Rapid characterization of Maillard reaction products in heat-treated honey by nanoelectrospray ionization mass spectrometry.

Amadori rearrangement products (ARPs) and α-dicarbonyl compounds (α-DCs) are critical intermediates in the Maillard chemistry. The screening of artificially heated honey (AH) is currently based on chromatography-mass spectrometry, which is commonly accompanied with the longer pretreatment and detection time. Here, low-abundance ARPs were detected directly in high-sugar environment by nanoelectrospray ionization mass spectrometry (nanoESI-MS) coupled with borosilicate glass capillaries (O-tips). When O-tips were replaced by borosilicate theta capillaries (θ-tips), the microdroplets allowed the derivatization of α-DCs to be accomplished on the millisecond timescale, rather than hours in conventional protocols. The results indicated that two ARPs and α-DCs of m/z 235 were significantly up-regulated in AH. Meanwhile, the straightforward differentiation between naturally matured honey (NH) and AH was achieved by nanoESI-MS fingerprints combined with multivariate analysis. The method may provide a rapid characterization of Maillard reaction products (MRPs), which exhibits the great application potential in other complex food matrix.

Citrus Honey Ameliorates Liver Disease and Restores Gut Microbiota in Alcohol-Feeding Mice.

Citrus honey (CH) is rich in nutrients that have a wide variety of biological functions, such as antibacterial, anti-inflammatory, and antioxidant activities, and which demonstrate therapeutic properties, such as anti-cancer and wound-healing abilities. However, the effects of CH on alcohol-related liver disease (ALD) and the intestinal microbiota remain unknown. This study aimed to determine the alleviating effects of CH on ALD and its regulatory effects on the gut microbiota in mice. In total, 26 metabolites were identified and quantified in CH, and the results suggested that the primary metabolites were abscisic acid, 3,4-dimethoxycinnamic acid, rutin, and two markers of CH, hesperetin and hesperidin. CH lowered the levels of aspartate aminotransferase, glutamate aminotransferase, and alcohol-induced hepatic edema. CH could promote the proliferation of Bacteroidetes while reducing the abundance of Firmicutes. Additionally, CH also showed some inhibitory effects on the growth of Campylobacterota and Turicibacter. CH enhanced the secretion of short-chain fatty acids (SCFAs), such as acetic acid, propionic acid, butyric acid, and valeric acid. Given its alleviating functions in liver tissue damage and its regulatory effects on the gut microbiota and SCFAs, CH could be a promising candidate for the therapeutic treatment of ALD.

Identification of the botanical origins of honey based on nanoliter electrospray ionization mass spectrometry.

The botanical origins of honey are important for the quality control and commercialization of honey. In this research, we established a nanoliter electrospray ionization mass spectrometry (Nano-ESI-MS) method to identify Castanopsis honey (CH), Eurya honey (EH), Dendropanax dentiger honey (DH), and Triadica cochinchinensis honey (TH). In total, 38 compounds were identified based on the collision-induced dissociation experiments by Nano-ESI-MS with 16 differential compounds and 7 quantified as potential differential markers. These four types of honey were distinguished from each other by their mass spectrometry data combined with multivariate analysis with three out of the 7 differential markers, i.e., phenethylamine, tricoumaroyl spermidine, and (+/-)-abscisic acid, identified as potential markers for CH, EH, and DH, respectively. Both the qualitative and quantitative results derived from Nano-ESI-MS were further verified by UPLC-Q/TOF-MS. Our studies provided the significant potential of the Nano-ESI-MS method in the identification of the botanical origins of different kinds of honey.

Identification and characterization of plant-derived biomarkers and physicochemical variations in the maturation process of Triadica cochinchinensis honey based on UPLC-QTOF-MS metabolomics analysis.

The maturation patterns of nectar into honey are not well understood. The current work selected Triadica cochinchinensis honey (TCH) at three maturity stages to systematically investigate the variation patterns in physicochemical parameters and metabolites. Based on both targeted and untargeted metabolomics analyses, the N1, N5, N10-(E)-tricoumaryl spermidine was identified as the plant-derived characteristic compound in TCH. A total of 26 compounds were quantified by UPLC-QTOF-MS using an external standard calibration method. Two patterns of the honey maturation process were identified based on the 723 metabolite signature transformations. The first was that the levels of plant-derived compounds with strong reducing activity were reduced, such as spermidine, flavonoids, and their derivatives. In contrast, the second pattern was that the maturation process of honey was accompanied by the formation of lactone glycoside analogs and organic acids, which may be facilitated by the enzymatic transformation of enzymes secreted by the bees.

Quality assessment of royal jelly based on physicochemical properties and flavor profiles using HS-SPME-GC/MS combined with electronic nose and electronic tongue analyses.

Royal jelly (RJ) is known for its unique flavor and nutritional value. However, the flavor changes of RJ during storage remain unclear. In this work, the flavor profiles of RJ during storage were evaluated by using headspace solid-phase micro-extraction gas chromatography-mass spectrometry (HS-SPME-GC/MS) combined with both electronic nose and electronic tongue analyses. Results revealed that the moisture, water-soluble protein, and whiteness were changed significantly at 25 °C. The holistic variation of RJ flavor exhibited evident distinction based on principal component analysis with electronic nose and electronic tongue. Among the total of 37 volatile compounds identified in RJ, the octanoic acid showed the highest contents of 47.61 % at 25 °C in 21 d. Seven volatile compounds, i.e., 2(3H)-furanone,5-butyldihydro-, 2-heptanone, trans-ß-ocimene, 2-nonen-4-one, 2-nonanone, methyl benzoate, and 2-octenoic acid (E), contributed largely to the typical overall flavor of RJ. This work provides an improved understanding of the flavor change of RJ during storage.

Honeycomb, a New Food Resource with Health Care Functions: The Difference of Volatile Compounds found in Apis cerana and A. mellifera Honeycombs.

The honeycomb composition is very complex, containing honey, royal jelly, pollen, and propolis, and thus contains a large number of bioactive ingredients, such as polyphenols and flavonoids. In recent years, honeycomb as a new functional food resource has been favored by many bee product companies, but the basic research on honeycomb is lacking. The aim of this study is to reveal the chemical differences between A. cerana honeycombs (ACC) and A. mellifera honeycombs (AMC). In this paper, we studied the volatile organic components (VOCs) of ACC and AMC by solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME/GC-MS). A total of 114 VOCs were identified in 10 honeycombs. Furthermore, principal component analysis (PCA) revealed that the chemical composition of ACC and AMC were different. Additionally, orthogonal partial least squares discrimination analysis (OPLS-DA) revealed that benzaldehyde, octanal, limonene, ocimene, linalool, α-terpineol, and decanal are the significant VOCs in AMC extracts, which are mainly derived from propolis. OPLS-DA model also identified 2-phenylethanol, phenethyl acetate, isophorone, 4-oxoisophorone, betula, ethyl phenylacetate, ethyl palmitate, and dihydrooxophorone as potential discriminatory markers of ACC, which likely contribute to protecting the hive against microorganisms and keep it clean.

Monofloral Triadica Cochinchinensis Honey Polyphenols Improve Alcohol-Induced Liver Disease by Regulating the Gut Microbiota of Mice.

Honey produced from medicinal plants holds great promise for human health. Increasing evidence suggests that the gut microbiota plays an important role in liver pathology after alcohol intake. The aim of this study was to identify the polyphenol composition of triadica cochinchinensis honey (TCH), and to study the potential effect of honey polyphenols on the regulation of gut microbes in mice with alcohol-induced liver injury and the improvement of alcohol-induced liver disease. For these purposes, a total of 190 compounds were identified and 27 of them were quantified by ultraperformance liquid chromatography coupled with quadrupole/time-of-flight mass spectrometry (UPLC-Q/TOF-MS) and we successfully established a mouse model of alcohol-induced liver injury. The results show that TCH polyphenols can significantly restore the levels of ALT and AST, and TCH intervention can significantly improve the pathological changes of liver tissue in alcohol-exposed mice. Additionally, a significant decrease was observed in Firmicutes/Bacteroidetes after TCH treatment. Moreover, KEGG pathways of ATP-binding cassette (ABC) transporters, two-component system and biosynthesis of amino acids enriched the most differentially expressed genes after TCH intervention for 8 weeks. Our results may have important implications for the use of TCH as a functional food component with potential therapeutic utility against alcohol-induced liver disease.

Peanut selenium distribution, concentration, speciation, and effects on proteins after exogenous selenium biofortification.

Fortification of Se is vital importance for both nutritional demand and prevention of Se-deficiency-related diseases. To better understand t selenium distribution, concentration, speciation, its effects on proteins, and cytotoxic activity, the biofortification of exogenous Se in peanut was conducted in this study. Our data have shown that foliar spraying of Se-riched fertilizer was more efficient for biotransformation of inorganic Se to organic Se by peanut plant. Besides, the Se content in peanut was increased in a dose-dependent manner. Our present study also confirmed that SeCys2, MeSeCys, and SeMet were the main Se speciation within peanut proteins. Moreover, the secondary structure and thermostability of peanut protein were altered as a result of the Se treatments, and these alterations could be attributed to the replacements of cysteine and methionine by selenocysteine and selenomethionine, respectively. The Se-enriched peanut protein could significantly inhibit the growth of Caco-2 and HepG2 in a concentration-dependent manner.

Improving in vitro bioaccessibility and bioactivity of carnosic acid using a lecithin-based nanoemulsion system.

As a phenolic terpenoid, carnosic acid (CA) mainly exists in rosemary, which can be effectively used for the treatment of degenerative and chronic diseases by taking advantage of its health-promoting bioactivities. However, the low solubility and dissolution of CA in aqueous solutions at ambient and body temperatures result in low stability and bioaccessibility during the digestion process, which limits its application scope in the functional foods industry. In this regard, a lecithin based nanoemulsion system (CA-NE) is employed in the present work to enhance the bioaccessibility and bioactivities of CA. It is revealed that the CA-NE under investigation exhibits high loading capacity (2.80 ± 0.15%), small particle size (172.0 ± 3.5 nm) with homogeneous particle distribution (polydispersity index (PDI) of 0.231± 0.025) and high repulsive force (zeta potential = -57.2 ± 0.24 mV). More importantly, the bioaccessibility of CA-NE is improved by 2.8-fold compared to that of CA in MCT oil. In addition, the cellular antioxidant assay (CAA) and cellular uptake study of the CA-NE in HepG2 cell models demonstrate a longer endocytosis process, suggesting the well-controlled release of CA from CA-NE. Furthermore, an improved anti-inflammatory activity was evaluated via the inhibition of the pro-inflammatory cytokines, nitric oxide (NO) and TNF-α production in LPS-stimulated RAW 264.7 macrophage cells. The results clearly demonstrated a promising application of CA-NE as a functional food.

Protein isolate from Stauntonia brachyanthera seed: Chemical characterization, functional properties, and emulsifying performance after heat treatment.

The seed of Stauntonia brachyanthera is usually regarded as waste after fructus processing. Here, the potential utilization value of the protein isolate (SSPI) from seeds was evaluated by investigating its physicochemical and functional properties. SSPI was a complex protein containing 7 distinct subunits that had high contents of most essential amino acids. The maximum foaming capacity of SSPI was 406.7 ± 41% at pH 9.0, and the water holding/oil adsorption capacities were 4.66 g/g and 9.06 g/g, respectively. SSPI aggregates with a particle size of 154.1 ± 5.2 nm was prepared after heat treatment, which was performed as a Pickering-like stabilizer for the structuring of water-in-oil-in-water emulsions. The outer droplet size of emulsions decreased as the aggregate concentration increased. Emulsion gels could be observed with the increasing aggregate concentration and oil fraction. Further study found that the stabilities of inner water-in-oil droplets and creaming were progressively increased by increasing the aggregate concentration during storage.

High-Throughput Monitoring of Multiclass Syrup Adulterants in Honey Based on the Oligosaccharide and Polysaccharide Profiles by MALDI Mass Spectrometry.

Honey is a natural product that could be easily adulterated with various cheaper sweeteners. In the present study, matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) was applied for the detection of honey adulteration based on oligosaccharide and polysaccharide profiles. MS-based strategy could reveal the presence of polysaccharides with higher degree of polymerization (DP ≥ 13) and abnormal trends of saccharides in adulterated honey samples, which could be used as indicators for the identification of honey adulteration with high-fructose corn syrup and corn syrup. MS/MS-based strategy was proposed to characterize the difference in the composition of oligosaccharide isomers between honey samples and adulterated ones with corn syrup or invert syrup, in which the [M+Cl]- of disaccharides, trisaccharides, and tetrasaccharides were fragmented to give diagnostic product ion pairs. The method is effective and robust for the high-throughput monitoring of honey adulteration, and provides a new perspective for the identification of other high-carbohydrate foods.

Development of antibacterial pectin from Akebia trifoliata var. australis waste for accelerated wound healing.

The fruit of Akebia trifoliata var. australis can be consumed as food. However, the peel of this fruit is typically regarded as waste. The application of such waste can create opportunities to produce new and valuable by-products. Herein, we have shown that citric acid extracted pectin (CEP) from Akebia trifoliata var. australis peel has good water solubility and high galacturonic units, which helps reduce AgNO3 into Ag nanoparticles (CEP-AgNPs) through a one-step, eco-friendly process. The resulting CEP-AgNPs showed sustained release of Ag+ and remarkable antibacterial activity. Subsequently, the CEP-AgNPs were processed into a CEP-Ag sponge with excellent water absorption and prolonged water retention properties. The CEP-Ag sponge could support the cell adhesion and proliferation. Most importantly, the sponge effectively facilitated a moist environment with bacterial disinfection capability which accelerated the healing of infected wounds. Thus, CEP-Ag sponge, a sustainable and high value by-product, was obtained from food waste.

Dummy-surface molecularly imprinted polymers on magnetic graphene oxide for rapid and selective quantification of acrylamide in heat-processed (including fried) foods.

Novel nano-sized dummy-surface molecularly imprinted polymers (DSMIPs) on a magnetic graphene oxide (GO-Fe3O4) surface were developed as substrates, using propionamide as a dummy template molecule for the selective recognition and rapid pre-concentration and removal of acrylamide (AM) from food samples. These products showed rapid kinetics, high binding capacity (adsorption at 3.68mg·g-1), and selectivity (imprinting factor α 2.83); the adsorption processes followed the Langmuir-Freundlich isotherm and pseudo-second-order kinetic models. Excellent recognition selectivity toward acrylamide was achieved compared to structural analogs, such as propionic and acrylic acids (selectivity factor ß 2.33, and 2.20, respectively). Moreover, DSMIPs-GO-Fe3O4 was used to quantify acrylamide in food samples, yielding satisfactory recovery (86.7-94.3%) and low relative standard deviation (<4.85%). Thus, our DSMIPs-GO-Fe3O4-based procedure was demonstrated to be a convenient and practical method for the separation, enrichment, and removal of acrylamide from food samples.

Preparation and Self-Assembly Mechanism of Bovine Serum Albumin-Citrus Peel Pectin Conjugated Hydrogel: A Potential Delivery System for Vitamin C.

In this study, a novel hydrogel (BSA-pectin hydrogel, BPH) was prepared via a self-assembly method by using the natural polymers of bovine serum albumin (BSA) and citrus peel pectin (pectin). The rheological properties and gel conformational structures were determined and showed that electrostatic and covalent interactions between BSA and pectin were the main mechanisms for the formation of BPH. The morphological characteristics of BPH included a stable and solid three-dimensional network structure with a narrow size distribution (polydispersity index <0.06). BPH was used as a delivery system to load the functional agent vitamin C (Vc). The encapsulation efficiency (EE) and release properties of Vc from BPH were also investigated. The results revealed that the EE of Vc into BPH was approximately 65.31%, and the in vitro Vc release from BPH was governed by two distinct stages (i.e., burst release and sustained release) in different pH solutions, with release mechanisms involving diffusion, swelling, and erosion. Meanwhile, the stability results showed that BPH was a stable system with an enhanced Vc retention (73.95%) after 10 weeks of storage. Thus, this three-dimensional network system of BPH may be a potential delivery system to improve the stability and bioavailability of functional agents in both food and non-food fields.

Preparation of photonic-magnetic responsive molecularly imprinted microspheres and their application to fast and selective extraction of 17ß-estradiol.

Photonic-magnetic responsive molecularly imprinted microspheres (PM-MIMs) were prepared by seed polymerization, through suitable functionalization of magnetic nanoparticles for further coating with photoresponsive functional monomer and imprinted layers, and then were successfully applied to the fast and selective extraction of 17ß-estradiol (17ß-E2) from real samples. The PM-MIMs possessed a sandwich micro-spherical structure containing Fe3O4 core, SiO2 middle layer, and MIPs shell with thickness of 25 nm. The PM-MIMs displayed excellent photoresponsive properties and could be rapidly separated from solutions under an external magnet. The PM-MIMs had specific affinity towards 17ß-E2 with high adsorption capacity (Qmax=0.84 mg g(-1)) and fast binding kinetics (Kd=26.08 mg L(-1)). The PM-MIMs proved to be an ideal photoswitch with the ability of reversible uptake and release of 17ß-E2 upon alternate 365 and 440 nm irradiation: 45.0% of 17ß-E2 released from the PM-MIMs upon 365 nm irradiation, and 94.0% of the released 17ß-E2 was rebound to the PM-MIMs at 440 nm. Accordingly, the PM-MIMs were applied for fast separation and extraction of 17ß-E2 followed by HPLC-UV determination, presenting the low limit of detection (LOD, S/N=3) and quantification (LOQ, S/N=10) of 0.18 and 0.62 µmol L(-1), respectively. The high recoveries for spiked milk powder and drinking water samples were in the range of 97.5-113.0% with relative standard deviations less than 4.4%. This study reasonably combined photonic response, magnetic separation and surface imprinting, which endowed the PM-MIMs with significant advantages of high adsorption capacity and fast binding kinetics, convenient separation and recycled use, and simple rapid eco-benign adsorption/elution processes for template molecules. Thus, the PM-MIMs based method may be a simple, rapid, convenient, cost-effective and environmentally-friendly way for simultaneous separation, enrichment and detection of trace 17ß-E2 in complicated matrices.

Preparation and characterization of superparamagnetic molecularly imprinted polymers for selective adsorption and separation of vanillin in food samples.

Novel water-compatible superparamagnetic molecularly imprinted polymers (M-MIPs) were prepared by coating superparamagnetic Fe3O4 nanoparticles with MIPs in a methanol-water reaction system. The M-MIPs were used for the selective adsorption and separation of vanillin from aqueous solution. The M-MIPs were characterized by X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), vibrating sample magnetometry (VSM), and scanning electron microscopy (SEM). Results indicated that a core-shell structure of M-MIPs was obtained by coating a layer of silica and MIPs on the surface of the Fe3O4 nanoparticles. The obtained M-MIPs possess a loose and porous structure and can be rapidly separated from the solution using a magnet. The adsorption experiments showed that the binding capacity of the M-MIPs was significantly higher than that of the superparamagnetic non-molecularly imprinted polymers (M-NIPs). Meanwhile, the adsorption of M-MIPs reached equilibrium within 100 min, and the apparent maximum adsorption quantity (Qmax) and dissociation constant (Kd) were 64.12 µmol g(-1) and 58.82 µmol L(-1), respectively. The Scatchard analysis showed that homogeneous binding sites were formed on the M-MIP surface. The recoveries of 83.39-95.58% were achieved when M-MIPs were used for the pre-concentration and selective separation of vanillin in spiked food samples. These results provided the possibility for the separation and enrichment of vanillin from complicated food matrices by M-MIPs.

Molecularly imprinted polymer on magnetic graphene oxide for fast and selective extraction of 17ß-estradiol.

A novel nanosized substrate imprinted polymer (MIPs-GO-Fe3O4) was developed on a magnetic graphene oxide (GO-Fe3O4) surface for selective recognition and fast removal of 17ß-estradiol (17ß-E2). The characteristics of MIPs-GO-Fe3O4 were evaluated by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy. and vibrating sample magnetometer (VSM). Results suggested that GO had a thin single-layer structure anchoring Fe3O4 nanoparticles and that the imprinted film was coated on the GO-Fe3O4 surface. MIPs-GO-Fe3O4 was sensitive to the magnetic field and could be easily separated using an external magnet. The adsorption results indicated that the kinetic value and binding capacity of MIPs-GO-Fe3O4 were 0.0062 g (mg·min)(-1) and 4.378 µmol g(-1), respectively. The Langmuir-Freundlich isotherm and pseudo-second-order kinetic models were the main adsorption mechanisms for MIPs-GO-Fe3O4. MIPs-GO-Fe3O4 showed excellent recognition selectivity, as well as enrichment and separation abilities for 17ß-E2 in complex matrices. MIPs-GO-Fe3O4 was also used to analyze 17ß-E2 in real food samples, and satisfactory recoveries such as 84.20% with relative standard deviation (RSD) of 4.67% at a spike of 0.5 µmol L(-1) were obtained. Thus, the MIPs-GO-Fe3O4-based method provided a convenient and practical platform for the separation, enrichment, and removal of 17ß-E2 in food samples.

Amphiphilic chitosan derivative-based core-shell micelles: synthesis, characterisation and properties for sustained release of Vitamin D3.

Novel amphiphilic chitosan derivative of N,N-dimethylhexadecyl carboxymethyl chitosan (DCMCs) was synthesised. The physical properties of DCMCs were characterised by Fourier transform-infrared spectroscopy, nuclear magnetic resonance spectroscopy, X-ray diffraction and differential scanning calorimetry. DCMCs can form core-shell micelles with low critical micelle concentration (31 mg L(-1)). The core-shell micelles exhibited spherical shape with positive charge (+50.7 mV) and narrow size distribution (polydispersity index <0.5). Vitamin D3 (VD3) was initially used to load into the core-shell micelles, and the solubility of VD3 was improved with higher encapsulation efficiency (53.2%). The in vitro release processes of VD3 from the core-shell micelles were initially rapid and then followed by a sustained release. The Higuchi model was the most suitable for describing the entire release procedure. DCMCs core-shell micelles are promising carriers for VD3 and other hydrophobic bioactive food factors.

Amphiphilic chitosan derivatives-based liposomes: synthesis, development, and properties as a carrier for sustained release of salidroside.

A novel amphiphilic chitosan derivative of N,N-dimethylhexadecyl carboxymethyl chitosan (DCMCs) was synthesized. The structure of DCMCs was confirmed via FT-IR and (1)H NMR, and the critical micelle concentration (CMC) was investigated by fluorescence spectroscopy. The results indicated that DCMCs has hydrophilic carboxyl and hydrophobic methylene groups and the CMC value was 23.00 mg·L(-1). The polymeric liposomes (DCMCs/cholesterol liposomes, DC-Ls) were developed, and its properties were evaluated. The DC-Ls exhibited multilamellar spheres with positive charge (+73.30 mV), narrow size distribution (PDI = 0.277), and good crystal properties. Salidroside was first to encapsulate into DC-Ls. Compared with traditional liposomes (phosphatidylcholine/cholesterol liposome, PC-Ls), DC-Ls showed higher encapsulation efficiency (82.46%) and slower sustained release rate. The in vitro salidroside release from DC-Ls was governed by two distinct stages (i.e., burst release and sustained release) and was dependent on the pH of the release medium. The case II transport and case I Fichian diffusion were the main release mechanisms for the entire release procedure. These results indicated that DC-Ls may be a potential carrier system for the production of functional foods that contain salidroside or other bioactive food ingredients.