Polysaccharide Structures and Their Hypocholesterolemic Potential

In vitro human colonic fermentation of coffee arabinogalactan and melanoidin-rich fractions

Coffee beverage is a source of dietary fiber composed by arabinogalactans, which can also be associated to proteins and phenolic compounds, originating melanoidins. Human colonic in vitro fermentations of coffee fractions, one rich in melanoidins (Mel) and the other in its parental polysaccharide arabinogalactans (AG), were performed in order to evaluate the metabolites produced by microbiota, namely short-chain fatty acids (SCFA), phenolic compounds, and bile acids. After 48 h of fermentation, a higher fermentability of the carbohydrate fraction of AG (62 %) than that of Mel (27 %) was observed, resulting in a SCFA content of 63 mM and 22 mM, respectively. Supplementation with AG and Mel fractions decreased the acetate:propionate ratio from 4.7 (in the absence of coffee fractions) to 2.5 and 3.5, respectively, suggesting a potential inhibition of HMG-CoA reductase, a rate-limiting enzyme for cholesterol synthesis. The fermentation of coffee fractions yielded dihydroferulic and dihydrocaffeic acids, known to have antioxidant properties. In the presence of Mel, it was observed a decrease (from 0.25 to 0.16 mg/mL) in the production of secondary bile acids, whose high content is associated to the development of several diseases, such as colorectal cancer, neurodegenerative and cardiovascular.

β-Glucan-based superabsorbent hydrogel acts as a gastrointestinal exoskeleton enhancing satiety and interfering fat hydrolysis

Fat and its hydrolysis products, fatty acids, are indispensable nutritional components; however, prolonged excessive fat consumption, particularly in western diets, contributes to the onset of obesity and multiple metabolic disorders. In this study, we propose a daily-ingestible hydrogel (denoted as βC-MA hydrogel) composed of natural β-glucan and sodium carboxymethylcellulose crosslinked by malic acid at 120 °C. This hydrogel exhibits rapid swelling performance, up to 24-fold within 1 min and 176-fold after 1 h in deionized water. It also lengthens gastric retention and increases endogenous satiety signal levels, potentially controlling appetite and reducing food intake. Furthermore, βC-MA hydrogels that enter the small intestine can effectively inhibit fat hydrolysis and decrease triglyceride synthesis and transport. Specifically, the hydrogels inhibit the release of free fatty acids (FFAs) by approximately 50 % during digestion, influence the translocation of triglycerides and FFAs across the intestinal epithelium, and reduce the serum triglyceride levels by 22.2 %. These findings suggest that βC-MA hydrogels could serve as a noninvasive gastrointestinal device for weight control, with the advantage of reducing food intake and restoring lipid metabolism homeostasis.

The effects of cereal β-glucans on cardiovascular risk factors and the role of the gut microbiome

The human gut microbiome has emerged as a key influencer of human health and disease, particularly through interactions with dietary fiber. However, national dietary guidelines worldwide are only beginning to capitalize on the potential of microbiome research, which has established the vital role of host-microbe interactions in mediating the physiological effects of diet on overall health and disease. β-glucans have been demonstrated to modulate the composition of the gut microbiota, leading to improved outcomes in cardiovascular disease (CVD). Raised serum cholesterol and blood pressure are important modifiable risk factors in the development of CVD and emerging evidence highlights the role of the gut microbiota in ameliorating such biomarkers and clinical characteristics of the disease. The proposed mechanism of action of β-glucans on the pathophysiological mechanisms of disease have yet to be elucidated. Validating gaps in the literature may substantiate β-glucans as a potential novel dietary therapy against modifiable risk factors for CVD and would further support the public health significance of including a habitual fiber-rich diet.

Regulation of glycose and lipid metabolism and application based on the colloidal nutrition science properties of konjac glucomannan: A comprehensive review

The physicochemical properties of dietary fiber in the gastrointestinal tract, such as hydration properties, adsorption properties, rheological properties, have an important influence on the physiological process of host digestion and absorption, leading to the differences in satiety and glucose and lipid metabolisms. Based on the diversified physicochemical properties of konjac glucomannan (KGM), it is meaningful to review the relationship of structural characteristics, physicochemical properties and glycose and lipid metabolism. Firstly, this paper bypassed the category of intestinal microbes, and explained the potential of dietary fiber in regulating glucose and lipid metabolism during nutrient digestion and absorption from the perspective of colloidal nutrition. Secondly, the modification methods of KGM to regulate its physicochemical properties were discussed and the relationship between KGM's molecular structure types and glycose and lipid metabolism were summarized. Finally, based on the characteristics of KGM, the application of KGM in the main material and ingredients of fat reduction food was reviewed. We hope this work could provide theoretical basis for the study of dietary fiber colloid nutrition science.

Characterization of the Structure and Physicochemical Properties of Soluble Dietary Fiber from Peanut Shells Prepared by Pulsed Electric Fields with Three-Phase Partitioning

This study evaluated the impact of pulsed electric fields (PEFs) combined with three-phase partitioning (TPP) extraction methods on the physicochemical properties, functional properties, and structural characterization of the soluble dietary fiber (SDF) derived from peanut shells (PS). The findings of this study indicated that the application of a PEF-TPP treatment leads to a notable improvement in both the extraction yield and purity of SDF. Consequently, the PEF-TPP treatment resulted in the formation of more intricate and permeable structures, a decrease in molecular weight, and an increase in thermal stability compared to SDFs without TPP treatment. An analysis revealed that the PEF-TPP method resulted in an increase in the levels of arabinose and galacturonic acid, leading to enhanced antioxidant capacities. Specifically, the IC50 values were lower in SDFs which underwent PEF-TPP (4.42 for DPPH and 5.07 mg/mL for ABTS) compared to those precipitated with 40% alcohol (5.54 mg/mL for DPPH, 5.56 mg/mL for ABTS) and PEF75 (6.60 mg/mL for DPPH, 7.61 mg/mL for ABTS), respectively. Notably, the SDFs which underwent PEF-TPP demonstrated the highest water- and oil-holding capacity, swelling capacity, emulsifying activity, emulsion stability, glucose adsorption, pancreatic lipase inhibition, cholesterol adsorption, nitric ion adsorption capacity, and the least gelation concentration. Based on the synthesis scores obtained through PCA (0.536 > -0.030 > -0.33), which indicated that SDFs which underwent PEF-TPP exhibited the highest level of quality, the findings indicate that PEF-TPP exhibits potential and promise as a method for preparing SDFs.

Updated Progress on Polysaccharides with Anti-Diabetic Effects through the Regulation of Gut Microbiota: Sources, Mechanisms, and Structure-Activity Relationships

Diabetes mellitus (DM) is a common chronic metabolic disease worldwide. The disturbance of the gut microbiota has a complex influence on the development of DM. Polysaccharides are one type of the most important natural components with anti-diabetic effects. Gut microbiota can participate in the fermentation of polysaccharides, and through this, polysaccharides regulate the gut microbiota and improve DM. This review begins by a summary of the sources, anti-diabetic effects and the gut microbiota regulation functions of natural polysaccharides. Then, the mechanisms of polysaccharides in regulating the gut microbiota to exert anti-diabetic effects and the structure-activity relationship are summarized. It is found that polysaccharides from plants, fungi, and marine organisms show great hypoglycemic activities and the gut microbiota regulation functions. The mechanisms mainly include repairing the gut burrier, reshaping gut microbiota composition, changing the metabolites, regulating anti-inflammatory activity and immune function, and regulating the signal pathways. Structural characteristics of polysaccharides, such as monosaccharide composition, molecular weight, and type of glycosidic linkage, show great influence on the anti-diabetic activity of polysaccharides. This review provides a reference for the exploration and development of the anti-diabetic effects of polysaccharides.

Structure-activity relationship of Caulerpa lentillifera polysaccharide in inhibiting lipid digestion

Caulerpa lentillifera polysaccharide (CLP) has been characterized as a sulfated polysaccharide which can effectively inhibit lipid digestion. However, little information was known regarding its inhibitory mechanisms. In the present study, desulfation and degradation were conducted to prepare the derivatives of CLP, and a series of chemical and spectroscopic methods were used to elucidate the structure-activity relationship of CLP on the inhibitory effect of lipid digestion. Results revealed that CLP possessed excellent binding capacities for sodium cholate, sodium glycocholate, and sodium taurocholate. In addition, CLP can effectively inhibit lipase activity by quenching the fluorescence intensity, changing the secondary structure, and decreasing the UV-Vis absorbance. Of note, sulfate groups in CLP took a vital role in inhibiting lipase activity, while the molecular weight of CLP showed a positive correlation with the binding activities of bile acids. Furthermore, adding CLP into the whey protein isolate (WPI) emulsion system also impeded lipid digestion, indicating that CLP can be a potential reduced-fat nutraceutical used in food emulsion systems.

Effects of dietary incorporation of Radix rehmanniae praeparata polysaccharide on growth performance, digestive physiology, blood metabolites, meat quality, and tibia characteristics in broiler chickens

Radix rehmanniae preparata polysaccharide (RRPP) is recognized as the primary bioactive compound in Radix rehmanniae preparata and has been extensively utilized in traditional Chinese medicine and functional food due to its diverse biological activities. However, this study has yet to explore the application of RRPP as a feed additive in broilers. This study investigated the effects of dietary RRPP on growth performance, meat quality, and physiological responses of broiler chickens. Two hundred eighty-eight 1-day-old Cobb 500 male broilers were randomly assigned to the 4 experimental groups with 6 replications and 12 birds/replicate. The 4 groups were fed the basal diet supplemented with 4 concentrations of RRPP (0, 300, 600, and 900 mg/kg, respectively). All RRPP levels did not affect the growth performance of broilers during the starter period (1-21 d), while during the grower (22-35 d) and overall (1-35 d) periods, body weight gain, feed conversion ratio, and European production efficiency index were linearly improved (P < 0.05) by incorporating RRPP at 600 and 900 mg/kg. Carcass characteristics, relative weight and length of intestinal segments, and meat quality and tibia criteria were not affected by dietary incorporation of RRPP. Dietary RRPP led to a linear increase (P < 0.05) in serum alkaline phosphatase, potassium, calcium and sulfhydryl levels, while reducing concentrations of hydrogen peroxide, LDL, triglycerides and total cholesterol. The addition of RRPP decreased (P < 0.05) the pH of the ileum and cecum at 21 and 35 d of age while not changing in the remaining intestinal segments. Dietary RRPP at 600 and 900 mg/kg linearly and quadratically (P < 0.05) increased the tibia ash content in chicken at 21 and 35 d of age. In conclusion, dietary supplementation of RRPP improved broiler chicken's growth, gut physiology, and tibia ash content, particularly at 600 and 900 mg/kg.

Free Radical-Mediated Grafting of Natural Polysaccharides Such as Chitosan, Starch, Inulin, and Pectin with Some Polyphenols: Synthesis, Structural Characterization, Bioactivities, and Applications-A Review

Polyphenols and polysaccharides are very important natural products with special physicochemical properties and extensive biological activities. Recently, polyphenol-polysaccharide conjugates have been synthesized to overcome the limitations of polysaccharides and broaden their application range. Grafted copolymers are produced through chemical coupling, enzyme-mediated, and free radical-mediated methods, among which the free radical-induced grafting reaction is the most cost-effective, ecofriendly, safe, and plausible approach. Here, we review the grafting reactions of polysaccharides mediated by free radicals with various bioactive polyphenols, such as gallic acid (GA), ferulic acid (FA), and catechins. A detailed introduction of the methods and their mechanisms for free radical-mediated grafting is given. Structural characterization methods of the graft products, including thin-layer chromatography (TLC), ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (NMR) analysis, and X-ray diffraction (XRD) are introduced. Furthermore, the biological properties of polyphenol-polysaccharide conjugates are also presented, including antioxidant, antibacterial, antidiabetic, and neuroprotection activities, etc. Moreover, the potential applications of polyphenol-polysaccharide conjugates are described. Finally, the challenges and research prospects of graft products are summarized.

Physicochemical properties and anti-diabetic ability of polysaccharides from a thinned peach fruit

Thinned peach fruit is a by-product with abundant yields. However, it is barely utilized. This study aimed to study the physicochemical properties and anti-diabetic ability of polysaccharides (PPSs) from a thinned peach fruit to investigate its application potential. Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) characterizations were performed together with tests to determine rheology properties, monosaccharide composition, and molecular weight of the obtained polysaccharide. Moreover, the antioxidant activity, α-amylase inhibitory activity, binding abilities to bile salts, and effects on type 2 diabetic mice were analyzed. The results indicated that PPS consisted of two components with molecular weights of 287.38 kDa and 12.02 kDa, accounting for 89.83% and 10.17% of the composition, respectively. The dominant monosaccharides were galactose, galacturonic acid, and arabinose, exhibiting α-configurations. The concentration was positively related to the viscosity of PPS. As the temperature was increased from 25 °C to 37 °C and the pH from 2.0 to 7.0, the viscosity decreased. The IC50 values for scavenging DPPH and ABTS were around 0.22 and 1.47 mg mL-1. Also, PPS could inhibit α-amylase ability and bind bile salts. The administration of PPS significantly inhibited emaciation, organ damage, improved oral glucose tolerance and insulin resistance, enhanced the content of short-chain fatty acids (SCFAs), and regulated blood lipid profiles and the composition and structure of colon microbiota in type-2 diabetic mice. These results provide new evidence for the potential of PPS as a bioactive ingredient with anti-diabetic properties for use in the food industry.

Polysaccharide-based biosorbents for cholesterol and bile salts in gastric-intestinal passage: Advances and future trends

Cholesterol is one of the hazard elements for many cardiovascular diseases, but many cholesterol-lowering drugs are expensive and unhealthy. Therefore, it is necessary to develop edible and safe biosorbents to reduce excess cholesterol and bile salts in the gastric-intestinal passage. Polysaccharide-based biosorbents offer a feasible strategy for decreasing them. This review summarized polysaccharide-based biosorbents that have been developed for adsorbing cholesterol and bile salts from the gastric-intestinal passage and analyzed common modification methods for these adsorbents. Finally, the adsorption models were also elucidated. Polysaccharides, including β-cyclodextrin, pectin, chitin/chitosan, dietary fiber extract, and cellulose, have been proposed for adsorbing cholesterol and bile salts in the gastric-intestinal passage as biosorbents. This is mainly due to the retention of pores, the capture of the viscosity network, and the help of hydrophobic interactions. In spite of this, the adsorption capacity of polysaccharides is still limited. Therefore, the modifications for them became the most popular areas in the recent studies of in vitro cholesterol adsorption. Chemical approaches namely grafting, (1) acetylation, (2) hydroxypropylation, (3) carboxymethylation, and (4) amination are considered to modify the polysaccharides for higher adsorption ability. Moreover, ultrasonic/microwave/pressure treatment and micron technology (microfluidization, micronization, and ball milling) are effective physical modification methods, while the biological approach mainly refers to enzymatic hydrolysis and microbial fermentation. The adsorption models are generally explained by two adsorption isotherms and two adsorption kinetics. In sum, it is reckoned that further food applications will follow soon.

Polysaccharide‑platinum complexes for cancer theranostics

Platinum anticancer drugs have been explored and developed in recent years to reduce systematic toxicities and resist drug resistance. Polysaccharides derived from nature have abundant structures as well as pharmacological activities. The review provides insights on the design, synthesis, characterization and associating therapeutic application of platinum complexes with polysaccharides that are classified by electronic charge. The complexes give birth to multifunctional properties with enhanced drug accumulation, improved tumor selectivity and achieved synergistic antitumor effect in cancer therapy. Several techniques developing polysaccharides-based carriers newly are also discussed. Moreover, the lasted immunoregulatory activities of innate immune reactions triggered by polysaccharides are summarized. Finally, we discuss the current shortcomings and outline potential strategies for improving platinum-based personalized cancer treatment. Using platinum-polysaccharides complexes for improving the immunotherapy efficiency represents a promising framework in future.

Mechanisms of action of coffee bioactive compounds - a key to unveil the coffee paradox

The knowledge of the relationship between the chemical structure of food components with their mechanisms of action is crucial for the understanding of diet health benefits. This review relates the chemical variability present in coffee beverages with the mechanisms involved in key physiological events, supporting coffee as a polyvalent functional food. Coffee intake has been related with several health-promoting properties such as neuroprotective (caffeine, chlorogenic acids and melanoidins), anti-inflammatory (caffeine, chlorogenic acids, melanoidins, diterpenes), microbiota modulation (polysaccharides, melanoidins, chlorogenic acids), immunostimulatory (polysaccharides), antidiabetic (trigonelline, chlorogenic acids), antihypertensive (chlorogenic acids) and hypocholesterolemic (polysaccharides, chlorogenic acids, lipids). Nevertheless, caffeine and diterpenes are coffee components with ambivalent effects on health. Additionally, a large range of potentially harmful compounds, including acrylamide, hydroxymethylfurfural, furan, and advanced glycation end products, are formed during the roasting of coffee and are present in the beverages. However, coffee beverages are part of the daily human dietary healthy habits, configuring a coffee paradox.

Bile Acid Sequestrants Based on Natural and Synthetic Gels

Bile acid sequestrants (BASs) are non-systemic therapeutic agents used for the management of hypercholesterolemia. They are generally safe and not associated with serious systemic adverse effects. Usually, BASs are cationic polymeric gels that have the ability to bind bile salts in the small intestine and eliminate them by excretion of the non-absorbable polymer-bile salt complex. This review gives a general presentation of bile acids and the characteristics and mechanisms of action of BASs. The chemical structures and methods of synthesis are shown for commercial BASs of first- (cholestyramine, colextran, and colestipol) and second-generation (colesevelam and colestilan) and potential BASs. The latter are based on either synthetic polymers such as poly((meth)acrylates/acrylamides), poly(alkylamines), poly(allylamines) and vinyl benzyl amino polymers or biopolymers, such as cellulose, dextran, pullulan, methylan, and poly(cyclodextrins). A separate section is dedicated to molecular imprinting polymers (MIPs) because of their great selectivity and affinity for the template molecules used in the imprinting technique. Focus is given to the understanding of the relationships between the chemical structure of these cross-linked polymers and their potential to bind bile salts. The synthetic pathways used in obtaining BASs and their in vitro and in vivo hypolipidemic activities are also introduced.

Contribution of non-ionic interactions on bile salt sequestration by chitooligosaccharides: Potential hypocholesterolemic activity

Chitooligosaccharides have been suggested as cholesterol reducing ingredients mostly due to their ability to sequestrate bile salts. The nature of the chitooligosaccharides-bile salts binding is usually linked with the ionic interaction. However, at physiological intestinal pH range (6.4 to 7.4) and considering chitooligosaccharides pKa, they should be mostly uncharged. This highlights that other type of interaction might be of relevance. In this work, aqueous solutions of chitooligosaccharides with an average degree of polymerization of 10 and 90 % deacetylated, were characterized regarding their effect on bile salt sequestration and cholesterol accessibility. Chitooligosaccharides were shown to bind bile salts to a similar extent as the cationic resin colestipol, both decreasing cholesterol accessibility as measured by NMR at pH 7.4. A decrease in the ionic strength leads to an increase in the binding capacity of chitooligosaccharides, in agreement with the involvement of ionic interactions. However, when the pH is decreased to 6.4, the increase in charge of chitooligosaccharides is not followed by a significant increase in bile salt sequestration. This corroborates the involvement of non-ionic interactions, which was further supported by NMR chemical shift analysis and by the negative electrophoretic mobility attained for the bile salt-chitooligosaccharide aggregates at high bile salt concentrations. These results highlight that chitooligosaccharides non-ionic character is a relevant structural feature to aid in the development of hypocholesterolemic ingredients.

Microencapsulated and Ready-to-Eat Beetroot Soup: A Stable and Attractive Formulation Enriched in Nitrate, Betalains and Minerals

Beetroot is a tuber rich in antioxidant compounds, i.e., betanin and saponins, and is one of the main sources of dietary nitrate. The aim of the present study was to microencapsulate a ready-to-eat beetroot soup by lyophilization using different encapsulating agents, which supply the required amount of bioactive nutrients. Particle size distributions ranged from 7.94 ± 1.74 to 245.66 ± 2.31 µm for beetroot soup in starch and from 30.56 ± 1.66 to 636.34 ± 2.04 µm in maltodextrin. Microparticle yields of powdered beetroot soup in starch varied from 77.68% to 88.91%, and in maltodextrin from 75.01% to 80.25%. The NO3− and total betalain contents at a 1:2 ratio were 10.46 ± 0.22 mmol·100 g−1 fresh weight basis and 219.7 ± 4.92 mg·g−1 in starch powdered beetroot soup and 8.43 ± 0.09 mmol·100 g−1 fresh weight basis and 223.9 ± 4.21 mg·g−1 in maltodextrin powdered beetroot soup. Six distinct minerals were identified and quantified in beetroot soups, namely Na, K, Mg, Mn, Zn and P. Beetroot soup microencapsulated in starch or maltodextrin complied with microbiological quality guidelines for consumption, with good acceptance and purchase intention throughout 90 days of storage. Microencapsulated beetroot soup may, thus, comprise a novel attractive strategy to offer high contents of bioaccessible dietary nitrate and antioxidant compounds that may aid in the improvement of vascular-protective effects.

Chemical composition and anti-cholesterol activity of tea (Camellia sinensis) flowers from albino cultivars

Albino tea cultivars are mutant tea plants with altered metabolisms. Current studies focus on the leaves while little is known about the flowers. To evaluate tea flowers from different albino cultivars, the chemical composition and anti-cholesterol activity of tea flowers from three albino cultivars (i.e., Baiye No.1, Huangjinya, and Yujinxiang) were compared. According to the results, tea flowers from Yujinxiang had more amino acids but less polyphenols than tea flowers from the other two albino cultivars. A reduced content of procyanidins and a high chakasaponins/floratheasaponins ratio were characteristics of tea flowers from Yujinxiang. In vitro anti-cholesterol activity assays revealed that tea flowers from Yujinxiang exhibited stronger activity in decreasing the micellar cholesterol solubility, but not in cholesterol esterase inhibition and bile salt binding. It was noteworthy that there were no specific differences on the chemical composition and anti-cholesterol activity between tea flowers from albino cultivars and from Jiukeng (a non-albino cultivar). These results increase our knowledges on tea flowers from different albino cultivars and help food manufacturers in the cultivar selection of tea flowers for use.

Water-Soluble Saccharina latissima Polysaccharides and Relation of Their Structural Characteristics with In Vitro Immunostimulatory and Hypocholesterolemic Activities

Brown macroalgae are an important source of polysaccharides, mainly fucose-containing sulphated polysaccharides (FCSPs), associated with several biological activities. However, the structural diversity and structure-function relationships for their bioactivities are still undisclosed. Thus, the aim of this work was to characterize the chemical structure of water-soluble Saccharina latissima polysaccharides and evaluate their immunostimulatory and hypocholesterolemic activities, helping to pinpoint a structure-activity relationship. Alginate, laminarans (F1, neutral glucose-rich polysaccharides), and two fractions (F2 and F3) of FCSPs (negatively charged) were studied. Whereas F2 is rich in uronic acids (45 mol%) and fucose (29 mol%), F3 is rich in fucose (59 mol%) and galactose (21 mol%). These two fractions of FCSPs showed immunostimulatory activity on B lymphocytes, which could be associated with the presence of sulphate groups. Only F2 exhibited a significant effect in reductions in in vitro cholesterol's bioaccessibility attributed to the sequestration of bile salts. Therefore, S. latissima FCSPs were shown to have potential as immunostimulatory and hypocholesterolemic functional ingredients, where their content in uronic acids and sulphation seem to be relevant for the bioactive and healthy properties.

Amaranth proteins and peptides: Biological properties and food uses

Amaranthus grains have attracted great attention due to its attractive health benefits. The grains have processing properties (e.g., starch related properties) similar to those of common cereals. Amaranth grains are gluten free and protein is a significant component of these grains. Proteins of the grains have been used in various food applications such as formulations of edible films and emulsions for controlled release of bioactive compounds. The proteins have been hydrolyzed using different enzymes to produce peptides and hydrolysates, which showed a range of biological functions including anti-hypertensive and antioxidant activities among others. They have been formulated into staple foods including breads and pastas for improved nutritional quality. This review summarizes the recent advances of the last 5 years in understanding the biological functions and food applications of proteins, protein hydrolysates and peptides from the grains of different Amaranthus species. Limitations in the studies summarized are critically discussed with an aim to improve the efficiency in amaranth grain protein and peptide research.

The lipid-lowering effects of fenugreek gum, hawthorn pectin, and burdock inulin

Objective

The present study aimed to investigate the lipid-lowering effects and mechanisms of fenugreek gum (FG), hawthorn pectin (HP), and burdock inulin (BI) on high-fat diet (HFD)-induced hyperlipidemic rats.

Methods

In this study, high-fat diet (HFD) together with fat emulsion administration were used to establish hyperlipidemia model. The biochemical indices were assayed after administration of FG, HP, and BI. Their effects were evaluated by factor analysis. Alterations of gut microbiota and short chain fatty acids (SCFAs) in the cecal were assessed to illustrate the mechanism of lipid lowering.

Results

The supplementation of FG, HP, and BI on HFD-fed rats decreased the levels of serum lipid and reduced the HFD-related liver and testicle damage. In the scatter plot of factor analysis, HP and BI were closer to normal fat diet (NFD) group in restoring the severity of hyperlipidemia, while FG and HP enhanced the excretion of cholesterol and bile acids (BAs). The levels of total SCFAs, especially butyric acid reduced by HFD were increased by HP. The ratio of Firmicutes to Bacteroidetes increased by HFD was reduced by HP and BI. FG, HP, and BI enriched intestinal probiotics, which were related to bile acid excretion or lipid-lowering.

Conclusions

FG inhibited the absorption of cholesterol and enhanced the excretion of it, as well as increased the abundance of beneficial bacteria. While BI restored the imbalance of intestinal microbiota. HP enhanced the excretion of cholesterol and BAs, and restored the imbalance of intestinal microbiota. It was also utilized by intestinal microorganisms to yield SCFAs. This study suggested that FG, HP, and BI possessed the potential to be utilized as dietary supplements for obesity management.

Effect of Coffee on the Bioavailability of Sterols

Absorption at the intestinal epithelium is a major determinant of cholesterol levels in the organism, influencing the entry of dietary cholesterol and the excretion of endogenous cholesterol. Several strategies are currently being followed to reduce cholesterol absorption, using both pharmacological agents or food ingredients with hypocholesterolemic properties. Coffee has recently been shown to affect cholesterol bioaccessibility, although it has not been shown if this translates into a decrease on cholesterol bioavailability. In this work, coffee obtained with different commercial roasting (light and dark) and grinding (finer and coarser) was evaluated regarding their effect on cholesterol absorption through Caco-2 monolayers, mimicking the intestinal epithelium. The fluorescent dehydroergosterol was used as a sterol model, which was shown to permeate Caco-2 monolayers with a low-to-moderate permeability coefficient depending on its concentration. In the presence of coffee extracts, a 50% decrease of the sterol permeability coefficient was observed, showing their potential to affect sterol bioavailability. This was attributed to an increased sterol precipitation and its deposition on the apical epithelial surface. A higher hypocholesterolemic effect was observed for the dark roasting and finer grinding, showing that the modulation of these technological processing parameters may produce coffees with optimized hypocholesterolemic activity.

Two Laminaria japonica polysaccharides with distinct structure characterization affect gut microbiota and metabolites in hyperlipidemic mice differently

Our previous study found dietary mannogluconic acid (MA) and fucogalactan sulfate (FS) from Laminaria japonica have distinct structure characterization and potential hypolipidemic effects in vitro. Herein, we compared the benefits of MA and FS on hyperlipidemia. The result showed only FS treatment decreased body weight and serum cholesterol levels. Compared with MA, FS was more effective in mitigating hepatic fat accumulation, promoting GSH-Px activity, reducing the MDA formation, and lowering the level of TNF-α in liver. Gut microbiota and metabolism analysis revealed that FS increased the relative abundance of beneficial bacteria and boosted the level of short chain fatty acids. Particularly, taurine and 3α,7α,12α-trihydroxy-24-oxo-5-β-cholestanoyl CoA were upregulated by FS, which might attribute to the increased Oscillibacter and thus affect the enterohepatic circulation of bile acids and serum TC level. Therefore, FS with more branches and sulfate ester groups could be a good lipid-lowering dietary supplement.

Structure, Physicochemical Property, and Functional Activity of Dietary Fiber Obtained from Pear Fruit Pomace (Pyrus ussuriensis Maxim) via Different Extraction Methods

In this study, soluble dietary fiber (SDF) and insoluble dietary fiber (IDF) were extracted from Pyrus ussuriensis Maxim pomace via three methods including enzymic extraction (EE), microwave-assisted enzymatic extraction (MEE), and three-phase partitioning (TPP). The effects of different extraction methods on the structure, physicochemical property, and functional activity of the extracted dietary fiber were evaluated. The results showed that different extraction methods had significant effects on the extraction yield, molecular weight distribution, thermal stability, antioxidant activity, and hypoglycemic activity in vitro, but resulted in no difference in the structure and composition of functional groups. It is noteworthy that SDF extracted by TPP has a more complex and porous structure, lower molecular weight, and higher thermal stability, as well as better physicochemical properties and in vitro hypoglycemic activity. IDF extracted by MEE showed the greatest water and oil holding capacity; the highest adsorption capacity for glucose, cholesterol, and nitrite ion; as well as the strongest inhibitory activity on α-amylase. These results suggest that PUP may be a source of cheap natural dietary fiber.

Amelioration of Obesity in Mice Fed a High-Fat Diet with Uronic Acid–Rich Polysaccharides Derived from Tremella fuciformis

Obesity is rapidly becoming an emerging disease in developing countries due to the Westernization of societies and lifestyle changes. This study evaluated the ameliorative effect of acidic heteropolysaccharides derived from Tremella fuciformis (TFPS) on high-fat diet (HFD; 34.9% fat)-induced obesity in mice. The TFPS exhibited high uronic acid content and high viscosity in water. The structural characteristics of TFPS showed that average molecular weight was 679 kDa, and the monosaccharide composition was galactose, glucose, fructose, xylose, fucose, and mannose at a ratio of 1.0:6.5:10.0:18.5:30.5:67.5. In an in vivo study, HFD-induced obese C57BL/6 mice were orally given a TFPS treatment at 1 and 2 g/kg of body weight for 8 weeks. The TFPS treatment significantly reduced features of obesity in the mice, namely weight gain, feed efficiency, body fat percentage, and serum cholesterol level and increased fecal lipid content, compared with mice fed an HFD with water. In addition, TFPS exhibited the inhibition of cholesterol micelles in vitro in a concentration-dependent manner. In conclusion, the TFPS treatment ameliorated the diet-induced obesity in the mice, presumably reducing fat absorption in the intestine by interfering with viscous TFPS.

Gamma-Irradiation-Induced Degradation of the Water-Soluble Polysaccharide from Auricularia polytricha and Its Anti-Hypercholesterolemic Activity

The water-soluble polysaccharides (APPs) isolated from the edible mushroom Auricularia polytricha were irradiated by γ-ray at doses of 10, 100, and 1000 kGy. The effect of gamma irradiation on the degradation of the polysaccharide was investigated. After irradiation treatment, the viscosity and molecular weight of APPs decreased with the increase in the irradiation dose. The changes in the enthalpy of APPs after irradiation treatment were observed. Meanwhile, SEM showed that R-APPs were crushed into fragments and the surfaces became smooth and wrinkled after irradiation. In further spectrum analysis, it was found that the glycoside bonds of the polysaccharides were broken and accompanied by the formation of double bonds. This suggested that gamma irradiation could cause the depolymerization and oxidation of polysaccharides. In addition, irradiated APPs could reduce the body weight of hyperlipidemia mice. The levels of serum and liver TC, TG, and serum LDH-c significantly decreased in hyperlipidemia mice after treatment by irradiated APPs. It indicated that gamma irradiation significantly improved the anti-hypolipidemic activity of APPs. The relationship between the physicochemical properties and hypolipidemic activity of polysaccharides was interpreted, which provides a theoretical basis for the further development of APP products. Gamma irradiation is a viable technology for macromolecular modification for degradation.