Abstract:Resistant starch (RS), as a novel dietary fiber, interacts with the gut microbiota, promoting the growth of some beneficial bacteria and the production of short-chain fatty acids, which is beneficial to human health. This review summarizes the classifications, preparations, structural characteristics, and physicochemical properties of resistant starch, as well as its effects on chronic kidney disease, including how it alleviates kidney damage and delays the progression of chronic kidney disease by regulating the gut microbiota, reducing uremic toxins, and systemic inflammation. The research findings provide a theoretical basis for the development of resistant starch-based foods with potential benefits for improving chronic kidney disease.

Abstract:Inflammatory bowel disease(IBD) is a chronic intestinal inflammatory disease, and additional nutritional support contributes to alleviate IBD symptoms. Studies have shown that dietary n-3 polyunsaturated fatty acids possess anti-inflammatory activity, while clinical trials have reported that additional supplementation with n-3 polyunsaturated fatty acids does not alleviate the disease symptoms in some IBD patients. Large-scale sequencing has revealed mutations in the n-3 polyunsaturated fatty acids receptor gene free fatty acid receptor 4(FFAR4). It remains unclear whether the variable effects of n-3 polyunsaturated fatty acids in IBD treatment are associated with the absence of the FFAR4 gene. In this study, the wild type(WT) and FFAR4 knockout (FFAR4KO) mice were used to establish the colitis models, concurrently supplemented with n-3 polyunsaturated fatty acids. The results showed that compared to those WT mice, the FFAR4KO mice exhibited more severer colitis under simultaneous n-3 polyunsaturated fatty acids supplementation, characterized by greater weight loss, higher disease activity index(DAI), increased colonic myeloperoxidase (MPO) activity, and higher mRNA levels of colonic inflammatory factors. This study provides a theoretical basis for precise nutritional intervention in IBD patients.

Abstract:To provide magnetic immobilized Mycobacterium tuberculosis isocitrate lyase(MtICL) suitable for affinity-driven enrichment screening of MtICL lead inhibitors from natural products, two hydrophilic magnetic beads were compared for immobilization of MtICL under the optimized conditions. MtICL was obtained via expression of recombinant 6×His-pET28a-ICL plasmid in E.coli BL21(DE3) and purification with Ni²⁺-NTA agarose column followed by characterization of enzymatic properties. Two amphoteric ion-rich hydrophilic magnetic beads, functionalized with carboxyl and Ni²⁺-NTA, were used to immobilize MtICL, respectively, for comparing their immobilization quantity, enzymatic activity, stability, and affinities for the known inhibitors. The apparent retention specific activity of carboxyl magnetic beads-immobilized MtICL was significantly higher than that of Ni²⁺-NTA magnetic bead-immobilized MtICL. When the mass ratio of carboxyl magnetic beads to protein was optimized to 60∶1, the apparent retention activity of the immobilized enzyme reached 85% of that of the free enzyme. The apparent saturated immobilization capacity of carboxyl magnetic beads for MtICL was (7.2±0.2) mg/g (calculated by magnetic beads weight, n=3). There was no significant difference in the affinity of carboxyl magnetic bead-immobilized MtICL for itaconic acid compared to that of free MtICL(P>0.05), and the stability was stronger. MtICL immobilized on carboxylic magnetic beads is suitable for the magnetic separation, affinite-driven, enrichment, and screening of MtICL inhibitors as anti-tuberculosis lead ligands from natural products.

Abstract:To investigate the effects of fermentation with lactic acid bacteria on the protein digestibility and quality characteristics of crackers, two types of lactic acid bacteria (Lactobacillus plantarum DN-1, Lactobacillus plantarum JN-1) were used in combination with yeast for fermentation to prepare biscuit products, respectively. The in vitro digestibility and nutritional indexes of protein and changes in quality and flavor of fermented crackers were determined. The results showed that compared with yeast-only fermented crackers and commercial soda biscuits, the in vitro digestibility of protein in crackers fermented with two types of lactic acid bacteria was both increased during the gastrointestinal digestion stage, with the highest in vitro digestibility of protein observed in crackers fermented with DN-1. The in vitro digestibility of protein increased from 81% to 86% compared with yeast-only fermented crackers during the intestinal digestion stage. Meanwhile, the hardness and crispness of cracker fermented with two types of lactic acid bacteria were both reduced. The results of solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) showed a significant increase in the total and species of esters and alcohols in crackers fermented with lactic acid bacteria. Compared with yeast-only fermented crackers, the relative content of esters and alcohols in DN-1-fermented crackers increased by 335% and 30%, respectively, with 26 and 24 species of esters and alcohols detected. Overall, fermentation with lactic acid bacteria can enhance the in vitro digestibility of protein in crackers, and improve and enrich the flavors of products.

Abstract:A method of simultaneous determination of 15 sulfonamides residues in aquatic products was established by solid phase extraction-high performance liquid chromatography (SPE-HPLC). The samples were extracted with ethyl acetate, degreased with n-hexane, and purified by polymer cation exchange (PCX) solid phase extraction column. The analysis was performed by high performance liquid chromatography with a chromatographic condition of separation on a Waters C₁₈ column (4.6 mm×250 mm, 5.0 μm) under gradient elution mode with methanol and PBS solution containing 1.1% acetic acid (0.01 mol/L) as the mobile phase. The target analytes were detected at the wavelength of 270 nm. The 15 sulfonamides were completely separated within 65 min, showing a good linear relationship within 0.5~10.0 μg/mL with correlation coefficients greater than 0.990 0. The limits of detection were in the range of 10~20 μg/kg, and the limits of quantitation were 20~60 μg/kg. The blank recovery rates of spiked samples at three mass fraction levels (500, 1 000, 2 000 μg/kg) ranged from 73.1% to 109.6% with the relative standard deviations (RSDs) of 1.0%~6.7%. The established detection method in this study showed good reproducibility, stability, and low detection limit. The residues of SAs in 10 different species of aquatic products from Jiangxi province were sampled and detected, and no residues were detected, indicating that the residues of SAs in aquatic products from Jiangxi province were not severe.

Abstract:In order to construct a high-quality recognition model for the six major tea categories, this study selected 370 samples and collected their near-infrared spectroscopy(NIRS). A rapid recognition model for the six major tea categories was developed by combined these data with spectral pre-processing, feature extraction and data mining classifier algorithms. The results indicated that: 1) Support vector machine(SVM) and random forest(RF) classifiers were both suitable for constructing rapid identification models for the six tea categories. 2) The SVM classifier was more suitable for modeling with the original spectrum(OS), and pre-processing algorithms tended to weaken the discriminatory performance of the models based on this classifier. 3) The RF algorithm was more suitable for modeling with pre-processing spectra, and the resulting models had a significant improvement in recognition accuracy (RA) and area under the curve (AUC) of the receiver operating characteristic curve compared to the OS models. 4) Among the feature extraction algorithms, the linear discriminant analysis(LDA) algorithm performed the best, yielding models with significantly improved RA compared to OS models. The optimal model, OS-LDA-SVM, achieved RA of 100.00% and AUC of 1.00, demonstrating high recognition rate, strong generalization ability, excellent model performance, and potential in industrial application. In summary, NIRS combined with pre-processing, feature extraction algorithms and classifiers to build models for the identification of the six tea categories was highly feasible. The models have high recognition accuracy and excellent performance, providing scientific, accurate, and efficient technical support for the rapid identification of tea categories in the tea trade, which could lay the foundation for the industrial application of international tea category identification models.

Abstract:The coating of areca nut with gelatin helps to enhance its gloss and water retention. However, the influence of gelatin concentration and bloom strength on coating performance is not yet clear. This study analyzed the differences in optical, mechanical, and water-barrier properties of gelatin-based films, and explored the causes of the variations in coating performance by infrared spectroscopy and X-ray diffraction. The results showed that the gelatin solution with the mass concentration of 100~150 g/L not only increased the gloss of areca nut by 8~15 times, but also endowed the film with good mechanical properties and water resistance. Although an increase in gelatin bloom strength enhanced the gloss of areca nut film, it had no significant effect on the mechanical properties and water resistance of the film. Differences in the content of intermolecular hydrogen bonding and triple helix structure in the film were crucial internal factors accounting for the different properties of gelatin coatings after film formation. Furthermore, the viscosity and coagulation temperature of the coating solution with a mass concentration of 100~150 g/L were more suitable for enhancing the uniformity of the coating film. This study can provide a scientific basis for the regulation of areca nut coating film performance and the rational selection of coating agents.

Abstract:In order to efficiently identify suspect transgenic positive samples in honey, ten transgenic promoters and terminators, i.e., CaMV35S promoter, NOS terminator, FMV35S promoter, NOS promoter, Ubi promoter, TA29 promoter, E9 terminator, OCS terminator, g7 terminator, CaMV35S terminator, were used as research targets. A series of experiments were conducted for these ten promoters and terminators, including primers combination screening, reaction condition optimization, sensitivity determination, and test comparison of quality control products. Three groups of multiple real-time fluorescence PCR reaction systems were established and applied to the detection of commercial honey. The result showed that the established three groups of multiple real-time fluorescence PCR reaction system could accurately detect the target gene, with sensitivities of 0.01, 0.04, 0.04 ng/μL, respectively. The tests of 14 genetically modified quality control products showed that the detection results of multiplex real-time fluorescence PCR and single-plex real-time fluorescence PCR were consistent. The screening of 40 commercial honeys showed that two honeys contained pCaMV35S and tNOS, and the others were not detected, greatly improving the detection efficiency. This method could provide a fast screening and detection technology for the detection of genetically modified ingredients in honey, and meanwhile, it could also be applicable to the detection of genetically modified ingredients in other products.

Abstract:To achieve a simple, rapid and efficient detection of two pathogens in shrimp products, a duplex fluorescent recombinase polymerase amplification(RPA) detection method was developed for infectious hypodermal and hematopoietic necrosis virus(IHHNV) and Enterocytozoon hepatopenaei (EHP). Primers and probes were designed based on the conserved sequences of IHHNV and EHP, and the duplex fluorescent RPA method was established. The specificity, sensitivity and repeatability of the method were validated. The results showed that the established method exhibited distinct amplification only for IHHNV and EHP. Detection using diluted plasmids of IHHNV and EHP demonstrated that the sensitivity of the duplex fluorescent RPA method for detecting IHHNV and EHP plasmids could reach 1×10² copies/μL. The method showed good repeatability with ten repeated plasmid samples. The method was employed to examine imported frozen shrimp samples, resulting in the discovery of one positive EHP and one positive IHHNV. Comparison of the detection results with fluorescent PCR showed consistency between the two methods. The method established in this research has important clinical significance for the distinguishing and detection of the two diseases, and can be applied to rapid screening methods for disease diagnosis in aquaculture farms, shrimp product production enterprises, and port laboratories.

Abstract:In order to study the characteristics of yeast extracts used in beverage, FA37 and FA39 were selected as the research objects, the main taste compounds and flavor substances were analyzed and the effects on four common sweeteners for beverages were discussed combined with sensory evaluation. First, the atomic absorption spectrophotometer was used to analyze the metal ions closely related to the flavors. The proportion of total free amino acids(TFAA) and the taste activity value (TAV) were calculated according to the composition of free amino acids to determine the contribution degree of flavor of each flavoring amino acid to the flavor of yeast extracts. The results showed that FA37 and FA39 contained less Na⁺ and K⁺, while the content of Zn²⁺ increased significantly. Meanwhile, the content of umami free amino acid decreased, while the proportion of sweet alanine was the highest, which helped to reduce the salty and umami tastes. In FA37 and FA39, peptides with the molecular weight below 1 000 were predominant, facilitating the enhancement of product flavor and thickness of taste. Subsequently, headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME/GC-MS) and electronic nose were used to analyze the flavor compounds, revealing that the relative contents of aldehydes were the highest in FA37 and FA39, and the main flavor substances of the two yeast extracts were 3-methylbutyraldehyde and benzaldehyde. Finally, sensory experiments demonstrated that FA37 and FA39 could enhance the sweetness intensity and sweetness speed of sweeteners, reduce the off-flavors, and improve the taste. In conclusion, the effects of yeast extracts used in beverage are promising, as they can not only reduce the off-flavors of sweeteners but also improve product quality through their unique flavors, which is of reference value for the development of new beverage products and the utilization of yeast extracts.

Abstract:To rapidly evaluate the differences in aroma compounds during the fermentation process of Pixian broad-bean paste, a metabolomics study was conducted using soft ionization by chemical reaction in transfer-mass spectrometry(SICRIT-MS) technology combined with multivariate statistical methods. The results revealed that SICRIT-MS completed a single detection in only 1~3 seconds. In addition, 18 differential components were identified in positive ion mode of mass spectrometry, and 11 in negative mode. These components can serve as potential characteristic markers to identify samples at different fermentation stages of broad-bean paste. The combination of SICRIT-MS and metabolomics techniques can provide the theoretical and technological support for rapid classification of Pixian broad-bean paste.

Abstract:To address the issue of heterogeneous expression products derived from proBMP10 (the precursor protein of bone morphogenetic protein 10, BMP10) in Chinese hamster ovary(CHO) cells caused by Furin, the mutations of proBMP10 at its Furin recognition sites, proBMP10-1 (R313K) and proBMP10-2(R316K), were constructed and site-directedly integrated into the genome of CHO-K1-BAK^-/BAX^- respectively. The recombinant CHO cell lines stably expressing the target proteins were successfully established. The results showed that the proBMP10-2 (R316K) was no longer cleaved by Furin and retained biological activity, while proBMP10-1 (R313K) continued to be cleaved by Furin.