Christiansenhiggins7428

Citrus fruit are consumed worldwide due to their excellent features, such as delicious taste and health-promoting compounds. However, section drying, a physiological disorder of citrus fruit, often occurs both in the preharvest and postharvest storage, causing a significant reduction in fruit quality and consumer acceptance. In this review, section drying of citrus fruit was divided into three types granulation, vesicle collapse and both above. The main causes, metabolic changes and mechanisms of section drying were discussed, respectively. Furthermore, the prevention methods of section drying in citrus fruit, including preharvest and postharvest methods, were also summarized. Given the significant influence of section drying in citrus fruit production, the mechanisms and prevention methods of section drying are worth further exploration. A better understanding of section drying may provide guidance for the prevention of this disorder and future breeding of citrus fruit.Fluindapyr is a pyrazolamide chiral fungicide of succinate dehydrogenase inhibitor (SDHIs) with two enantiomers. Pesticide enantiomers often exhibit different biological activities, toxicity due to their different enantioselectivity. Therefore, it is important to separate fluindapyr enantiomers and assess each enantiomer. In this study, fluindapyr enantiomers were baseline separated by supercritical fluid chromatography-mass spectrometry in 2 min. The limit of quantification (LOQ) of this method was 5 μg/kg. The developed method was applied to monitor the fluindapyr enantiomers in cucumber and tomato, the data showed that R-(-)-fluindapyr was preferentially degraded in tomato leaves, S-(+)-fluindapyr was preferentially degraded in cucumber leaves, and fluindapyr enantiomers had no enantioselective degradation behavior in two fruits. It is proved again that enantiomers have different enantioselective degradation behavior with the different plant species and even to different parts of the same plant. The enantioselectivity is likely to be caused by different biodegradation enzyme systems.This study investigated the Maillard reaction of infant formulas (IFs) produced by four thermal treatments during simulated consumption storage. Among the four sterilization conditions, seventy-five degrees, 2 min was considered the optimal sterilization treatment. The loss of available lysine, 3-DG content and FAST (fluorescence of advanced Maillard products and soluble tryptophan) index was lower in the initial IF produced by this treatment. After storage at 37 °C, 57% RH, the largest loss of available lysine was 71.41%. 5-hydroxymethylfurfural content increased to 7.28 mg/100 g with storage temperature and time, regardless of humidity. The content of α‑dicarbonyl compounds fluctuated during storage, and it was estimated that the maximum daily intake was 7.05 mg for 3-deoxyglucuronide and 3.6 mg for glyoxal. The average Nε-carboxymethyllysine concentration during storage at 37 °C was 615.844 ng/mL. At 37 °C, 75% RH, the highest FAST index was 87.11% and ΔE* was 29.95. Compared with thermal treatment, unfavorable storage conditions further promote the occurrence of the Maillard reaction. In particular, the storage temperature should be strictly controlled.A modified QuEChERS LC-MS/MS method was developed for 107 pesticides analysis in animal lipids such as pork lard, mutton tallow, chicken oil and butter. check details The challenges for high fat matrices clean up were studied in details by optimizing dispersive purification adsorbents coupled with rapid low temperature assistant methods. The method validation was carried out using pork lard and further appplied to other matrices by testing their recoveries. Good linearities were obtained with correlation coefficients greater than 0.99. Sensitive LOQs ranged from 5.0-50.0 μg kg-1. Both inter-day and intra-day precisions were lower than 20% indicating the good precision and accuracy of this method. The method applied to four animal lipids with 93%∼100% of analytes revealed satisfactory recoveries (ranged from 70% to 120%) and RSD (≤20%) at 10 µg kg-1and 50 µg kg-1 spiking levels respectively related to the matrix.This study aims to produce oligosaccharides by microwave-assisted hydrothermal hydrolysis of agarose, which is a more environmentally friendly and green economical approach than acid or enzymatic hydrolysis. Under the optimized condition of 160 °C and 25 min, total liquefaction of agarose was achieved, the dominant products in the hydrolysate are agaro-oligosaccharides (AOs), with only a small portion of d-galactose and 5- hydroxymethylfurfural (5-HMF). This approach can produce even and odd number AOs simultaneously, which is due to the random hydrolysis of α-1,3 glycosidic linkage at first and subsequent hydrolysis of the β-1,4 glycosidic linkage at the reducing end. The yield of AOs of a low degree of polymerization (DP) can reach about 57% of the theoretical maximum, while the total yield of AOs is over 90%. In conclusion, microwave-assisted hydrothermal hydrolysis is a way of producing oligosaccharides from agarose with extra-high efficiency and practical significance.In-situ, real-time and sensitive detection of multiple pesticide residues in food is always an important issue in food safety. Herein, a novel multifunctional bead-string like Ag nanowires@zeolitic imidazolate framework-8 (Ag NW@ZIF-8) core-shell nanochains was successfully synthesized and utilized as surface-enhanced Raman scattering (SERS) substrate for in-situ and simultaneous detection of pesticide residues. Due to the microporous framework structure of ZIF-8 shell and the plasmon property of Ag NWs core, the Ag NWs@ZIF-8 composite was demonstrated to have strong adsorption performance and high SERS activity (enhancement factor 4.6 × 107). The Ag NWs@ZIF-8 based SERS strategy achieved sensitive detection of two water-insoluble pesticides methylparathion and carbaryl with detection limits as low as 7.6 × 10-9 M and 5.7 × 10-9 M, as well as the in-situ detection of multi-pesticide residues on fruits and vegetables with acceptable recovery ranged from 77.4 % to 117.5 %, demonstrating its great potential for in-situ and rapid detection of food contaminants.A kinetic model was proposed by using a multiresponse kinetic modeling approach for Maillard and caramelization reactions in low moisture foods at neutral pH containing a moderate amount of amino acid and sucrose but a restricted amount reducing sugar. The change in the amount of sucrose, protein-bound lysine, free amino acids, and certain products of Maillard reaction was monitored during roasting of sunflower seed, pumpkin seed, flaxseed, peanut, and almond at 160 and 180 °C. A slightly different model was proposed for pumpkin seed due to its difference in compositional and physicochemical characteristics as expressed by principal component analysis. Accordingly, 3-deoxyglucosone formation via sugar degradation; 5-hydroxymethylfurfural formation from 3-deoxyglucosone and only in pumpkin seeds the conversion of N-ε-fructoselysine to glyoxal and Heyns product to 1-deoxyglucosone were found to be quantitatively important. N-ε-carboxymethyllysine and N-ε-carboxyethyllysine mainly originated through oxidation of N-ε-fructoselysine and the reaction of methylglyoxal with lysine residue, respectively.Most of the water-soluble zinc protoporphyrin IX (ZnPP) in Parma ham mainly exists as complexes with hemoglobin and myoglobin (ZnPP-Hb and ZnPP-Mb). To elucidate the formation mechanism of these complexes, a new experimental model to produce higher amount of water-soluble ZnPP complexes was established. ZnPP-Hb was detected as the main water-soluble ZnPP complex in this model, which is the same as that in Parma ham. Adding exogenous Hb into this model promoted higher ZnPP formation than with Mb added, indicating that Hb was the superior substrate for generating ZnPP compared to Mb. The increase in non-heme iron content with ZnPP formation in both the Hb- and Mb-added groups indicated that the release of iron ion from heme was a crucial step in ZnPP formation. ZnPP-Hb was formed when ZnPP non-enzymatically bound with apo-Hb. These results revealed the mechanism of why ZnPP-Hb is more dominant in Parma ham than to ZnPP-Mb.Dimeric quinoline-based Schiff base was developed (DQS) for the specific detection of Pb2+ ion via fluorimetry. DQS coordinates with Pb2+, a variation in fluorescence intensity with enhanced radical blue shift was observed due to the restriction of CN rotation, CN isomerization, and photoinduced electron transfer (PET) mechanisms. In addition, the intramolecular charge transfer (ICT) from electron-donating morpholine to phenylene diamine acceptor linked quinoline bridge is responsible for the blue-shifted fluorescence enhancement in the DQS-Pb2+ complex. The binding stoichiometry of DQS Pb2+ (12) was confirmed by host-guest titration and mass spectrometry. The limit of detection (LOD) of the DQS was found to be 1.3 × 10-7 M for Pb2+ ion. The DQS sensing ability of Pb2+ was further applied into milk and honey samples, smartphone, bio-imaging and to construct of an INHIBIT molecular logic gate.The effective adsorption and sensitive determination of microcystin-LR (MC-LR) are crucial for the environment and human health. In this work, a highly fluorinated magnetic covalent organic framework (denoted as Fe3O4@TabTfa-F4) was synthesized through a simple strategy. The morphology and structure of the as-prepared Fe3O4@TabTfa-F4 were investigated and Fe3O4@TabTfa-F4 showed that it had a high specific surface area (442.3 m² g-1), high fluorine content (6.0%), large pore volume (0.255 cm³ g-1), and strong magnetic responses (31.0 emu g-1). The new sorbent Fe3O4@TabTfa-F4 was applied for MC-LR adsorption. The adsorption behavior was investigated, and the results followed pseudo-second-order kinetics and the Langmuir adsorption model. The excellent adsorption capacities for MC-LR (Qmax = 495.1 mg g-1) may be due to the formation of numerous hydrogen bonds, hydrophobic interaction, and π-π stacking interaction between MC-LR and Fe3O4@TabTfa-F4. Afterward, Fe3O4@TabTfa-F4 was used to extract MC-LR from aqueous samples, followed by high-performance liquid chromatography incorporated with UV spectroscopy. The major parameters that influenced the extraction performance were investigated. The developed method exhibited good linearity in the range of 0.25-20 ng L-1. Under the optimum conditions, limits of detection (S/N=3), limits of quantitation (S/N=10), enrichment factor and relative standard deviation were calculated to be 0.041 ng mL-1, 0.13 ng mL-1, 425, and 9.6%, respectively. The spiked recoveries ranged within 75.3%-108.6%. These findings indicate that Fe3O4@TabTfa-F4 has potential application to the adsorption and sensitive detection of MC-LR from aqueous samples.Peptidic drugs with wide spectrum of physiological activity are of interest for cheating athletes and can be misused as doping in sports. A growing number of small peptide drugs capable of enhancing performance are included in the prohibited list issued by World Anti-Doping Agency (WADA), therefore the improvement of the detection methods is constantly needed. In the present study, a screening assay was developed comprising 54 prohibited small peptides and the related substances in urine by means of the alkaline pre-activated weak cation exchange-solid phase extraction (WCX-SPE) with liquid chromatography-high resolution mass spectrometry (LCHRMS). This method performed good enrichment and purification effect of traditional WCX for basic peptides, and also improve the purification power of acidic peptides, which significantly expanded the coverage of detection substances. The method was validated in accordance with WADA relevant criteria and validated with a main focus on qualitative parameters including selectivity, limits of detection (0.