Bile Salt Binding Research Articles

Novel Guanidinium-Functionalized Stigmasterol for Bile Salt Binding and Serum Cholesterol Reduction: Synthesis, Interaction Mechanisms, and In Vivo Function.

A novel amphiphilic guanidyl-functionalized stigmasterol hydrochloride (GFSH) was designed and synthesized as bile salt sequestrants for cholesterol reduction. GFSH exhibited a considerable in vitro capacity for bile salt binding in gastrointestinal digestion and alleviated hypercholesterolemia in vivo. GFSH spontaneously interacted with sodium cholate via synergistic electrostatic, hydrophobic, and hydrogen-bonding interactions. The effects of GFSH on serum cholesterol reduction in mice fed a high-fat-high-cholesterol diet were explored by measuring the expression of key transcription factors related to bile acid metabolism. GFSH produced a dose-dependent reduction in weight gain, hepatic fat accumulation, and fecal and blood markers. Real-time quantitative polymerase chain reaction (RT-qPCR) and western blot analyses demonstrated GFSH-induced expression of hepatic CYP7A, LXRα, and LDL-R. GFSH exerts the cholesterol-lowering activity by inducing the bile acid metabolism.

Enhancement of physicochemical, in vitro hypoglycemic, hypolipidemic, antioxidant and prebiotic properties of oat bran dietary fiber: Dynamic high pressure microfluidization

To improve the physicochemical and functional properties of oat bran dietary fiber (ODF) and the comprehensive utilization of oat bran, dynamic high-pressure microfluidization (DHPM) was utilized to treat ODF at different pressures. The particle size, physicochemical, functional and probiotic properties of the ODF samples were analyzed to investigate the modification effect of DHPM. After DHPM modification, the microstructure of ODF was broken, the particle size decreased and the specific surface area increased, with the best effect under 420 MPa pressure treatment. The structural breakage and the increase in the specific surface area of ODF may led to the enhancement of its physicochemical and functional properties, and it had greater advantages in terms of the water retention capacity (2.13 ± 0.01 g/g), oil retention capacity (8.46 ± 0.07 g/g), bile salt binding capacity (52.67 ± 1.21 mg/g) and cholesterol binding capacity (1.03 ± 0.02 mg/g). cholesterol binding capacity (1.03 ± 0.02 mg/g). Meanwhile, ODF also remodelled the gut microbiota of the obese population and increased the relative abundance of beneficial bacteria. In conclusion, DHPM treatment effectively enhanced the physicochemical and functional properties of ODF and broadened its applications in the food industry.

Cholesterol-Lowering Effect of Polysaccharides from Cyclocarya paliurus In Vitro and in Hypercholesterolemia Mice.

In this study, a new component of Cyclocarya paliurus polysaccharides (CPP20) was precipitated by the gradient ethanol method, and the protective effect of CPP20 on hypercholesterolemia mice was investigated. In vitro, CPP20 had the ability to bind bile salts and inhibit cholesterol micelle solubility, and it could effectively clear free radicals (DPPH•, •OH, and ABTS+). In vivo, CPP20 effectively alleviated hypercholesterolemia and liver damage in mice. After CPP20 intervention, the activity of antioxidant enzymes (SOD, CAT, and GSH-Px) and the level of HDL-C in liver and serum were increased, and the activity of aminotransferase (ALT and AST) and the level of MDA, TC, TG, LDL-C, and TBA were decreased. Molecular experiments showed that CPP20 reduced cholesterol by regulating the mRNA expression of antioxidation-related genes (SOD, GSH-Px, and CAT) and genes related to the cholesterol metabolism (CYP7A1, CYP27A1, SREBP-2, HMGCR, and FXR) in liver. In addition, CPP20 alleviated intestinal microbiota disturbances in mice with hypercholesterolemia and increased levels of SCFAs. Therefore, CPP20 alleviates hypercholesterolemia by alleviating oxidative damage, maintaining cholesterol homeostasis, and regulating gut microbiota.

Fermentation of Lonicera caerulea by complex probiotics and its Effect on hypolipidemic

Hyperlipidemia is a crucial risk factor in inducing fatty liver, hypertension, atherosclerosis, and cerebrovascular diseases. Currently, functional food has become a research hotspot in the hypolipidemic. Lonicera caerulea is a potential raw material that has various bioactive compounds. This study aimed to investigate the effects of single and compound strains on the fermentation of Lonicera caerulea. Meanwhile, the effect on the hypolipidemic of fermented products was detected. The results showed that L. paracasei and S. thermophilus had lower metabolic levels in Lonicera caerulea juice among all six tested strains. Then, the fermented product co-fermented with B. bifidum and L. casei exhibits the highest lipid-lowering activity compared to other combinations and single strains. The pancreatic lipase inhibition rate and the bile salt binding capacity were higher at 65.39% and 2.93 mg/mL when the compound probiotic was compounded as a ratio of 2:1. And with the extension of fermentation time, the content of flavonoids in the system also increased. In addition, the levels of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and the activities of aspartate transaminase (AST) and alanine aminotransferase (ALT) in HepG2 cells were decreased by the treatment of fermented juice. The fermented Lonicera caerulea plays a positive role in regulating cell lipid metabolism. In conclusion, Fermentation is a feasible way to develop Lonicera caerulea resources. And the fermentation of complex lactic acid bacteria is a promising processing to enhance the lipid-lowering activity of Lonicera caerulea.

Deciphering conformational changes in human serum albumin induced by bile salts using spectroscopic and molecular modeling approaches

Bile salts are physiologically-important natural amphiphilic biosurfactants synthesized in the liver and play a vital role in the solubilization and digestion of dietary lipids, cholesterol, and other fat-soluble compounds in the body. Bile salts also exhibit pharmacological and biological uses as carriers for transporting scarce water-soluble drugs and other chemicals owing to their unique emulsifying, solubilizing capacities and micelle forming ability. In this context, we present an endeavor towards the possibilities underlying the interaction and binding between the most abundant plasma protein namely, human serum albumin (HSA) and bile salts to demonstrate an intriguing interplay of hydrophobic, electrostatic and hydrogen bonding effects using steady state absorption, fluorescence emission, anisotropy, time-resolved emission, and molecular modelling approaches. The outcome illuminates how amphiphilic interfaces of bile salts under various physico-chemical conditions trigger the conformational changes and binding affinities of native and molten-globule forms of HSA. To elucidate non-covalent interactions during HSA-bile salt supramolecular host–guest complex formation, changes in intrinsic (tryptophan) and extrinsic (ANS) fluorescence have been investigated. The results reveal upon binding of bile salts in subdomain IIA of HSA, the protein undergoes conformational changes mediated primarily by hydrophobic interactions. Furthermore, time-resolved fluorescence measurements provide important structural and dynamical insights into the protein-bile salt supramolecular complexes. Additionally, molecular docking studies on these complexes clearly reveal spontaneous binding of bile salts into subdomain IIA of HSA while suggesting that the binding affinity decreases with the decreasing order of hydrophobicity of the bile salts (NaDC > NaC > NaTC) (ΔGdock = −29.64 kJ mol−1, −26.15 kJ mol−1, −14.35 kJ mol−1), respectively. This study exclusively highlights the molecular mechanism of conformational perturbation in the native (pH 7) and molten-globule (pH 3) forms of HSA, induced by bile salts. We believe that the results reported herein will be helpful in the design and formulation of protein-bile salt-based pharmacological carriers suitable for drug delivery.

Structural changes and bile salt-binding ability of modified whey protein isolate: Before and after in vitro digestion

In response to digestion complex environments, protein's ability to bind bile salts (BS) will be altered. This study aimed to assess the different effects of in vitro digestion on the BS-binding capacity of fermentation-organic acid compound-modified and unmodified WPI. According to the results, modified WPI can increase the degree of hydrolysis, reduce the sulfhydryl group content, and expose aromatic amino acids during digestion, indicating that the BS-binding ability of WPI is dependent on the hydrogen bond content. The more residual of surface hydrophobicity and β-sheet and β-turn contents suggested that exposure of hydrophobic groups of modification would promote BS-binding with hydrophobic of modified WPI in simulated digestion, consistent with the change in sulfhydryl content and surface hydrophobicity. This further confirms the higher binding ability of WPI for BS through hydrophobic interactions. In addition, the apparent viscosity and viscoelasticity of modified WPI were increased, which contributed to improved BS binding. Further, the modification enhanced the content of fragmented polymers with a molecular weight less than or equal to 3.3 kDa after digestion. Based on peptidomics, it was concluded that FLPYPYYAKP and ALKALPMHIRL were polypeptides with strong cholesterol-lowering effects, with a significant difference between modified and unmodified WPI.

Effect of red algae powder on gel properties and in vitro hypolipidemic activity of fish balls

In this study, gel properties and in vitro hypolipidemic activity of fish balls with red algae powder including Porphyra and Bangia fusco-purpurea powder were investigated after frozen storage for 7 d. Water holding capacity and gel structure are important factors affecting the quality of minced fish products. The results showed that Porphyra powder at 0.5 % significantly increased water holding capacity of fish balls while Bangia fusco-purpurea powder not (p ≥ 0.05), and both Porphyra and Bangia fusco-purpurea powder enhanced protein interactions, the cross-linking of actin and gel network structure, but 1.0 % of them decreased water holding capacity, resulting the loose and irregular gel structure of fish balls with excessive aggregation partially (p < 0.05). Moreover, both Porphyra and Bangia fusco-purpurea powder higher than 0.5 % could significantly improve the bile salt binding ability of fish balls (p < 0.05), especially Bangia fusco-purpurea powder at 1.0 % also significantly increased the inhibition rate of pancreatic lipase of fish balls (p < 0.05), suggesting the enhanced hypolipidemic activity for fish balls with red algae powder. These findings indicated that surimi products with desirable gel and hypolipidemic activity can be designed by adding appropriate type and concentration of red algae powder.

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.

Mechanism of germination inhibition of Clostridioides difficile spores by an aniline substituted cholate derivative (CaPA).

Clostridioides difficile infection (CDI) is the major identifiable cause of antibiotic-associated diarrhea and has been declared an urgent threat by the CDC. C. difficile forms dormant and resistant spores that serve as infectious vehicles for CDI. To cause disease, C. difficile spores recognize taurocholate and glycine to trigger the germination process. In contrast to other sporulating bacteria, C. difficile spores are postulated to use a protease complex, CspABC, to recognize its germinants. Since spore germination is required for infection, we have developed anti-germination approaches for CDI prophylaxis. Previously, the bile salt analog CaPA (an aniline-substituted cholic acid) was shown to block spore germination and protect rodents from CDI caused by multiple C. difficile strains and isolates. In this study, we found that CaPA is an alternative substrate inhibitor of C. difficile spore germination. By competing with taurocholate for binding, CaPA delays C. difficile spore germination and reduces spore viability, thus diminishing the number of outgrowing vegetative bacteria. We hypothesize that the reduction of toxin-producing bacterial burden explains CaPA's protective activity against murine CDI. Previous data combined with our results suggests that CaPA binds tightly to C. difficile spores in a CspC-dependent manner and irreversibly traps spores in an alternative, time-delayed, and low yield germination pathway. Our results are also consistent with kinetic data suggesting the existence of at least two distinct bile salt binding sites in C. difficile spores.

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.

Interactions in Aqueous Mixtures of Cationic Hydroxyethyl Cellulose and Different Anionic Bile Salts.

It is known that the reduction of blood cholesterol can be accomplished through foods containing a large number of dietary fibers; this process is partially related to the binding of bile salt to fibers. To gain new insights into the interactions between dietary fibers and bile salts, this study investigates the interactions between cationic hydroxyethyl cellulose (catHEC) and sodium deoxycholate (NaDC) or sodium cholate (NaC), which have a similar structure. Turbidity measurements reveal strong interactions between catHEC and NaDC, and under some conditions, macroscopic phase separation occurs. In contrast, the interactions with NaC are weak. At a catHEC concentration of 2 wt %, incipient phase separation is approached at concentrations of NaC and NaDC of 32.5 and 19.3 mM, respectively. The rheological results show strong interactions and a prominent viscosification effect for the catHEC/NaDC system but only moderate interactions for the catHEC/NaC system. Both cryogenic transmission electron microscopy and small-angle X-ray scattering results display fundamental structural differences between the two systems, which may explain the stronger interactions in the presence of NaDC. The surmise is that the extended structures formed in the presence of NaDC can easily form connections and entanglements in the network.

Purification, identification and hypolipidemic activities of three novel hypolipidemic peptides from tea protein

In this study, hypolipidemic peptides were obtained from tea protein by enzymatic hydrolysis, ultrafiltration and high-performance liquid chromatography. Subsequently, the hypolipidemic peptides were identified by mass spectrometry and screened through molecular docking technology, and the hypolipidemic activities and mechanisms of the active peptides were explored. The results showed that the hydrolysate of hypolipidemic peptides obtained by pepsin hydrolysis for 3 h had good bile salt binding ability. After purification, identification and molecular docking screening, three novel hypolipidemic peptides FLF, IYF and QIF were obtained. FLF, IYF and QIF can interact with the receptor proteins 1LPB and 1F6W through hydrogen bonds, π-π bonds, hydrophobic interactions and van der Waals forces, thus exerting hypolipidemic activities. Activity studies showed that, compared with the positive controls, FLF, IYF and QIF had excellent sodium taurocholate binding abilities, pancreatic lipase inhibitory activities and cholesterol esterase inhibitory activities. Moreover, FLF, IYF and QIF can effectively inhibit lipogenic differentiation of 3T3-L1 preadipocytes, reduce intracellular lipid and low-density lipoprotein content and increase high-density lipoprotein content. These results indicated that the three novel hypolipidemic peptides screened in this study had excellent hypolipidemic activities and were expected to be used as natural-derived hypolipidemic active ingredients for the development and application in functional foods.

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.

Structural changes and cholesterol-lowering in denatured whey protein isolate: Malic acid combined enzymolysis

Binding of bile salts (BS) and protein has been linked to cholesterol reduction. However, the interaction between the protein structural and binding of BS ability was unclear. The goals of this study were to investigate the relationship among the structure, morphology, and functional properties of hydrolytic peptides of whey protein isolate (WPI) for four groups: control (no treatment), malic acid acidolysis [WPI + MA(DL)], enzymolysis (WPI-E), and enzymolysis combined with MA acidolysis [WPI-E+MA(DL)]. We found that the combination of enzymolysis and acidolysis could significantly improve the bile salt-binding ability of WPI (p < 0.05) by changing the structure and morphology of the protein compared with that in the other groups. An increase in the degree of hydrolysis, reduction in sulfhydryl group content, and exposure of aromatic amino acids indicated that WPI bound to the bile salts through hydrogen bond interactions. Additionally, the increase in surface hydrophobicity and β-sheet, β-turn, and random structure contents according to Fourier transform infrared spectroscopy indicated an exposure of hydrophobic groups. This further confirmed that WPI exhibited higher bile salt-binding ability through hydrophobic interactions. Sodium dodecyl sulphate-polyacrylamide gel electrophoresi (SDS-PAGE), Tricine-SDS-PAGE, scanning electron microscopy, and particle size analysis revealed that the hydrophobic groups exposed to the protein surface were aggregated and formed fragmented polymers with a molecular weight of approximately 3.3 kDa. Moreover, differential scanning calorimetry and rheology revealed that these polymers exhibited higher thermal stability, apparent viscosity, and viscoelasticity, and the viscosity was positively correlated with binding ability. Thus, the relationship between the structure, morphology and functional characteristics of hydrolytic peptides in the study can provide good data for designing innovative new peptides that ameliorate cholesterol and lipid metabolism. And it has good application value for the development of healthy and functional food.

Structural and Dynamic Determinants of Molecular Recognition in Bile Acid-Binding Proteins.

Disorders in bile acid transport and metabolism have been related to a number of metabolic disease states, atherosclerosis, type-II diabetes, and cancer. Bile acid-binding proteins (BABPs), a subfamily of intracellular lipid-binding proteins (iLBPs), have a key role in the cellular trafficking and metabolic targeting of bile salts. Within the family of iLBPs, BABPs exhibit unique binding properties including positive binding cooperativity and site-selectivity, which in different tissues and organisms appears to be tailored to the local bile salt pool. Structural and biophysical studies of the past two decades have shed light on the mechanism of bile salt binding at the atomic level, providing us with a mechanistic picture of ligand entry and release, and the communication between the binding sites. In this review, we discuss the emerging view of bile salt recognition in intestinal- and liver-BABPs, with examples from both mammalian and non-mammalian species. The structural and dynamic determinants of the BABP-bile–salt interaction reviewed herein set the basis for the design and development of drug candidates targeting the transcellular traffic of bile salts in enterocytes and hepatocytes.

Hypolipidaemic and antioxidant effects of various Chinese dark tea extracts obtained from the same raw material and their main chemical components

In order to investigate the hypolipidaemic and antioxidant effects of various dark teas produced from different post-fermentation using the same raw material, a hyperlipidaemia zebrafish model combined with binding bile salts assay and antioxidant assays were performed in this study. Results showed that the hypolipidaemic effect of dark tea extracts increased significantly (p < 0.05) while the antioxidant ability decreased sharply compared with raw material. Particularly, Liupao tea (50%) and Pu-erh tea (48%) showed promising hypolipidaemic potential; however, the antioxidant capacity of Pu-erh tea decreased (31–49%) most dramatically. Besides, the levels of total polyphenols and catechins decreased sharply, but theabrownin, gallic acid, and caffeine increased significantly after post-fermentation. Moreover, the potential mechanisms of regulating hyperlipidaemia by dark tea extracts were discussed. These results suggest that microbial fermentation significantly affects the bioactivity of dark teas, and provide theoretical basis for processing and improving of dark tea products for hyperlipidaemia therapy.

Functional, physicochemical and structural properties of soluble dietary fiber from rice bran with extrusion cooking treatment

The effects of extrusion cooking treatment with different parameters (when the screw speed was 250 rpm/min and the material moisture was 17 %, the extrusion cooking temperature were 100 °C, 120 °C, 140 °C, 160 °C, 180 °C, respectively; when the screw speed was 250 rpm/min and the extrusion cooking temperature was 160 °C, the material moisture were 11 %, 14 %, 17 %, 20 %, 23 %, respectively) on the functional, physicochemical and structural properties of soluble dietary fiber (SDF) from rice bran were investigated. The water and oil retention capacity (WRC and ORC), water solubility (WS), in vitro binding capacities (bile salt, cholesterol and glucose binding capacity) and antioxidant capacities of SDF were higher when extrusion cooking temperatures were 100 °C and 120 °C. The in vitro binding capacities and antioxidant capacities of SDF were higher when material moisture contents were 11 % and 14 %. However, the ORC, in vitro binding capacities and antioxidant capacities decreased when extrusion cooking temperature was higher than 140 °C and material moisture was higher than 14 %. The results of FT-IR spectrum indicated that the structure of SDF from rice bran was changed after extrusion cooking treatment. The extrusion cooking treatment at low temperature and low material moisture was more beneficial to the properties of SDF. This study may provide basic information for the utilization of SDF from rice bran with extrusion cooking treatment.

Mycoprotein ingredient structure reduces lipolysis and binds bile salts during simulated gastrointestinal digestion.

Mycoprotein is the fungal biomass obtained by the fermentation of Fusarium venenatum, whose intake has been shown to lower blood lipid levels. This in vitro study aimed to understand the mechanisms whereby mycoprotein can influence lipid digestion by reducing lipolysis and binding to bile salts. Mycoprotein at 30 mg mL-1 concentration significantly reduced lipolysis after 60 min of simulated intestinal digestion with oil-in-water emulsion (P < 0.001) or 10 min of incubation with tributyrin (P < 0.01). Furthermore, mycoprotein effectively bound bile salts during simulated small intestinal digestion, but only after being exposed to the acidic environment of the preceding gastric phase. However, the extent of bile salts sequestered by mycoprotein was decreased by pepsin and lipase-colipase activity. Besides, extracted mycoprotein proteins showed bile salt binding activity, and proteins with a molecular weight of ∼37 kDa showed resistance to trypsin hydrolysis. Thus, eleven extracted mycoprotein proteins (> 37 kDa) were identified by liquid chromatography-tandem mass spectrometry. In addition, the viscosity of mycoprotein digesta appeared to have no impact on bile salt binding since no statistically significant differences were detected between samples exposed or not to the previous gastric step. This study has identified mechanisms by which mycoprotein can reduce blood lipid levels.

Comparing the chemical composition of dietary fibres prepared from sugarcane, psyllium husk and wheat dextrin

A dietary fibre prepared from sugarcane stalk was compared with psyllium husk and wheat dextrin. In contrast to the other dietary fibres, sugarcane fibre was found to contain significant amounts of insoluble dietary fibre (73–86%), lignin (18.66–20.23%), and rare minerals such as chromium (0.67–2.54 mg/100 g) and manganese (1.07–2.34 mg/100 g). Analysis of the ethanol extract also detected compounds with antioxidant activity. Characterisation of five sugarcane fibres prepared from selected strains, harvest periods (growth or storage phase), and processing conditions showed these factors influenced the final composition. Furthermore, using in vitro digestion, we found that potassium, magnesium, chromium, and zinc in were bioaccessible in sugarcane samples. Also, sodium was shown to bind to the sugarcane fibre potentially indicating bile salt binding activity. Results from this study support the use of sugarcane as a source of dietary fibre in functional foods.