Pectin mediates the mechanism of host blood glucose regulation through intestinal flora.

Pectin is a complex polysaccharide found in plant cell walls and interlayers. As a food component, pectin is benefit for regulating intestinal flora. Metabolites of intestinal flora, including short-chain fatty acids (SCFAs), bile acids (BAs) and lipopolysaccharides (LPS), are involved in blood glucose regulation. SCFAs promote insulin synthesis through the intestine-GPCRs-derived pathway and hepatic adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) pathway to promote hepatic glycogen synthesis. On the one hand, BAs stimulate intestinal L cells and pancreatic α cells to secrete Glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) through receptors G protein-coupled receptor (TGR5) and farnesoid X receptor (FXR). On the other hand, BAs promote hepatic glycogen synthesis through AMPK pathway. LPS inhibits the release of inflammatory cytokines through Toll-like receptors (TLRs)-myeloid differentiation factor 88 (MYD88) pathway and mitogen-activated protein kinase (MAPK) pathway, thereby alleviating insulin resistance (IR). In brief, both SCFAs and BAs promote GLP-1 secretion through different pathways, employing strategies of increasing glucose consumption and decreasing glucose production to maintain normal glucose levels. Notably, pectin can also directly inhibit the release of inflammatory cytokines through the -TLRs-MYD88 pathway. These data provide valuable information for further elucidating the relationship between pectin-intestinal flora-glucose metabolism.

Novel liquid fermentation medium of Cordyceps militaris and optimization of hydrothermal reflux extraction of cordycepin.

In this study, we developed a novel liquid fermentation medium of Cordyceps militaris using pupa powder and wheat bran as nitrogen resources instead of the traditionally used peptone. This process not only reduced the cost by approximately 50%, but increased production by over 30%. Then, we explored a method to extract and purify cordycepin by combining hydrothermal reflux extraction with macroporous resin adsorption, which is inexpensive and suitable for the industrial production. The optimum conditions for hydrothermal reflux were extracting three times at 95 °C with 1:10 sample-to-water ratio, and the cordycepin purity with macroporous resin HPD-100 reached 95.23%.[Formula: see text].

Discovery and identification of antimicrobial peptides in Sichuan pepper (Zanthoxylum bungeanum Maxim) seeds by peptidomics and bioinformatics.

Antimicrobial peptides (AMPs) have generated growing attention because of the increasing bacterial resistance. However, the discovery and identification of AMPs have proven to be challenging due to the complex purification procedure associated with conventional methods. For the reasons given above, it is necessary to explore more efficient ways to obtain AMPs. We established a new method for discovery and identification of novel AMPs by proteomics and bioinformatics from Zanthoxylum bungeanum Maxim seeds protein hydrolysate directly. This process was initially achieved by employing ultra-performance liquid chromatography-electrospray ionization-mass spectrometry/mass (UPLC-ESI-MS/MS) spectrometry to identify peptides derived from Z. bungeanum Maxim seed protein hydrolysates. Three online servers were introduced to predict potential AMPs. Sixteen potential AMPs ranging from 1.5 to 2.7 kDa were predicted and chemically synthesized, one of which, designated NP-6, inhibited activity against all the tested strains according to antimicrobial assay. Time-killing assay indicated that NP-6 could quickly kill almost all the Escherichia coli within 180 min and Staphylococcus aureus at 360 min. Moreover, the simulation 3D structure of NP-6 was consisted of α-helix and random coil, and this was verified by circular dichroism (CD) spectra. At last, the scanning electron microscope (SEM) images of E. coli and S. aureus treated by NP-6 demonstrated that NP-6 had a significant effect on bacteria cell morphology. Our findings provide an efficient approach for discovery of AMPs, and Z. bungeanum Maxim seeds may be a nature resource to extract antimicrobial agents.

Mechanism of antimicrobial peptide NP-6 from Sichuan pepper seeds against E. coli and effects of different environmental factors on its activity.

A novel antimicrobial peptide named NP-6 was identified in our previous work. Here, the mechanisms of the peptide against Escherichia coli (E. coli) were further investigated, as well as the peptide's resistance to temperature, pH, salinity, and enzymes. The transmission electron microscopy (TEM), confocal laser scanning microcopy (CLSM), and flow cytometric (FCM) analysis, combined with measurement of released K+, were performed to evaluate the effect of NP-6 E. coli cell membrane. The influence of NP-6 on bacterial DNA/RNA and enzyme was also investigated. The leakage of K+ demonstrated that NP-6 could increase the permeability of E. coli cell membrane. The ATP leakage, FCM, and CLSM assays suggested that NP-6 caused the disintegration of bacterial cell membrane. The TEM observation indicated that NP-6 could cause the formation of empty cells and debris. Besides, the DNA-binding assay indicated that NP-6 could bind with bacterial genomic DNA in a way that ethidium bromide (EB) did, and suppress the migration of DNA/RNA in gel retardation. Additionally, NP-6 could also affect the activity of ß-galactosidase. Finally, the effect of different surroundings such as heating, pH, ions, and protease on the antimicrobial activity of NP-6 against E. coli was also investigated. Results showed that the peptide was heat stable in the range of 60~100 °C and performed well at pH 6.0~8.0. However, the antimicrobial activity of NP-6 decreased significantly in the presence of Mg2+/Ca2+, and after incubation with trypsin/proteinase K. The results will provide a theoretical support in the further application of NP-6.

ProLo: Localization via Projection for Three-Dimensional Mobile Underwater Sensor Networks.

We study the problem of three-dimensional localization of the underwater mobile sensor networks using only range measurements without GPS devices. This problem is challenging because sensor nodes often drift with unknown water currents. Consequently, the moving direction and speed of a sensor node cannot be predicted. Moreover, the motion devices of the sensor nodes are not accurate in underwater environments. Therefore, we propose an adaptive localization scheme, ProLo, taking these uncertainties into consideration. This scheme applies the rigidity theory and maintains a virtual rigid structure through projection. We have proved the correctness of this three-dimensional localization scheme and also validated it using simulation. The results demonstrate that ProLo is promising for real mobile underwater sensor networks with various noises and errors.

Electrochemistry Study of Permselectivity and Interfacial Electron Transfers of a Branch-Tailed Fluorosurfactant Self-Assembled Monolayer on Gold.

We investigated the permselectivity and interfacial electron transfers of an amphiphilic branch-tailed fluorosurfactant self-assembled monolayer (FS-SAM) on a gold electrode by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The FS-SAM was prepared by a self-assembly technique and a "click" reaction. The barrier property and interfacial electron transfers of the FS-SAM were also evaluated using various probes with different features. The FS-SAM allowed a higher degree of permeation by small hydrophilic (Cl- and F-) electrolyte ions than large hydrophobic (ClO4- and PF6-) ones. Meanwhile, the redox reaction of the Fe(CN)63- couple was nearly completely blocked by the FS-SAM, whereas the electron transfer of Ru(NH3)63+ was easier than that of Fe(CN)63-, which may be due to the underlying tunneling mechanism. For hydrophobic dopamine, the hydrophobic bonding between the FS-SAM exterior fluoroalkyl moieties and the hydrophobic probes, as well as the hydration resistance from the interior hydration shell around the oligo (ethylene glycol) moieties, hindered the transport of hydrophobic probes into the FS-SAM. These results may have profound implications for understanding the permselectivity and electron transfers of amphiphilic surfaces consisting of molecules containing aromatic groups and branch-tailed fluorosurfactants in their structures.

An Overview of Plant Phenolic Compounds and Their Importance in Human Nutrition and Management of Type 2 Diabetes.

In this paper, the biosynthesis process of phenolic compounds in plants is summarized, which include the shikimate, pentose phosphate and phenylpropanoid pathways. Plant phenolic compounds can act as antioxidants, structural polymers (lignin), attractants (flavonoids and carotenoids), UV screens (flavonoids), signal compounds (salicylic acid, flavonoids) and defense response chemicals (tannins, phytoalexins). From a human physiological standpoint, phenolic compounds are vital in defense responses, such as anti-aging, anti-inflammatory, antioxidant and anti-proliferative activities. Therefore, it is beneficial to eat such plant foods that have a high antioxidant compound content, which will cut down the incidence of certain chronic diseases, for instance diabetes, cancers and cardiovascular diseases, through the management of oxidative stress. Furthermore, berries and other fruits with low-amylase and high-glucosidase inhibitory activities could be thought of as candidate food items in the control of the early stages of hyperglycemia associated with type 2 diabetes.

Incorporation of cellulose nanocrystals to improve the physicochemical and bioactive properties of pectin-konjac glucomannan composite films containing clove essential oil.

This study aimed to investigate the effectiveness of cellulose nanocrystals (CNC) isolated from cotton in augmenting pectin (PEC)/konjac glucomannan (KGM) composite films containing clove essential oil (CEO) for food packaging application. The effects of CNC dosage on film properties were examined by analyzing the rheology of film-forming solutions and the mechanical, barrier, antimicrobial, and CEO-release properties of the films. Rheological and FTIR analysis revealed the enhanced interactions among the film components after CNC incorporation due to its high aspect ratio and abundant hydroxyl groups, which can also prevent CEO droplet aggregation, contributing to form a compact microstructure as confirmed by SEM and 3D surface topography observations. Consequently, the addition of CNC reinforced the polysaccharide matrix, increasing the tensile strength of the films and improving their barrier properties to water vapor. More importantly, antibacterial, controlled release and kinetic simulation experiments proved that the addition of CNC could further slow down the release rate of CEO, prolonging the antimicrobial properties of the films. PEC/KGM/CEO composite films with 15 wt% CNC was found to have relatively best comprehensive properties, which was also most effective in delaying deterioration of grape quality during the storage of 9 days at 25 °C.

Effects of High-Pressure Homogenization Treatment on the Development of Antioxidant Zanthoxylum bungeanum Leaf Powder Films for Preservation of Fresh-Cut Apple.

This study determined that Zanthoxylum bungeanum leaves (ZBLs) are rich in functional components such as cellulose, protein, flavone, and polyphenols. Therefore, they were used as the main raw material, with sodium alginate as a thickener and glycerol as a plasticizer, to investigate the preparation of active films from ZBL powder through high-pressure homogenization (HPH). The physical, optical, mechanical, and antioxidant properties of the films were evaluated, and their application in preserving fresh-cut apples was examined. The results showed that the optimal concentration of ZBL powder was 1.5% under a 30 MPa HPH treatment. The resulting HPH-treated films exhibited a denser microstructure and improved water vapor barrier properties and mechanical strength. Compared to the films without HPH treatment, the tensile strength increased from 4.61 MPa to 12.13 MPa, the elongation at break increased from 21.25% to 42.86%, the water vapor permeability decreased from 9.9 × 10-9 g/m·s·Pa to 8.0 × 10-9 g/m·s·Pa, and the transparency increased from 25.36% to 38.5%. Compared to the control group, the fresh-cut apples packaged with the HPH-treated ZBL active films exhibited effective preservation of apple quality during a five-day period at 4 °C and 70% humidity, showing better preservation effects than the other groups. In conclusion, the use of HPH treatment in developing novel biopolymer active films from ZBL powders with enhanced properties holds potential for various applications.

Sustainable Starch/Lignin Nanoparticle Composites Biofilms for Food Packaging Applications.

Construction of sustainable composite biofilms from natural biopolymers are greatly promising for advanced packaging applications due to their biodegradable, biocompatible, and renewable properties. In this work, sustainable advanced food packaging films are developed by incorporating lignin nanoparticles (LNPs) as green nanofillers to starch films. This seamless combination of bio-nanofiller with biopolymer matrix is enabled by the uniform size of nanofillers and the strong interfacial hydrogen bonding. As a result, the as-prepared biocomposites exhibit enhanced mechanical properties, thermal stability, and antioxidant activity. Moreover, they also present outstanding ultraviolet (UV) irradiation shielding performance. As a proof of concept in the application of food packaging, we evaluate the effect of composite films on delaying oxidative deterioration of soybean oil. The results indicate our composite film could significantly decrease peroxide value (POV), saponification value (SV), and acid value (AV) to delay oxidation of soybean oil during storage. Overall, this work provides a simple and effective method for the preparation of starch-based films with enhanced antioxidant and barrier properties for advanced food packaging applications.

Effects of cinnamon essential oil-loaded Pickering emulsion on the structure, properties and application of chayote tuber starch-based composite films.

The use of non-conventional starch sources to develop biodegradable and bioactive starch-based films have attracted increasing attention recently. In this study, a nonconventional chayote tuber starch (CTS) was functionalized by zein-pectin nanoparticle-stabilized cinnamon essential oil (CEO) Pickering emulsion (ZPCO) to develop a novel bioactive composite films for food packaging application. Results demonstrated that antibacterial ZPCO featuring long-term stability was successfully obtained. FTIR and SEM analyses suggested that ZPCO have favorable dispersibility and compatibility with CTS matrix. With ZPCO increasing, the transmittance, tensile strength, and moisture content of composite films decreased, whereas their elongation at break, antimicrobial and antioxidant activities increased. ZPCO added at an appropriate level (2 %) can improve water-resistance of the films and reduce water vapor permeability. More importantly, ZPCO can achieve a slower sustained-release of CEO from composite films into food simulants. Furthermore, the composite film containing 2 % ZPCO is safe and nontoxic as proved by cell cytotoxicity test, and it can significantly prolong the shelf life of ground beef by showing the lowest total volatile base nitrogen and best acceptable sensory characteristic. Overall, the incorporation of ZPCO into CTS films offers a great potential application as a bioactive material in the food packing.

Effect of hydroxypropyl-ß-cyclodextrin and lecithin co-stabilized nanoemulsions on the konjac glucomannan/pullulan film.

In this study, the various ratio of hydroxypropyl-ß-cyclodextrin (HPCD) to lecithin (LEC) was 0:1, 0.5:1, 1:1, 1.5:1 and 2:1 (w/w) co-stabilized cinnamon essential oil (CEO) nanoemulsions were prepared. These nanoemulsions were successfully incorporated in the konjac glucomannan/pullulan polysaccharides-based film matrix. The composition of nanoemulsions and the effect of various nanoemulsions on rheological, mechanical, Water vapor permeability, optical, color, morphology properties, and CEO retention rate of the composite films were characterized. The results demonstrated that HPCD and LEC nanoemulsions had small particle size under 120 nm and high stability during 21 days storage, the incorporation of nanoemulsions reduced the viscosity of film-solution, transmittance, Water vapor permeability and mechanical properties of films, but an appropriate HPCD content 1:1 w/w of nanoemulsions could restored the mechanical properties of the films. Otherwise, 1:1 w/w of nanoemulsion film also exhibited a more compact and uniform structure, Furthermore, 2:1 w/w of nanoemulsion films with high retention rate of CEO, and the antioxidant and better antibacterial activities against E. coli and S. aureus. The nanoemulsion films utilized in this study also prolonged the shelf life of Agaricus bisporus mushrooms and cherries while maintaining their commercial value.

A Facile Strategy for Development of pH-Sensing Indicator Films Based on Red Cabbage Puree and Polyvinyl Alcohol for Monitoring Fish Freshness.

This study aimed to develop a novel pH-sensing biopolymer film based on red cabbage puree (RCP) incorporated with polyvinyl alcohol (PVA), which was utilized for monitoring fish freshness during storage at 25 °C. A homogenized RCP suspension with a mean particle size of 12.86 ± 0.03 µm and a total anthocyanin concentration of 292.17 ± 2.65 mg/L was directly used as a film-forming substance and anthocyanin source to blend with PVA, showing visual changes in color and ultraviolet-visible spectra within a pH of 2-12. Rheological and microstructural studies certified the strong interactions and good compatibility between the RCP and PVA, resulting in better mechanical properties and water resistance of the composite film than those of a pure RCP film, but without affecting its pH sensitivity. When used for fish freshness monitoring at 25 °C, the developed RCP/PVA film presented visible color differences from purple to yellow, which corresponded to the spoilage threshold of the total volatile basic nitrogen and the total viable count in fish samples. The study highlights that anthocyanin-rich purees of fruits and vegetables, in this case red cabbage puree, can be fully utilized to develop eco-friendly pH-sensing indicator films for intelligent food packaging.

Composition, structure and flavor mechanism of numbing substances in Chinese prickly ash in the genus Zanthoxylum: A review.

Chinese prickly ash is known for producing a typical pungent sensation in Sichuan Cuisine. Accumulating evidence suggest a series of health benefits and pharmacological effects associated with prickly ash. Therefore, a systematic analysis of the composition, structural properties, detection, and flavor mechanism of numbing substances is highly necessitated to address their future application. Sanshool-based unsaturated amides are the primary cause of tingling. The numbing substances have poor stability and are prone to oxidation and decomposition reactions due to their highly unsaturated conjugated diene structures. Pungent sensations evoked by different sanshools are distinct, which is attributed to different mechanisms of interaction with membrane ion channels (TRPV1, TRPA1, and KCNK). In this paper, the composition, structural properties (such as isomerization, oxidation), detection, and flavor mechanism of numbing substances of prickly ash were summarized. The prospective application and future research direction of numbing substances in the prickly ash industry were also proposed.

A coarse-refine segmentation network for COVID-19 CT images.

The rapid spread of the novel coronavirus disease 2019 (COVID-19) causes a significant impact on public health. It is critical to diagnose COVID-19 patients so that they can receive reasonable treatments quickly. The doctors can obtain a precise estimate of the infection's progression and decide more effective treatment options by segmenting the CT images of COVID-19 patients. However, it is challenging to segment infected regions in CT slices because the infected regions are multi-scale, and the boundary is not clear due to the low contrast between the infected area and the normal area. In this paper, a coarse-refine segmentation network is proposed to address these challenges. The coarse-refine architecture and hybrid loss is used to guide the model to predict the delicate structures with clear boundaries to address the problem of unclear boundaries. The atrous spatial pyramid pooling module in the network is added to improve the performance in detecting infected regions with different scales. Experimental results show that the model in the segmentation of COVID-19 CT images outperforms other familiar medical segmentation models, enabling the doctor to get a more accurate estimate on the progression of the infection and thus can provide more reasonable treatment options.

Degradation and transformation mechanisms of numbing substances: Hydroxyl-α-sanshool & hydroxyl-ß-sanshool from Zanthoxylum bungeanum exposed to acid environment.

In present work, Zanthoxylum bungeanum meal (ZBM) used as experimental material, the stability of typical alkylamides (hydroxyl-α-sanshool and hydroxyl-ß-sanshool) in ZBM under different acidification conditions was investigated, in order to reveal degradation or transformation mechanism of numbing substances from Z. bungeanum exposed to acid environment and its transform direction. The alkylamides content of ZBM was detected by using HPLC after different conditions of acidification. The results indicated that hydroxyl-α-sanshool and hydroxyl-ß-sanshool under the concentration of hydrochloric acid is 14% decreased by 80% after only 0.5 h. Moreover, some of the components undergo isomerization and addition reactions in the process of acidification, the products of isomerization are hydroxyl-ε-sanshool and (1Z,2E,4E,8E,10E)-N-(2-hydroxy-2-methylpropyl)dodeca-2,4,8,10-tetraenimidic acid; and the product of the addition reaction is (2E,6E,8E,10E)-1-chloro-1-(2-hydroxy-2-methylpropyl)amino)dodeca-2,6,8,10-tetraen-1-ol, which indicated that acid environment has greatly changed the numbing substances in Z. bungeanum and its products.

A label-free electrochemical aptasensor based on AuNPs-loaded zeolitic imidazolate framework-8 for sensitive determination of aflatoxin B1.

In this study, an electrochemical aptasensor for sensitive detection of aflatoxin B1 (AFB1) was fabricated by electrodepositing gold nanoparticles (AuNPs) on the glass carbon electrode (GCE) modified with zeolitic imidazolate framework-8 (ZIF-8). The high specific surface area of AuNPs/ZIF-8 nanocomposite increased the aptamers loading on the electrode surface. When compared to other previously reported sensors, the developed aptasensor exhibited a wider linear range of 10.0 to 1.0 × 105 pg/mL with a lower limit of detection (LOD) of 1.82 pg/mL under the optimized conditions. Furthermore, the obtained results revealed that the constructed aptasensor exhibited outstanding selectivity, reproducibility and stability. Moreover, the aptasensor was successfully employed to detect the AFB1 in corn oil and peanut oil samples, with recoveries ranging from 93.49% to 106.9%, demonstrating the potential application value of this methodology.

Identification of two bitter components in Zanthoxylum bungeanum Maxim. and exploration of their bitter taste mechanism through receptor hTAS2R14.

Bitterness is an inherent organoleptic characteristic affecting the flavor of Zanthoxylum bungeanum Maxim. In this study, the vital bitter components of Z. bungeanum were concentrated through solvent extraction, sensory analysis, silica gel chromatography, and thin-layer chromatographic techniques and subsequently identified by UPLC-Q-TOF-MS. Two components with the highest bitterness intensities (BIs), such as 7-methoxycoumarin and 8-prenylkaempferol were selected. The bitter taste perceived thresholds of 7-methoxycoumarin and 8-prenylkaempferol were 0.062 mmol/L and 0.022 mmol/L, respectively. Moreover, the correlation between the contents of the two bitter components and the BIs of Z. bungeanum were proved. The results of siRNA and flow cytometry showed that 7-methoxycoumarin and 8-prenylkaempferol could activate the bitter receptor hTAS2R14. The results concluded that 7-methoxycoumarin and 8-prenylkaempferol contribute to the bitter taste of Z. bungeanum.

Incorporation of Lipids into Wheat Bran Cellulose/Wheat Gluten Composite Film Improves Its Water Resistance Properties.

This work evaluated the improvement effects of lipids incorporation on water resistance of composite biodegradable film prepared with wheat bran cellulose/wheat gluten (WBC/WG) using an alkaline-ethanol film forming system. Four types of lipids, paraffin wax (PW), beeswax (BW), paraffin oil (PO), and oleic acid (OA), were tested. We found that PW, BW, and PO incorporation at 5-20% improved water vapor permeability (WVP) and surface hydrophobicity of prepared films. Particularly, incorporation of 15% BW could best improve the water resistance properties of the film, with the lowest WVP of 0.76 × 10-12 g/cm·s·Pa and largest water contact angle (WCA) of 86.18°. Incorporation of OA led to the decline in moisture barrier properties. SEM images revealed that different lipids incorporation changed the morphology and of the composite film, and cross-sectional morphology indicated BW-incorporated film obtained more uniform and compact structures compared to other films. Moreover, Fourier transform infrared spectra indicated that the incorporation of PW or BW enhanced the molecular interactions between the film components, confirmed by the chemical shift of characteristic peaks at 3277 and 1026 cm-1. Differential scanning calorimetry results revealed that incorporation of PW, BW, and PO increased films' melting point, decomposition temperatures, and enthalpy values. Furthermore, the presence of most lipids decreased tensile strength and elongation at the break of the film. Overall, the composite film containing 15% BW obtained the most promising water resistance performance and acceptable mechanical properties, and it thus most suitable as a hydrophobic biodegradable material for food packaging.

Optimization, characterization and rheological behavior study of pectin extracted from chayote (Sechium edule) using ultrasound assisted method.

Pectin is one of high-value functional food ingredients. Better knowledge of properties of chayote pectin would help to promote the application of the chayote as a pectin source. In this study, ultrasound-assisted extraction (UAE) was used to extract chayote pectin. The extraction parameters were optimized by a Box-Behnken response surface design. The highest yield (6.19%) was obtained at a liquid/solid ratio of 50 mL/g, ultrasonic temperature of 70 °C and ultrasonic time of 40 min as optimized extraction conditions. The chemical properties, spectral information and rheological properties of pectin extracted with UAE under the optimum conditions (PEUO) were measured and the results indicated that the PEUO exhibited a low degree of esterification, high molar mass (2.47 × 106 g/mol) and suitable foaming capacity. The PEUO featured a stronger antioxidant capacity compared to commercially apple pectin and the PEUO solutions (1%, 2%, 3% and 5%) showed a non-Newtonian behavior. Hence, PEUO may provide beneficial characteristics to find use in food industry.