Characterization of the properties of amphiphilic, alkaline soluble polysaccharides from sugar beet pulp

Preparation and characterization of O/W emulsion stabilized by lysozyme and sugar beet pectin complexes formed by electrostatic self-assembly

Food-grade protein-polysaccharide complex particles exhibit remarkable efficacy in stabilizing emulsions. In the present investigation, binary complexes of lysozyme (LY) and sugar beet pectin (SBP) were synthesized through electrostatic self-assembly and subsequently utilized for stabilizing emulsions. The self-assembly behavior and formation mechanisms of the LY-SBP binary complexes were investigated by systematically varying the charge and density through pH adjustments. The results indicated that the LY-SBP complexes exhibited the most robust electrostatic interactions at a pH of 6.2, leading to the formation of highly insoluble complexes with the smallest particle sizes (300.2 nm). These complexes demonstrated a superior capacity to reduce interfacial tension compared to LY alone. Fluorescence spectroscopy, Fourier-transform infrared spectroscopy, and microstructural analysis provided further insights into the complexation mechanism. The results suggested that hydrogen bonding interactions played a crucial role in the formation of LY-SBP complexes. Notably, the emulsion stabilized with 1.5 % LY-SBP showed better emulsification stability against freeze-thaw cycles, storage, and high ionic conditions, compared to emulsions stabilized with only LY. This improved salt tolerance renders LY-SBP emulsions more suitable for a variety of food processing applications.

Gum arabic-stabilized emulsion systems: Underlying mechanisms for enhancing storage and digestion stability of curcumin

Although the benefits of gum arabic (GA) in developing emulsion systems are well known, the mechanism underlying its stability-enhancing effect of GA in emulsion systems stabilized with curcumin remains unclear. This study used GA-stabilized emulsion system, containing 10 wt% medium-chain triglycerides and 0.1 % curcumin. Results demonstrated that when the GA concentration exceeded 0.5 wt%, the interface layer reached saturation, maintaining a consistent thickness of approximately 34.8 nm. The curcumin-containing emulsion demonstrated good stability during storage at room temperature and heating treatment, effectively protecting the curcumin. However, during in vitro intestinal digestion, the formation of salt and protein bridges caused the aggregation of oil droplets, resulting in an increase in the droplet size to 975.2 nm, while the curcumin content remained stable. Additionally, the in vitro release rate of encapsulated curcumin (44.0 %) was significantly higher than that of free curcumin (19.5 %). In conclusion, this study elucidated the stability-enhancing mechanism of GA-stabilized emulsions for curcumin and highlighted the potential of GA in developing emulsion systems for the encapsulation of these compounds.

Structural characterization and antioxidant activity mechanism of the ferulic acid-rich subfraction from sugar beet pectin

The feruloylated sugar chain in sugar beet pectin (SBP) is a natural polyphenol-polysaccharide complex. Its low abundance often leads to be neglected, thereby hindering its bioactivity and mechnism research. In this study, SBP-3 A, a novel feruloylated polysaccharide fragment, was isolated from sugar beet pectin utilizing enzymatic digestion. The presence of ferulic acid on SBP-3 A was confirmed through high-performance liquid chromatography (HPLC), with a mass fraction of 22.5 μg/mg. The average molecular weight was determined to be 33.31 kDa. Methylation analysis, and nuclear magnetic resonance (NMR) spectra revealed that SBP-3 A is a heteroglycan with the main chain structure of →2)-α-Rhap-(1 → 4)-α-GalpA-(1 → 2)-α-Rhap-(1→, and the branched chain structure of ferulic acid (FA) → 3,4)-β-Galp-(1 → 2,4)-α-Rhap-(1→. Subsequently, the antioxidant activity of SBP-3 A was evaluated using the Caenorhabditis elegans (C. elegans). SBP-3 A improved antioxidant enzymes and non-enzymatic defense system, decreased reactive oxygen species levels, and up-regulated the mRNA expression of sod-3, skn-1, and daf-16, while down-regulated the expression of age-1 in C. elegans. Moreover, SBP-3 A modulated the gut flora by favorably affecting the abundances of Lactobacillus, Ligilactobacillus, and Akkermansia, thereby enhancing antioxidant capacity in C. elegans. Consequently, the aforementioned findings support the potential application of SBP-3 A as a functional food for treating oxidative stress-related illnesses.

Elucidation of the structural changes of hemicellulose and cellulose in sunflower seed during roasting

This study evaluated the structural changes in hemicellulose and cellulose from sunflower seeds before and after roasting at 160°C, 190°C, and 220°C. Sugar composition, molecular weight, Fourier transform infrared spectrometry, thermogravimetric, and NMR analyses were utilized to determine the structural properties of these polysaccharides and detect the volatile compounds. The results showed that roasting destroyed the microstructure of these hemicelluloses and cellulose. Glucose and arabinose of hemicellulose were more easily degraded than other sugars during roasting. The galacturonic acid content increased from 7.8% to 46.66% after roasting. The hemicellulose obtained at 220°C had a backbone of D-xylose residues with a β-(1→4)-linkage. The molecular weight of cellulosic polysaccharides decreased with the increase of roasting temperature. The crystallinity increased from 28.92% to 31.86% revealing that mainly the amorphous regions of cellulosic polysaccharides were destroyed by roasting. After roasting, the volatile compounds of these polysaccharides were rich in furfural, which was produced by caramelization and the Maillard reaction, contributing to the characteristic aroma of roasted sunflower seeds. This study provides some information on the relationship between structural changes of polysaccharides and the formation of flavor during roasting sunflower seeds.

Gum arabic as a sole wall material for constructing nanoparticle to enhance the stability and bioavailability of curcumin

In this study, a kind of nanoparticle prepared using gum arabic as a sole wall material for loading curcumin was obtained. The properties and digestive characteristics of the curcumin-loaded nanoparticle were determined. Results showed that the maximum loading amount of the nanoparticle was 0.51 µg/mg with an approximately 500 nm size. The Fourier transform infrared (FTIR) spectrum showed that the complexation was mainly related to the -C[bond, double bond]O, -CH, and -C-O-C- groups. The curcumin-loaded nanoparticle exhibited good stability under highly concentrated salinity stress, and the stability of the curcumin loaded in nanoparticles was significantly higher than that of free curcumin under ultraviolet radiation. The curcumin loaded in nanoparticle was released mainly in the intestinal digestion stage, and the release process was sensitive to the pH changes rather than protease. In conclusion, these nanoparticles can be a potential nanocarrier for enhancing the stability of curcumin which can be applied in the salt-containing food system.

Pickering emulsions synergistically stabilized by sugar beet pectin and montmorillonite exhibit enhanced storage stability and viscoelasticity

Sugar beet pectin (SBP) is a naturally occurring emulsifying type of pectin fabricated into nanocomposites with montmorillonite (MMT) and then introduced as a stabilizer for high internal phase emulsions (HIPEs). SBP-MMT composites performed well in emulsifying medium-chain triglyceride with an oil volume fraction (φ) of 0.1-0.85 and SBP/MMT mass ratios of 1:0.1-1:0.75. The two representative high internal phase emulsions stabilized by SBP-MMT composites at different SBP/MMT mass ratios exhibited good stability against creaming and coalescence. In these emulsion systems, SBP and MMT formed a network in the continuous phase that markedly improved the rheological properties, including the storage modulus (by 3 orders of magnitude). Confocal light scattering microscopy analysis indicated that a fraction of MMT could work synergistically with SBP in adsorbing on oil droplet surfaces, enhancing stability. SBP-MMT composites stabilized high internal phase emulsions destabilized after the freeze-thaw treatment (-40 °C for 20 h and 25 °C for 4 h) but could be facilely re-emulsified via high-speed shearing. The gastrointestinal digestion behaviors were also modified by stabilizing SBP and MMT. Overall, this work reveals a hitherto undocumented strategy for fabricating highly stable emulsions based on SBP-MMT composites which have huge prospects for application in the food and related industries.

The properties and formation mechanism of ovalbumin-fucoidan complex

The polymeric materials formed by proteins and polysaccharides through molecular interactions have attracted public attention. In this study, a novel binary complex consisting of ovalbumin (OVA) and fucoidan (FUC) was obtained by electrostatic self-assembly. The self-assembly properties and the formation mechanism of the OVA-FUC binary complex were investigated by changing the charging degree and density of complex through altering pH value and polysaccharides proportion. Structural changes during the OVA-FUC electrostatic self-assembly process were investigated by a phase diagram, ζ-potential, and particle size. The optimal conditions for preparing soluble OVA-FUC binary complex were determined by the protein retention rate and insoluble solids content. Results showed that the soluble OVA-FUC binary complex could be obtained at the pH of 3.5 to 5, and the insoluble OVA-FUC binary complex was generated at the pH of 2.5 to 3.5. The OVA-FUC binary complex (19 ± 0.29 mN/m) possessed a medium ability to reduce interfacial tension of the water-oil interface compared with OVA (15 ± 1.13 mN/m) and FUC (24 ± 0.3 mN/m), indicating that OVA-FUC binary complex has good amphiphilicity and can be applied as a potential pH-controlled emulsifier in function food systems for delivering bioactive substances.

A critical review of RG-I pectin: sources, extraction methods, structure, and applications

In recent years, RG-I pectin isolated by low-temperature alkaline extraction methods has attracted the attention of a large number of researchers due to its huge health benefits. However, studies on other applications of RG-I pectin are still lacking. In this study, we summarized the sources (e.g. potato pulp, sugar beet pulp, okra, apple pomace, citrus peel, pumpkin, grapefruit, ginseng, etc.), extraction methods, fine structure and applications of RG-I pectin in physiological activities (e.g. anti-cancer, anti-inflammatory, anti-obesity, anti-oxidation, immune regulation, prebiotics, etc.), emulsions, gels, etc. These neutral sugar side chains not only endow RG-I pectin with various physiological activities but the entanglement and cross-linking of these side chains also endow RG-I pectin with excellent emulsifying and gelling properties. We believe that this review can not only provide a comprehensive reading for new workers interested in RG-I pectin, but also provide a valuable reference for future research directions of RG-I pectin.

Thermomechanically micronized sugar beet pulp: Emulsification performance and the contribution of soluble elements and insoluble fibrous particles

In this work, thermomechanically micronized sugar beet pulp (MSBP), a micron-scaled plant-based byproduct comprised of soluble elements (∼40 wt%) and insoluble fibrous particles (IFPs, ∼60 wt%), was used as a sole stabilizer for oil-in-water emulsion fabrication. The influence of emulsification parameters on the emulsifying properties of MSBP was investigated, including emulsification techniques, MSBP concentration, and oil weight fraction. High-speed shearing (M1), ultrasonication (M2), and microfludization (M3) were used to fabricate oil-in-water emulsions (20% oil) with 0.60 wt% MSBP as stabilizer, in which the d_4,3 value was 68.3, 31.5, and 18.2 μm, respectively. Emulsions fabricated by M2 and M3 (higher energy input) were more stable than M1 (lower energy input) during long-term storage (30 days) as no significant increase of d_4,3. As compared to M1, the adsorption ratio of IFPs and protein was increased from ∼0.46 and ∼0.34 to ∼0.88 and ∼0.55 by M3. Fabricated by M3, the creaming behavior of emulsions was completely inhibited with 1.00 wt% MSBP (20% oil) and 40% oil (0.60 wt% MSBP), showing a flocculated state and could be disturbed by sodium dodecyl sulfate. The gel-like network formed by IFPs could be strengthened after storage as both viscosity and module were significantly increased. During emulsification, the co-stabilization effect of the soluble elements and IFPs enabled a compact and hybrid coverage onto the droplet surface, which acted as a physical barrier to endow the emulsion with robust steric repulsion. Altogether, these findings suggested the feasibility of using plant-based byproducts as oil-in-water emulsion stabilizers.

Valorizing protein-polysaccharide conjugates from sugar beet pulp as an emulsifier

Inspired by the emulsion stability of sugar beet pulp pectin, the hydrophobic protein fraction in sugar beet pulp (SBP) is expected to feature high interfacial activity. This work retrieved alkaline extracted protein-polysaccharide conjugates (AEC) from partially depectinized SBP by hot alkaline extraction. AEC was protein-rich (57.20 %), and the polysaccharide mainly comprised neutral sugar, which adopted a rhamnogalacturonan-I pectin-like structure. The hydrophobic polypeptide chains tangled as a dense 'core' with polysaccharide chains attached as a hydrated 'shell' (hydrodynamic radius of ~110 nm). AEC could significantly decrease the oil-water interfacial tension (11.58 mN/m), featuring superior emulsification performance than three control emulsifiers, especially the excellent emulsifying stability (10 % oil) as the emulsion droplet size of 0.438 and 0.479 μm for fresh and stored (60 °C, 5 d) emulsions, respectively. The relationship of molecular structure to emulsification was investigated by specific enzymic modification, suggesting the intact macromolecular structure was closely related to emulsifying activity and that the NS fraction contributed greatly to emulsifying stability. Moreover, AEC was highly efficient to stabilize gel-like high internal phase emulsions (oil fraction 0.80) with low concentration (0.2 %) and even high ionic strength (0-1000 mM). Altogether, valorizing AEC as an emulsifier is feasible for high-value utilization of SBP.

Comparative characterization of sugar beet fibers to sugar beet pectin and octenyl succinic anhydride modified maltodextrin in aqueous solutions using viscometry, conductometry, tensiometry and component analysis

BACKGROUND

Knowledge about specific functional characteristics, such as viscosimetric, conductometric, tensiometric and structural properties of polysaccharide aqueous solutions is highly important in the successful and adequate application in food emulsion formulation. For the first time detailed characterization of sugar beet fibers aqueous solutions in comparison to high molecular weight (sugar beet pectin) and low molecular weight [octenyl succinic anhydride (OSA) maltodextrin] hydrocolloids/stabilizers was performed through viscometry, conductometry, tensiometry and component analysis.

RESULTS

Sugar beet fibers and its water-soluble fraction were investigated. All sugar beet fiber samples showed substantial surface-active properties but different effect on the viscosity values of aqueous solutions. Sugar beet pectin had higher impact on aqueous solutions viscosity values compared to sugar beet fiber samples. Structural bonding between investigated polysaccharides were evaluated through conductometric measurements. Intermolecular linking and probable embedding of OSA maltodextrin molecules into the sugar beet fiber complex structure was detected in conductometric studies. The increased concentration of sugar beet fibers in the presence of sugar beet pectin led to the accelerated increase in specific conductivity values indicating effects of 'macromolecular crowding', intermolecular and intramolecular conformation changes and charge formation.

CONCLUSIONS

Detailed characterization of sugar beet fibers provided scientific insight towards fundamental characteristics of sugar beet fiber aqueous solutions. The presented characteristics are particularly applicable in the field of food emulsion stabilization due to the presented surface-active properties of sugar beet fibers as well as specific characteristics of investigated multi-polysaccharide systems. © 2022 Society of Chemical Industry.

The effect of structure and preparation method on the bioactivity of polysaccharides from plants and fungi

Polysaccharides are not only the main components in the cell walls of plants and fungi, but also a structure that supports and protects cells. In the process of obtaining polysaccharides from raw materials containing cell walls, the polysaccharides on the cell walls are the products and also a factor that affects the extraction rate. Polysaccharides derived from plants and fungi have mild characteristics and exhibit various biological activities. The biological activity of polysaccharides is related to their chemical structure. This review summarizes the effects of the physicochemical properties and structure of polysaccharides, from cell walls in raw materials, that have an impact on their biological activities, including molecular weight, monosaccharide composition, chain structure, and uronic acid content. Also, the structure of certain natural polysaccharides limits their biological activity. Chemical modification and degradation of these structures can enhance the pharmacological properties of natural polysaccharides to a certain extent. At the same time, the processing method affects the structure and yield of polysaccharides on the cell wall and in the cell. The extraction and purification methods are summarized, and the effects of preparation methods on the structure and physiological effects of polysaccharides from plants and fungi are discussed.

Enhancing the Emulsification and Photostability Properties of Pectin from Different Sources Using Genipin Crosslinking Technique

Pectin is a potential polysaccharide-based emulsifier, but the stabilized emulsions suffer from insufficient emulsion stability. Therefore, modification is needed to enhance its emulsification performance to cater to practical applications. The genipin-crosslinking strategy was used in this work to modify pectin with different sources and extraction conditions. Chemical composition analysis, molecular weight (Mw), and radius of gyration (Rg) measurement revealed that sugar beet pectin (SBP) has a more compact and flexible conformation than commercial citrus pectin (CP) and apple pectin (AP), indicated by the significantly (p < 0.05) larger Mw/Rg of SBP (18.1−11.3 kg/mol/nm) than CP (8.3 kg/mol/nm) and AP (8.0 kg/mol/nm). Crosslinking modification significantly increased the Mw, radius of gyration, and viscosity. This significantly (p < 0.05) improved the emulsifying stability (a smaller increase in droplets size) by the contribution of both thicker adsorbed hydrated layers at the oil-water interface with a stronger steric-hindrance effect and larger viscosity effect to slow down droplet collision. The formation of a blue-black substance from crosslinking reaction was able to block the UV radiation, which significantly improved the photostability of β-carotene-loaded emulsions. Altogether, genipin-crosslinking is feasible to modify pectin of different sources to enhance the emulsion stability and for use as a vehicle for delivering bioactive compounds.

Physicochemical properties of whey protein isolate and alkaline soluble polysaccharide from sugar beet pulp conjugates formed by Maillard reaction and genipin crosslinking reaction: A comparison study

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Emulsifying activity of ASP2 was obviously improved by graftingwith WPI.

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ASP2 self-crosslinking could be excuted by both maillard reaction and genipin crosslinking reaction.

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WPI linked with carbonyl group contributed more efficiency to emulsifying activity of PPC than linked with amino group of ASP2.

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Calcium bridge effect could not be efficiently inhibited by grafting ASP2 with WPI.

This study aim to investigate the effect of alkaline soluble polysaccharide from sugar beet pulp (ASP2) grafted with whey protein isolate (WPI) by two linking models (grafting on amino group or carbonyl group) on its emulsifying properties. Results demonstrated that the d_4,3 value of WPI, M−AW, M−AA, G-AW and G-AA stabilized emulsions was 0.18 μm, 0.28 μm, 0.72 μm, 0.56 μm and 0.83 μm, respectively, suggesting the higher emulsifying activity of the products prepared by Maillard reaction compared with the products obtained from genipin crosslinking reaction. After storage, the d_4,3 increment was 1.05 μm, 0.21 μm, 0.31 μm, 0.2 μm and 0.15 μm for WPI, M−AW, M−AA, G-AW and G-AA stabilized emulsions, respectively, indicating that the new generated polymers held stronger emulsifying stability compared with WPI. However, the aggregates emerged in high calcium emulsions system indicated that grafting with WPI could not efficiently reduce the sensitivity of ASP2 to calcium.

Grape seed proanthocyanidin-loaded gel-like W/O/W emulsion stabilized by genipin-crosslinked alkaline soluble polysaccharides-whey protein isolate conjugates: Fabrication, stability, and in vitro digestion

The present work aims to fabricate the genipin-crosslinked alkaline soluble polysaccharides-whey protein isolate conjugates (G-AWC) to stabilize W/O/W emulsions for encapsulation and delivery of grape seed proanthocyanidins (GSP). After crosslinking reaction, the molecular weight was increased and surface hydrophobicity was decreased. Then, the G-AWC and polyglycerol polyricinoleate (PGPR, a lipophilic emulsifier) were employed to prepare a GSP-loaded W/O/W emulsion with the addition of gelatin and sucrose in W₁ phase via a two-step procedure. Creamed emulsion could be fabricated at W₁/O volume fraction (Φ) of 10%-70% and further increased Φ to 75% or even up to 90% could obtain gel-like emulsion with notably elastic behaviors. In the W₁/O/W₂ emulsion with Φ of 80%, the encapsulation efficiency (EE) of GSP reached up to 95.86%, and decreased by ca. 10% after a week of storage. Moreover, the encapsulated GSP in the emulsion showed a remarkably higher bioaccessibility (40.72%) compared to free GSP (13.11%) in the simulated gastrointestinal digestion. These results indicated that G-AWC-stabilized W/O/W emulsions could be an effective carrier to encapsulate water-soluble bioactive compounds with enhanced stability and bioaccessibility.

Pectic polysaccharides from edible halophytes: Insight on extraction processes, structural characterizations and immunomodulatory potentials

The preparation, chemical properties and bio-activities of polysaccharides derived from halophytes have gained an increasing interest in the past few years. Phytochemical and pharmacological reports have shown that carbohydrates are important biologically active compounds of halophytes with numerous biological potentials. It is believed that the mechanisms involved in these bio-activities are due to the modulation of immune system. The main objective of this summary is to appraise available literature of a comparative study on the extraction, structural characterizations and biological potentials, particularly immunomodulatory effects, of carbohydrates isolated from halophytes (10 families). This review also attempts to discuss on bioactivities of polysaccharides related with their structure-activity relationship. Data indicated that the highest polysaccharides yield of around 35% was obtained under microwave irradiation. Structurally, results revealed that the most of extracted carbohydrates are pectic polysaccharides which mainly composed of arabinose (from 0.9 to 72%), accompanied by other monosaccharides (galactose, glucose, rhamnose, mannose and xylose), significant amounts of uronic acids (from 18.9 to 90.1%) and some proportions of fucose (from 0.2 to 8.3%). The molecular mass of these pectic polysaccharides was varied from 10 to 2650 kDa. Hence, the evaluation of these polysaccharides offers a great opportunity to discover novel therapeutic agents that presented especially beneficial immunomodulatory properties. Moreover, reports indicated that uronic acids, molecular weights, as well as the presence of sulfate and unmethylated acidic groups may play a significant role in biological activities of carbohydrates from halophyte species.

Rheological characterization of RG-I chicory root pectin extracted by hot alkali and chelators

This work aimed to extract gelatinous chicory root pectin (CRP) and evaluated the rheological behavior of the dispersions and gels. CRP was extracted by citric acid (CEP), alkaline (AEP), ammonium oxalate (OEP) and sodium citrate (SEP). The yield, molecular weight (Mw) and the degree of esterification (DE) of pectin samples varied from 8.8 to 14.8% (w/w), 204 to 336 k Da and 4.0 to 47.4%, respectively. AFM studies showed self-organize on mica of CEP, revealing a random coil conformation due to the interaction of multiple branching, whereas, AEP exhibited long linear filamentous structures. The flow behavior study verified the pseudoplastic character of CEP and SEP at 25 °C, while OEP and AEP belonged to dilatant fluid, besides, a closed hysteresis loop was observed when the CEP concentration increased to 1.5%. OEP gel was thermo insensitive and stiff, AEP gel presented most sensitive to calcium ion but more brittle, and SEP was observed a weak syneresis in spite of the poor gelation property. The texture analysis indicated OEP gel had a superior firmness and chewiness. These findings demonstrated that CRP may be attractive as a thickener or gelling agent to modulate textures of sugar-free and calcium content food.

A review on bioactive compounds of beet (Beta vulgaris L. subsp. vulgaris) with special emphasis on their beneficial effects on gut microbiota and gastrointestinal health

This review discusses the available literature concerning the bioactive compounds of beet (Beta vulgaris L.) and their ability to modulate the gut microbiota and parameters indicative of gastrointestinal health. Data of published literature characterize beet as a source of a variety of bioactive compounds (e.g. diet fiber, pectic-oligosaccharides, betalains and phenolics) with proven beneficial effects on human health. Beet extracts and pectin and pectic-oligosaccharides from beet have shown able to modulate positively gut microbiota composition and activity, with noticeable bifidogenic effects, in addition to stimulate the growth and metabolism of probiotics. Beet betalains and phenolics seem to increase the production of metabolites (e.g. short chain fatty acids) by gut microbiota and probiotics, which are linked with different beneficial effects on host health. The outstanding contents of betalains and phenolics with antioxidant, anti-inflammatory and anti-carcinogenic properties have been linked to the positive effects of beet on gastrointestinal health. Beet should be a healthy choice for use in domestic meal preparations and a source of ingredients to formulate added-value functionalized food products.

Physicochemical Characterization of a Polysaccharide from Green Microalga Chlorella pyrenoidosa and Its Hypolipidemic Activity via Gut Microbiota Regulation in Rats

A bioactive polysaccharide from microalga Chlorella pyrenoidosa (CPP) was successively prepared via DEAE-52 and G-100 columns. Nuclear magnetic resonance analysis showed that the main glycosidic bonds were composed of 1,2-linked-α-l-Fucp, 1,4-linked-α-l-Rhap, 1,4-linked-β-l-Araf, 1-linked-α-d-Glcp, 1,3-linked-β-d-GlcpA, 1,4-linked-β-d-Xylp, and 1,3,6-linked-β-d-Manp. Its molecular weight was 5.63 × 10⁶ Da. The hypolipidemic effect and intestinal flora regulation of CPP on diet-induced rats were evaluated through histopathology and biochemistry analyses. CPP could improve plasma and liver lipid metabolism and accelerate the metabolism of the cecal total bile acids and short-chain fatty acids. CPP has also upregulated the adenosine-monophosphate-activated protein kinase α and downregulated the acetyl-CoA carboxylase, sterol regulatory element-binding protein 1c, and β-hydroxy β-methylglutaryl-CoA expressions. Moreover, with the 16S rRNA gene sequencing, it was revealed that the composition of intestinal flora changed drastically after treatment, such as the bloom of Coprococcus_1, Lactobacillus, and Turicibacter, whereas there was a strong reduction of the [Ruminococcus]_gauvreauii_group. The above results illustrated that CPP might be served as an effective ingredient to ameliorate lipid metabolism disorders and intestinal flora in hyperlipidemia rats.

Comparative Studies of Combined Influence of Variables on the Esterification Degree of Pectin Extracted by Sulfuric Acid and Citric Acid

The influence of extraction variables on degree of esterification (DE) of pectin was studied due to the significant effects of DE on the properties of the pectin-based functional biomaterials. The extracting agents (sulfuric acid and citric acid), pH value of extraction solution, extraction time, and temperature were selected to study the hydrolysis reaction of carboxylic acid ester by response surface methodology (RSM). The hydrolysis reaction occurred more violently in the weak organic acid solution than that in the strong inorganic acid solution. The DE was significantly influenced by pH of extraction solution, extraction time, and temperature through the analysis of variance. In addition, the values of DE reduced with the increasing of extraction temperature, lapse of time, and decreasing of pH value. What is more, the effects of extraction conditions on the yield, monosaccharide composition, content of protein, and ferulic acid were also studied. It is evident that the lower pH value contributed to higher extraction yield. The content of Total CH and GalA of pectin extracted by sulfuric acid were higher than that of pectin extracted by citric acid, and the content of monosaccharide showed an opposite trend.