Amino Acid Profile Research Articles

Nutritional properties of commercially important cephalopods from the south-west coast of India

Cephalopods are widely regarded as healthy and nutritionally rich seafood resources. This study focuses on analysing the nutritional composition of six commercially important edible cephalopod species viz., Cistopus indicus, Amphioctopus marginatus, Amphioctopus aegina, Sepia pharaonis, Sepia elliptica and Sepia aculeata, from the Malabar coast of the Indian peninsula. The selected cephalopods were determined to be a rich source of protein ranging from 12.41 to 19.02 g 100 g-1. The amino acid profile demonstrated a balanced ratio of essential to non-essential amino acids (0.93-1.63) with a higher concentration of essential amino acids, attributing enhanced biological value of proteins in these cephalopods. S. pharaonis recorded the highest arginine-to-lysine ratio (~1.77), indicating excellent cholesterolemic index. Notably, octopus species had the lowest total cholesterol content (~100 mg 100 g-1) compared to cuttlefish species which recorded higher cholesterol levels (~160 mg 100 g-1). A. marginatus recorded more significant quantities of polyunsaturated fatty acids (PUFA) (36.85% total fatty acids) among all the species studied. Octopus species exhibited significantly greater Σn-3/Σn-6 ratio than cuttlefish species. The ideal atherogenicity/thrombogenicity indices (<1.0) in the edible tissues of the studied cephalopods qualify these species as potentially healthy food. A. aegina was found to exhibit greater vitamin E (α-tocopherol) contents (17.84 IU), whereas ascorbic acid was pronounced more in A. marginatus (47.06 μg 100 g-1). The higher vitamin D3 content in A. aegina (96.23 μg 100 g-1) among the species studied, highlights its potential role in preventing osteoporosis in adults. Among microelements such as iron and zinc were found in significant quantities in the cephalopod species studied. The findings from the current study provide valuable insights into the nutritional benefits of these species, positioning them as promising candidates for the seafood industry as possible healthy dietary options. Keywords: Amino acid composition, Atherogenicity index, Cephalopods, Fatty acid composition, Thrombogenicity index

Fractionation, characterization, and assessment of nutritional and immunostimulatory protein-rich polysaccharide-protein complexes isolated from Lentinula edodes mushroom

This study aimed to fractionate and characterize the protein-rich polysaccharide-protein (PSP) complexes from a well-known edible mushroom, Lentinula edodes, and assess their nutritional and immunostimulatory properties. Crude PSP isolated from the mushroom water extract was purified by anion exchange chromatography, yielding fractions PSP-F1 and PSP-F2 containing 66.1 % and 74.0 % protein, respectively. Both fractions exhibited primarily β-sheet and random-coil protein structures, though the crude PSP fraction exhibited an additional α-helix structure. On SDS-PAGE, PSP-F1 showed two molecular weight bands, one below 10 kDa and another at 34 kDa, and PSP-F2 showed several bands, one below 10 kDa and others between 34 and 95 kDa. The nutritional value of essential and non-essential amino acid profiles was in the order of PSP-F2 > PSP-F1 > crude PSP; the amino acid ratio coefficient values of the crude PSP, PSP-F1, and PSP-F2 were 63 %, 67 %, and 72 %, respectively. The combination of PS and PSP fractions exhibited stronger immunoactivity than PSP-F1 or PSP-F2 alone. PSP-F2 showed a higher immunostimulatory activity than PSP-F1 in RAW264.7 cell culture. PSP-F2 was also more abundant of easily absorbed high-quality proteins. The results provide useful references for dietary and medicinal uses of PSP fractions in L. edodes and other edible mushrooms.

Study of the jellyfish Rhizostoma pulmo hydrolysis and characterization of the obtained product

The purpose of this work is to develop technological parameters for the hydrolysis of barrel jellyfish Rhizostoma pulmo involving the use of enzymatic agents «Enzy-mix» and alcalase, available through the domestic market, as well as to investigate the amino acid and mineral composition of the resultant hydrolysate.Methods used: the process of hydrolysis has been assessed based on the changes in peptide concentrations in the hydrolysate, the content of amino nitrogen, and the degree of hydrolysis. To investigate its chemical, amino acid, and mineral composition, the standard methods were used. Novelty: the use of jellyfish for hydrolysis after its thawing and the hydrolysis procedure not involving the addition of water into the raw material subjected to hydrolysis present a novel approach.Result: the optimal regime for hydrolysis of barrel jellyfish Rh. pulmo after its thawing has been identified, which was characterized by the use of 1% alcalase at the temperature 55±2 °C and duration of 1 h. It has been shown that alcalase is more effective in terms of amino nitrogen accumulation than enzymatic agent «Enzy-mix». The values of amino nitrogen after 1 h of hydrolysis involving the use of 1% alcalase were higher than the values of the same parameter obtained during the 3-hour hydrolysis involving 1.5% «Enzy-mix» at the temperature 40±2 °C. The hydrolysate, after its concentration to the dry matter exceeding 30%, contains no less than 15.1±0.59% of protein represented by 48% of essential amino acids, out of which leucine and isoleucine prevail (15 %). Among non-essential amino acids, the most prominent was glycine (17 %). For all essential amino acids, except for valine, the amino acid score exceeds 100%. In humans, consumption of around 20 g of the hydrolysate covers the daily physiological requirement of magnesium.Practical significance: the obtained data on the amino acid profile and mineral composition of the barrel jellyfish Rh. pulmo hydrolysate provide the basis for its consideration as a promising ingredient for the functional nutrition products.

Assessment of the effect of lactic acid bacteria fermentation on IgE-/IgG-binding ability and nutritional properties of cow milk.

Cow milk (CM) is an important food source for humans, and food allergy caused by CM has attracted attention worldwide. To our knowledge, systematic studies about the effects of Lactobacillus paracasei, Lactobacillus plantarum, and Pediococcus pentosaceus on the IgE-/IgG-binding ability and nutritional properties of CM are very rare. In this study, L. paracasei, L. plantarum, and P. pentosaceus fermentation on the IgE-/IgG-binding ability was determined by Enzyme-Linked Immunosorbent Assay (ELISA), and the protein quality, amino acid profile, and color were systematically evaluated. The results showed that these LAB strains exhibited higher protein degradation ability, and the IgE reactivity reduction rate was 41.03%-60.00% and the IgG reduction rate was 29.86%-67.20%, respectively. Additionally, the nutritional value was improved obviously, and the color was altered significantly, which was conductive to develop dairy products. These findings provided a theoretical foundation for the development of hypoallergenic dairy products. PRACTICAL APPLICATION: In this study, L. paracasei, L. plantarum and P. pentosaceus could be considered as good potential candidates for solving cow milk allergy owing to their decreased IgE/IgG binding ability andimproved nutritional and sensory properties, which provide a promising strategy to develop hypoallergenic dairy products.

Impact of alkaline solution, carbohydrase and biomass:solvent on extraction efficiency, and protein and amino acid profiles of Palmaria palmata protein extracts

The impact of using different alkaline solutions, carbohydrases and changing the biomass to solvent volume ratio (biomass:solvent) on protein content, protein and biomass yield recovery in protein enriched extracts from Palmaria palmata (red seaweed) was studied. Protein extraction with alkaline solutions, i.e., NaOH, KOH, Ca(OH)2 and Na2CO3 (at 0.12 M) along with (and without) carbohydrases B, BD and L (containing xylanase, a mixture of xylanase and cellulase, and a combination of cellulase, xylanase and polygalacturonase activities, respectively) was assessed. Principal component analysis was used to assess correlations (if any) between the different alkaline solvents, carbohydrases and changing biomass:solvent on extraction efficiency. The highest protein content (56.64 ± 0.43 % (w/w)) was obtained using KOH assisted extraction with carbohydrase BD. The highest protein and biomass yield recoveries (70.65 ± 1.38 and 21.99 ± 0.43 % (w/w), respectively) were obtained on extraction using NaOH assisted with carbohydrases BD. Electrophoretic, amino acid profile and amino acid score analyses displayed differences depending on the alkaline solvent used for protein extraction. Appropriate selection of the alkaline solvent, carbohydrase and biomass:volume combination during protein extraction can contribute to the production of compositionally enhanced high-quality protein concentrates from P. palmata.

Heritability and Genetic Correlations of Carcass and Meat Quality Traits in White and Brown Strains of Japanese Quail

Successful breeding programs for Japanese quails rely on accurately estimating genetic parameters linked to economically important traits such as body weight, carcass characteristics, and meat quality. The objective of the present study was to evaluate body weight (BW) characteristics, carcass attributes, and their genetic correlations with select meat quality traits in two strains of Japanese quail (white and brown). A total of 530 quail chicks, with 265 from each strain, were included in the analysis. At six weeks of age, the quails were slaughtered, and carcass traits as well as amino acid profiles were measured. For BW traits, the heritability (h2) estimates ranged from 0.27 at d 1 to 0.36 at d 42. The h2 estimated for carcass traits ranged from 0.19 for liver weight, to 0.42 for carcass yield (CY). The h2 estimated for drip loss (DL) of meat quality was 0.21, and the h2 estimate was 0.35 for the meat's ultimate Ph (Phu). White quail quails recorded the heaviest weight of all carcass traits. Also, white quails had the highest water-holding capacity (WHC), yellowness (b*), and lightness (L*) with the lowest level of DL, cooking losses (CL), and redness (a*) in muscles compared with brown quails. A high genetic correlation of 0.32 was noted between CW carcass weight (CW) and b*. For the pHU, a negative correlation of -0.11 was exhibited with BW. In contrast, L* appeared to have a positive but smaller relationship with CW and CY. High negative correlations were noted for b* with BW and CY -0.24 and -0.27, respectively. The CW showed a moderate relationship (0.19) with CL. In conclusion, the current study revealed that the white quail strain had high BW, as well as the finest carcass traits and meat quality. Therefore, white plumage Japanese quail might be preferred as a meat-producing strain. Keywords: Amino acid, Carcass, Genetic correlation, Meat quality, Heritability, Quail

An Expedited Qualitative Profiling of Free Amino Acids in Plant Tissues Using Liquid Chromatography-Mass Spectrometry (LC-MS) in Conjunction With MS-DIAL.

The estimation of relative levels of amino acids is crucial for understanding various biological processes in plants, including photosynthesis, stress tolerance, and the uptake and translocation of nutrients. A wide range of liquid chromatography (LC; HPLC/UHPLC)-based methods is available for measuring the quantity of amino acids in plants. Additionally, the coupling of LC with mass spectrometry (MS) significantly enhanced the robustness of existing chromatographic methods used for amino acid quantification. However, accurate annotation and integration of mass peaks can be challenging for plant biologists with limited experience in analyzing MS data, especially in studies involving large datasets with multiple treatments and/or replicates. Further, there are instances when the experiment demands an overall view of the amino acids profile rather than focusing on absolute quantification. The present protocol provides a detailed LC-MS method for obtaining a qualitative amino acids profile using MS-DIAL, a versatile and user-friendly program for processing MS data. Free amino acids were extracted from the leaves of control and Tomato leaf curl Palampur virus (ToLCPalV)-infected Nicotiana benthamiana plants. Extracted amino acids were derivatized and separated using UHPLC-QTOF, with each amino acid subsequently identified by aligning mass data with a custom text library created in MS-DIAL. Further, MS-DIAL was employed for internal standard-based normalization to obtain a qualitative profile of 15 amino acids in control and virus-infected plants. The outlined method aims to simplify the processing of MS data to quickly assess any modulation in amino acid levels in plants with a higher degree of confidence.

Amino Acid Content in the Muscles of the Red Deer (Cervus elaphus) from Three Types of Feeding Grounds

This study aimed to analyze the amino acid profile, with a particular focus on the nutritional value of the protein of the longissimus lumborum (LL) and the semimembranosus (SM) muscles of deer originating from three feeding grounds: forest (FFG); conventional (CFG) grounds; organic farm (OFG). This is the first time that deer from an organic farm feeding ground have been included in this study. The muscles were collected from 36 deer carcasses with equal proportions of sex and 31 months of age. This study demonstrated significantly higher essential amino acid (EAA) and non-essential amino acid (NEAA) contents in the muscles of deer from the FFG and CFG compared to the OFG. However, the EAA-to-NEAA ratio was significantly higher for the muscles of deer from the OFG. The muscles of the FFG and CFG deer were characterized by a higher concentration of lysine as well as acidic and tasty amino acids compared to the OFG deer, with the muscles of the latter exhibiting a higher percentage of branched-chain amino acids (BCAA). The results obtained can be used professionally by nutrition specialists in preventive and therapeutic diets and breeders to make decisions about farm location and deer feeding strategies.

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.

Uncovering cocoa shell as a safe bioactive food ingredient: Nutritional and toxicological breakthroughs

This work aimed to analyze the chemical composition of the cocoa shell flour (CSF) and aqueous extract (CSE) and conduct acute and sub-chronic toxicity assays to ensure safety. CSF was composed of 59.1 % dietary fiber, primarily insoluble fiber (48.1 %). CSE consisted entirely of soluble fiber (72.8 %), mainly pectic polysaccharides. The amino acid profile revealed CSF's potential as a high-quality plant protein source, whereas CSE was rich in free amino acids, especially leucine, valine, and alanine (59.6–62.5 mg 100 g−1). Higher levels of macroelements, especially potassium, were found in CSE. Silicon was the most abundant microelement, and heavy metal levels were within acceptable limits for both cocoa shell matrices. This study confirmed the bioactive potential of CSF and CSE, enriched in phenolic compounds and methylxanthines, including theobromine, caffeine, gallic acid, (+)-catechin, as well as N-phenylpropenoyl-l-amino acids. The high theobromine content in both matrices, especially in CSE (2605.3 mg 100 g−1), did not harm the mice's health; acute and sub-chronic toxicity studies demonstrated the safety of oral administration of CSF and CSE in mice, showing no lethality or remarkable histopathological changes. This research supports the safe use of CSF and CSE, establishing these ingredients as suitable for incorporation into food products.

Valorization of the solid fraction of wine lees through optimized accelerated autolysis: Effect of temperature, pH and solid concentration on free-amino acid concentration

Winemaking, as an agro-industrial process, generates substantial amounts of by-products, notably grape pomace and wine lees. The latter constitutes the residue left behind during the racking or bottling of wine, consisting mainly of dead yeast cells, ethanol, phenolic compounds, tartrates, and other compounds. Within the framework of by-products’ valorization, the rich content of dead yeast cells in wine lees render them conducive to the production of a yeast extract substitute through autolysis. In the present study, the effect of pretreatment, temperature, pH, and solid concentration on the efficiency of white wine lees autolysis was investigated. Moreover, the effect of enzyme addition and dynamic thermal protocols were investigated. Efficiency assessment was based on the increase of free α-amino nitrogen (FAN) found in the autolysate. The finding revealed a significant increase of FAN in all cases, with treated and untreated white wine lees reaching a maximum increase of 477% and 834%, respectively. Furthermore, the amino acid profile of autolysates was significantly affected by the autolysis temperature. These results hold promise for the comprehensive, holistic valorization of wine lees, suggesting their potential use as a nutrient source for microorganisms, such as wine yeast, or even as a grape must nitrogen modulator. Consequently, this by-product can be integrated back into the same industrial process from which it originates, namely winemaking. This not only aligns with the principles of circular economy but also underscores the potential for sustainable development within wineries.

Targeted metabolomics of muscle amino acid profles and hepatic transcriptomics analyses in grass carp (Ctenopharyngodon idellus) fed with broad beans

While tissue amino acid compositions reflect that of the dietary protein source, and the liver orchestrates amino acid metabolism. In this study, we investigated the muscle amino acid profiles in ordinary and crisp grass carp. The 22 amino acids were measured, and seventeen showed significant concentration differences. To understand the molecular mechanisms behind changes, we analyzed the liver transcriptome, and the 2519 differentially expressed genes (DEGs) were identified, with 1156 up-regulated and 1363 down-regulated genes. DEGs were enriched in ribosome-related biological processes. KEGG pathway analysis showed enrichment in tryptophan metabolism, lysine degradation, valine, leucine and isoleucine degradation, galactose metabolism, and glutathione metabolism with up-regulated genes, arginine and proline metabolism, arginine biosynthesis and alanine, aspartate, amino sugar and nucleotide sugar metabolism, N-Glycan biosynthesis and glutamate metabolism with down-regulated genes. A protein-protein interaction network with 260 nodes and 249 edges was constructed, and 3 modules were extracted. The top 10 hub genes with close connections to other nodes were ITM1, STT3B, SEL1L, UGGT1, MLEC, IL1B, ALG5, KRTCAP2, NFKB2, and IRAK3. In summary, this study identified candidate genes and focused on amino acid and glycan metabolism pathways, providing a reference for further investigation into liver amino acid metabolism in grass carp fed with broad beans.

Discarded blue mussel (Mytilus edulis): a feed ingredient that maintains growth performance of juvenile gilthead seabream (Sparus aurata) while fishmeal and fish oil are removed

ABSTRACT The total substitution of fishmeal (FM) and fish oil (FO) with sustainable feed ingredients, while maintaining acceptable growth performances and fish composition, is a challenge. Mussels have a high protein content, with essential amino acid and fatty acid (FA) profiles similar to those of FM. This study aimed to assess the potential to rear gilthead seabream (Sparus aurata) on a plant-based feed (without FM and FO) to which mussels were added. Subsequent effects on growth performance, protein content, and FA concentrations were studied. Juvenile gilthead seabream were reared for 46 days in water temperature of 21°C, in a recirculated aquaculture system composed of three fish tanks, each corresponding to one treatment: in the FMFO treatment, 342 fish were fed a commercial feed that contained FM and FO; in the plant-based feed (PBF) treatment, 345 fish were fed an experimental feed that contained only plant-based ingredients; in the mussel feed (MF) treatment, 342 fish were fed the feed from PBF supplemented with fresh mussel flesh from which the shells had been removed. Fish weighed a mean of 6.7 ± 1.3 g at stocking in each treatment. At harvest, the mean weight of fish from FMFO and MF were significantly different (23.1 ± 4.3 and 23.1 ± 5.2 g, respectively) than that from PBF (15.5 ± 3.6 g) (p < .05). Compared to the feed from FMFO, the feed from PBF decreased the percentages of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and saturated FA (14:0, 16:0) in fish, but increased those of 18:1, 18:2 n-6 and 18:3 n-3 FA. Compared to the feed from PBF, the feed from MF increased the EPA+DHA concentration in fish by 21%. Thus, adding fresh mussels to a plant-based feed yielded similar growth performances and survival rate as a commercial feed. It also improved the FA composition of fish compared to that of fish fed a plant-based feed.

Authentication of porcine, bovine, and fish gelatins based on quantitative profile of amino acid and chemometric analysis

Gelatin is a biological macromolecule derived from the partial hydrolysis of collagen protein. This paper describes a sensitive and rapid method for the detection of gelatin sources based on the composition of amino acids. Hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry (HILIC-MS/MS) and chemometric tools such as principle component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were used for the analysis and spectral classification, respectively. Twenty amino acids are identified and quantified with the limit-of-detection (LOD) of 0.03–2.62 μg/mL and limit-of-quantification (LOQ) of 0.10–7.93 μg/mL, a precision of 0.19–11.21% and 0.03–13.62% (%RSD) for intra and inter-day, respectively, and a total recovery of 85.1–107.6%. Porcine gelatin showed correlation with glycine, proline, hydroxyproline, tyrosine glutamine, and glutamic acid; Bovine gelatin was correlated with lysine, leucine, and isoleucine histidine, phenylalanine, and alanine, and fish gelatin showed correlation with methionine, threonine, serine arginine and cysteine in PCA analysis. Verification of the developed method was confirmed by using different commercial and laboratory prepared gelatin products containing gelatin and the samples were successfully categorized into their respective sources.

Hepatic and extrahepatic metabolic modulation in hbv-related decompensated cirrhosis and acute-on-chronic liver failure

ABSTRACT Acute-on-chronic liver failure (ACLF) and decompensated cirrhosis (DC) are life-threatening syndromes that can develop at the end-stage of chronic hepatitis B virus (HBV) infection. Both ACLF and DC are complicated by hepatic and extrahepatic pathogeneses. To better understand the compartment-specific metabolic modulations related to their pathogenesis, HBV-DC, HBV-ACLF patients, and controls (30 each) were analyzed by metabolomics using portal (Port), hepatic vein (Hep), and peripheral (Peri) serum. Compartment ratios of metabolites (RatioHep/Port, RatioPeri/Hep, and RatioPort/Peri) were calculated. The liver tissues (10 per group) were analyzed using transcriptomics and metabolomics. An additional 75 patients with ACLF, 20 with DC, and 20 with liver cirrhosis (LC) were used to confirm oxlipid dysregulation. Both multi-omics datasets suggest suppressed energy, amino acid, and pyrimidine metabolism in the ACLF/DC liver. The serum metabolomic variations were contributed primarily by disease rather than sampling compartments, as both HBV-ACLF and HBV-DC patients demonstrated abnormal profiles of amino acids and peptides, indoles, purines, steroids, and benzimidazoles. In ACLF/DC patients, impaired hepatic metabolism resulted in a highly correlated hepatic and portal vein serum metabolome and release of inflammatory lipids and heme metabolites from the liver. HBV-ACLF showed higher RatioPeri/Hep of extrahepatic inflammatory oxlipids, while HBV-DC patients showed higher RatioPort/Peri of gut microbial metabolites. An inflammatory oxlipid outburst was confirmed in the early stages of HBV-ACLF. The inflammatory effects of the selected oxlipids were confirmed in monocytes. These findings support a synergy between liver-specific mechanisms and systemic inflammation in ACLF/DC development, and that pro-inflammatory oxlipids are metabolic signatures of early HBV-ACLF.

Combatting stunting: The vital role of animal protein in early childhood nutrition

Stunting is a global issue that significantly affects the quality of human resources and a nation's future competitiveness. Therefore, this study aimed to explore the role of animal protein in preventing stunting in early childhood using an exploratory approach. The procedures were carried out using a qualitative descriptive design by conducting a literature review and collecting secondary data. The results showed that animal foods (eggs, milk, and meat) contained bioactive compounds and essential amino acid profiles (valine, leucine, isoleucine, phenylalanine, tryptophan, lysine, histidine, methionine, and threonine), indicating the ability to provide the required nutrients and prevent stunting. In addition, optimizing nutrition in the first 1000 days of life starting from the conception phase until the age of 2 years by consuming a variety of nutritious foods containing animal protein at every meal was expected to prevent the condition. The results also revealed that providing sufficient animal foods that were physically and economically accessible to all individuals in society was a major challenge. Therefore, efforts were needed from the government to realize the goal of reducing stunting in Indonesia. Keywords: Stunting, Early Childhood, Animal Foods, Protein

Extraction and characterisation of gelatine from yellowfin tuna skin pretreated with a eutectic solvent

The accumulation and management of waste generated during the processing of seafood products is one of the major current challenges in the fishery industry. Among these residues, fish skin stands out for its high collagen content, from which high-quality gelatine can be obtained. However, conventional methods for gelatine extraction are time-consuming and complex processes that involve the use of strong acidic and alkaline solutions, leading to serious environmental concerns. This research studied the use of a eutectic solvent, formed by two safe and environmentally friendly compounds such as sodium acetate trihydrate and urea, to pretreat the skin of yellowfin tuna before the extraction of gelatine. Two different times of pretreatment were tested, and the subsequent extraction was carried out in warm water, resulting in much higher yields of gelatine (0.3 g/g wet fish skin) than previous studies. Additionally, using FT-IR analysis and amino acid profiling, it was observed that the pretreatment time did not significantly affect the structure or composition of the gelatine. However, some variation was found in its molecular weight distribution and therefore in its rheological properties: with an increase in the pretreatment time, both the molecular weight and the storage modulus of the gel also increased, as well as the gelation and melting temperatures. This contribution offers a simplified process that reduces environmental impact and provides the opportunity to tailor the final product.

The Use of Horse and Donkey Meat to Enhance the Quality of the Traditional Meat Product (Kaddid): Analysis of Physico-Chemical Traits.

The aim of this study was to evaluate the use of horse and donkey meat in the production of kaddid-a traditional dish typically not made with these meats-from a physical and chemical perspective. The results showed that both meats exhibit similar water retention during cooking, contributing to comparable tenderness and juiciness, with no significant differences in pH values, indicating similar quality (p > 0.05). However, their amino acid profiles differ: horse meat contains lower levels of glutamate (p < 0.05), methionine (p < 0.01), isoleucine (p < 0.05), and leucine (p < 0.05), but higher levels of proline (p < 0.05), histidine (p < 0.01), and lysine (p < 0.001) compared to donkey meat. Both meats provide essential amino acids. Horse meat is richer in saturated and monounsaturated fatty acids (32.44% and 39.58%, respectively), while donkey meat has a higher content of polyunsaturated fatty acids (31.51%), with a more favorable PUFA/SFA ratio, suggesting better cardiovascular health benefits. In terms of dried meat, donkey kaddid has a higher protein (17.45 g/100 g) and lower fat content (2.1 g/100 g) compared to horse kaddid (16.7 g/100 g, and 3.5 g/100 g, respectively) (p < 0.05). These findings inform consumer choices and production practices, promoting the use of horse and donkey meat for kaddid production.

Antioxidative, Glucose Management, and Muscle Protein Synthesis Properties of Fish Protein Hydrolysates and Peptides.

The marine environment is an excellent source for many physiologically active compounds due to its extensive biodiversity. Among these, fish proteins stand out for their unique qualities, making them valuable in a variety of applications due to their diverse compositional and functional properties. Utilizing fish and fish coproducts for the production of protein hydrolysates and bioactive peptides not only enhances their economic value but also reduces their potential environmental harm, if left unutilized. Fish protein hydrolysates (FPHs), known for their excellent nutritional value, favorable amino acid profiles, and beneficial biological activities, have generated significant interest for their potential health benefits. These hydrolysates contain bioactive peptides which are peptide sequences known for their beneficial physiological effects. These biologically active peptides play a role in metabolic regulation/modulation and are increasingly seen as promising ingredients in functional foods, nutraceuticals and pharmaceuticals, with potential to improve human health and prevent disease. This review aims to summarize the current in vitro, cell model (in situ) and in vivo research on the antioxidant, glycaemic management and muscle health enhancement properties of FPHs and their peptides.

Identification of amino acids metabolomic profiling in human plasma distinguishes lupus nephritis from systemic lupus erythematosus

Lupus nephritis (LN) is an immunoinflammatory glomerulonephritis associated with renal involvement in systemic lupus erythematosus (SLE). Given the close relationship between plasma amino acids (AAs) and renal function, this study aimed to elucidate the plasma AA profiles in LN patients and identify key AAs and diagnostic patterns that distinguish LN patients from those with SLE and healthy controls. Participants were categorized into three groups: normal controls (NC), SLE, and LN. Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was employed to quantify AA levels in human plasma. Principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) were utilized to identify key AAs. The diagnostic capacity of the models was assessed using receiver operating characteristic (ROC) curve analysis and area under the ROC curve (AUC) values. Significant alterations in plasma AA profiles were observed in LN patients compared to the SLE and NC groups. The OPLS-DA model effectively separated LN patients from the SLE and NC groups. A joint model using histidine (His), lysine (Lys), and tryptophan (Trp) demonstrated exceptional diagnostic performance, achieving an AUC of 1.0 with 100% sensitivity, specificity, and accuracy in predicting LN. Another joint model comprising arginine (Arg), valine (Val), and Trp also exhibited robust predictive performance, with an AUC of 0.998, sensitivity of 93.80%, specificity of 100%, and accuracy of 95.78% in distinguishing between SLE and LN. The joint forecasting models showed excellent predictive capabilities in identifying LN and categorizing lupus disease status. This approach provides a novel perspective for the early identification, prevention, treatment, and management of LN based on variations in plasma AA levels.