Degree Of Hydrolysis Research Articles

Enhancing the anti-thixotropic properties of waxy maize starch modified by different α-amylases and its underlying molecular mechanism

The large thixotropy of the starch-thickened foods is often unfavorable in many applications. This study examined the contribution of the proportion of amylopectin chain length to time-dependence of starch gels. The α-amylase (AM) from Bacillus stearothermophilus and maltogenic α-amylase (MA) from Bacillus subtilis were used to trim amylopectin in different reaction patterns. HPLC, HPAEC and IBC data suggested AM attacked B-chains (DP 12–36), causing an increment in number of the chains with DP 6–12, whereas MA primarily trimmed the short B-chains (DP 12–18) and partial A-chains (DP 9–12) to generate short chains with DP 6–9. Interestingly, the recovery of AM-gels was faster than MA-gels at the same degree of hydrolysis when subjected to shear according to the linear correlation analysis. When releasing the same mass of sugar, shortening of the long internal chains played an important role in reducing time dependence of starch gel rather than the external side chains. Possible models were proposed to illustrate the differences in the mechanism of rapid-recovery caused by different side-chain distributions. The outcome provided a new perspective to regulate the thixotropy behavior of starch through enzyme strategies in the granular state.

Sonocatalysis: Eco-design strategy for developing novel inorganic sonogels for the conservation of stone heritage

Products designed to form continuous inorganic networks from alkoxysilanes frequently include organic solvents because of the necessity to turning the precursors miscible with water and because dilution is required for certain applications. Thus, there is a demand for efficient mixtures employing eco-design strategies. This study explores the feasibility of sonocatalysis to prepare homogeneous mixtures with water to initiate sol-gel reactions and as the dilution agent. The approach allowed to design and prepare viable mixtures with unique tetraethoxysilane(TEOS):H2O ratios (1:4 to 1:32). By managing the ultrasonic irradiation parameters, it was possible to formulate mixtures with high degree of hydrolysis, appropriate condensation ratios, and capable to create sonogel materials containing other desired features for stone conservation. The water content manages the gelling times and gel deposition rates through a dilution effect, which might be useful to minimize undesirable side effects of conservation treatments, such as excessive pore occlusion. For instance, a TEOS:H2O ratio of 1:32 results in a very low gel deposition rate.Furthermore, the applicability and efficacy of successful mixtures was preliminary assessed, and it was demonstrated that the resulting inorganic networks, primarily composed of SiOSi bonds, can enhance the hardness and surface resistance of soft stones. This potential strengthening effect improves gradually with increasing TEOS:H2O ratios. The mixtures deserve further studies aimed at enhancing understanding of their consolidation characteristics.The advances achieved also opens the door for producing innovative dual-role hybrid inorganic-organic sonogels that can be used for materials protection and surface consolidation.

Effect of limited hydrolysis with endopeptidase on bitterness properties of wheat gluten hydrolysates

The application of limited hydrolysis on wheat gluten (WG) has been found to be a highly effective method for improving a wide range of functional properties associated with plant protein. However, the bitter peptides formed during this process have an unpleasant bitterness. To provide a theoretical framework for de-bittering techniques, this study examined the modulation of bitterness intensity in wheat gluten hydrolysates (WGHs) by manipulating enzyme cleavage sites and degree of hydrolysis (DH). It was found that the bitter peptide's release content increased significantly, and the bitterness threshold decreased markedly with increasing DH. Furthermore, the structure-bitterness threshold association of bitter peptides was investigated. The results indicated that peptide segments in molecular weights (MW) from 500 to 1000 exhibited the greatest influence on bitterness threshold compared to peptides with other MWs. The percentage of total hydrophobic amino acid content and position of some hydrophobic amino acids in the amino acid sequence had a significant effect on the bitterness threshold. Finally, 47 peptides were identified by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analysis. These peptides were mainly small peptides with less than 13 amino acid residues and MW below 1500 Da, and most of them had Q values higher than 5855 J/mol.

Low-cost protein extracts and hydrolysates from plant-based agro-industrial waste: Inputs of interest for cultured meat

The main challenge in large-scale cultured meat production is replacing fetal bovine serum (FBS), an expensive, animal-derived component in the cell culture medium. This study explored the use of plant-based agro-industrial waste as an economical and nutritionally beneficial alternative to FBS. Soybean and peanut bran were processed to obtain extracts and protein hydrolysates rich in proteins, low molecular weight peptides, and amino acids. The results confirmed the presence of essential nutritional factors conducive to the growth and viability of animal cells in vitro. Protein extracts formed mainly by globulins and albumins resemble the composition of FBS. The hydrolysates contained a protein content similar to FBS and were particularly abundant in leucine and proline. The molecular weight distribution of the peptides indicated a high degree of hydrolysis. Cost analysis revealed that utilizing plant waste for protein inputs could be a favorable approach to reducing cultured meat production costs.

Renewing the potential of rice crop residues as value-added products in the cosmetics industry

Purpose of this study is to explore the extraction of potentially valuable cosmetic ingredients from rice crop residues, aiming to mitigate their environmental impact. MethodsWe employed AOAC methods to analyze the fat, protein, ash, fiber, soluble, and insoluble carbohydrate content in these residues. To identify sugars rich in galactose and acidic sugars, a total soluble carbohydrate extraction was performed. Cellulose, as part of the insoluble carbohydrates, was isolated through alkaline and acid hydrolysis, while sodium silicate was derived from the ash. Characterization of insoluble cellulose and silicate involved techniques like FTIR, DSC, PXRD, microphotography, porosity assessments, and water absorption studies. For proteins, alkaline solubilization and precipitation at the isoelectric point were utilized, with quantification via BCA and amino acid profiling through gas chromatography. Evaluation of radical scavenging capacity using DPPH led to the calculation of apparent molecular weight via SDS-PAGE. ResultsThe results revealed low levels of gum, mucilage, and pectin in both residues, contrasting with a high concentration of insoluble polysaccharides. Among these, Iβ cellulose displayed potential attributes for cosmetic applications due to its oil and water adsorption characteristics. However, silicates obtained from the ashes did not exhibit direct use potential. In terms of protein extraction, we observed antioxidant properties, with enhanced performance through enzymatic hydrolysis, achieving a hydrolysis degree of 30.41% and a DPPH radical absorption rate exceeding 70%. ConclusionRice residues, particularly husk and straw, shown valuable substances suitable for potential cosmetic applications, encompassing cellulose, hydrolyzed proteins, and ash as a silicate precursor.

Insights into enzymatic hydrolysis: Exploring effects on antioxidant and functional properties of bioactive peptides from Chlorella proteins

Chlorella protein hydrolysate (CPH) is highly valued for its protein content, solubility, and functionality. Our main aim is to produce CPH via enzymatic hydrolysis using pepsin, alkaline, trypsin, and pancreatic enzymes and to analyze its amino acid composition, antioxidant activity, functional, and physiological properties. After the extraction and preparation of bioactive peptides (BAPs) derived from Chlorella protein, they were enzymatically hydrolyzed using the mentioned enzymes, and the degree of hydrolysis (DH) was evaluated. Our results showed that samples fabricated with trypsin and alkaline enzymes had the highest water-holding capacity (WHC) (3.8 g water/g dry matter) and oil-holding capacity (OHC) (5.7 g oil/g dry matter), respectively. Enzymatic hydrolysis with alkaline enzyme and trypsin showed the strongest radical scavenging activities of DPPH (83.2%) and ABTS (77.5%), respectively. Additionally, hydroxyl radical scavenging activity (HRSA) and reducing power of crude protein increased after enzymatic hydrolysis. Enzymatic hydrolysis also increased the metal-chelating activity. Based on these findings, it can be concluded that CPH has the best potential in improving the nutritional and functional properties of food ingredients and products.

Effects of Lacticaseibacillus paracasei XJ-003 on the allergenicity and antigenicity of milk proteins during fermentation

Fermentation with lactic acid bacteria (LAB) provides an effective method to alleviative cow milk allergy. In this research, we identified a specific strain of Lacticaseibacillus paracasei, named as XJ-003, that exhibited stable proteolytic activity and had the capability to reduce milk protein allergenicity. After various safety evaluation tests and genetic-level analysis, it was confirmed that XJ-003 is a safe LAB to use. SDS-PAGE analysis revealed that the hydrolysis efficiency of XJ-003 fermentation on casein was better than that of whey protein. During fermentation, the antigenicity of all milk proteins significantly reduced (p < 0.05), and α-casein exhibited a 67.74% reduction in antigenicity at the end of fermentation. Additionally, after 8 h of fermentation, the allergenicity of all proteins significantly reduced by 33.25%–56.94% (p < 0.05). The fluctuations in antigenicity and allergenicity throughout the fermentation process were attributed to continuous hydrolysis and the release of new epitopes. However, we did not find a direct relationship among the degree of hydrolysis, antigenicity, and allergenicity. It is concluded that the reduction of protein allergenicity is not only attributable to the proteolytic of LAB but is also influenced by the specificity of protein hydrolysis. Therefore. It is not appropriate to screen LAB that can alleviate CMA only according to degree of hydrolysis and antigenicity of the proteins.

Effects of Matrix Structure on Protein Digestibility and Antioxidant Property of Different Soybean Curds During In Vitro Digestion.

This study compared the three most common types of tofu (soybean curd), which were prepared by using magnesium chloride (MgCl2 tofu), calcium sulfate (CaSO4 tofu), and glucono-δ-lactone (GDL tofu) coagulants. The results showed that GDL tofu had a higher water holding capacity than MgCl2 tofu and CaSO4 tofu, which was attributed to its high surface hydrophobicity and disulfide bond content. GDL tofu possessed the lowest firmness, gumminess, and chewiness, along with a uniform network structure and a thin protein matrix. In contrast, MgCl2 tofu exhibited an inhomogeneous network structure with a thick protein matrix. Combining the results of protein hydrolysis degree, SDS-PAGE, and free amino acids during in vitro digestion, it was indicated that the degree of protein digestion in GDL tofu was the highest. After intestinal digestion, GDL tofu had the highest total phenolic content, ferric reducing antioxidant power, and DPPH value. These results demonstrated the superior protein digestibility and antioxidant property of GDL tofu during in vitro digestion due to its structural characteristics that facilitate enzyme diffusion in the matrix. The findings offer insight into the protein digestibility and antioxidant properties of different types of tofu during digestion from structural characteristic perspective and valuable reference information for consumer dietary nutrition.

Incorporation of spray-dried encapsulated bioactive peptides from coconut (Cocos nucifera L.) meal by-product in bread formulation.

This study aimed to stabilize and mask the bitterness of peptides obtained from the enzymatic hydrolysis of coconut-meal protein with maltodextrin (MD) and maltodextrin-pectin (MD-P) as carriers via spray-drying. Essential (~35%), hydrophobic (~32%), antioxidant (~15%), and bitter (~45%) amino acids comprised a significant fraction of the peptide composition (with a degree of hydrolysis of 33%). The results indicated that the peptide's production efficiency, physical and functional properties, and hygroscopicity improved after spray-drying. Morphological features of free peptides (fragile and porous structures), spray-dried with MD (wrinkled with indented structures), and MD-P combination (relatively spherical particles with smooth surfaces) were influenced by the process type and feed composition. Adding free and microencapsulated peptides to the bread formula (2% W/W) caused changes in moisture content (35%-43%), water activity (0.89-0.94), textural properties (1-1.6 N), specific volume (5.5-6 cm3/g), porosity (18%-27%), and color indices of the fortified product. MD-P encapsulated peptides in bread fortification resulted in thermal stability and increased antioxidant activity (DPPH and ABTS+ radical scavenging: 4.5%-39.4% and 31.6%-46.8%, respectively). MD-P (as a carrier) could maintain sensory characteristics and mask the bitterness of peptides in the fortified bread. The results of this research can be used to produce functional food and diet formulations.

Enzymatic Hydrolysis Optimization of Yak Whey Protein Concentrates and Bioactivity Evaluation of the Ultrafiltered Peptide Fractions.

Yak whey protein concentrates (YWPCs) have good functional properties, but there is still a gap in the study of their peptides. In this study, peptides were obtained by enzymatic hydrolysis, and the bioactivity of each ultrafiltration fraction was evaluated using an optimal process. YWPCs were isolated and purified from yak milk as the raw material. Alkaline protease, trypsin, and papain were used to hydrolyze YWPCs. The protease with the highest degree of hydrolysis (DH) and peptide concentration was selected as the most suitable enzyme. The effects of pH, temperature, time, and the enzyme-to-substrate ratio (E/S) on the DH and peptide concentration were investigated, and response surface methodology was utilized to optimize the hydrolysis process. The hydrolysate was separated using ultrafiltration membranes with molecular weight cut-offs of 10 kDa, 5 kDa, 3 kDa, and 1 kDa. The bioactivity of each ultrafiltration component was analyzed, including the inhibition rates of α-amylase and xanthine oxidase (XOD) activities and the scavenging rates of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation radicals. The results indicated that alkaline protease was the best enzyme for hydrolyzing YWPCs. The peptide concentration in the YWPC hydrolysate was the highest (17.21 mg/mL) at a pH of 8 and a concentration of 7500 U/g, after 2.5 h at 62 °C. The enzymatic hydrolysate was ultrafiltered to yield four peptide fractions, of which the <1 kDa peptides exhibited the highest α-amylase inhibitory activity (22.06%), XOD inhibitory activity (17.15%), and ABTS cationic free radical scavenging rate (69.55%). This demonstrates the potential of YWPC hydrolyzed peptides for hypoglycemic, uric acid-lowering, and antioxidant applications, providing a theoretical basis for the high-value utilization of YWPCs.

Protein hydrolysates of Moringa oleifera seed: Antioxidant and antihyperglycaemic potential as ingredient for the management of type-2 diabetes

New plant proteins with high nutritional quality and biological properties are actively searched worldwide. Moringa oleifera seed protein isolate was prepared from defatted flour and hydrolyzed using four proteases namely trypsin, pepsin, Alcalase, and thermolysin. Then, antioxidant activity and cellular glucose uptake properties of the hydrolysates were assessed. A high degree of hydrolysis was obtained for hydrolysate prepared using trypsin (60.07%), followed by pepsin (57.14%), Alcalase (50.68%), and thermolysin (45.45%). Thermolysin hydrolysate was the most antioxidant efficient (IC50 0.15 and 0.74 mg/mL for 2,2′-azino-bis(acide 3-ethylbenzothiazoline-6-sulfonique) diammonium salt (ABTS) and 2,2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, respectively). Trypsin hydrolysate stimulated high glucose uptake by yeast cells (12.34–35.28%). In the absence of insulin, Alcalase hydrolysate was the most efficient for glucose uptake by the muscle, with the rate ranging from 22.03% to 29.93% after 30 min, then from 29.55% to 34.6% after 60 min. The four hydrolysates improved glucose uptake by the muscle in the presence of insulin with the rate ranging from 46.88% to 58.03% after 30 min, and from 50% to 58.18% after 60 min. Therefore, Moringa oleifera seed proteins could be used to prepare peptides as components of functional foods for the management of type-2 diabetes.

Increased reactive carboxyl and free alfa-amino groups from fish type I collagen peptides by Alcalase® hydrolysis exhibit higher antibacterial and antioxidant activities

Abstract This study aimed to generate low molecular weight peptides (LMWP) from fish collagen type I hydrolysed by increasing activity of Alcalase® from 0.0 to 12.0 (AU-A per 100 g) at 55 °C and 7.4 of pH for 3 h 40 min. The results showed that all enzyme activity levels caused 34–55 % reductions in protein recovery, 1.0–3.0 folds’ increase in free α-amino groups and 1.7–3.2 folds’ increase in carboxyl groups. Degree of hydrolysis ranged from 20 to 30 % with increasing enzyme activity. The number average molecular weight significantly reduced from 3200 g/mol in 0.0 AU-A per 100 g enzyme activity to 1151, 1398, 1175, 1040 and 1246 g/mol in 2.4, 4.8, 7.2, 9.6 and 12.0 AU-A per 100 g enzyme activities, respectively. Depending upon enzyme activity level, the produced LMWP with reactive carboxyl and amino end-groups exhibited 2.5- to 4.0-fold increases in antioxidant capacity and 1.0–3.5 log cfu/ml inhibition of four pathogen bacteria. Highest inhibition of 2.5 log cfu/ml in Escherichia coli was obtained from 2.4 AU-A per 100 g enzyme activity and 3.5 log cfu/ml in Listeria monocytogenes from 9.6 and 12.0 AU-A per 100 g enzyme activity levels. Infrared spectroscopy clearly identified reactive end-groups and showed remarkably differences in molar absorptivity of various molecular regions between non-enzyme and enzyme treated collagen type I molecule. A 9.6 and 12.0 AU-A per 100 g enzyme activity levels were found optimally effective to generate LMWP. In conclusion, LMWP exhibited high antioxidant and antibacterial activity due to increased functional reactive end-groups, and these bio-active peptides may have greater potentialities in various food and pharmaceutical applications.

Optimization of Hydrolysis Conditions, Isolation, and Identification of Biologically Active Peptides Derived from Acheta domesticus for Antioxidant and Collagenase Inhibition.

The study aimed to optimize hydrolysis conditions and isolate and identify bioactive peptides with anti-skin aging effects from Acheta domesticus (house cricket). A. domesticus proteins underwent hydrolysis using Alcalase® and optimized conditions using response surface methodology through a face-centered central composite design. Variable controls (enzyme-substrate concentration (E/S), time, and temperature) were assessed for their impact on activities against collagenase, 2,2-diphenyl-1-picrylhydrazyl radical (DPPH●), and degree of hydrolysis of protein hydrolysate (PH). PH was also investigated for composition, anti-skin aging, and anti-inflammatory effects. Amino acid sequences with potent anti-skin aging activity were isolated and identified using ultrafiltration, gel filtration chromatography, and liquid chromatography coupled with tandem mass spectrometry, employing de novo sequencing. Optimal conditions for producing PH with maximum anti-skin aging activity were an E/S concentration of 2.1% (w/w), 227 min, and 61.5 °C. Glutamic acid was a predominant amino acid and PH exhibited a molecular weight below 15 kDa. Additionally, PH displayed significant activities against collagenase, hyaluronidase, DPPH●, lipid peroxidation, and NF-κB-mediated inflammation (p < 0.05). Three novel anti-skin aging peptides were identified-Ala-Val-Thr-Lys-Ala-Asp-Pro-Tyr-Thr-Asp-Gln, Thr-Val-Met-Glu-Leu-Asn-Asp-Leu-Val-Lys-Ala-Phe, and Val-Pro-Leu-Leu-Glu-Pro-Trp-exhibiting the most potent collagenase and DPPH● inhibition. Therefore, this study proposed that PH, produced with Alcalase® under optimal conditions, emerges as a promising substance with potent anti-skin aging activity for the cosmeceutical industry.

Advances in Understanding the Antioxidant and Antigenic Properties of Egg-Derived Peptides.

Pepsin, trypsin and proteinase K were used in the present study to hydrolyse the proteins from whole eggs, yolks or whites, and the resulting hydrolysates were characterised in terms of antioxidant and IgE-binding properties, using a combination of in vitro and in silico methods. Based on the degree of hydrolysis (DH) results, the egg yolk proteins are better substrates for all the tested enzymes (DH of 6.2-20.1%) compared to those from egg whites (DH of 2.0-4.4%). The SDS-PAGE analysis indicated that pepsin and proteinase K were more efficient compared to trypsin in breaking the intramolecular peptide bonds of the high molecular weight egg proteins. For all the tested substrates, enzyme-assisted hydrolysis resulted in a significant increase in antioxidant activity, suggesting that many bioactive peptides are encrypted in inactive forms in the parent proteins. The hydrolysates obtained with proteinase K exhibited the highest DPPH radical scavenging activity (124-311 µM Trolox/g protein) and the lowest residual IgE-binding capacity. The bioinformatics tools revealed that proteinase K is able to break the integrity of the main linear IgE-binding epitopes from ovalbumin and ovomucoid. It can be concluded that proteinase K is a promising tool for modulating the intrinsic properties of egg proteins.

Characterisation of a capsular polysaccharide from Moraxella nonliquefaciens CCUG 348T

Moraxella nonliquefaciens is a commensal of the human upper respiratory tract (URT) but on rare occasions is recovered in cases of ocular, septic and pulmonary infections. Hence there is interest in the pathogenic determinants of M. nonliquefaciens, of which outer membrane (OM) structures such as fimbriae and two capsular polysaccharide (CPS) structures, →3)-β-D-GalpNAc-(1→5)-β-Kdop-(2→ and →8)-α-NeuAc-(2→, have been reported in the literature. To further characterise its surface virulence factors, we isolated a novel CPS from M. nonliquefaciens type strain CCUG 348T. This structure was elucidated using NMR data obtained from CPS samples that were subjected to various degrees of mild acid hydrolysis. Together with GLC-MS data, the structure was resolved as a linear polymer composed of two GalfNAc residues consecutively added to Kdo, →3)-β-D-GalfNAc-(1→3)-α-D-GalfNAc-(1→5)-α-(8-OAc)Kdop-(2→.Supporting evidence for this material being CPS was drawn from the proposed CPS biosynthetic locus which encoded a potential GalfNAc transferase, a UDP-GalpNAc mutase for UDP-GalfNAc production and a putative CPS polymerase with predicted GalfNAc and Kdo transferase domains. This study describes a unique CPS composition reported in Moraxella spp. and offers genetic insights into the synthesis and expression of GalfNAc residues, which are rare in bacterial OM glycans.

Pomelo (Citrus grandis (L.) Osbeck) sponge layers as a potential source of soluble dietary fiber: Evaluation of its physicochemical, structural and functional properties.

Pomelo sponge layer (PSL) had been considered as a potential source of soluble dietary fiber (SDF), while they were mostly disposed of as waste. To promote high-value utilization of pomelo wastes, this study extracted SDF from PSL of six varieties of pomelo, and their physicochemical, structural and functional properties were investigated. Results indicated that all PSL-SDFs showed good physicochemical and functional properties. Among them, PSL-SDF from grapefruit (GRSDF) showed better water holding capacity and swelling capacity, whereas Shatian pomelo PSL-SDF and Guanxi pomelo PSL-SDF had the highest thermal stability and oil holding capacity, respectively. Furthermore, compared with other PSL-SDFs, GRSDF displayed the lowest hydrolysis degree coupled with the best antioxidant and probiotic growth-promoting abilities. Finally, the correlation analysis showed that multiple beneficial effects of PSL-SDFs were markedly associated with their molecular weight and the concentrations of total phenolic, total flavonoids, rhamnose, galacturonic acid, glucose and arabinose. Collectively, these findings contributed to a better understanding of the physicochemical and functional properties of SDFs extracted from different PSLs, which provided a scientific basis for the development of PSL-SDFs into functional foods.

A Comprehensive Investigation of Tenderization Methods: Evaluating the Efficacy of Enzymatic and Non-Enzymatic Methods in Improving the Texture of Squid Mantle — A Detailed Comparative Study

AbstractIn this study, enzymatic [papain (P), bromelain (B), and A. oryzae-derived fungal protease (FP); enzyme ratios: 0.012 (v/v), 38 °C, 50 min] and non-enzymatic [control (C; saline), mineral water (95%)–lemon juice (5%) (ML) (1/2:w/v), 38 °C, 50 min)] tenderizing methods on European squid mantle (Loligo vulgaris Lamarck, 1798) were investigated. Scanning electron microscope (SEM) imaging, water holding capacity (WHC), cooking loss (CL), total free amino acids (TFAA), total soluble protein (TSP), hydroxyproline (Hyp), and Fourier-transform infrared spectroscopy (FTIR) analyses were performed on uncooked samples. pH, water activity (aw), color, nutritional changes, amino acids (AA), total volatile basic-nitrogen (TVB-N), Warner-Bratzler shear (WBS), texture profile analysis (TPA), and sensory evaluations were performed on both uncooked and cooked samples. A significant decrease in protein content was observed in group P (12.86%) compared to untreated (U) squid (15.16%). During frying, group P absorbed more cooking oil (8.37%) than the other groups. A higher degree of hydrolysis was observed in the enzymatically tenderized groups than in non-enzymatic groups, and a shift in secondary protein structures in favor of random coils. Hydrolysis was confirmed by Hyp and AA analyses. The total AA content order was found as B &lt; P &lt; FP &lt; C &lt; ML &lt; U. ML and FP groups have relatively higher total bitter and umami AA compositions, especially in uncooked samples. FP and ML groups had more favorable results across all analyses, especially in terms of the sensory results, nutritional values, and TPA results of cooked samples. It is concluded that both methods are very convenient regarding industrial usage.

Production of Medium Chain Length Polyhydroxyalkanoate from Waste Cannabis sativa Biomass

This works aims to evaluate a process to convert residual medical Cannabis sativa stalks into medium chain length polyhydroxyalkanoate (mcl-PHA), using chemical pretreatment and enzymatic hydrolysis to obtain sugars as a carbon source for a fermentation process with Pseudomonas aeruginosa. Chemical composition analysis revealed a content of structural polysaccharides of 57.64%. Thermochemical pretreatments with 2% sulfuric acid or 2% sodium hydroxide were capable of partially removing hemicellulose and lignin, as well as increasing cellulose crystallinity. Pretreated biomass was subjected to hydrolysis using commercial cellulase cocktails Celluclast® 1.5 L and Cellic® CTec3. Acid pretreatment showed an adverse effect on hydrolysis yield of holocellulose, decreasing to 39.5%; compared to 44.4% of untreated biomass. Alkaline pretreatment increased degree of hydrolysis up to 73.3%. Shake flask fermentation of hydrolysate with Pseudomonas aeruginosa produced cell growth of 1.65 g/L and a mcl-PHA titer of 0.41 g/L. Extracted polymer presented characteristic FTIR bands for PHAs, glass transition temperature of − 50.8 °C, melting temperature of 48.9 °C, possibly allowing its use in the biomedical industry. The developed process represents a potential way to valorize Cannabis waste stalks, using alkaline pretreatment, enzymatic hydrolysis with Celluclast® 1.5 L and fermentation with Pseudomonas aeruginosa. Further work should focus on improving yield of the obtained polyhydroxyalkanoate in fermentation, in order to improve industrial feasibility of the entire process and, in turn, increasing revenue of the medical Cannabis industry.Graphical

Effect of different pretreatments on the hydrolysis efficiency and flavor of squid viscera (Dosidicus gigas)

In order to better utilize the proteins in squid viscera (Dosidicus gigas), the effects of different pretreatments on the degree of hydrolysis (DH) and volatile compounds of hydrolysates were studied. The DH was used as an indicator to select alkaline protease as the optimal protease from 8 types of proteases. The hydrolysis conditions of alkaline protease and the flavor of the hydrolysates were investigated through single-factor, response surface methodology, and pretreatment-assisted hydrolysis experiments. The results showed that alkaline protease had the highest DH (42.08 ± 0.58%), with enzyme dosage of 1.5%, hydrolysis temperature of 45 °C, hydrolysis time of 5 h, and liquid-solid ratio of 4:1. The DH of the ultrasound group was significantly higher than other groups, with the highest DH (45.67 ± 0.34%) after ultrasound for 40 min (U40). The proportion of molecular weight < 1 kDa and the content of free amino acids (1613.64 mg/100 g) were the highest at U40. The electronic nose results indicated that the composition of organic sulfur and aliphatic compounds in U40 showed significant differences compared to other products. The U40 sample had the highest type and content of volatile compounds (especially benzaldehyde), which was more conducive to the volatilization of flavor substances. In conclusion, U40 pretreatment can effectively improve the DH and flavor of hydrolysates.

In vitro digestion mimicking conditions in adults and elderly reveals digestive characteristics of pork from different cooking ways

This study aimed to investigate the impact of three cooking ways (sous vide (SV), frying (FR) and roasting (RO)) on pork protein digestion characteristics under conditions simulating healthy adult (control, C) and elderly individuals with achlorhydria (EA). Changes in degree of hydrolysis (DH), SDS-PAGE profiles, zeta potential, particle size and secondary structure during digestion were evaluated. Our results revealed the EA condition markedly affected the protein digestion process of pork with different cooking ways. The DH values of SV (25.62%), FR (21.38%) and RO (19.40%) under the EA condition were significantly lower than those of under the control condition (38.32%, 33.00% and 30.86%, respectively). Moreover, differences were also observed among three cooking ways under the EA condition. For a given cooking way, the differences between control and EA conditions gradually diminished from the gastric to the intestinal phase. Under a certain digestion condition, SV maintained the highest degree of digestion throughout the process, particularly under the EA condition. Therefore, we conclude that pork cooked by sous vide is more recommendable for the elderly considering protein digestibility.