweed, Eucheuma denticulatum. Response surface methodology (RSM) applying Box–Behnken design (BBD) was used on three parameters including temperature (105–135 °C), hydrolysis time (15–35 min) and sulfuric acid concentration (0.05–0.2 M). Optimized fractions with good prebiotic activity were characterized using high-performance size-exclusion chromatography (HP-SEC) and Fourier transform infrared spectroscopy (FT-IR). Eucheuma denticulatum oligosaccharides fraction 1 (ED-F1) was shown to promote the growth of beneficial gut microbiota including Lactobacillus plantarum, L. casei, L. acidophilus, Bifidobacterium animalis and B. longum with the highest prebiotic activity score of 1.64 ± 0.17. The optimization studies showed that hydrolysis time was the most significant parameter for the oligosaccharides yield. Optimal hydrolysis conditions for ED-F1 were 120 °C, 21 min, 0.12 M H2SO4 with the highest yield achieved (11.15 g/100 g of dry weight). The molecular weight of ED-F1 was determined at 1025 Da while FT-IR analysis revealed the presence of sulfated oligosaccharides with similar characteristics of i-carrageenan. These findings signify the innovative method for the efficient production of seaweed derived prebiotic oligosaccharides, which could be a promising source of functional food ingredients for the development of health foods and beverages.