Chemical structure and prebiotic activity of a Dictyophora indusiata polysaccharide fraction.

This study aimed to investigate the chemical structure and prebiotic activity of a Dictyophora indusiata polysaccharide fraction DIP0p. Our results indicated that DIP0p belongs to a heteropolysaccharide composed of glucose, galactose, mannose and xylose, accounting for 53.25 %, 24.18 %, 19.19 % and 3.37 %, respectively. Methylation and NMR results suggested that the main glycosidic bonds of DIP0p is →3)-Glcp-(1 â†’ with →4)-Glcp-(1→, →3,4)-Glcp-(1→, →3,4)-Galp-(1 â†’ and →6)-Manp-(1 â†’ branches. In addition, DIP0p increased the abundance of benificial bacteria during the in vitro fecal fermentation, including Phascolarctobacterium, Parabacteroides and Bifidobacterium. It is remarkable that DIP0p improved the level of acetic acid, propionic acid, and butyric acid of the fermentation system, which were 1.31, 1.52, and 2.64 folds higher than the Controls, respectively. In summary, this study comprehensively analyzed the structure and probiotic activity of DIP0p, which providing a theoretical basis for the development of the functional foods.

Pressure-controlled steam explosion as pretreatment for efficient extraction of Tremella fuciformis polysaccharide: Structure and bioactivity.

Tremella fuciformis (TF) is a mushroom with rich nutritional and medicinal value. This study aimed to develop an efficient extraction technique for TF polysaccharide (TFP) to enhance its health benefits. TF was subjected to steam explosion (SE) pretreatment at 0.5, 1.0, and 1.5 MPa for 60 s, followed by polysaccharide extraction. The extraction yield of TFP increased from 15.42 % to 50.16 % at 1.0 MPa. SE disrupted the dense structure of TFP, significantly improving total sugar and uronic acid contents, monosaccharide molar percentages of mannose and glucose, specific surface area, and ζ potential by 0.16, 0.4, 0.01, 0.83, 0.19, and 0.26 times at 0.5 MPa (P < 0.05). With increasing SE pressure, the thermal stability of TFP was enhanced, while its elasticity, viscosity, molecular weight, and particle size were reduced. TFP at 0.5 MPa significantly extended the lifespan of Drosophila melanogaster, with Tmax reaching 74 d for females and 60 d for males at a dosage of 0.015625 %, indicating a 0.32-fold enhancement. TFP enhanced climbing ability and antioxidant stress resistance, increased antioxidant enzyme activities and total antioxidant capacity, and reduced malondialdehyde levels, indicating its anti-aging effects. These findings provide theoretical and technical support for the high-value development and utilization of TFP.

Dictyophora indusiata polysaccharide attenuated LPS-induced intestinal inflammation of mice via the TLR4/JNK signaling pathway.

BACKGROUND: Dictyophora indusiata polysaccharide is an important bioactive component of D. indusiata, playing an important role in alleviating inflammation. The present study aimed to investigate the anti-inflammatory effect and mechanism of D. indusiata polysaccharide on lipopolysaccharide (LPS)-induced intestinal inflammation in mice. RESULTS: Our results indicated that D. indusiata polysaccharide ameliorated intestinal inflammation of mice by increasing the body weight, the number of goblet cells and decreasing inflammatory cell infiltration. In addition, D. indusiata polysaccharide significantly up-regulated expression of ZO-1, Occuldin mRNA, which were 2.55-fold and 2.28-fold higher than the LPS group, respectively. In particular, D. indusiata polysaccharide effectively inhibited the Toll-like receptor 4 (TLR4)/ c-Jun NH2-terminal kinase (JNK) signalling pathway which was 0.34-fold and 0.49-fold of gene expression and 0.41-fold and 0.39-fold of protein expression in the LPS group, respectively. CONCLUSION: The results of the present study suggested that D. indusiata polysaccharide exerted anti-inflammatory and intestinal protective effects by inhibiting the TLR4/JNK signaling pathway, which will provide a basis for the potential value of D. indusiata polysaccharide as prebiotics in food applications. © 2024 Society of Chemical Industry.

Extraction and characterization of hepatoprotective polysaccharides from Anoectochilus roxburghii against CCl4-induced liver injury via regulating lipid metabolism and the gut microbiota.

Anoectochilus roxburghii polysaccharides exhibit notable hepatoprotective effects, but the underlying substance basis and mechanisms remain unknown. In this study, four new polysaccharides named ARP-1a, ARP-1b, ARP-2a and ARP-2b, were isolated from A. roxburghii. Their structural characteristics were systematically analyzed using HPGPC, HPLC, GC-MS, IR and NMR analysis. ARP-1a, the leading polysaccharide isolated from A. roxburghii, was further evaluated for its hepatoprotective effects on acute liver injury mice induced by CCl4. ARP-1a significantly reduced the serum ALT, AST, TNF-α, IL-1ß and IL-6 levels, liver MDA content, and increased the SOD and CAT activities and GSH level in liver. H&E staining revealed that ARP-1a pretreatment could markedly relieve liver injury. Further mechanism exploration indicated that ARP-1a could relieve CCl4-induced oxidative damage through activating the Nrf2 signaling. In addition, metabolomics, lipidomics and 16S rRNA amplicon sequencing were used to elucidate the underlying mechanisms of ARP-1a. Multi-omics analysis indicated that ARP-1a exerted hepatoprotective effect against CCl4-induced acute liver injury by regulating lipid metabolism and modulating the gut microbiota. In conclusion, the above results suggest that ARP-1a can be considered a promising and safe candidate for hepatoprotective drug, as well as a potential prebiotic for maintaining intestinal homeostasis and promoting human intestinal health.

Insights into impact of chlorogenic acid on multi-scale structure and digestive properties of lotus seed starch under autoclaving treatment.

The interaction between polyphenols and starch is an important factor affecting the structure and function of starch. Here, the impact of chlorogenic acid on the multi-scale structure and digestive properties of lotus seed starch under autoclaving treatment were evaluated in this study. The results showed that lotus seed starch granules were destroyed under autoclaving treatment, and chlorogenic acid promoted the formation of loose gel structure of lotus seed starch. In particular, the long- and short-range ordered structure of lotus seed starch-chlorogenic acid complexes were reduced compared with lotus seed starch under autoclaving treatment. The relative crystallinity of A-LS-CA complexes decreased from 23.4 % to 20.3 %, the value of R1047/1022 reduced from 0.87 to 0.80, and the proportion of amorphous region increased from 10.26 % to 13.85 %. In addition, thermal stability, storage modulus and loss modulus of lotus seed starch-chlorogenic acid complexes were reduced, indicating that the viscoelasticity of lotus seed starch gel was weakened with the addition of chlorogenic acid. It is remarkable that chlorogenic acid increased the proportion of resistant starch from 58.25 ± 1.43 % to 63.85 ± 0.96 % compared with lotus seed starch under autoclaving treatment. Here, the research results provided a theoretical guidance for the development of functional foods containing lotus seed starch.

Dietary fiber-rich Lentinula edodes stems influence the structure and in vitro digestibility of low-moisture extruded maize starches.

Low-moisture extrusion (LME) can be used to improve the utilization of dietary fiber-rich Lentinula edodes stems (LES). The incorporation of dietary fiber can affect heat-induced interactions of starch molecules, which are critical for modifying starch characteristics via LME. In this work, a blend of LES and maize starch was extruded into a product at low moisture (30 %, w/v). The structure, physicochemical properties, and in vitro digestibility of extruded maize starches were investigated at different LES levels. The results showed that low levels (<7 %) of LES increased the crystallinity of LME-produced starch, while high levels (>7 %) did not. Because of the LES's soluble to insoluble dietary fiber ratios, the increased crystallinity of LES-added starch led to greater molecular ordering and the formation of an elastic gel after LME. At a suitable LES level (~3 %), highly crystallized starches were resistant to enzymolysis and had a high proportion of resistant starch. The obtained findings would contribute to a better understanding of how dietary fiber-rich LES affects starch extrusion and provide an alternative use for boosting the value of LES by-products.

Steam Explosion Pretreatment of Polysaccharide from Hypsizygus marmoreus: Structure and Antioxidant Activity.

This paper investigated the effects of steam explosion (SE) pretreatment on the structural characteristics and antioxidant activity of Hypsizygus marmoreus polysaccharides (HPS). Hypsizygus marmoreus samples were pretreated at different SE temperatures (120-200 °C) and polysaccharides were extracted using the water extraction and alcohol precipitation method. The results showed that SE pretreatment improved the extraction rate of HPS. Under the conditions of SE treatment time of 60 s and temperature of 160 °C, the extraction rate of HPS was the highest (8.78 ± 0.24%). After SE pretreatment, the structural changes of HPS tended to enhance the antioxidant activity, which showed that the content of Gal and Man in the monosaccharide composition increased and the molecular weight decreased. When testing antioxidant activity in vitro, the ability of SE-pretreated HPS to scavenge DPPH radicals, hydroxyl radicals, and superoxide anion radicals was better than that of HPS without SE pretreatment. Our findings shed light on SE pretreatment as an efficient method for extracting active polysaccharides, providing a new way to improve their extraction rate and biological activity.

Effects of steam explosion pretreatment on the digestive properties and gut microbiota of Laminaria japonica polysaccharide.

BACKGROUND: Laminaria japonica polysaccharide, which is an important bioactive substance of Laminaria japonica with anti-inflammatory and antioxidant effects. In this study, the molecular weight, functional groups and surface morphology were investigated to evaluate the digestive properties of Laminaria japonica polysaccharide before and after steam explosion. RESULTS: The results indicated that the Laminaria japonica polysaccharide entered the large intestine to be utilized by the gut microbiota after passing through the oral, gastric and small intestinal. Meanwhile, Laminaria japonica polysaccharide of steam explosion promoted the growth of beneficial bacteria Phascolarctobacterium and Intestinimonas, and increased the content of acetic, propionic and butyric acids, which was 2.29-folds, 2.60-folds and 1.63-folds higher than the control group after 48 h of fermentation. CONCLUSION: This study reveals that the effect of steam explosion pretreatment on the digestion in vitro and gut microbiota of Laminaria japonica polysaccharide will provide a basic theoretical basis for the potential application of Laminaria japonica polysaccharide as a prebiotic in the food industry. © 2024 Society of Chemical Industry.

Properties and functions of acylated starch with short-chain fatty acids: a comprehensive review.

Short-chain fatty acids (SCFAs) are the primary energy source of colonic epithelial cells, but oral SCFAs are digested, absorbed, or degraded before reaching the colon. The acylated starch with SCFAs can be fermented and release specific SCFAs under the action of colonic intestinal microbiota. This review first introduces the preparation method, reaction mechanism, and substitution factors. Second, the structure, physical and chemical properties, in vitro function, and mechanism of acylated starch were expounded. Finally, the application of acylated starch in foods is introduced, and its safety is evaluated, providing a basis for the further development of acylated starch-based foods. The acylated starch obtained by different acylation types and preparation methods is different in particle, molecular, and crystal structures, leading to changes in the function and physicochemical properties. Meanwhile, acylated starch has the functional potential of targeted delivery of SCFAs to the colon, which can increase SCFAs in feces and intestine, selectively regulate the intestinal microbiota, and produce a prebiotic effect conducive to host health. The safety of acetylated starch has been supported by relevant studies, which have been widely used in various food fields and have great potential in the food industry.

Porphyra haitanensis glycoprotein regulates glucose homeostasis: targeting the liver.

In this study, we investigated the effects of glycoprotein (PG)-mediated regulation of Porphyra haitanensis on liver glucose metabolism in hyperglycemic mouse models, and sought to establish the underlying mechanism, as determined by the changes in liver gene expression and metabolic profiles. The results showed that 30-300 mg kg-1 PG upregulated the expression of the liver genes Ins1, Ins2, Insr, Gys2, Gpi1, Gck, and downregulated the expression of G6pc, G6pc2, and G6pc3, in a concentration-dependent manner. 300 mg kg-1 PG downregulated the concentrations of glucose-related metabolites in the liver, but upregulated lactic acid, 2-aminoacetic acid, and glucose-1-phosphate concentrations. It was assumed that PG regulated liver glucose metabolism by enriching insulin secretion, glycolysis/gluconeogenesis, and the AMPK signaling pathway, and promoting insulin secretion, glycogen synthesis, and glycolysis. Our findings supported the development of P. haitanensis and its glycoproteins as novel natural antidiabetic compounds that regulated blood glucose homeostasis.

Comparison of anti-allergic activities of different types of lotus seed resistant starch in OVA-induced mouse model.

Currently, evidence from observational studies suggests dietary fiber intake may be associated with decreased risk of food allergy. As a type of dietary fiber, resistant starch was also widely reported to possess anti-allergic properties. However, there is a relative paucity of studies assessing the influence of resistant starch types on their anti-allergic activity and its possible underlying mechanisms. In the current study, the anti-allergic effects of RS3-type (retrograded starch), RS4-type (chemically modified starch, cross-bonded), and RS5-type (starch-palmitic acid complex) of lotus seed resistant starch were evaluated in the OVA (100 mg/kg)-induced food allergic mice model. The results showed that oral administration of RS3 or RS4 lotus seed resistant starch (0.3 g/100 g b.w.) for 25 days significantly improved adverse symptoms of food allergy such as weight loss, increases in allergy symptom score and diarrhea rate; with significant reduction of serum specific antibody IgE, TNF-α, IL-4 levels and improved Th1/Th2 balance being observed. The mechanism may involve the regulation of lotus seed resistant starch on intestinal flora and the metabolites short-chain fatty acids and bile acids. Taken together, the findings may enhance understanding towards ameliorative effects of resistant starch on food allergy, and offer valuable insights for the exploration of novel anti-allergic bioactive compounds.

In vitro digestive properties of Dictyophora indusiata polysaccharide by steam explosion pretreatment methods.

Dictyophora indusiata is medicinal and edible fungi containing various nutrients. The aim of this study was to investigate the efficient extraction and structural evolution of Dictyophora indusiata polysaccharide during the vitro digestion based on steam explosion pretreatment methods. In this study, the extraction rate of Dictyophora indusiata polysaccharide was optimized by steam explosion pretreatment methods, which was 2.46 folds that of the water extraction method. In addition, the digestion and fermentation properties of Dictyophora indusiata polysaccharide before and after steam explosion were evaluated in vitro by the changes of molecular weights, total and reducing sugars levels, surface morphology and functional groups, which showed that the structure of Dictyophora indusiata polysaccharide remained stable after salivary-gastric digestion, and partially entered the large intestine, where it could be utilized by gut microbiota. Dictyophora indusiata polysaccharide promoted the increase of beneficial bacteria Megamonas and increased the content of acetic acid, propionic acid and butyric acid, which was 2.17, 2.81, 2.43 folds that of the CON group after fermentation for 24 h, and 1.87, 2.77, 1.90 folds that of the CON group after fermentation for 48 h, respectively. This study will provide theoretical basis for the high value utilization of Dictyophora indusiata polysaccharide.

Characterization of Volatile Flavor Compounds and Aroma Active Components in Button Mushroom (Agaricus bisporus) across Various Cooking Methods.

To investigate the impact of various cooking methods on the volatile aroma compounds of button mushroom, gas chromatography-mass spectrometry (GC-MS) and electronic nose (E-nose) were utilized for aroma analysis. The results indicated that the E-nose was able to effectively distinguish between the samples prepared using different cooking methods. In the raw, steamed, boiled and baked samples, 37, 23, 33 and 35 volatiles were detected, respectively. The roasting process significantly contributed to the production of flavor compounds, giving button mushroom its distinctive flavor. Sixteen differential aromas were identified based on the p-value and VIP value. Additionally, the cluster analysis of differential aroma substances revealed a stronger odor similarity between the steamed and raw groups, consistent with the results of the OPLS-DA analysis of overall aroma components. Seven key aromas were identified through OAV analysis and omission experiments. In addition, 1-octen-3-one was identified as the main aroma component of cooked button mushroom. The findings of the study can be valuable for enhancing the flavor of cooked button mushroom.

Quality properties of fish ball with abalone and its relationship with sensory properties.

In this work, whiteness, water-holding capacity, gel strength, textural profile analysis were performed to examine the quality of fish balls with abalone (FBA). In addition, a correlation between quality and sensory properties was established. The addition of abalone significantly increased the water holding capacity, gel strength and textural properties of FBA, and decreased their whiteness, the best overall quality was achieved at 9 % w/w abalone addition. The E-nose and E-tongue results revealed that the addition of abalone changed the flavour of FBA. HS-SPME-GC-MS identified 65 volatile organic compounds (VOCs) and proved to be effective in reducing fishy flavour. E-nose can distinguish between the VOCs in FBA. Moreover, Umami and 1-octen-3-ol can serve as important indicators to observe changes in the quality of FBA, as they were positively connected with WHC, gumminess, chewiness, resilience, a*, hexanal, etc. The results provided a theoretical basis for the development of abalone and surimi products.

Comprehensive Effects of Potassium Lactate, Calcium Ascorbate and Magnesium Chloride as Alternative Salts on Physicochemical Properties, Sensory Characteristics and Volatile Compounds in Low-Sodium Marinated Beef.

The search for alternative salt formulations similar to sodium chloride and their effect on marinated meat products is of great significance to the low-sodium meat processing industry. The main purpose of this study was to investigate the effect of partially replacing sodium chloride with potassium lactate, calcium ascorbate, and magnesium chloride on the sodium content, water activity and distribution, protein solubility, microstructure, sensory characteristics and volatile flavor compounds in low-sodium marinated beef. The sodium content in the test group decreased up to 28% compared to 100% in the sodium chloride group C1. The formulation including 60% sodium chloride and a total of 40% compound alternative salts in groups F1 and F2 increased their myofibril fragmentation index and promoted the disruption of the myogenic fiber structure. Group F1 (the ratio of potassium lactate, calcium ascorbate and magnesium chloride was 2:1:1) performed higher solubility of myofibrillar proteins and lower transverse relaxation value than group F2 detected by low-field nuclear magnetic resonance, which indicated that F1 formulation was beneficial to promote the solubility of myofibrillar proteins and attenuate the water mobility of marinated beef. Moreover, group F1 had a more similar microstructure and more similar overall sensory attributes to group C1 according to the scanning electron microscopy. The sensory evaluation showed higher peak intensity and response values of volatile flavor compounds than group C1 and C2 (only 60% sodium chloride) when detected using gas chromatography-ion mobility spectrometry technology, which indicated that the compound alternative salts of group F1 can improve the lower quality of low-sodium marinated beef and perform similar attributes to the C1 sample regarding moisture distribution and microstructure and even performs better than it with regards to flavor. Therefore, the F1 formula possessed greater potential for application in low-sodium marinated meat products.

A novel exopolysaccharide from Weissella cibaria FAFU821: Structural characterization and cryoprotective activity.

Exopolysaccharides produced by Weissella cibaria has attracted increasing attention owing to their biological activity. Here, a strain was isolated from the home-made fermented octopus, which was identified as W. cibaria FAFU821. In addition, the polysaccharide were isolated and purified by cellulose DE-52 column and Sephadex G-100 column, and named EPS821-1. In this work, the structure of EPS821-1 and its cryoprotective activity on Bifidobacterium longum subsp. longum F2 were investigated in vitro. These results suggested that the EPS821-1 is a novel glucan, which mainly consists of α-(1 â†’ 6) linkage with α-(1 â†’ 4), α-(1 â†’ 4,6) and α-(1 â†’ 3,6) residue as branches. In addition, EPS821-1 existed the three-dimensional network structure and exhibited the excellent cryoprotective activities for B. longum subsp. longum F2, which was 2.75 folds higher than that of the controls. This study provided scientific evidence and insights for the application of EPS821-1 as cryoprotection in food field.

Sea cucumber peptides positively regulate sexual hormones in male mice with acute exhaustive swimming: possibly through the Ca2+/PKA signaling pathway.

Sea cucumber peptides (SCPs) have been proven to have many active functions; however, their impact on testosterone synthesis and the corresponding mechanism are not yet clear. This study attempts to explore the effects of SCPs on sex hormone regulation in acute exhaustive swimming (AES) male mice and the possible mechanisms. In the present study, SCP intervention significantly prolonged exhaustive swimming time and reduced exercise metabolite accumulation. The reproductive ability-related parameters including penile index, mating ability, testicular morphology, and sperm storage were dramatically improved by SCP intervention. Notably, SCPs markedly reversed the AES-induced decrease in serum testosterone (T), estradiol (E2), and follicle-stimulating hormone (FSH) levels. Moreover, treatment with a high dose of SCP (0.6 mg per g bw) significantly enhanced the expression of testosterone synthesis-related proteins in testis, meanwhile markedly increasing the gene expression of StAR, Hsd17b3, Hsd17b2, Ldlr, and Cyp19a1. Serum metabolomics results indicated that SCP intervention notably upregulated the expression of 1-stearoyl-2-arachidonoyl-sn-glycerol but downregulated the concentrations of succinate and DL-lactate. Furthermore, serum metabolomics combined with testicular transcriptome, western blot, and correlation analyses demonstrated that SCPs may regulate testosterone synthesis via the Ca2+/PKA signaling pathway. This study indicated that the SCP could be a potential dietary supplement to improve the symptoms of decreased sex hormones related to exercise fatigue.

Molecular cloning of the hepcidin gene from crescent sweetlips (Plectorhinchus cinctus) and characterization of its encoded antimicrobial peptide.

Hepcidin has been identified as an important antimicrobial peptide exerting important innate immunomodulatory activities in many fish species. In the present study, reverse transcription PCR coupled with the rapid amplification of cDNA ends was used to obtain the full-length cDNA of the crescent sweetlips hepcidin gene, which is 829 bp in length and includes an 273 bp ORF encoding a peptide with 90 amino acid residues. Sequence alignment showed a typical RXKR motif and eight conserved cysteine residues in the deduced amino acid sequences. Four disulfide bonds were predicted to form between these eight cysteines, which may stabilize the hairpin structure in hepcidin molecule. Furthermore, phylogenetic analysis showed that the deduced amino acid sequences of crescent sweetlips hepcidin had high sequence homology to hepcidins from fish species of Eupercaria. In addition, the crescent sweetlips hepcidin peptide demonstrated a strong antimicrobial activity in vitro against several types of pathogenic bacteria in fish. In conclusion, the obtained results suggested that crescent sweetlips hepcidin possessed the typical structure similar to other fish hepcidins and had strong antibacterial activity, which showed great potential in the prevention of fish diseases in aquaculture.

Effects of Tremella fuciformis Mushroom Polysaccharides on Structure, Pasting, and Thermal Properties of Chinese Chestnuts (Castanea henryi) Starch Granules under Different Freeze-Thaw Cycles.

The purpose of this study was to investigate the effect of Tremella fuciformis polysaccharides on the physicochemical properties of freeze-thawed cone chestnut starch. Various aspects, including water content, crystallinity, particle size, gelatinization, retrogradation, thermal properties, rheological properties, and texture, were examined. The results revealed that moderate freezing and thawing processes increased the retrogradation of starch; particle size, viscosity, shear type, hinning degree, and hardness decreased. After adding Tremella fuciformis polysaccharide, the particle size, relative crystallinity, and gelatinization temperature decreased, which showed solid characteristics. Consequently, the inclusion of Tremella fuciformis polysaccharide effectively countered dehydration caused by freezing and thawing, reduced viscosity, and prevented the retrogradation of frozen-thawed chestnut starch. Moreover, Tremella fuciformis polysaccharide played a significant role in enhancing the stability of the frozen-thawed chestnut starch. These findings highlight the potential benefits of incorporating Tremella fuciformis polysaccharides in starch-based products subjected to freeze-thaw cycles.

Effects of crosslinking with sodium trimetaphosphate on structural, physicochemical, rheological and in vitro digestibility properties of purple sweet potato starch.

Purple sweet potato starch (PSPS) was modified using different amounts of sodium trimetaphosphate (0, 3-12%). Phosphorus content, crosslinking (CL), and substitution levels increased after modification. CL led to gradual agglomeration with each other through adhesion, compared to 0% STMP. X-ray diffraction did not change, but crystalline properties, swelling index, and peak viscosity increased, and solubility and glycaemic index decreased after crosslinking. Crosslinking increased, leading to a decrease of greater significance at 3% CL. Resistant starch was increased from 60.51 to 83.32%. G' and G'' values for crosslinking starch samples varied from 3086.00-5507.50 Pa and 513.92-800.30 Pa, respectively, after sweep test. The flow behavior index < 1 indicates that CL starch pastes are shear-thin. Positive and negative correlations were observed between gelatinized starch enthalpy and RS and between SDS and GI, respectively. The results lay the groundwork to comprehend the properties and relationships of CLPSPS and promote its possible use in foods.