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

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

Rapid and efficient high-performance liquid chromatography-ultraviolet determination of total amino acids in protein isolates by ultrasound-assisted acid hydrolysis.

This study presents the optimization and validation of an ultrasound-assisted acid method for the HPLC-UV determination of amino acids in plant-based proteins. The research focuses on enhancing hydrolysis efficiency and reducing environmental impact. Ultrasound treatment significantly accelerated hydrolysis by creating cavitation, which increases local pressure and temperature, leading to faster reaction rates. The optimal condition was a 30-minute treatment at 90 °C with 6 M hydrochloric acid. The 9-fluorenylmethyloxycarbonyl chloride derivatization was best performed at pH 9.0 using borate buffer, ethanol as the organic solvent, and a 5-minute derivatization time with a 5 mM concentration. The method's analytical performance, validated according to FDA guidelines, showed excellent selectivity, specificity, linearity (r2 > 0.999), accuracy (recovery between 80-118 %), and precision (RSD<10.9). The analysis of 15 plant-based proteins revealed distinct amino acid profiles. Compared to traditional acid hydrolysis methods, the ultrasound-assisted approach demonstrated no significant difference in results (p-value > 0.05), confirming its reliability. The optimized ultrasound-assisted method is a reliable and efficient alternative for amino acid analysis, offering significant cost and time savings while maintaining high analytical performance. These findings are crucial for nutritional planning and developing functional foods to improve health outcomes.

Synthesis of Keratin Nanoparticles Extracted from Human Hair through Hydrolysis with Concentrated Sulfuric Acid: Characterization and Cytotoxicity.

Human hair, composed primarily of keratin, represents a sustainable waste material suitable for various applications. Synthesizing keratin nanoparticles (KNPs) from human hair for biomedical uses is particularly attractive due to their biocompatibility. In this study, keratin was extracted from human hair using concentrated sulfuric acid as the hydrolysis agent for the first time. This process yielded KNPs in both the supernatant (KNPs-S) and precipitate (KNPs-P) phases. Characterization involved scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), Zeta potential analysis, X-ray diffraction (XRD), and thermogravimetric analysis (TG). KNPs-S and KNPs-P exhibited average diameters of 72 ± 5 nm and 27 ± 5 nm, respectively. The hydrolysis process induced a structural rearrangement favoring ß-sheet structures over α-helices in the KNPs. These nanoparticles demonstrated negative Zeta potentials across the pH spectrum. KNPs-S showed higher cytotoxicity (CC50 = 176.67 µg/mL) and hemolytic activity, likely due to their smaller size compared to KNPs-P (CC50 = 246.21 µg/mL), particularly at concentrations of 500 and 1000 µg/mL. In contrast, KNPs-P did not exhibit hemolytic activity within the tested concentration range of 32.5 to 1000 µg/mL. Both KNPs demonstrated cytocompatibility with fibroblast cells in a dose-dependent manner. Compared to other methods reported in the literature and despite requiring careful washing and neutralization steps, sulfuric acid hydrolysis proved effective, rapid, and feasible for producing cytocompatible KNPs (biomaterials) in single-step synthesis.

Optimisation of acid hydrolysis conditions of choline esters and mass spectrometric determination of total choline in various foods.

Determining the content of the nutrient choline in foods and obtaining the required amount from the diet are crucial. One way to measure choline in foods is by converting choline esters to free choline via acid hydrolysis, followed by quantifying the total choline, as adopted by the AOAC method (AOAC-Choline); however, certain choline esters are difficult to hydrolyse. Here, we investigated various acid hydrolysis conditions to establish a reliable method for determining the total choline in foods by detecting free choline using highly sensitive and selective mass spectrometry. Hydrolysis in 0.055 mol/L HCl for 8 h in an autoclave (121 °C) was found to be optimal for the hydrolysis of choline esters in various foods. Twenty-four foods, including grains, seed, vegetables, fruits, mushroom, algae, fish, meats, beverage, processed foods, and egg, were measured. The trends in the total choline content were consistent with previous reports; however, the choline content was 10-20% higher than that measured using AOAC-Choline. Therefore, re-evaluation of the total choline content in foods using our constructed method is recommended. This reassessment will allow for a more reliable determination of choline intake for maintaining health.

Effect of Glycerol and Sisal Nanofiber Content on the Tensile Properties of Corn Starch/Sisal Nanofiber Films.

Currently, petroleum-derived plastics are widely used despite the disadvantage of their long degradation time. Natural polymers, however, can be used as alternatives to overcome this obstacle, particularly cornstarch. The tensile properties of cornstarch films can be improved by adding plant-derived nanofibers. Sisal (Agave sisalana), a very common low-cost species in Brazil, can be used to obtain plant nanofibers. The goal of this study was to obtain sisal nanofibers using low concentrations of sulfuric acid to produce thermoplastic starch nanocomposite films. The films were produced by a casting technique using commercial corn starch, glycerol, and sisal nanofibers, accomplished by acid hydrolysis. The effects of glycerol and sisal nanofiber content on the tensile mechanical properties of the nanocomposites were investigated. Transmission electron microscopy findings demonstrated that the lowest concentration of sulfuric acid produced fibers with nanometric dimensions related to the concentrations used. X-ray diffraction revealed that the untreated fibers and fibers subjected to acid hydrolysis exhibited a crystallinity index of 61.06 and 84.44%, respectively. When the glycerol and nanofiber contents were 28 and 1%, respectively, the tensile stress and elongation were 8.02 MPa and 3.4%. In general, nanocomposites reinforced with sisal nanofibers showed lower tensile stress and higher elongation than matrices without nanofibers did. These results were attributed to the inefficient dispersion of the nanofibers in the polymer matrix. Our findings demonstrate the potential of corn starch nanocomposite films in the packaging industry.

Neokestose suppresses the increase in plasma glucose caused by oral administration of sucrose in a streptozotocin­induced diabetic rat.

Neokestose is considered to have a prebiotic function. However, the physiological activity of neokestose remains unknown. Neokestose has a blastose, a sucrose analog, in its structure. We previously demonstrated that oral administration of blastose to diabetic rats suppressed the increase in plasma glucose (PG) concentration after sucrose administration. Therefore, neokestose might have a similar effect. In this study, we investigated the effects of neokestose on PG concentrations and the mechanism of its action. We first administered neokestose orally to streptozotocin-induced diabetic rats and observed that the expected consequent increase in PG concentration was significantly suppressed. Next, we examined the inhibitory effect of neokestose on glycosidase activity, but observed only a slight inhibitory effect. Therefore, we hypothesized that neokestose might be hydrolyzed by gastric acid to produce blastose. We performed an acid hydrolysis of neokestose using artificial gastric juice. After acid hydrolysis, peaks corresponding to neokestose and its decomposition products including blastose were observed. Therefore, we suggest that neokestose and blastose, a decomposition product, synergistically inhibit glycosidase activity. These findings support the potential use of neokestose as a useful functional oligosaccharide that can help manage plasma glucose concentrations in patients with diabetes mellitus.

Simultaneous High-Performance Recovery and Extended Acid-Catalyzed Hydrolysis of Oleuropein and Flavonoid Glycosides of Olive (Olea europaea) Leaves: Hydrothermal versus Ethanol Organosolv Treatment.

Olive leaves (OLLs) are an exceptional bioresource of natural polyphenols with proven antioxidant activity, yet the applicability of OLL extracts is constrained by the relatively high polarity of the major polyphenols, which occur as glycosides. To overcome this limitation, OLLs were subjected to both hydrothermal and ethanol organosolv treatments, fostered by acid catalysis to solicit in parallel increased polyphenol recovery and polyphenol modification into simpler, lower-polarity substances. After an initial screening of natural organic acids, oxalic acid (OxAc) was found to be the highest-performing catalyst. The extraction behavior using OxAc-catalyzed hydrothermal and ethanol organosolv treatments was appraised using kinetics, while treatment optimization was accomplished by deploying response-surface methodology. The comparative assessment of the composition extracts produced under optimal conditions of residence time and temperature was performed with liquid chromatography-tandem mass spectrometry and revealed that OLLs treated with 50% ethanol/1.5% HCl suffered extensive oleuropein and flavone glycoside hydrolysis, affording almost 23.4 mg hydroxytyrosol and 2 mg luteolin per g dry weight. On the other hand, hydrothermal treatment with 5% OxAc provided 20.2 and 0.12 mg of hydroxytyrosol and luteolin, respectively. Apigenin was in all cases a minor extract constituent. The study presented herein demonstrated for the first time the usefulness of using a natural, food-grade organic acid to perform such a task, yet further investigation is needed to maximize the desired effect.

Physicochemical Properties of Cellulose Nanocrystals Extracted from Postconsumer Polyester/Cotton-Blended Fabrics and Their Effects on PVA Composite Films.

The utilisation of cotton waste as precursors in the synthesis of nanocrystalline cellulose has gained significant attention. This approach suggests a sustainable solution to address the growing concern of textile waste accumulation while simultaneously producing a valuable material. The main aim of this study is to examine the properties of cellulose nanocrystals (CNCs) obtained from postconsumer polyester-cotton waste and assess the effect of different fabric structures on the extraction and these properties. To acquire nanocellulose, a thorough decolourisation pretreatment process was utilised, which involved the treatment of polyester-cotton waste with sodium dithionite and hydrogen peroxide. Consequently, the postconsumer material was then treated with an acid hydrolysis method employing a 64% (v/v) sulphuric acid solution at 50 °C for 75 min, resulting in the formation of CNCs with average yield percentages ranging from 38.1% to 69.9%. Separation of the acid from the CNC was facilitated by a centrifugation process followed by dialysis against deionised water. Uniform dispersion was then achieved using ultrasonication. A variety of analytical techniques were employed to investigate the morphological, chemical, thermal, and physical properties of the isolated CNCs. Among these techniques, attenuated total reflection-Fourier-transform infrared spectroscopy (ATR-FTIR), energy-filtered transmission electron microscopy (EF-TEM), thermogravimetric analysis (TGA), and X-ray diffraction (XRD) were utilised to analyse the CNCs. The findings indicated that the separated CNCs exhibited a rod-shaped morphology, measuring between 78 and 358 nm in length and 5 and 16 nm in diameter, and also exhibited high crystallinity (75-89%) and good thermal stability. The extracted CNCs were mixed with polyvinyl alcohol (PVA) and glycerol to assess their reinforcing effect on plastic films. The prepared composite film exhibited improved mechanical properties and thermal stability. Incorporating CNCs led to a 31.9% increase in the tensile strength and a 42.33% rise in the modulus of elasticity. The results from this research proved that CNCs can be extracted from postconsumer mixed fabrics as a potential solution to effectively address the mounting concerns surrounding waste management in the textile industry and also provide avenues for enhancing the qualities of eco-friendly composite films.

Long-lasting, biochemically modified mRNA, and its frameshifted recombinant spike proteins in human tissues and circulation after COVID-19 vaccination.

According to the CDC, both Pfizer and Moderna COVID-19 vaccines contain nucleoside-modified messenger RNA (mRNA) encoding the viral spike glycoprotein of severe acute respiratory syndrome caused by corona virus (SARS-CoV-2), administered via intramuscular injections. Despite their worldwide use, very little is known about how nucleoside modifications in mRNA sequences affect their breakdown, transcription and protein synthesis. It was hoped that resident and circulating immune cells attracted to the injection site make copies of the spike protein while the injected mRNA degrades within a few days. It was also originally estimated that recombinant spike proteins generated by mRNA vaccines would persist in the body for a few weeks. In reality, clinical studies now report that modified SARS-CoV-2 mRNA routinely persist up to a month from injection and can be detected in cardiac and skeletal muscle at sites of inflammation and fibrosis, while the recombinant spike protein may persist a little over half a year in blood. Vaccination with 1-methylΨ (pseudouridine enriched) mRNA can elicit cellular immunity to peptide antigens produced by +1 ribosomal frameshifting in major histocompatibility complex-diverse people. The translation of 1-methylΨ mRNA using liquid chromatography tandem mass spectrometry identified nine peptides derived from the mRNA +1 frame. These products impact on off-target host T cell immunity that include increased production of new B cell antigens with far reaching clinical consequences. As an example, a highly significant increase in heart muscle 18-flourodeoxyglucose uptake was detected in vaccinated patients up to half a year (180 days). This review article focuses on medical biochemistry, proteomics and deutenomics principles that explain the persisting spike phenomenon in circulation with organ-related functional damage even in asymptomatic individuals. Proline and hydroxyproline residues emerge as prominent deuterium (heavy hydrogen) binding sites in structural proteins with robust isotopic stability that resists not only enzymatic breakdown, but virtually all (non)-enzymatic cleavage mechanisms known in chemistry.

Metal Ion-Induced Acid Hydrolysis Strategy for the One-Step Synthesis of Tough and Highly Transparent Hydrolyzed Polyacrylamide Hydrogels.

Polyacrylamide (PAM) hydrogel is hard to enhance through coordination bonds because amide groups rarely coordinate with metal ions strongly in an aqueous solution. It is known that the aqueous solution of ZrOCl2.8H2O can be strongly acidic depending on its concentration. Consequently, through a facile one-step metal ion-induced acid hydrolysis strategy (MIAHS), tough and highly transparent hydrolyzed PAM physical hydrogels are prepared by using ZrOCl2.8H2O in this work. The formation of the partially hydrolyzed PAM physical hydrogels elucidates that the side reaction of imidization during common acid hydrolysis of PAM can be perfectly overcome because the structure of the Zr(IV) ion and its interaction with amide groups promote selective acidic hydrolysis from amide to carboxyl groups. Compared to most coordination cross-linked hydrogels, which need at least two-step fabrication, the hydrolyzed PAM hydrogel via MIAHS can be obtained by one-step synthesis due to the weak interaction between amide groups and Zr(IV). The obtained PAM hydrogel cross-linked by hydrogen bonds and coordination bond between Zr(IV) and carboxyl is a multibond network (MBN) and can achieve hierarchical energy dissipation, which exhibits excellent mechanical properties (tensile strength of 3.15 MPa, elongation at break of 890%, and toughness of 17.0 MJ m-3), high transparence (transmittance of 95%), and outstanding conductivity (5.6 S m-1) at water content of 80 wt %. The high gauge factor (from 2.24 to 12.8 as the strain increases from 0 to 400%) endows the hydrolyzed PAM hydrogels with promising application as strain sensors. Furthermore, in addition to ZrOCl2.8H2O, the fact that various hydrolyzable compounds of Ti(IV), Zr(IV) Hf(IV), and Sn(IV) can also fabricate tough hydrolyzed PAM hydrogels verifies the universality of MIAHS. Therefore, the simple, efficient, and universal MIAHS will shed new light on preparing functional PAM-based hydrogels.

Acid-hydrolyzed phenolic extract of parsley (Petroselinum crispum L.) leaves inhibits lipid oxidation in soybean oil-in-water emulsions.

The antioxidant activity of the natural phenolic extracts is limited in particular food systems due to the existence of phenolic compounds in glycoside form. Acid hydrolysis post-treatment could be a tool to convert the glycosidic polyphenols in the extracts to aglycones. Therefore, this research investigated the effects of an acid hydrolysis post-treatment on the composition and antioxidant activity of parsley extracts obtained by an ultrasound-assisted extraction method to delay lipid oxidation in a real food system (i.e., soybean oil-in-water emulsion). Acid hydrolysis conditions were varied to maximize total phenolic content (TPC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. When extracts were exposed to 0.6 M HCl for 2 h at 80 ℃, TPC was 716.92 ± 24.43 µmol gallic acid equivalent (GAE)/L, and DPPH radical scavenging activity was 66.89 ± 1.63 %. Not only did acid hydrolysis increase the concentrations of individual polyphenols, but it also resulted in the release of new phenolics such as myricetin and gallic acid. The extract's metal chelating and ferric-reducing activity increased significantly after acid hydrolysis. In soybean oil-in-water emulsion containing a TPC of 400 µmol GAE/L, the acid-hydrolyzed extract had an 11-day lag phase for headspace hexanal compared to the 6-day lag phase of unhydrolyzed extract. The findings indicated that the conversion of glycosidic polyphenols to aglycones in phenolic extracts can help extend the shelf-life of emulsion-based foods.

Production and Characterization of Nanocellulose from Maguey (Agave cantala) Fiber.

Plant fibers have been studied as sources of nanocellulose due to their sustainable features. This study investigated the effects of acid hydrolysis parameters, reaction temperature, and acid concentration on nanocellulose yield from maguey (Agave cantala) fiber. Nanocellulose was produced from the fibers via the removal of non-cellulosic components through alkali treatment and bleaching, followed by strong acid hydrolysis for 45 min using sulfuric acid (H2SO4). The temperature during acid hydrolysis was 30, 40, 50, and 60 °C, and the H2SO4 concentration was 40, 50, and 60 wt. % H2SO4. Results showed that 53.56% of raw maguey fibers were isolated as cellulose, that is, 89.45% was α-cellulose. The highest nanocellulose yield of 81.58 ± 0.36% was achieved from acid hydrolysis at 50 °C using 50 wt. % H2SO4, producing nanocellulose measuring 8-75 nm in diameter and 72-866 nm in length, as confirmed via field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analysis. Fourier-transform infrared spectroscopy (FTIR) analysis indicated the chemical transformation of fibers throughout the nanocellulose production process. The zeta potential analysis showed that the nanocellulose had excellent colloidal stability with a highly negative surface charge of -37.3 mV. Meanwhile, X-ray diffraction (XRD) analysis validated the crystallinity of nanocellulose with a crystallinity index of 74.80%. Lastly, thermogravimetric analysis (TGA) demonstrated that the inflection point attributed to the cellulose degradation of the produced nanocellulose is 311.41 °C.

The Effect of Acid Hydrolysis on the Pickering Emulsifying Capacity of Tartary Buckwheat Flour.

The effect of sulfuric acid hydrolysis on the Pickering emulsifying capacity of Tartary buckwheat flour (TBF) rich in starch was evaluated for the first time. The results indicate that the sulfuric acid concentration and hydrolysis time had a significant impact on the Pickering emulsifying capacity of acid-hydrolyzed Tartary buckwheat flour (HTBF). A low sulfuric acid concentration (1-2 mol/L) could reduce the particle size of HTBF, but it also decreased the Pickering emulsifying ability. At a sulfuric acid concentration of 3 mol/L, appropriate treatment time (2 and 3 days) led to particle aggregation but significantly improved wettability, thereby resulting in a rapid enhancement in emulsifying capacity. Under these conditions, the obtained HTBF (HTBF-D2-C3 and HTBF-D3-C3) could stabilize medium-chain triglyceride (MCT)-based Pickering high-internal-phase emulsions (HIPEs) with an oil-phase volume fraction of 80% at the addition amounts (c) of ≥1.0% and ≥1.5%, respectively. Its performance was significantly superior to that of TBF (c ≥ 2.0%). Furthermore, at the same addition amount, the droplet size of HIPEs constructed by HTBF-D3-C3 was smaller than that of HTBF-D2-C3, and its gel strength and microrheological performance were also superior to those of HTBF-D2-C3, which was attributed to the higher wettability of HTBF-D3-C3. The findings of this study can facilitate the in-depth application of Tartary buckwheat and provide references for the development of novel Pickering emulsifiers.

Comparison of lactic and propionic acid hydrolysis for production of xylo-oligosaccharides and ethanol from polysaccharides in Toona sinensis branch.

Xylan-type hemicellulose hydrolysis by an organic acid solution for the production of xylo-oligosaccharides (XOS) is efficient and eco-friendly, but the effects of different organic acids on XOS production from Toona sinensis branch (TB) biomass is limited. In this work, under the conditions of 170 °C for 60 min, 33.1 % and 38.7 % XOS yields were obtained from polysaccharides present in TB by 2 % lactic acid (LA) and 6 % propionic acid (PA), respectively. Then 77 % of the lignin was removed by hydrogen peroxide-acetic acid pretreatment system, and 39.5 % and 44.7 % XOS yield were obtained from polysaccharides in delignification TB by 2 % LA and 6 % PA, respectively. It was found that PA hydrolysis, especially from delignified TB, resulted in higher XOS yield and purity compared to LA hydrolysis. Moreover, the content of byproducts (xylose, hydroxymethyl-furfural and furfural) in PA hydrolysate was lower. Following the hydrolysis process, the simultaneous saccharification and fermentation of the TB solid residue achieved an ethanol yield of 71.5 %. This work proposed an integrated process to preferentially convert the TB hemicellulose into valuable XOS and then convert the cellulose into ethanol. This process had the advantages of eliminating the need for isolation and purification of xylan, and the potential to obtain multiple products from the same raw material.

Structural Characterization and Screening for Anti-inflammatory Activity of Polysaccharides with Different Molecular Weights from Astragali Radix.

Astragali Radix polysaccharides (APSs) exhibit a broad spectrum of biological activity, which is mainly related to immune regulation. At present, most available studies focus on total APSs or a certain component of APSs. However, systematic structural study and screening for the anti-inflammatory activity of polysaccharides with different molecular weights (MW) have yet to be conducted. In this study, lipopolysaccharide (LPS)-induced RAW264.7 macrophages were used as a model to investigate the anti-inflammatory activity of APSs and its fractions. The results revealed that fraction APS-I had better anti-inflammatory effects than APS-II. After APS-I was hydrolyzed by trifluoroacetic acid (TFA), the resulting degradation products oligosaccharides were fully methylated. These derivatized oligosaccharides were further analyzed by MALDI-TOF-MS and UPLC-Q-Exactive-MS/MS. The results showed that APS-I was a hetero-polysaccharide with a molecular weight of about 2.0×106 Da, mainly consisting of glucose (46.8 %) and galactose (34.4 %). The degree of polymerization of Astragali Radix oligosaccharides (APOS) was 2-16. APOS were identified as 1,4-glucooligosaccharides and 1,4-galactooligosaccharides. The findings of this study lay the foundation for further elucidation of structure-function relationships of APSs and provide guidance for the development of anti-inflammatory drugs.

Unveiling structure and performance of tea-derived cellulose nanocrystals.

In this study, cellulose was extracted from black tea residues to produce black tea cellulose nanocrystals (BT-CNCs) using an optimized acid hydrolysis method. The structure and performance of BT-CNCs were evaluated. The results showed that the optimal conditions for acidolysis of BT-CNCs included a sulfuric acid concentration of 64 %, a solid-liquid ratio of 1:18 (w/v), a hydrolysis temperature of 45 °C, and a hydrolysis time of 50 min. The optimization process resulted in a 44.8 % increase in the yield of BT-CNCs, which exhibited a crystallinity of 68.57 % and were characterized by the typical cellulose I structure. The diameters of the particles range from 5 to 45 nm, and they exhibit aggregation behavior. Notably, BT-CNCs demonstrated excellent storage stability, and the Tyndall effect occurred when exposed to a single beam of light. Although the thermal stability of BT-CNCs decreased, their primary thermal degradation temperature remained above 200 °C. The colloidal nature of BT-CNCs was identified as a non-Newtonian fluid with "shear thinning" behavior. This study introduces a novel method to convert tea waste into BT-CNCs, increasing the yield of BT-CNCs and enhancing waste utilization. BT-CNCs hold promise for application in reinforced composites, offering substantial industrial value.

Efficient acid hydrolysis for compound-specific δ15N analysis of amino acids for determining trophic positions.

Compound-specific isotope analysis of nitrogen in amino acids (CSIA-AA, δ15NAA) has gained increasing popularity for elucidating energy flow within food chains and determining the trophic positions of various organisms. However, there is a lack of research on the impact of hydrolysis conditions, such as HCl concentration and hydrolysis time, on δ15NAA analysis in biota samples. In this study, we investigated two HCl concentrations (6 M and 12 M) and four hydrolysis times (2 h, 6 h, 12 h, and 24 h) for hydrolyzing and derivatizing AAs in reference materials (Tuna) and biological samples of little egret (n = 4), night heron (n = 4), sharpbelly (n = 4) and Algae (n = 1) using the n-pivaloyl-iso-propyl (NPIP) ester approach. A Dowex cation exchange resin was used to purify amino acids before derivatization. We then determined δ15NAA values using gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). The results revealed no significant differences (p > 0.05) in δ15NAA values among samples treated with different HCl concentrations or hydrolysis times, particularly for δ15NGlx (range: 21.0-23.5‰) and δ15NPhe (range: 4.3-5.4‰) in Tuna (12 M). Trophic positions (TPs) calculated based on δ15NAA at 2 h (little egret: 2.9 ± 0.1, night heron: 2.8 ± 0.1, sharpbelly: 2.0 ± 0.1 and Algae: 1.3 ± 0.2) were consistent with those at 24 h (3.1 ± 0.1, 2.8 ± 0.1, 2.2 ± 0.1 and 1.1 ± 0.1, respectively), suggesting that a 2-h hydrolysis time and a 6 M HCl concentration are efficient pretreatment conditions for determining δ15NAA and estimating TP. Compared to the currently used hydrolysis conditions (24 h, 6 M), the proposed conditions (2 h, 6 M) accelerated the δ15NAA assay, making it faster, more convenient, and more efficient. Further research is needed to simplify the operational processes and reduce the time costs, enabling more efficient applications of CSIA-AA.

Utilization of Lumpfish (Cyclopterus lumpus) Skin as a Source for Gelatine Extraction Using Acid Hydrolysis.

Lumpfish (Cyclopterus lumpus) is an underutilized marine resource that is currently only being exploited for roe. Lumpfish skin was pre-treated with alkali (0.1M NaOH) and acid (0.1M HCl) at a skin to chemical ratio of 1:10 for 24 h at 5 °C to remove non-collagenous proteins and minerals. The pre-treated skin was washed, and gelatine was extracted with 0.1M of acetic acid at three different ratios (1:5, 1:10, and 1:15), time (12,18, and 24 h), and temperature combinations (12, 28, and 24 °C). The highest total extraction yield (>40%) was obtained with combinations of extraction ratios of 1:15 and 1:10 with a longer time (24 h) and higher temperature (18-24 °C). The highest gelatine content was obtained with an extraction period of 24 h and ratio of 1:10 (>80%). SDS-PAGE analysis confirmed the presence of type-I collagen. A rheological evaluation indicated melting and gelling temperatures, gel strength, and viscosity properties comparable to existing cold-water gelatine sources.

Bacterial cellulose nanocrystals obtained through enzymatic and acidic routes: A comparative study of their main properties and in vitro biological responses.

Cellulose nanocrystals (CNCs) are crystalline domains isolated from cellulosic fibers. They have been utilized in a wide range of applications, such as reinforcing fillers, antibacterial agents and manufacturing of biosensors. Whitin this context, the aim of this work was to obtain and analyze CNCs extracted from bacterial nanocellulose (BNC) using two distinct methods combined with milling pre-treatment: an acidic hydrolysis using 64 % sulfuric acid and an enzymatic hydrolysis using a commercial cellulase enzyme mixture. The CNCs obtained from the enzymatic route (e-CNCs) were observed to be spherical nanoparticles with diameter of 56 ± 11 nm. In contrast, the CNCs from the acid hydrolysis (a-CNCs) appeared as needle-shaped nanoparticles with a high aspect ratio with lengths/widths of 158 ± 64 nm/11 ± 2 nm. The surface zeta potential (ZP) of the a-CNCs was -30,8 mV, whereas the e-CNCs has a potential of +2.70 ± 3.32 mV, indicating that a-CNCs consisted of negatively charged particles with higher stability in solution. Although the acidic route resulted in nanocrystals with a slightly higher crystallinity index compared to the enzymatic route, e-CNCs was found to be more thermally stable than BNC and a-CNCs. Here, we also confirmed the safety of a-CNCs and e-CNCs using L929 cell line. Lastly, this article describes two different CNCs synthesis approaches that leads to the formation of nanoparticles with different dimensions, morphology and unique physicochemical properties. To the best of our knowledge, this is the first study to yield spherical nanoparticles as a result of BNC enzymatic treatment.

Enhancement of oleanolic acid concentration through acid hydrolysis of saponin-rich extracts from Chenopodium berlandieri.

The study investigated Chenopodium berlandieri to analyze its oleanolic acid (OA) content. Response surface methodology with central composite design was used to improve saponin extraction, varying temperature, ethanol, and sample-to-solvent ratio. Best conditions (65 °C, 50% ethanol, 1:10 ratio) yielded 53.45 ± 0.63 mg/g of extract from Huauzontle seeds. Temperature linearly impacted extract yield, while temperature and ethanol influenced total saponin content. Hydrolyzing saponin-rich extracts produced OA-rich extracts. Characterization via HPLC-ELSD and LC-MS identified OA4 as the most concentrated OA saponin (5.54 ± 0.16 mg/g). OA alone reached 2.02 ± 0.12 mg/g. Acid hydrolysis increased OA content by up to 3.27×, highlighting the potential of hydrolyzed Huauzontle extracts as a natural ingredient for various industries due to enhanced OA content.