Glutamic Acid Content Research Articles

Effects of Exogenous Chlorinated Amino Acetic Acid on Cadmium and Mineral Elements in Rice Seedlings.

To explore the effect of exogenous application of chlorinated amino acetic acid on cadmium (Cd) transport characteristics in rice seedlings, X24 and Z35 rice were taken as the research objects to carry out hydroponics experiments, and the changes of Cd content in rice seedlings, rice mineral elements and amino acid content in rice were analyzed. The results showed that exogenous application of 1.2 mmol·L-1 chlorinated amino acetic acid inhibited cadmium in shoots and roots of rice seedlings; Cd content in shoots and roots were reduced by up to 62.19% and 45.61%, respectively. The majority of cadmium was in the cell wall of shoots and roots; this decreased with the increase of the concentration of chlorinated acetic acid. In addition, the Mn content in shoots and Ca content in roots of rice seedlings increased significantly after the application of chlorinated amino acetic acid. The results of amino acid analysis showed that the contents of aspartic acid, glutamic acid and cystine in rice seedlings were increased. These results indicate that exogenous application of chlorinated amino acetic acid is beneficial to the synthesis of aspartic acid, glutamic acid and cysteine in rice seedlings, increases the content of Mn in shoots and Ca in roots of rice seedlings, and significantly alleviates cadmium stress in seedlings. This provides a theoretical basis for the development of an environmentally friendly Cd-lowering foliar fertilizer for rice.

Effects of Adding NPK fertilizer and Spraying Glutamic Acid on the Growth of Tecoma stans

This study was carried out at the College of Agriculture \ Horticulture Department \ Tikrit University for the 2021 growing season, in order to show the effect of spraying glutamic acid in different in three concentrations, and adding a balanced fertilizer (NP K) (20 20 20) in three quantities, on some characteristics of the mineral content of Tecoma stans. Spraying plants with three concentrations of glutamic acid (0.50, 0.25, 0) mg L -1, and adding a balanced fertilizer (NP K) in three quantities (1, 0.5, 0) grams of fertilizer / anvil and the interaction between them to show their effect on the characteristics of the mineral content in the leaves For Tecoma stans, according to a randomized complete block design. The results of the study indicated that the plants treated with a concentration of (0.50) mg L -1, and the addition of (1) g/anvil of (NP K) fertilizer for Tecoma tree recorded a significant increase in all studied traits compared to With the control treatment, the percentage of the mineral content characteristics was (1.975%) for the nitrogen concentration in the leaves, and (12.493%) for the protein content, and the phosphorous concentration was (1.841%) and (1.84%) for the potassium concentration, while the electrolyte concentration was (7,925%). Compared with the lowest values recorded by the control treatment of no spraying with acid and without adding fertilizer, it was (1.850%) and (11.303%), (1.723%), (1.752%), (6.64%) in the leaves. for (nitrogen, protein, phosphorous, potassium and carbohydrates) respectively.

Subchronic tolerance trials of graded oral supplementation with ornithine hydrochloride or citrulline in healthy adults

Ornithine and citrulline are amino acids used in dietary supplements and nutritional products consumed by healthy consumers, but the safe supplementation levels of these compounds are unknown. The objective of this study was to conduct two 4-week clinical trials to evaluate the safety and tolerability of graded dosages of oral ornithine (as hydrochloride) and citrulline. Healthy male adults (n = 60, age 41.4 ± 1.5 years) completed graded dosages of either ornithine hydrochloride (3.2, 6, 9.2, and 12 g/day) or citrulline (6, 12, 18, and 24 g/day) supplement for 4 weeks with 2-week wash-out periods in between. Primary outcomes included vitals, a broad spectrum of circulating biochemical analytes, body weight, sleep quality, and mental self-assessment. In the ornithine hydrochloride supplementation group, minor increase in plasma aspartic acid and glutamic acid concentrations was observed at the highest intake dosages. In the citrulline supplementation group, minor changes in laboratory data for serum lactate dehydrogenase and plasma amino acid concentration of lysine, methionine, threonine, aspartic acid, glutamic acid, glutamine and ornithine, arginine, and citrulline itself were measured. No other changes in measured parameters were observed, and study subjects tolerated 4-week-long oral supplementation of ornithine hydrochloride or citrulline without treatment-related adverse events. A clinical, no-observed-adverse-effect-level (NOAEL) of ornithine hydrochloride and citrulline supplementation in healthy adult males was determined to be 12 g/day and 24 g/day (4 weeks), respectively.

Analysis of microbial community and its correlation with flavor compounds during Congee fermentation

We investigated the structural changes in the microbial flora during the fermentation process (with primers added for fermentation) of Congee and its influence on the flavor compounds of Congee using high-throughput sequencing technology. W detected and analyzed the bacterial and fungal community dynamics. In addition, gas chromatography–mass spectrometry, electronic nose technology, and electronic tongue technology were used to monitor the changes in the flavor compounds of Congee at different fermentation time points; the correlation between the two was analyzed. The Illumina MiSeq sequencing showed bacterial in Congee samples at different fermentation stages belonged mainly to genera Lactobacillus, Kosakonia, and Enterococcus. The major fungal genera were Yarrowia, Dipodascus, and Pichia. Gas chromatography–mass spectrometry (GC-MS) revealed that 90 volatile compounds were detected in the Congee samples during the fermentation process, among which ethyl acetate, eucalyptol, nonanal, heptyl ethyl acid, and acetic acid constituted important aroma compounds in Congee. In addition, 16 amino acids were detected from the Congee samples. At 48 h of fermentation, the content of total amino acids increased to twice that at 0 h of fermentation; the contents of glutamic acid and aspartic acid were the highest. The electronic nose technology revealed that the W5S (nitrogen oxide), W1S (methyl) and W1W (sulfide sensitive) sensors showed a higher response to Congee samples. In terms of taste, the response signals of Congee, sweetness, and saltiness were the strongest. The covariance between microbial flora and flavor compounds was analyzed by Spearman's correlation analysis. Ralstonia was significantly positive correlation with found with pyridine, butanoic acid, hexanoic acid, and D-limonene (p < 0.05), and a significant negative correlation with hexadecanoic acid and ethyl ester (p < 0.05). Bacillus exerted a significant positive correlation with heptanoic acid and ethyl ester (p < 0.05). Yarrowia was positively correlated with compounds such as heptanoic acid, ethyl ester, ethyl 2-methyl butyrate (p < 0.05) and negatively correlated with 2-Dece0l, (E)-, Hepta0l (p < 0.05). Dipodascus was negatively correlated with compounds such as naphthalene, furan, 2-pentyl-, butanedioic acid (p < 0.05). In all, Ralstonia, Bacillus, Yarrowia, and Dipodascus exerted positive effects on the formation of the Congee flavor.

Urine metabolomic characteristics of female patients with occupational chronic cadmium poisoning after 15 years of treatment.

Occupational chronic cadmium poisoning (OCCP) can cause irreversible organ damage. Currently, no effective treatment is available for OCCP, and effective and sensitive biomarkers for treatment evaluation are still lacking. In this study, metabolomics techniques were used to analyze changes in endogenous metabolites in the urine of patients with OCCP after 15 years of treatment. Thirty urine samples from female patients with OCCP and healthy female controls (n = 15 per group) were assessed using gas chromatography-time-of-flight mass spectrometry and ultra-high-performance liquid chromatography-Q-Exactive mass spectrometry. The OCCP group had higher concentrations of blood urea nitrogen and urinary cadmium but near-normal urinary concentrations of β2 -microglobulin and retinol-binding protein. Compared with the control group, the OCCP group had 66 significantly different metabolites with a variable importance in projection score >1 and p < 0.05. These differential metabolites were involved in various metabolic pathways, such as creatine metabolism, nicotinate and nicotinamide metabolism, the pentose phosphate pathway, d-glutamine and d-glutamate metabolism, and amino acid metabolism. Compared with the control group, the OCCP group had significantly higher urinary concentrations of creatine, glutamic acid, quinolinic acid and nicotinic acid. In a receiver operator characteristic analysis, the area under the curve of creatine was higher than those for glutamic acid, quinolinic acid and nicotinic acid, indicating that urinary concentrations of creatine could be used as a sensitive biomarker for the diagnosis and prognosis of OCCP and for monitoring its treatment.

Qi Wei Anti-burn Tincture Remodels Liver Metabolic Pathways and Treats Burn Wounds Efficiently.

This work aims to elucidate the molecular mechanism of Qi Wei anti-burn Tincture (QW) on wound healing in burnt mice using metabolomics and molecular biology techniques. A scald model was first established in Kunming mice. After treatment, biochemical indicators for liver function and burnt skin tissues were then evaluated via biochemical detection and HE staining, respectively. Liver tissues were further analyzed for differential metabolites, inflammatory factors, and mRNA levels of cytokines using metabolomics and molecular biology techniques. Involved metabolic pathways were also identified using software. QW treatment did promote the healing of the burn wounds in Kunming mice with a downregulation of ALP, ALT, and AST to normal levels. In mouse liver tissue, the contents of glutamine, aspartic acid, and citrulline were significantly reduced, while the contents of 5-hydroxyproline, taurine, hypotaurine, and glutamic acid significantly increased. These major differential compounds are involved in the arginine metabolic pathway, nitrogen excretion, and the metabolism of taurine and hypotaurine, suggesting that QW reprogramed the above metabolic processes in the liver. Furthermore, the application of QW increased the expression of TGF-β1 and FGF-2 and reduced the levels of TNF-α, IL-1β, IL-6, and reactive oxygen species in the liver of mice induced by burn injury. This study found that QW treatment promoted metabolic pathway remodeling in the liver, which might be a potential mechanism for QW to treat burn wounds.

Activation of Calcium-Sensing Receptor in the Area Postrema Inhibits Food Intake via Glutamatergic and GABAergic Signaling Pathways.

A high-protein diet has become a popular way to lose weight. Calcium-sensing receptor (CaSR) is activated by amino acids in addition to calcium ions. CaSR shows dense expression in the area postrema (AP), which participates in feeding regulation. The effect of CaSR in the AP on food intake and the potential mechanism involved is investigated. Male C57BL/6 mice are used to observe the effect of R568 (agonist of CaSR) on food intake. Enzyme-linked immunosorbent assay, immunofluorescence staining, and chemogenetics are used to explore the neural signaling involved. CaSR activation in the AP inhibited acute feeding; R568 increases the content of glutamate and γ-aminobutyric acid (GABA) in the AP, whereas only glutamatergic neurons mediate the effect of R568. GABA-A receptor and ionic glutamate receptor (N-methyl-D-aspartate receptor [NMDAR]) in the paraventricular nucleus of hypothalamus (PVN) are involved in the effect of R568. Promotion of oxytocin (OT) synthesis in the PVN also participates in the effect of R568, and this mechanism is mediated by NMDAR in the PVN. CaSR activation in the AP suppresses feeding, and AP-PVN glutamatergic and GABAergic signaling pathways are involved.

Effect of non-essential amino acids (proline and glutamic acid) and sugar polyol (sorbitol) on brood of honey bees

Dietary nutrients provide fuel for the growth and development of insects as well as chemicals for their tissue construction. Apis mellifera L., an important pollinator, collects nectar and pollens from different plants to get their nutritional needs. Honey bees use protein for growth and development and carbohydrates as energy sources. Pollens predominantly contain proline and glutamic acid (non-essential amino acids). This is the first study to evaluate the role of proline, glutamic acid and sorbitol on bee broods. The composition of the diet can optimize the in vitro rearing process. Therefore, we elaborated on the possible impact of these amino acids and sugar alcohol on bee broods. This study aimed to achieve this objective by rearing honey bee larvae under different concentrations of proline, glutamic acid, and sorbitol (1, 4 and 8%), which were supplemented into the standard larval diet. The supplementation of proline helped the quick development of larvae and pupae of honey bees, whereas developmental time only decreased in pupae in the case of glutamic acid. The duration of the total bee brood development was the shortest (20.1 and 20.6 days) on Pro8 and Glu4, respectively. Proline only increased larvae survival (93.8%), whereas glutamic acid did not increase the survival of any brood stage. Pupal and adult weights were also increased with proline and glutamic acid-supplemented diets. Sorbitol did not change the developmental period of the honey bee brood but increased larval survival (93.7%) only at the lowest concentration (Sor1). The small concentration of sorbitol can be used to increase the survival of the honey bee brood. However, a higher concentration (Sor8) of sorbitol reduced the body weight of both pupae and adults. This study predicted that rearing bee brood could be one of the factors for the selectivity of pollen with higher proline and glutamic acid during the foraging of bees.

Variations of Raw Milk Components and Amino Acid Profiles in Different Dairy Buffalo Crossbreds

This study aimed to assess the relationship between milk components and amino acid (AA) profiles among different buffalo crossbreds in Bangladesh. A total of thirty-six (36) lactating buffaloes were selected from Murrah, Nili-Ravi, and Mehsana crossbreds, and they were assigned to 03 groups, each with 12 buffaloes. The total experimental period was 10 weeks, including the initial 10 days of diet adjustment. The results from the experiment revealed that milk protein, fat, and total solids contents of Murrah crossbred was significantly (p&lt;0.05) higher than Mehsana and Nili-Ravi crossbreds. In contrast, the lactose content of all buffalo crossbreds was statistically similar (p&gt;0.05). In the case of milk amino acid contents, all the milk samples entailed a higher concentration of Glutamic acid (0.9-1.00 g/100 g of milk), whereas Cysteine had the lowest concentration (0.02-0.05 g/100 g). The most prevalent essential amino acids were Leucine, Lysine, and Phenylalanine, whereas the most prevalent non-essential amino acids were Glutamic acid, Proline, Asparagine, and Serine. Lysine, Isoleucine, Leucine, Phenylalanine, Cysteine, and Histidine concentrations differed significantly (p&lt;0.05), and at the same time as the other 11 AAs concentrations were found non-significant (p&gt;0.05). The highest Lysine: Methionine ratio observed in Murrah buffalo was about 3.20%, while in Mehsana and Nili-Ravi buffalo was about 2.80 and 2.50%, respectively. Thus, it was evident from the study that the raw milk components and amino acid composition vary considerably in the different lactating buffalo crossbreds. Finally, the compositional data of raw milk may create the way of sustainable use of milk from dairy buffalo crossbreds and improve food and nutrition security, particularly in developing countries.

Natural flavoring formulations of straw mushrooms and quality test with variations in temperature and drying time

Mushrooms contain a substance known as glutamic acid, that produce a savory taste which has the potential to be developed into a natural flavoring. The research began with the determination of amino acid levels in three phases of harvesting straw mushrooms, namely: the egg phase, the bud phase and the adult phase, by using High Performance Liquid Chromatography which aims to determine the harvesting phase with the highest glutamic acid content. The test results of amino acid levels showed the adult phase contained the highest glutamic acid levels of 49.08 mg/g. Furthermore, the manufacture of straw mushroom flour was performed with temperature variations of 60° C and 70° C and drying times of 6, 7 and 8 hours. Then the flavoring formulation was completed by mixing mushroom flour and other dry additives namely shallots, garlic, white pepper, tapioca flour, salt and sugar. The resulting flavoring test is conducted using a description test by assessing the sensory properties of natural flavorings, namely color, aroma, taste and texture. Based on a panelist rating, F2 (60°C, 7 hours) has the best score for color (3.88) and aroma (3.32). F5 (70°C, 7 hours) has the best score for taste (3.24) and F1 (60°C, 6 hours) has the best score for texture (2.08). The conclusion of this study is that mushrooms have a very high potential to be deformalized into natural flavorings, as well as the natural flavoring quality parameters of mushrooms is influenced significantly by temperature parameters and drying time

Changes of γ-Aminobutyric Acid, Phytoestrogens, and Biofunctional Properties of the Isoflavone-Enriched Soybean (Glycine max) Leaves during Solid Lactic Acid Fermentation

The present study documents the changes in the γ-aminobutyric acid (GABA), the total phenolic (TP), total flavonoid (TF), and isoflavone contents, the antioxidant activities and the digestive enzyme inhibition during the solid lactic acid fermentation of isoflavone-enriched soybean leaves (IESLs) with starters Lactiplantibacillus plantarum P1201 and Levilactobacillus brevis BMK184. The contents of glutamic acid (GA) and GABA remained almost unchanged during fermentation with P1201. In contrast, the contents of GABA increased from 144.24 to 173.09 and 175.59 mg/100 g, and the contents of GA decreased from 43.68 to 18.26 and 11.25 mg/100 g during the IESLs’ fermentation with BMK184 and the combined use of P1201 + BMK184, respectively. The total isoflavone content decreased during fermentation, but the isoflavone aglycone levels increased; in fact, the levels of daidzein and genistein were the highest after the use of P1201 + BMK184 (2265.57 μg/g) and BMK184 (1055.27 μg/g), respectively, at 72 h of fermentation. Correspondingly, the DPPH (90.90%), the ABTS (91.09%), and the hydroxyl (74.88%) radical scavenging activities, the ferric reducing/antioxidant power (2.45), as well as the α-glucosidase (49.86%) and pancreatic lipase (37.30%) inhibition activities exhibited their highest levels after fragmentation with P1201 + BMK184.

Method and metrological characteristics of measuring the mass fraction of monosodium glutamate in biological matrices

Over the last century the people’s mode of life and eating habits has dramatically changed: the people of developed countries began to consume fast food, and also started disorderly and frequent snacking. The production of dietary meals and the increase of food assortment, including food produced from low-quality ingredients, led to the manufacturer’s necessity to use a large number of functional ingredients, i. e. those that improve taste of the food. Monosodium glutamate (MSG) is one of the widely used additives. Monosodium L-Glutamate (E621) is the sodium salt of glutamic acid found in all protein foods; it is used throughout the world as a food flavor enhancer. The legislation of the Russian Federation limits the content of monosodium glutamate, or additive E621, in a food product. Due to the fact that the glutamic acid takes the major weight in the monosodium glutamate molecule, which molecule is naturally present in almost all food products, the weight of the molecule of the E621 additive was determined by content of this amino acid expressed in terms of monosodium glutamate. In connection with the foregoing, it became necessary to develop a method for the quantitative determination of the mass fraction of monosodium glutamate introduced into food during the production of food products. Within the framework of this research a new method for determining the share of added monosodium glutamate is proposed, which is not associated with the natural content of glutamic acid. The authors have developed a method for determining the mass fraction of monosodium glutamate in food products with the help of high performance liquid chromatography with precolumn derivatization. This research presents metrological assessment of the developed methodology, determines accuracy rates and reproducibility factors in two concentrations ranges. For a range of 0.1 to 1%, the reproducibility is set at 17% and the accuracy rate is set at 30%. For the range of 1–10%, the reproducibility is 6%, the accuracy rate is 10% respectively. Also, during the development of the method, the lower limits for the quantitative determination (Limit of Detection — LOD) and qualitative determination (Limit of Quantification — LOQ) of the method were calculated. LOQ was equal to 0.01% and LOD accounted for 0.1%. The method has successfully passed the metrological certification and is included in the Register of Measurement Methods of the Russian Federation. It can be used by accredited laboratories for assessment and control of food quality.

Nutritional Composition and Health-Promoting Properties of Amasi: A South African Fermented Milk Product

This study investigated the effect of fermentation conditions (time and temperature) on the nutritional composition and health-promoting properties of raw milk, optimized naturally fermented amasi, and amasi fermented with starter culture. The composition of the products, including chemical analysis, amino acids, mineral composition, and fatty acids, as well as health-promoting properties (total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity assays (2,2-Azinobis (3-Ethyl-Benzothiazone-6-Sulphonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH)) were investigated. The results showed that the fermentation conditions (time and temperature) significantly affected the ash contents of both fermented samples. Fermentation was also observed to have increased the contents of most of the essential and non-essential amino acids. A high concentration of glutamic acid was observed in optimized naturally fermented amasi at 32 °C (OP32, 6.30 g/100 g), followed by starter-culture-fermented amasi at 25 °C (SC25, 5.58 g/100 g) and then starter-culture-fermented amasi at 32 °C (SC32, 5.35 g/100 g), with optimized naturally fermented amasi at 32 °C (OP25, 4.46 g/100 g) having the lowest concentration. A similar trend in the composition of minerals was also observed, with potassium being the most abundant (110.1–134.5 µg/g). The TPC, TFC, and the antioxidant activities were significantly improved by fermentation, while a significant reduction in free fatty acids was recorded. In conclusion, the fermentation conditions had a significant effect on the nutritional and health-promoting properties of amasi. The results provided in this study could provide nutritional information regarding the composition of amasi, which can be beneficial to produce a high-quality product.

Development of technology for obtaining protein hydrolysate from offal of category II

The object of research chosen in the work is low-value products of slaughter and processing of livestock, in particular by-products of category II. Having a sufficient protein content and a number of other properties necessary for the production of protein hydrolysates. At the same time, the use of such secondary products seems promising, since in this case, on the one hand, prerequisites are created for the creation of low-waste technologies, and on the other hand, it becomes possible to produce combined products with an optimal ratio of nutrients. The research results show a high content of glycine, alanine, glutamic acid, serine, and proline in wool by-products, i. e. those amino acids that are mainly contained in collagen. Collagen hydrolysate was obtained by enzymatic hydrolysis of legs with a put joint. Taking into account the peculiarities of the preparation of the components, the technological process was worked out and a technological scheme for obtaining protein hydrolysate was proposed.

Effect of carbohydrate levels under autumn defoliation on cold tolerance during the subsequent flowering season in pear

Freezing injury to the flowers of deciduous fruit trees is being increasingly emphasized in the context of global warming due to low temperatures in spring. The annual accumulation of nutrients is affected by reserves in the organs during tree growth. In this study, changes in the total carbohydrate (TC), total starch (TS), and soluble solid (SS) content of shoots and changes in cold tolerance and free amino acid (FAA) and free sugar (FS) content of flowers were investigated to determine the effects of carbohydrate and FAA levels on the cold tolerance of pear flowers under autumn defoliation. The freezing injury rate of flowers increased with 50% and 100% defoliation at -2.8 °C. The TC, TS, and SS content in one-year-old shoots decreased after 100% defoliation; the TS content was reduced to one-third. Additionally, the FS and FAA content in flowers at the white-bud stage decreased due to defoliation. In particular, the sorbitol and glutamic acid content decreased after defoliation. These results suggest that maintaining carbohydrate levels is necessary to protect the flowers of pear and other deciduous fruit trees from low temperatures during the flowering season.

Interactions between dopamine transporter and N-methyl-d-aspartate receptor-related amino acids on cognitive impairments in schizophrenia

BackgroundCognitive impairments, the main determinants of functional outcomes in schizophrenia, had limited treatment responses and need a better understanding of the mechanisms. Dysfunctions of the dopamine system and N-methyl-d-aspartate receptor (NMDAR), the primary pathophysiologies of schizophrenia, may impair cognition. This study explored the effects and interactions of striatal dopamine transporter (DAT) and plasma NMDAR-related amino acids on cognitive impairments in schizophrenia. MethodsWe recruited 36 schizophrenia patients and 36 age- and sex-matched healthy controls (HC). All participants underwent cognitive assessments of attention, memory, and executive function. Single-photon emission computed tomography with 99mTc-TRODAT and ultra-performance liquid chromatography were applied to determine DAT availability and plasma concentrations of eight amino acids, respectively. ResultsCompared with HC, schizophrenia patients had lower cognitive performance, higher methionine concentrations, decreased concentrations of glutamic acid, cysteine, aspartic acid, arginine, the ratio of glutamic acid to gamma-aminobutyric acid (Glu/GABA), and DAT availability in the left caudate nucleus (CN) and putamen. Regarding memory scores, Glu/GABA and the DAT availability in left CN and putamen exhibited positive relationships, while methionine concentrations showed negative associations in all participants. The DAT availability in left CN mediated the methionine-memory relationship. An exploratory backward stepwise regression analysis for the four biological markers associated with memory indicated that DAT availability in left CN and Glu/GABA remained in the final model. ConclusionsThis study demonstrated the interactions of striatal DAT and NMDAR-related amino acids on cognitive impairments in schizophrenia. Future studies to comprehensively evaluate their complex interactions and treatment implications are warranted.

Physicochemical property optimization and nutrient redistribution in the muscle of sub-adult grass carp (Ctenopharyngodon idella) by conjugated linoleic acid.

We studied the effects of conjugated linoleic acid (CLA) on the amount of nutrients, flavour substances, and healthcare fatty acids, the physicochemical properties, and the potential molecular mechanisms in the muscles of sub-adult grass carp (Ctenopharyngodon idella). Fish were fed graded levels of CLA (0.0, 3.1, 6.4, 9.6, 12.7, and 15.9g/kg diets) for 60days. Protein, glutamic acid, alanine, inosine monophosphate (IMP), eicosapentaenoic acid (EPA; 20:5n-3), docosahexaenoic acid (DHA; 22:6n-3), and total CLA contents (p<0.05) increased in CLA 3.1∼12.7, 6.4∼9.6, 6.4∼9.6, 6.4∼15.9, 3.1∼9.6, 3.1∼9.6, and 3.1∼15.9g/kg diet, respectively (p<0.05). In addition, optimal CLA significantly increased pH24, shear force, collagen content, and myofibre density in the muscle (P<0.05); however, it decreased myofibre diameter (p<0.05). We concluded that 6-9g/kg CLA in the diet could improve the flesh quality of sub-adult grass carp.

Temporal kinetics of changes in color, phytochemicals, γ-aminobutyric acid, enzyme activity and antioxidant activity of coffee leaves during postharvest storage

Understanding the kinetics of changes in the quality attributes and enzyme activity of coffee leaves during storage is essential to preparing high-quality coffee leaf tea. In the present study, the impacts of different storage temperatures and times on the color, phytochemical composition, amino acids, the activity of enzymes (glutamate decarboxylase (GAD), diamine oxidase (DAO), polyamine oxidase (PAO), γ-aminobutyraldehyde dehydrogenase (AMADH), γ-aminobutyric acid transaminase (GABA-T), glutamate dehydrogenase (GDH), polyphenol oxidase (PPO), and peroxidase (POD)), and antioxidant activity of coffee leaves were investigated. The results showed that low-temperature storage effectively delayed the production of browning color and retained nutrients and antioxidant activity in coffee leaves during storage. The content of 5-caffeoylquinic acid (5-CQA) decreased by 43.5%, 31.1%, and 17.5% when coffee leaves stored for 7 d at 25, 4, and -20 ℃, respectively. The total phenolic content (TPC) and antioxidant activity had negative correlation with the storage time and the activities of PPO and POD were enhanced with prolonged storage time and higher storage temperature. The content of γ-aminobutyric acid (GABA) increased (2.45–3.32 folds) when stored at -20 ℃ within 21 d, which was associated with the decrease of glutamic acid content and the increased activity of GAD. The kinetics of changes in color index L*, total color change (ΔE), TPC, and ABTS and DPPH scavenging capacities fitted the first-order kinetic model and the activation energies ranged from 15.66 to 24.67 kJ/mol, indicating that coffee leaves are prone to deterioration during storage, especially at high temperature. This study indicates that low-temperature storage can effectively prevent the quality loss of coffee leaves while increasing the bioactive compound GABA.

Isolation, purification, and characterization of novel melanin from the submerged fermentation of Rhizobium radiobacter

In this study, a novel water-insoluble bacterial melanin was first isolated and purified from the fermentation culture of Gram-negative bacterial Rhizobium radiobacter ATCC 1333 through the thermal acid-alkali treatment. The highest extracellular melanin production was 3.46 ± 0.07 g·L−1 when the initial glutamic acid concentration was 10 g·L−1. The molecular weight of the purified bacterial melanin (TPBM) was 686 g/mol. The molecular formula (C34H30N4O12) and chemical structure were defined based on FT-IR, MALDI-TOF/MS, Py–GC/MS NMR (1H and 13C), and elemental analyses. Furthermore, UV–vis spectroscopy results indicated that TPBM showed maximum absorption at around 222 nm. TPBM was easily soluble in alkaline solutions, but hardly-soluble in aqueous and majority of the organic solvents. In addition, TPBM was stable to temperature, light, reducing agent, and most metal ions. However, TPBM could be bleached when subjected to the action of oxidants and precipitated with FeCl3 and AgNO3. TPBM (50 µg·mL−1) possessed high DPPH free radical (89.74% ± 1.10%) and hydroxyl scavenging properties (84.12% ± 1.31%). Finally, TPBM displayed potential anti-bacterial properties against E. coli, S. aureus, A. baumanii, and M. albican. These results provided a theoretical basis for the later development and utilization of TPBM.

Gonad traits in the sea urchin Mesocentrotus nudus fed on the kelp Eisenia bicyclis: Gametogenesis promotion and lack of sea urchin-like taste

Perennial Eisenia bicyclis kelp beds are one of the main fishing grounds for the sea urchin Mesocentrotus nudus, whose gonad is highly valued. However, little is known about the gonad quality of sea urchins fed on this species of kelp. Feeding with two other kelp species, the biennial Saccharina japonica blade or sporophylls of the annual Undaria pinnatifida, is known to improve the gonad quality of M. nudus. The present study investigated the dietary effects of blades of E. bicyclis on gonad quality of M. nudus in comparison with feeding on S. japonica blade or U. pinnatifida sporophylls. The gonad index of urchins fed E. bicyclis (UEB) increased from 8.2 to 16.9, similar to those fed on S. japonica (USJ), which was significantly lower than those fed on sporophylls of U. pinnatifida (UUP). Of UEB, 69% had premature gonads, indicating that UEB gonads were significantly advanced to maturation compared with those of USJ or UUP, most of which were still in the growing stage. The uncoupling of gonad size and advance to maturation is not explained by the high protein content in E. byciclis, suggesting that unknown substances in E. bicyclis can promote gonad maturation. UEB gonads improved color, texture and contents of glutamic acid, alanine, and arginine similar to results obtained with USJ. However, the methionine and valine contents of UEB gonads were below the threshold of detection, explaining the lack of sea urchin-like taste of the gonads. Many unpleasant odors were detected from the gonads of UEB. In conclusion, gonad flavor of UEB is inferior compared with that of USJ or UUP. Further research is required to understand the details of gametogenesis under dietary supplementation with the species-specific compounds present in E. bicyclis.