Amino Acid Analysis Research Articles

A new green approach to L-histidine and β-alanine analysis in dietary supplements using rapid and simple contactless conductivity detection integrated with high-resolution glass-microchip electrophoresis.

The analysis of dietary supplements is far less regulated than pharmaceuticals, leading to potential quality issues. Considering their positive effect, many athletes consume supplements containing L-histidine and β-alanine. A new microfluidic method for the determination of L-histidine and β-alanine in dietary supplement formulations has been developed. For the first time, capacitively coupled contactless conductivity detection was employed for the microchip electrophoresis of amino acids in real samples. A linear relationship between detector response and concentration was observed in the range of 10-100µmol L-1 for L-histidine (R2 = 0.9968) and β-alanine (R2 = 0.9954), while achieved limits of detection (3 × S/N ratio) were 4.2µmol L-1 and 5.2µmol L-1, respectively. The accuracy of the method was confirmed using recovery experiments as well as CE-UV-VIS and HPLC-UV-VIS techniques. The developed method allows unambiguous identification of amino acids in native form without chemical derivatization and with the possibility of simultaneous analysis of amino acids with metal cations.

Analytical data of Acacia nilotica var. Nilotica gum

This study aimed to characterize the exudate gum from Acacia nilotica var. nilotica in Sudan and compare its physicochemical properties to Acacia seyal var. seyal and Acacia senegal var. senegal (gum Arabic). Samples were collected from six different states in Sudan over three seasons. The gum had a moisture content of 10.50%, ash content of 1.86%, pH value of 5.19, specific optical rotation of +94.70, intrinsic viscosity of 10.44 cm3 g-1, nitrogen content of 0.024%, protein content of 0.16%, acid equivalent weight of 1907.82, and total uronic acid content of 10.18%. Sugar content analysis revealed arabinose (41.20%), galactose (17.43%), and rhamnose (10.68%). Potassium was the predominant cation, followed by calcium, magnesium, sodium, lead, and iron. Acacia nilotica was classified as part of the Gummeferae series and exhibited a positive specific optical rotation. The Number average molecular weight (Mn) was estimated using osmometric measurements and gel permeation chromatography. The gum had a higher molecular weight and lower intrinsic viscosity compared to gum Arabic, suggesting a spheroidal shape of molecule. Amino acid analysis showed similarities with gum Arabic, with hydroxyproline and serine as principal amino acids. Variations in cationic composition were attributed to differences in soil type among collection locations. KEY WORDS: Physicochemical characterization, Acacia senegal var. senegal gum, Acacia seyal var. seyal gum, Acacia nilotica var. nilotica gum, gammiferae Bull. Chem. Soc. Ethiop. 2024, 38(4), 839-852.                                                          DOI: https://dx.doi.org/10.4314/bcse.v38i4.2

Impact of non‐thermal processing on the nutritional quality and bioactive properties of Industrial hempseed flours and protein isolate

AbstractThere is an unmet demand for plant‐based ingredients with desirable nutritional, techno‐functional properties, and health benefits. In this study, the composition, nutritional quality, and bioactives in industrial hempseed flours and protein isolate generated by milling, germination, isoelectric precipitation (IEP), and enzyme‐assisted extraction (EAE) were evaluated. Moisture, ash, fat, protein, phytic acid, tannin, and trypsin inhibitor content of the hempseed flours and protein isolate were 2.80%–6.46%, 5.07%–28.89%, 0.00%–31.44%, 22.71%–89.94%, 0.55%–1.05%, 274.24–1300.76 μg/g, and 0.00–42.66 U/g, respectively. IEP resulted in the highest protein content (89.94%), indicative of its effective to isolate hempseed protein. Germination and IEP significantly reduced phytic acid and tannin contents by 1.53‐ and 3.63‐fold, respectively. All processing methods improved in vitro protein digestibility (IVPD). SDS‐PAGE analysis revealed comparable band patterns in milled and protein isolate, with a strong 50 kDa band attributed as edestin. Amino acid analysis showed that EAE augmented total essential amino acids, particularly protease. Milling and pronase treatment yielded the highest and lowest IVPD‐corrected amino acid score (IVPDCAAS) of 76% and 47%, respectively. Milled and germinated flours contained varying amounts of γ‐tocopherol, lutein, zeaxanthin, α‐carotene, and β‐carotene. Germinated flour exhibited elevated levels of total phenolic (14.36 mg/g), and flavonoid (1.76 mg/g) contents, FRAP, TEAC, and DPPH compared to the other flours suggesting superior antioxidant capacity. Strong positive correlations (r >0.70) were found between IVPD and phytic acid for the protein isolate, total phenolic content, and FRAP for IEP and germinated flours. Overall, hempseed flours with diverse properties could be produced using non‐thermal processing.

Isotopic evidence of high reliance on plant food among Later Stone Age hunter-gatherers at Taforalt, Morocco.

The transition from hunting-gathering to agriculture stands as one of the most important dietary revolutions in human history. Yet, due to a scarcity of well-preserved human remains from Pleistocene sites, little is known about the dietary practices of pre-agricultural human groups. Here we present the isotopic evidence of pronounced plant reliance among Late Stone Age hunter-gatherers from North Africa (15,000-13,000 cal BP), predating the advent of agriculture by several millennia. Employing a comprehensive multi-isotopic approach, we conducted zinc (δ66Zn) and strontium (87Sr/86Sr) analysis on dental enamel, bulk carbon (δ13C) and nitrogen (δ15N) and sulfur (δ34S) isotope analysis on dentin and bone collagen, and single amino acid analysis on human and faunal remains from Taforalt (Morocco). Our results unequivocally demonstrate a substantial plant-based component in the diets of these hunter-gatherers. This distinct dietary pattern challenges the prevailing notion of high reliance on animal proteins among pre-agricultural human groups. It also raises intriguing questions surrounding the absence of agricultural development in North Africa during the early Holocene. This study underscores the importance of investigating dietary practices during the transition to agriculture and provides insights into the complexities of human subsistence strategies across different regions.

Metabolomic analysis of rumen-protected branched-chain amino acids in primiparous dairy cows

IntroductionPeripartal cows are susceptible to a negative energy balance due to inadequate nutrient intake and high energy requirements for lactation. Improving the energy metabolism of perinatal dairy cows is crucial in increasing production in dairy cows.MethodsIn this study, we investigated the impact of rumen-protected branched-chain amino acid (RPBCAA) on the production performance, energy and lipid metabolism, oxidative stress, and immune function of primiparous dairy cows using metabolomics through a single-factor experiment. Twenty healthy primiparous Holstein cows were selected based on body condition scores and expected calving date, and were randomly divided into RPBCAA (n = 10) and control (n = 10) groups. The control group received a basal diet from calving until 21 d in milk, and the RPBCAA group received the basal diet and 44.6 g/d RPLeu, 25.14 g/d RPIle, and 25.43 g/d RPVal.ResultsIn comparison to the control group, the supplementation of RPBCAA had no significant effect on milk yield and milk composition of the dairy cows. Supplementation with RPBCAA significantly increased the concentrations of insulin, insulin growth factor 1, glucagon, and growth hormones, which are indicators of energy metabolism in postpartum cows. The very low density lipoprotein, fatty acid synthase, acetyl coenzyme A carboxylase, and hormone-sensitive lipase contents of the RPBCAA group were significantly greater than that of the control group; these metrics are related to lipid metabolism. In addition, RPBCAA supplementation significantly increased serum glutathione peroxidase and immunoglobulin G concentrations and decreased malondialdehyde concentrations. Liquid chromatography–mass spectrometry (LC-MS) analysis revealed 414 serum and 430 milk metabolic features. Supplementation with RPBCAA primarily increased concentrations of amino acid and lipid metabolism pathways and upregulated the abundance of serotonin, glutamine, and phosphatidylcholines.DiscussionIn summary, adding RPBCAA to the daily ration can influence endocrine function and improve energy metabolism, regulate amino acid and lipid metabolism, mitigate oxidative stress and maintain immune function on primiparous cows in early lactation.

The TRAF3-DYRK1A-RAD54L2 complex maintains ACE2 expression to promote SARS-CoV-2 infection.

The expression of ACE2 is essential for the entry of SARS-CoV-2 into host cells. We identify a new complex-the TDR complex-that acts to maintain the abundance of ACE2 in host cells. The identification and characterization of the TDR complex provide new targets for the development of therapeutics against SARS-CoV-2 infection. By analysis of SARS-CoV-2 virus replicating in cells expressing low levels of ACE2, we identified mutations in spike (P1079T) and nucleocapsid (S194L) that overcome the restriction of limited ACE2. Functional analysis of these key amino acids in S and N extends our knowledge of the impact of SARS-CoV-2 variants on virus infection and transmission.

Analysis of carcass traits, meat quality, amino acid and fatty acid profiles between different duck lines

To investigate the effect of genetic selection on meat quality in ducks, twenty of each fast growth ducks (LCA) and slow growth ducks (LCC) selected from F6 generation of Cherry Valley ducks (♂) x Liancheng white ducks (♀) were analyzed for carcass characteristics, meat quality (physicochemical and textural characteristics), amino acid and fatty acid profiles at 7 wk. Results showed that live body weight, slaughter weight, eviscerated yield and abdominal fat percentage of LCA were significantly higher than those in LCC ducks (P < 0.01). Moreover, the average area and diameter of myofiber were larger in LCA than LCC ducks (P < 0.01). The breast and thigh muscles of LCA exhibited significantly lower water holding capacity and thermal loss compared with LCC ducks (P < 0.01). In addition, the content of nonessential amino acids (Glu, Asp, and Arg) in breast muscles and Asp, Ser, Thr, and Met in thigh muscles was higher in LCC than LCA ducks (P < 0.05). The proportion of polyunsaturated fatty acids (PUFA) in breast muscles of LCC was higher than LCA ducks (P < 0.05). However, the content of saturated fatty acids (SFA) in breast and thigh muscles of LCA was higher compared with LCC ducks (P < 0.05). The proportion of monounsaturated fatty acids (MUFA) in thigh muscles was significantly higher in LCC compared with LCA ducks (P < 0.01). Finally, multiple traits were evaluated by applying principal component analysis (PCA) and the results indicated that PUFA and SFA in breast muscles of LCA played important roles in meat quality, followed by Warner-Bratzler shear force (WBSF) and MUFA. However, water holding capacity (WHC) had a dominant effect in meat quality of thigh muscles in both LCA and LCC ducks.

Luteolin-incorporated fish collagen hydrogel scaffold: An effective drug delivery strategy for wound healing

In clinical practice, wound care has always been challenging. Hydrogels play a key role in facilitating active wound recovery by absorbing exudates, maintaining moisture, and alleviating pain through cooling. In this study, type I collagen was isolated from the skin of crucian carp (Carassius carassius) and verified by amino acid analysis, FTIR, and SDS-PAGE. By adopting a new approach, luteolin was added to collagen hydrogels in situ after being dissolved in an alkaline solution. XRD and SEM confirmed the luteolin was incorporated and entirely distributed throughout the hydrogel. The plastic compression improved the young's modulus of hydrogel to 15.24 ± 0.59 kPa, which is adequate for wound protection. The drug loading efficiency was 98 ± 1.47 % in the selected formulation. The luteolin-incorporated hydrogel enabled regulated drug release. We assessed the cytotoxicity using MTT and live-dead assays, as well as examined the hemocompatibility to determine the biocompatibility of the hydrogel. In vivo experiments showed that the hydrogel with luteolin had the highest wound closure rate (94.01 ± 2.1 %) and improved wound healing with granular tissue formation, collagen deposition, and re-epithelialization. These findings indicate that this efficient drug delivery technology can accelerate the process of wound healing.

Physiological high temperatures alter the amino acid metabolism of bovine early antral follicles.

Heat stress reduces the developmental competence of bovine oocytes during the growth phase; however, the detailed mechanisms remain unclear. Amino acids play various critical roles in follicular development, including protein synthesis and as energy sources. We performed in vitro growth (IVG) culture of oocyte-cumulus-granulosa complexes (OCGCs) to assess the amino acid metabolism of small follicles at high temperatures. We isolated OCGCs from early antral follicles (0.5-1.0 mm) and subjected them to IVG culture for 12 days. OCGCs in the heat shock group were cultured under a temperature cycle of (38.5°C: 5 h, 39.5°C: 5 h, 40.5°C: 5 h, and 39.5°C: 9 h) to reproduce the body temperature of lactating cows under a hot environment. OCGCs in the control group were cultured at a constant temperature of 38.5°C for 24 h. Of the surviving OCGCs, those showing similar morphology and size between the groups were selected for amino acid analysis. We analyzed the free amino acids and their metabolites in the culture medium and calculated the depletion or appearance of molecular species. The depletion of three essential amino acids (isoleucine, leucine, and valine), two non-essential amino acids (aspartic acid and glycine), and ornithine was higher in the heat shock group (P < 0.05). Alanine depletion was lower in the heat shock group (P < 0.05). We concluded that heat exposure alters the amino acid metabolism of OCGCs isolated from early antral follicles, which might be involved with the diminished developmental potential of oocytes during summer.

A micro-extraction/derivatization method for RP-HPLC-FLD analysis of amino acids in wild boar meat

Methods that are easy to use, spend small amounts of reagents, and have minimal human interference are precious tools in different areas. Sus scrofa is the wild animal most used in human diet, however, the knowledge about its protein fraction is still scarce. In this work, a method for 22 amino acids quantification was optimized and applied to the analysis of meat from animals of different ages and genders. The optimization of acid and basic hydrolyses reveal an ideal mass between 75 and 100 mg, with 3 mL of hydrolysis reagent, and 22 h for a maximum extraction of tryptophan. The hydrolysates were automatically derivatized using few µL, and the compounds were analyzed by reversed phase - high performance liquid chromatography with fluorescence detection. For comparison purposes, total protein was assessed, using the Kjeldahl method. The method showed high precision and accuracy, as well as very low limits of detection and quantification, with good potential to be applied to other animal meats. Significant differences were found between the amino acid profile of different animals (e.g. aspartic acid and taurine contents were slightly higher in juveniles than in adults).

Recent Advancement in the Fabrication of Colorimetric and Fluorometric Sensors for the Detection of Basic Amino Acids

Abstract:: Due to the biological importance of amino acids, the development of optical probes for these compounds has become a popular research topic in recent years. The amino acid fluorescence or colorimetric sensors are organized according to the reactions the amino acids go through and the related structural classification. Works on reaction-based chemosensors are categorized as either imine formation, Michael addition, thiazinane or thiazolidine formation, cleavage of a sulfonate ester, cleavage of a disulfide, metal complexes-displace coordination, or other mechanisms depending on the mechanisms between sensors and amino acids. Amino acids (AA), which comprise most proteins, are small molecules with a wide range of functional side-chain groups. Amino acids, therefore, have a variety of roles in physiological processes. Histidine (His), a member of this family, is required for tissue growth and repair as well as for weight gain. Lysine (Lys), another member of this family, is intimately linked to the Krebs-Henseleit cycle and polyamine synthesis, and an adequate amount of lysine in the diet is necessary for animals' metabolic processes and weight gain. Because it controls the transfer of metal elements in biological bases, tryptophan (Trp) is crucial to biological processes like protein synthesis, animal growth, and plant development. The majority of proteins are composed of amino acids (AA), which are tiny molecules with a variety of functional side chain groups. As a result, amino acids play a number of different roles in physiological processes. This family member's histidine (His) is necessary for weight gain, tissue growth, and repair. Another member of this family, lysine (Lys), is crucial for the Krebs-Henseleit cycle and polyamine production, and animals' metabolic activities and weight gain depend on appropriate lysine intake. Tryptophan (Trp) is an essential component of biological processes like protein synthesis, animal growth, and plant development because it regulates the transfer of metal elements in biological bases. Numerous attempts have been made to create new procedures for amino acid analysis as a result of the rising focus on human health, disease diagnosis, and therapy. Currently, spectroscopic, chromatographic, or electrochemical analytical methods are most frequently employed to identify and characterize amino acids. However, each method has certain disadvantages, such as the need for equipment and trained personnel, operational simplicity, analytical cost, test speed, and detection. Based on the important distinguishing characteristics of various amino acids to date, much research has been done on optical probes using indicator-displacement tests, metal complex coordination, particular interactions between probes and amino acids, and other techniques. We further subdivided the reaction-based probes into the following groups: production of imines, Michael addition, thiazinane or thiazolidine, cleavage of sulfonate ester, cleavage of disulfide, and others. Metal complexes-displace coordination. Due to some amino acids' similarity in structure and reactivity, it is still challenging to develop sensors that can selectively and sensitively identify amino acids from one another, such as the three biological thiols Cys, Hcy, and GSH. Specific reactions between probes and amino acids and other techniques have been extensively researched based on the significant characteristic features of diverse amino acids to date. We further divided the reaction-based probes into the following categories: metal complexes-displace coordination, imine creation, Michael addition, thiazinane or thiazolidine formation, cleavage of a sulfonate ester, cleavage of a disulfide; and others.

Resurgence of respiratory syncytial virus with dominance of RSV-B during the 2022-2023 season.

Respiratory syncytial virus (RSV) is a common cause of upper and lower respiratory tract infections. This study aimed to explore the prevalence of respiratory syncytial virus (RSV) and other respiratory viruses in Bulgaria, characterize the genetic diversity of RSV strains, and perform amino acid sequence analyses of RSV surface and internal proteins. Clinical and epidemiological data and nasopharyngeal swabs were prospectively collected from patients with acute respiratory infections between October 2020 and May 2023. Real-time PCR for 13 respiratory viruses, whole-genome sequencing, phylogenetic, and amino acid analyses were performed. This study included three epidemic seasons (2020-2021, 2021-2022, and 2022-2023) from week 40 of the previous year to week 20 of the following year. Of the 3,047 patients examined, 1,813 (59.5%) tested positive for at least one viral respiratory pathogen. RSV was the second most detected virus (10.9%) after SARS-CoV-2 (22%). Coinfections between RSV and other respiratory viruses were detected in 68 cases, including 14 with SARS-CoV-2. After two seasons of low circulation, RSV activity increased significantly during the 2022-2023 season. The detection rates of RSV were 3.2, 6.6, and 13.7% in the first, second, and third seasons, respectively. RSV was the most common virus found in children under 5 years old with bronchiolitis (40%) and pneumonia (24.5%). RSV-B drove the 2022-2023 epidemic. Phylogenetic analysis indicated that the sequenced RSV-B strains belonged to the GB5.0.5a and GB5.0.6a genotypes. Amino acid substitutions in the surface and internal proteins, including the F protein antigenic sites were identified compared to the BA prototype strain. This study revealed a strong resurgence of RSV in the autumn of 2022 after the lifting of anti-COVID-19 measures, the leading role of RSV as a causative agent of serious respiratory illnesses in early childhood, and relatively low genetic diversity in circulating RSV strains.

Integrate analysis of metabolome and transcriptome of three Fragaria × ananassa cultivars to stablish the non-volatile compounds of strawberry flavor

The flavor attribute of Fragaria × ananassa Duch. would decide consumers’ selection of preferred strawberry commercial cultivars. The roles of volatile compounds in strawberry aroma have been well-studied while knowledge regarding the non-volatile compounds is limited. Some non-volatile compounds which are involved in consumers preference of strawberry have been reported, contributions of non-volatile compounds for strawberry flavor remain ambiguous. This study explored the strawberry flavor influences of essential non-volatile compounds by comparing biosynthesis pathways of cultivars exhibiting distinct flavor characteristics. The widely targeted metabolome generated global profiles of three cultivars including 521 known non-volatile compounds. The differential accumulation analysis and precise quantification of soluble sugars, organic acids, polyphenols and free amino acids (FAAs) predicted fructose, citric acid, kaempferol and pelargonin-3-glucoside were key compounds involved in the sweetness, acidity and astringency of strawberries. Further, the conjoint analysis of metabolites and 824 differentially expressed genes revealed that flavonoid biosynthesis, phenylpropanoid metabolism and citrate cycle pathways decided the content difference of key flavor compounds. Within these pathways, several structure genes were predicted as potential regulators of organic acids, flavonoids and umami-taste FAAs. These findings would be helpful in identification of non-volatile compounds and genes responsible for strawberry flavor.

Multi-staged temperature control of the gelling properties and flavor quality of preserved eggs

The gelling properties and flavor quality of preserved eggs are affected by temperature reached during pickling. In response, this study investigates the effects of different temperature-controlled techniques on the gelling properties and flavor quality of preserved eggs. The results show that compared with an overall constant temperature and a two-stage temperature-controlled technique, the P-12-18-30 °C three-stage temperature-controlled pickling model produced the best texture properties of the preserved egg white gel, as further verified by LF-NMR and SEM analysis. The results of amino acid analysis also show that the taste intensity of free amino acids in the P-12-18-30 °C group was significantly increased, especially for umami amino acids. In addition, the results of the electronic noise show that the volatile components of preserved eggs subjected to different temperature-controlled pickling techniques were similar, mainly consisting of short-chain alkanes; alcohols, aldehydes, ketones, and some aromatic compounds; long-chain alkane aliphatic groups; and inorganic sulfides, and there was no significant difference in the content of each flavor substance. In conclusion, this study offers theoretical basis for temperature-controlled pickling of preserved egg with better gel quality.

Effect of Different Cooking Methods on the Aroma and Taste of Chicken Broth.

A single combi oven, known for its versatility, is an excellent choice for a variety of chicken soup preparations. However, the impact of universal steam ovens on the flavor quality of chicken soup remains unclear. This study aimed to explore the impact of different cooking methods on the aroma and taste of chicken soup. Three cooking methods with various stewing times were compared: ceramic pot (CP), electric pressure cooker (EPC), and combi oven (CO). Analyses were conducted using electron-nose, electron-tongue, gas chromatography-ion mobility spectrometry (GC-IMS), automatic amino acid analysis, and chemometric methods. A total of 14 amino acids, including significant umami contributors, were identified. The taste components of CP and CO chicken soups were relatively similar. In total, 39 volatile aroma compounds, predominantly aldehydes, ketones, and alcohols, were identified. Aldehydes were the most abundant compounds, and 23 key aroma compounds were identified. Pearson's correlation analyses revealed distinct correlations between various amino acids (e.g., glutamic acid and serine) and specific volatile compounds. The aroma compounds from the CP and CO samples showed similarities. The results of this study provide a reference for the application of one-touch cooking of chicken soup in versatile steam ovens.

Enhanced dietary reconstruction of Korean prehistoric populations by combining δ13C and δ15N amino acids of bone collagen.

Compound specific stable isotope analysis of amino acids (CSIA-AA) is a powerful tool for determining dietary behaviors in complex environments and improving dietary reconstructions. Here, we conducted CSIA-AA on human (n = 32) and animal (n = 13) remains from two prehistoric archaeological sites (Mumun, Imdang) to assess in more detail the dietary sources consumed by prehistoric Korean populations. Results of estimated trophic position (TP) using Δ15NGlx-Phe show that the Imdang individuals consumed aquatic resources, as well as terrestrial resources. Principal component analysis (PCA) using δ13C and δ15N essential amino acid (EAA) values show that the Imdang humans closely cluster with game birds and terrestrial herbivores, whilst the Mumun humans closely cluster with C4 plants. Quantitative estimation by a Bayesian mixing model (MixSIAR) indicates that the Imdang humans derived a large proportion of their proteins from terrestrial animals and marine fish, whereas the main protein sources for the Mumun humans were C4 plants and terrestrial animals. Additionally, the comparison between the EAA and bulk isotope models shows that there is a tendency to overestimate the consumption of plant proteins when using bulk isotopic data. Our CSIA-AA approach reveals that in prehistoric Korea there were clear differences in human diets through time. This study adds to a growing body of literature that demonstrates the potential of CSIA-AA to provide more accurate estimations of protein consumption in mixed diets than previous bulk isotopic studies.

Effects of Heating Treatment on the Physicochemical and Volatile Flavor Properties of Argentinian Shortfin Squid (Illex argentinus).

In this study, the effect of different heating temperatures (80, 90, 100, and 121 °C) on the physicochemical and volatile flavor properties of fried mantles (Argentinian shortfin) was investigated. The squid mantles were soaked in a maltose syrup solution (20% w/v) for 10 s and fried in soybean oil for 10 s (160 °C), vacuum-packed, and processed at different temperatures for 10 min. Then, the squid mantles were subjected to colorimetric analysis, sensory evaluation, free amino acid analysis, and texture profile analysis. In addition, the volatile organic compounds (VOCs) in the squid mantles were analyzed. The results revealed that lower treating temperatures (80 and 90 °C) improved the chromatic and textural properties, along with organoleptic perception. Additionally, the content of amino acid in the squid mantles treated at 121 °C was significantly lower than that of the samples treated at other temperatures (p < 0.05). Headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) was used to detect 41 VOCs, including their monomers and dimers. Among these detected VOCs, the contents of alcohols, ketones, and pyrazines were positively correlated with temperature. However, the content of aldehydes in the squid mantles gradually decreased as the heating temperature increased (p < 0.05). The combined HS-GC-IMS and E-nose results revealed that the lower temperatures (80 and 90 °C) were more suitable for flavor development and practical processing. This study provides valuable information for properly controlling the heating process of squid products, as well as flavor and practical applications for the aquatic industry.

Metabolomic Analysis of Amino Acid and Organic Acid Profiles in Tissue From Ovarian Cancer Patients Using High-Performance Liquid Chromatography-Tandem Mass Spectrometry (HPLC-MS/MS) and Gas Chromatography-Tandem Mass Spectrometry (GC-MS/MS)

Targeted metabolomics studies on organic acids (OAs) and amino acids (AAs) were performed to search for biomarkers for ovarian cancer progression. Simultaneous AA profiling analysis method was developed through LC-MS/MS. Under optimal conditions, method showed good linearity (r ≥ 0.998) with limits of detection (LOD) ≤ 0.22 ng/mL and limits of quantification (LOQ) of ≤0.72 ng/mL. Repeatability varied from 1.4 to 17.3 relative standard deviation (%RSD) and accuracy varied from −20.6% to 12.1% relative error (% RE). Twenty-six AAs and 13 OAs were detected in the analyses of ovarian tissue from patients with benign ovarian tumors (BOT), borderline tumors (BT), and ovarian serous carcinoma (OSC). Star pattern recognition analysis was performed by normalizing each group to the BOT group. The star symbol plots in the BT and OSC groups were distinct and easily distinguished from those in the BOT group. The BT and the OSC groups exhibited higher 3-hydroxybutyric acid and lactic acid levels, lower pyruvic acid and OA levels in the TCA cycle, and alterations in AA metabolic patterns in comparison to the BOT group. Especially, citrulline and leucine were significantly reduced, while fumaric acid and malic acid significantly increased in the OSC group compared to the BT group. The BT and the OSC groups were completely separated in orthogonal partial least squares-discriminant analysis (OPLS-DA) and heatmap analysis. These findings, elevated ketone body levels, increased anaerobic glycolysis, reduced energy production related to mitochondrial dysfunction in the TCA cycle, and AA metabolic patterns associated with the impaired antioxidant system, may explain the characteristic metabolic reprogramming and Warburg effect related to the progression of the OSC into malignancy.

Sustainable valorization of protein-rich tannery saline wastewater: Protein hydrolysate synthesis via protease and Fe3O4 porous carbon catalyst

The objective of the current study is to produce valuable protein hydrolysates (PHs) by fragmenting the proteins in protein-rich tannery wastewater (TANWWpro) through a protease-immobilized nanoporous carbon catalyst (PNPCC). The protease was isolated from the microorganism Lysinibacillus fusiformis MR1 and it contains 385 U/mL of proteolytic activity. For the immobilization of protease onto PNPCC, the ideal conditions were 2 h, pH 6–8, and 30–40 °C. FTIR, TGA, DSC, and XRD analyses were used to evaluate the protease immobilization on AGF-NPCC. For protein fragmentation, the appropriate pH, which was determined at 6, the ideal duration and temperature of 120 min at 30 °C as well as the required quantity of PNPCC were optimized. HPLC-free amino acid analysis has been used to validate the generation of PHs from TANWWpro, while electroanalytical methods including impedance spectroscopy and cyclic voltammetry have been used to establish their varied redox characteristics. Furthermore, PHs were extracted by using a Fe3O4- impregnated nanoporous carbon catalyst (Fe3O4-NPCC) and the SEM images verified the impregnation of Fe3O4 onto NPCC. Overall, employing the PNPCC and Fe3O4-NPCC, the generation and extraction of PHs from TANWWpro were both performed effectively.

Comparative Study of Carcass Characteristics and Meat Quality of Local Mediterranean Donkey Breeds.

This study aimed to evaluate carcass and meat quality traits in Masri (n = 14) and North African (n = 14) male donkeys, raised in a semi-intensive breeding system, grazing on mountainous areas, with supplementation of 1 kg of barley per day per animal, slaughtered at 5 (±0.48) years old. Compared to Masri, the North African population exhibited higher (p < 0.05) final body weights (181.7 ± 2.1 and 212.5 ± 7.6 kg) and cold carcass weights (101.7 ± 1.3 and 116.2 ± 4.5 kg), but lower (p < 0.05) cold dressing percentages (56.0 ± 0.4 and 54.6 ± 0.4%). Meat quality analyses showed higher (p < 0.05) cooking loss values in Masri meat (43.9 ± 0.8 vs. 39.9 ± 1.2%). Among the meat color parameters, the hue value was higher (p < 0.05) in North African samples (0.42 ± 0.01 vs. 0.39 ± 0.1). Meat from North African donkeys had higher (p < 0.05) dry matter, fat, and protein contents. Meat amino acid analysis revealed abundant levels of lysine, leucine, and methionine, in both populations. Donkey meat from both populations presented a high polyunsaturated fatty acids content, resulting in polyunsaturated fatty acids/saturated fatty acids and omega 6/omega 3 ratios for all breeds close to the recommended values for human health. Atherogenic and thrombogenic indices were also suggested to have positive effects on consumers' artery health. The characteristics of donkey meat present intriguing nutritional aspects compared to ruminant meat, and its production should be encouraged in the rural development of inner-Mediterranean areas.