TMT proteomics establishes correlations between solar drying and quality modifications in Penaeus vannamei.

This study investigated proteomic changes in Penaeus vannamei in half-dried and dried shrimp using tandem mass-tag technology. After performing the drying treatment, the tandem mass-tag results revealed 1,162,306 spectra, 2997 quantifiable proteins, and 72 differentially expressed proteins (DEPs) compared with that in the untreated group. A total of 29 DEPs were found in the half-dried shrimp, while 49 DEPs were found in the dried shrimp. Bioinformatic analyses based on Gene Ontology term enrichment, Kyoto Encyclopedia of Genes and Genomes pathway enrichment, and protein-protein interactions showed that the DEPs were primarily involved in protein structure and fat metabolism. A correlation analysis between the DEPs and quality indicators showed that 45 DEPs were significantly associated with shrimp quality traits, with certain proteins potentially representing markers of color and texture. Of these, arthrodial cuticle protein AMP16.3 might be a protein marker for color, while heat shock protein 21, WH2 domain-containing protein, and myosin heavy chain 1 might be markers of shrimp muscle textural properties. These results provide a systematic understanding of the quality difference between half-dried and dried P. vannamei from the perspective of proteomics and have potential scientific significance and practical value for improving the quality of dried products.

Effects of electron beam irradiation on protein oxidation and textural properties of shrimp (Litopenaeus vannamei) during refrigerated storage.

Protein oxidation leads to changes in shrimp texture, which affects sensory profile and consumer acceptability. This study aimed to evaluate the impact of electron beam irradiation (EBI) on protein oxidation and textural properties of Litopenaeus vannamei during refrigerated storage. Results revealed that EBI treatment and storage increased the protein oxidation level of shrimps. Shrimps irradiated with ≥ 7 kGy exhibited remarkably higher (P < 0.05) reactive oxygen species, turbidity, and carbonyl contents, and remarkably lower (P < 0.05) Ca2+-ATPase activity, surface hydrophobicity, solubility, and total sulfhydryl contents compared to the control group (0 kGy) on the 7th day of storage. Shrimps irradiated with 3 and 5 kGy exhibited remarkably higher (P < 0.05) hardness, springiness, and chewiness compared to the control group (14.99 N, 1.26 mm, and 3.19 mJ). Collectively, suitable EBI doses of 3-5 kGy were recommended in shrimp preservation to inhibit texture softening by inducing moderate protein oxidation.

Analytical strategies based on untargeted and targeted metabolomics for the accurate authentication of organic milk from Jersey and Yak.

Organic milk has a high risk of food fraud as it can easily be adulterated with non-organic milk. This study aimed to identify metabolite markers for assessing the authenticity of organic milk from Jersey and Yak. In the untargeted strategy, ultra-high performance liquid chromatography-Q Exactive HF-X mass spectrometer coupled with chemometrics analysis was used to screen and identify tentative markers of organic milk from Jersey and Yak. In the targeted strategy, a quick and easy method of ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed to quantify three markers. The peptide of Thr-Ala-Val and D-biotin were determined to be metabolite markers for distinguishing organic and non-organic Jersey milk, whereas trimethylamine N-oxide was determined to be a metabolite marker for distinguishing organic and non-organic Yak milk. These findings provide critical information to facilitate assessments of organic milk authenticity.

Evaluating the influence of straw mulching and intercropping on nitrogen uptake, crop growth, and yield performance in maize and soybean.

Introduction: Intercropping and straw mulching are sustainable agricultural practices that can positively affect crop growth and development, especially together. Methods: A split-plot experimental design was used to investigate the effects of intercropping and straw mulching on crop growth, crop yield, nitrogen uptake, and photosynthetic characteristics. The main plot focused on three planting patterns: soybean monoculture (S), maize monoculture (M), and maize/soybean intercropping (I). The subplot structure consisted of four levels of straw mulching (0, 4.8, 7.2, 9.6 t ha-1). Results: Interaction and variance analyses showed that straw mulching, intercropping, and their interaction had significant effects on plant height, stem diameter, leaf area index, chlorophyll content, nitrogen uptake, photosynthetic characteristics, and crop yield. Based on two-year averages for maize and soybean, the net photosynthetic rate (Pn) was up to 51.6% higher, stomatal conductance (Sc) was up to 44.0% higher, transpiration rate (Tr) was up to 46.6% higher, and intercellular carbon dioxide concentration (Ci) was up to 25.7% lower relative to no mulching. The maximum increases of Pn, Sc, and Tr of intercropped maize were 15.48%, 17.28%, and 23.94%, respectively, and the maximum Ci was 17.75% lower than that of monoculture maize. The maximum increase of Pn, Sc, and Tr of monoculture soybean was 24.58%, 16.90%, and 17.91%, respectively, and the maximum Ci was 13.85% lower than that of intercropped soybean. The nitrogen uptake of maize and soybean in the mulching treatment was 24.3% higher than that in the non-mulching treatment; the nitrogen uptake of intercropped maize was 34.2% higher than that of monoculture maize, and the nitrogen uptake of monoculture soybean was 15.0% higher than that of intercropped soybean. The yield of maize and soybean in the mulching treatment was 66.6% higher than that in the non-mulching treatment, the maize yield under intercropping was 15.4% higher than that under monoculture, and the yield of monoculture soybean was 9.03% higher than that of intercropped soybean. Discussion: The growth index and photosynthesis of crops are important parts of yield formation. The results of this study confirmed that straw mulching, intercropping, and their interaction can ultimately increase crop yield by improving crop growth, nitrogen uptake, and photosynthesis. This result can be used as the theoretical basis for the combined application of these measures in agriculture.

Evaluation of Indigenous Yeasts Screened from Chinese Vineyards as Potential Starters for Improving Wine Aroma.

Exploitation of the biodiversity of native wine yeast is a means of modifying the sensory characteristics of wine. Samples from different regions in China were analysed to screen native isolates as potential starter cultures. Through morphological and molecular biological analyses, we found six species, belonging to four genera (Hanseniaspora, Saccharomyces, Rhodotorula and Metschnikowia). These species were subjected to stress tolerance assays (ethanol, glucose, SO2 and pH), enzymatic activity tests (sulphite reductase activity, ß-glucosidase activity and protease activity) and fermentation tests. Saccharomyces cerevisiae showed a high tolerance to ethanol and completed fermentation independently. Hanseniaspora demonstrated good enzymatic activity and completed sequential fermentation. The fermentation experiment showed that the PCT4 strain had the best aroma complexity. This study provides a reference for selecting new starters from the perspective of flavour enzymes and tolerance and diversifying the sensory quality of wines from the region.

A TMT-based proteomic approach for investigating the effect of electron beam irradiation on the textural profiles of Litopenaeus vannamei during chilled storage.

To elucidate the effect of electron beam irradiation (EBI) on the textural quality of Litopenaeus vannamei, the tandem-mass-tag labeled proteomic method was conducted to illustrate the protein changes in shrimp muscle. The results suggested that shrimp irradiated with 5 kGy exhibited optimum textural traits of hardness, springiness, and chewiness. In total, 486 proteins were identified as differentially abundance proteins (DAPs) in multiple comparison groups. Bioinformatics analysis revealed that most of DAPs participated in cellular process, binding, and catalytic. etc. Various signaling pathways, such as RNA transport and oxidative phosphorylation, were notably enriched by DAPs. The correlation analysis indicated that some DAPs such as Myosin-XVIIIa, projectin, and beta-thymosin 3 were remarkably correlated with the textural properties, which could be proposed as potential biomarkers to assess the irradiation-induced textural variation in shrimp. This study provided an insightful understanding at the protein level to improve the application of EBI to shrimp preservation.

Effects of ultrasonic-microwave combination treatment on the physicochemical, structure and gel properties of myofibrillar protein in Penaeus vannamei (Litopenaeus vannamei) surimi.

The objective of this study was to evaluate the effects of single ultrasound (360 W, 20 min), single microwave (10 W/g, 120 s) and ultrasonic-microwave combination treatment on shrimp surimi gel properties. The structure and physicochemical properties of myofibrillar protein (MP) were also determined. Low-field nuclear magnetic resonance showed that the fluidity of water molecules and the moisture content decreased, the stability and water holding capacity (WHC) increased after single ultrasound, single microwave and ultrasonic-microwave combination treatment. Compared with the traditional water bath treatment, ultrasound and microwave treatment reduced the total sulfhydryl content and promoted the formation of intermolecular disulfide bonds and hydrophobic interactions, which improved the compactness of the network structure of shrimp surimi gel. Moreover, Fourier transform infrared spectroscopy and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis revealed that these treatments not only inhibited the degradation of MP, but also decreased the α-helix content and increased the ß-sheet content. The three treatments also significantly reduced the particle size and decreased the solubility of MP. Overall, the effect of ultrasonic-microwave combination treatment was superior to that of either single treatment.

Independent and combined effects of ultrasound and transglutaminase on the gel properties and in vitro digestion characteristics of bay scallop (Argopecten irradians) adductormuscle.

The effects of transglutaminase (TGase) addition (0.4-1.2 g/100g), ultrasound (120-720 W, 20 min), and their combination on the gel properties and in vitro digestion characteristics of bay scallop adductor muscle were studied. The gel strength of the gel sample with TGase content of 0.8 g/100g (TG-0.8) was 58.2% higher than that of the control sample (CON). The gel sample treated with ultrasound at 480 W (UT-480) had the highest gel strength. The strength of the gel prepared by combination of 0.8 g/100g TGase and 360 W ultrasound (UT-TG) was 82.3% higher than that of CON. The whiteness and water holding capacity of the gel increased regardless of the addition of TGase or ultrasound treatment. SDS-PAGE patterns showed that the myosin heavy chain of the treated samples became thinner, and the changes of actin and tropomyosin were not significant. The scanning electron microscopy results of gel samples prepared by ultrasound combined with TGase showed a denser structure, which was related to the lowest total sulfhydryl content and TCA-soluble peptide content. The results of dynamic rheology show that the UT-TG sample had the highest G' value, followed by TG-0.8. The in vitro digestion characteristics of the selected gel samples were also discussed. The degree of protein hydrolysis and the content of free amino acids in TG-0.8 samples were the lowest, which improved after ultrasound treatment. Overall, the combination of appropriate ultrasound treatment and TGase addition provides an effective means for improving gel properties and digestibility of scallop surimi product.

Effect of Commercial Yeast Starter Cultures on Cabernet Sauvignon Wine Aroma Compounds and Microbiota.

Commercial Saccharomyces cerevisiae plays an important role in the traditional winemaking industry. In this study, the correlation of microbial community and aroma compound in the process of alcohol fermentation of Cabernet Sauvignon by four different commercial starters was investigated. The results showed that there was no significant difference in the fermentation parameters of the four starters, but there were differences in microbial diversity among the different starters. The wine samples fermented by CEC01 had higher microbial abundance. GC-MS detected a total of 58 aromatic compounds from the fermentation process by the experimental yeasts. There were 25 compounds in the F6d variant, which was higher than in other samples. The PCA score plot showed that 796 and F15 yeast-fermented wines had similar aromatic characteristic compositions. According to partial least squares (PLS, VIP > 1.0) analysis and Spearman's correlation analysis, 11, 8, 8 and 10 microbial genera were identified as core microorganisms in the fermentation of 796, CEC01, CECA and F15 starter, respectively. Among them, Leuconostoc, Lactobacillus, Sphingomonas and Pseudomonas played an important role in the formation of aroma compounds such as Ethyl caprylate, Ethyl caprate and Ethyl-9-decenoate. These results can help us to have a better understanding of the effects of microorganisms on wine aroma and provide a theoretical basis for improving the flavor quality of Cabernet Sauvignon wine.

Ultrasonic pretreatment improves the gelation properties of low-salt Penaeus vannamei (Litopenaeus vannamei) surimi.

The effects of different ultrasonic pretreatments (120-600 W, 20 min; 360 W, 10-30 min) on the gel properties of shrimp surimi were investigated. Gel properties and protein functional properties were analysed to clarify the mechanism of action of ultrasound. The gel strength, water holding capacity and surface hydrophobicity of shrimp surimi gel increased initially and then decreased with the increase in ultrasound power or time, but the change in total sulfhydryl content showed the opposite trend, which indicated that proper ultrasound pretreatment could improve the gel properties of shrimp surimi, expand the protein to a greater extent and expose more SH groups and hydrophobic groups. According to scanning electron microscopy observation, ultrasound made shrimp surimi gel form a denser gel network. Fourier transform infrared analysis indicated that the α-helix content in shrimp surimi gel decreased initially and then increased with the increase of in ultrasound power or time, whereas the change in ß-sheet content showed the opposite trend. And the protein was the most stable in 360 W/20 min pretreatment. SDS-PAGE patterns showed that proper ultrasound inhibited the degradation of actin and troponin C. In addition, dynamic rheology illustrated that the G' values of the ultrasonic pretreatment group were higher than that of the control group, indicating that ultrasound could improve the elasticity and stability of shrimp surimi gel. The results suggested that the shrimp surimi gel pretreated by 360 W/20 min ultrasound showed the best gel properties. Furthermore, the correlation between the indexes affecting the properties of the gel was analyzed. This study provides a new technical means to improve the gel properties of shrimp surimi.

A case of milk traceability in small-scale districts-Inner Mongolia of China by nutritional and geographical parameters.

As far as we known, recent studies on the origin of agricultural products rarely focus on the source of cities or counties even small-scale districts, but traceability of small-scale districts of food is the research trend and difficulty of future researches. The most commonly used methods of origin tracing researches are stable isotope and element technology, because these indicators are directly related to local geographical environment. However, when the region of traceability is very close, it is necessary to find new parameters to enhance the accuracy of traceability in small-scale districts. This study uses a combination of nutritional (amino acids) and geographical parameters (stable isotopes, elements) to trace the origin of milk from eleven districts located in five cities of Inner Mongolia. The results showed that the combination of nutritional (amino acids) and geographical parameters (stable isotopes, elements) was the best source tracing method.

[Simultaneous determination of 10 unapproved sedative drugs in feeds by ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry].

A new analytical method using ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was developed for screening and confirmation of 10 unapproved sedative drugs in feeds. The samples were extracted using the solution of methanol-0.1 mol/L HCl (9:1, v/v), and the extracts were centrifuged and then directly purified through MCX cartridges. The identification and detection were achieved in positive electrospray ionization (ESI) mode using Q-TOF-MS. The potential of UPLC-Q-TOF MS for confirmatory analysis was shown by determining the accurate mass of all the compounds and fragment ions upon collision-induced-dissociation (CID) at different energies. The extra mass measurement errors for all the sedative drugs were found to be within 5 ppm. The calibration graphs were linear in the concentration range of 5-100 microg/L with the correlation coefficients more than 0.99 for the 10 drugs. The limits of quantification (LOQ, S/N = 10) were 8 microg/kg for nitrazepam, zolpidem and thioridazine; 10 microg/kg for thriazolam, estazolam, diazepam, promethazine, chlorpromazine and midazolam; 20 microg/kg for clozapine. The recoveries for all the compounds in feeds were 60.6%-108.5% with the relative standard deviations less than 10% at the spiked levels of LOQ, 2LOQ and 4LOQ.

[Investigation of enhancing effect for hydride generation-atomic fluorescence of transition metal elements].

A mechanism of hydride generation based on disassembly reaction of hydrogen-transferred interim state [M(BH4)m]* was developed by investigating the effect of reaction medium acidity on hydride generation. The effects of Co2+ and Ni2+, phenanthroline and 8-hydroxyquinoline on hydride generation-atomic fluorescence signals of Zn, Cd, Cu and Ni were studied, respectively, and their enhancing mechnism was discussed. The enhancing effect Co2+ and Ni2+ on the fluorescence signals of Zn and Cd was due to the increase in transmission efficiency of hydride of Zn and Cd. There was a synergic enhancing effect between phenanthroline or 8-hydroxyquinoline and Co2+ on the fluorescence signals of Zn and Cd, however no synergic enhancing effect between phenanthroline and 8-hydroxyquinoline on the fluorescence signals of Zn and Cd. The simulative action of cationic surfactant, anion surfactant and non-ionic surfactant surfactant to hydride generation was investigated. It is shown that both cationic surfactant and non-ionic surfactant have obvious enhancing effect on the fluorescence signals of analytes because of the decrease in surface tension of reaction solution. The release characteristics of hydride from the absorption solution containing surfactant was ulteriorly examined by using graphite furnace atomic absorption spectrometry, and the mechanism of enhancing effect of surfactant on hydride generation and transmission was proposed.

[Simultaneous determination of residues of six imidazolinone herbicides in adzuki beans by high performance liquid chromatography-electrospray ion trap tandem mass spectrometry].

A method for the simultaneous determination of six pesticides in adzuki beans by high performance liquid chromatography-electrospray ion trap tandem mass spectrometry was developed and evaluated. The sample was extracted with 0.1 mol/L NH4HCO3 (pH 5)-methanol (70 : 30, v/v). The extract was partitioned with dichloromethane, and cleaned up with gel permeation chromatography. The separation was performed on an Inertsil ODS-3 column (150 mm x 2.1 mm, 5 microm) with the gradient elution of methanol and 1% acetic acid as mobile phase. The identification and quantification were performed by electrospray ion trap mass spectrometry with selected ion monitoring mode. The calibration curves of imidazolinone herbicides showed good linearities in the range of 10 - 200 microg/L (5 -100 microg/L for imazaquin) with the correlation coefficients between 0.998 7 and 0.999 7. The limits of detection ranged between 0.2 microg/kg and 0.5 microg/kg (S/N = 3). The average recoveries of six imidazolinone herbicides spiked in adzuki beans ranged between 81.6% and 99.4% (n = 6) with the relative standard deviations of 3.1% -7.8%. The method has been used for the determination of 6 imidazolinone herbicides simultaneously in adzuki beans with easy operation, high accuracy and good precision.

Simultaneous determination of trace cadmium and mercury in Chinese herbal medicine by non-dispersive atomic fluorescence spectrometry using intermittent flow vapor generator.

A method was proposed for the simultaneous determination of trace cadmium and mercury by vapor generation non-dispersive atomic fluorescence spectrometry using an intermittent flow system. The effects of the parameters on the performance were studied systematically. The parameters such as acid concentration of the reaction medium, flow rate of the carrier gas and shield gas, the observation height and the atomizer temperature, etc. which affected the sensitivity, were optimized. Ascorbic acid, cobalt ion and thiourea were used as enhancement reagents or masking agents to enhance the generation efficiency of the volatile species of Cd and Hg. The mechanisms of their effects on vapor generation were investigated. In the presence of thiourea and ascorbic acid, the influences of some coexisting elements on the determination of cadmium and mercury were investigated. The detection limits (3sigma) were 0.010 microg l(-1) for Cd and 0.019 microg l(-1) for Hg, respectively. The relative standard deviations for Cd and Hg at 1.00 microg l(-1) were 2.6% and 0.97% (n = 11), respectively. The proposed method has been satisfactorily applied to the determination of trace cadmium and mercury in Chinese herbal medicine.

Rapid method for the determination of trace fluoride and activation of ion-selective electrode.

A method for activating ISE is proposed that can allow determination of the fluoride concentration at ng mL(-1) level with good precision and accuracy. Fluoride ISE is activated in 0.5 mol L(-1) HClO4 medium and then fluoride is determined in the same medium. The linear range for the determination of fluoride is between 1.00 x 10(-2)-1.00 x 10(-7) mol L(-1), and the detection limit of the method is 1.0 ng mL(-1). The advantage of this method is that it is free from the use of TISAB solution while being, time-saving and labor-saving. A mechanism study of the activation of FISE in HClO4 medium is explained. The method has been used for the determination of trace fluoride in milk and flour with satisfactory results.