Physicochemical properties of pectins from okra (Abelmoschus esculentus (L.) Moench)

Physicochemical evaluation, structural characterization, in vitro and in vivo bioactivities of water-soluble polysaccharides from Luobuma (Apocynum L.) tea

Luobuma tea is made from the leaves of Apocynum hendersonii (Bt) and A. venetum (Ht) and has been used for a very long time in China and Japan as herbal tea. This study isolated water-soluble polysaccharides from the two species` teas. Physicochemical properties, structural properties, in vitro and in vivo antioxidant and immunomodulatory activities were determined for the first time. The results showed that the Bt and Ht polysaccharides with molecular weights of 31.21 and 49.11 kDa, respectively, composed of arabinose, galactose, rhamnose, glucose, xylose, fucose, and mannose. A dose-dependent nitric oxide production and interleukin-6 inhibitory effects were obtained. Also, they suppressed the expression of cyclooxygenase-2, tumor necrosis factor-α and interleukin-6 mRNA in LPS-induced RAW 264.7 macrophages. Likewise, Bt and Ht have significantly reduced edema in the paws of mice after carrageenan injection. These results suggested that the Luobuma teas polysaccharides can be explored as potential antioxidants and anti-inflammatory agents.

3D Printing of Naturally Derived Adhesive Hemostatic Sponge

Hydrogel hemostatic sponges have been recognized for its effectiveness in wound treatment due to its excellent biocompatibility, degradability, as well as multi-facet functionalities. Current research focuses on optimizing the composition and structure of the sponge to enhance its therapeutic effectiveness. Here, we propose an adhesive hydrogel made from purely natural substances extracted from okra and Panax notoginseng. We utilize 3-dimensional (3D) printing technology to fabricate the hemostatic hydrogel scaffold, incorporating gelatin into the hydrogel and refining the mixing ratio. The interaction between gelatin and okra polyphenols contributes to successful injectability as well as stability of the printed scaffold. The okra in the scaffold exhibits favorable adhesion and hemostatic effects, and the total saponins of Panax notoginseng facilitate angiogenesis. Through in vitro experiments, we have substantiated the scaffold's excellent stability, adhesion, biocompatibility, and angiogenesis-promoting ability. Furthermore, in vivo experiments have demonstrated its dual functionality in rapid hemostasis and wound repair. These features suggest that the 3D-printed, natural substance-derived hydrogel scaffolds have valuable potential in wound healing and related applications.

The effect of okra (Abelmoschus esculentus l.) Powder Addition on Qualities of Gluten-free Chiffon Cake

Rice flour (100%, 97.4%, 94.7%, 89.5% (w/w)) and okra powder (2.6%-10.5%) were used to replace wheat flour to make gluten-free chiffon cakes. The effects of okra powder addition on the physicochemical, color, texture, moisture content, total phenolic content, antioxidant, and sensory scores of cakes were evaluated. The batter viscosity, chewiness, ash, protein, fat, total phenolics, and antioxidant activities (1,1-diphenyl-z-picrylhydrazyl hydrate and reducing power) of cakes showed an increasing trend with okra powder addition. Gluten-free chiffon cake containing 5.3% okra powder showed significantly (p < 0.05) higher protein and ash contents as compared to their control and chiffon cake made with wheat flour. Nevertheless, center height, volume index, L*, a*, and b* values, and white index of gluten-free cake decreased with increased okra powder levels. The sensory characteristics of wheat and gluten-free chiffon cakes substituted with 2.6%-5.3% okra powder showed no difference (p > 0.05). Nevertheless, the sensory scores of the 5.3% okra powder addition cake obtained a higher preference than other gluten-free cakes. Although the overall acceptability of gluten-free chiffon cake supplemented with 10.5% okra flour had a lower (p < 0.05) overall acceptability (2.84) than all cake samples, it was still shown acceptable to consumers. Gluten-free rice chiffon cakes with high nutrient contents and antioxidant activities can be processed by the incorporation of okra powder of less than 10.5% to increase the diversification of gluten-free foods. Gluten-free cakes with high amounts of okra powder addition would produce cake having high water content, total phenol content, 1,1-diphenyl-z-picrylhydrazyl hydrate radical scavenging activity, reducing power, hardness, chewiness, cohesiveness, batter viscosity, ash, and crude protein content through principal component analysis.

Valorization of cocoa pod side streams improves nutritional and sustainability aspects of chocolate

Chocolate production faces nutritional, environmental and socio-economic challenges present in the conventional cocoa value chain. Here we developed an approach that addresses these challenges by repurposing the often-discarded pectin-rich cocoa pod endocarp and converting it into a gel. This is done using cocoa pulp juice concentrate to replace traditional sugar from sugar beets. Although swelling of fibres, proteins and starches can limit gel incorporation, our proposed chocolate formulation contains up to 20 wt% gel. It also has comparable sweet taste as traditional chocolate while offering improved nutritional value with higher fibre and reduced saturated fatty acid content. A cradle-to-factory life cycle assessment shows that large-scale production of this chocolate could reduce land use and global warming potential compared with average European dark chocolate production. The process also provides opportunities for diversification of farmers' income and technology transfer, offering potential socio-economic benefits for cocoa-producing regions.

Plant polysaccharides extracted by high pressure: A review on yields, physicochemical, structure properties, and bioactivities

Polysaccharides are biologically essential macromolecules, widely exist in plants, which are used in food, medicine, bioactives' encapsulation, targeted delivery and other fields. Suitable extraction technology can not only improve the yield, but also regulate the physicochemical, improve the functional property, and is the basis for the research and application of polysaccharide. High pressure (HP) extraction (HPE) induces the breakage of raw material cells and tissues through rapid changes in pressure, increases extraction yield, reduces extraction time, and modifies structure of polysaccharides. However, thus far, literature review on the mechanism of extraction, improved yield and modified structure of HPE polysaccharide is lacking. Therefore, the present work reviews the mechanism of HPE polysaccharide, increasing extraction yield, regulating physicochemical and functional properties, modifying structure and improving activity. This review contributes to a full understanding of the HPE or development of polysaccharide production and modification methods and promotes the application of HP technology in polysaccharide production.

Comparison on emulsifying and emulgelling properties of low methoxyl pectin with varied degree of methoxylation from different de-esterification methods

Low methoxyl pectin (LMP) with different degree of methoxylation (DM, 40-50 %, 20-30 % and 5-10 %) were prepared from commercially available citrus pectin using high hydrostatic pressure assisted enzymatic (HHP-pectin) and traditional alkaline (A-pectin) de-esterification method. The results showed that both de-esterification methods and DM exhibited LMPs with varied physicochemical, structural, and functional properties. As the DM decreased, LMP showed a decrease in molecular weight (Mw), while an increase in negative charges and rhamnogalacturonan I (RG-I) ratio, accompanied with better emulsion stability, emulsion gel strength and water-holding properties. Relative to A-pectin, HHP-pectin had higher Mw and lower RG-I side chain ratio, contributing to its better thermal stability, apparent viscosity, and emulgelling properties. HHP-pectin with lower DM (5-10 %) showed superior thickening, emulsifying and emulgelling properties, while that with higher DM (40-45 %) had superior thermal stability, which provided alternative for de-esterification and targeted structural modification of pectin.

Optimization and mechanism of the novel eco-friendly additives for solidification and stabilization of dredged sediment

Solidification/stabilization technology is commonly used in the rehabilitation of dredged sediment due to its cost-effectiveness. However, traditional solidification/stabilization technology relies on cement, which increases the risk of soil alkalization and leads to increased CO2 emissions during cement production. To address this issue, this study proposed an innovative approach by incorporating bentonite and citrus peel powder as additives in the solidifying agent, with the aim of reducing cement usage in the dredged sediment solidification process. The research results showed that there is a significant interaction among cement, bentonite, and citrus peel powder. After response surface methodology (RSM) optimization, the optimal ratio of the cementitious mixture was determined to be 14.86 g/kg for cement, 5.85 g/kg for bentonite, and 9.31 g/kg for citrus peel powder. The unconfined compressive strength (UCS) of the solidified sediments reached 3144.84 kPa. The reaction products of the solidification materials, when mixed with sediment, facilitated adsorption, gelation, and network structure connection. Simultaneously, the leaching concentration of heavy metals was significantly decreased with five heavy metals (Zn, As, Cd, Hg, and Pb) leaching concentrations decreasing by more than 50%, which met the prescribed thresholds for green planting. This study demonstrated the ecological benefits of employing bentonite and citrus peel powder in the solidification process of dredged sediment, providing an effective solution for sediment solidification.

Comparative study on chain conformations, physicochemical and rheological properties of three acidic polysaccharides from Opuntia dillenii Haw. fruits

In this study, three acidic polysaccharides (OFPP-1, OFPP-2 and OFPP-3) were isolated from the pulps of Opuntia dillenii Haw. fruits, and their chain conformations, physicochemical and rheological properties were investigated. The molecular weight and conformational parameters (Mw, Mn, Mz, Rg and Rh) of OFPPs in 0.1 M NaNO3 solution were detected by HPSEC-MALLS-RI. In addition, based on the parameters ρ and v, it was concluded that these three polysaccharide chains exhibited sphere-like conformation in 0.1 M NaNO3 solution, which was consistent with AFM and TEM observations. Furthermore, the Congo Red experiment showed that OFPP-2 had a triple-helix structure, which may be conducive to its biological activity. This study also found that OFPPs were semi-crystalline structures with high thermal and pH stability. The rheological analyses indicated that the apparent viscosity of OFPPs solutions exhibited concentration-, temperature-, and pH-dependence, and the viscoelasticity of them was affected by molecular characteristics and concentration. The results of this study are helpful to elucidate the structure-activity relationship of OFPPs. Moreover, this study can provide theoretical reference for the application of OFPPs as bioactive ingredients or functional materials in the food, pharmaceutical and cosmetic industries and the development and utilization of the O. dillenii Haw. fruits resource.

An okra polysaccharide (Abelmoschus esculentus) reinforced green hydrogel based on guar gum and poly-vinyl alcohol double network for controlled release of nanocurcumin

A novel green hydrogel (PGCO) of Okra (Abelmoschus esculentus) mucilage-reinforced poly-vinyl alcohol-guar gum (PG) cross-linked by citric acid containing nanocurcumin (NC) as a model drug is reported. The citric acid (CA) cross-linked hydrogel (PGC) without okra is also prepared. The hydrogels are characterized using FTIR, XRD, FE-SEM, and TGA techniques. Okra reinforced green hydrogel (PGCO) provided comparable swelling behaviour with better mechanical and thermal properties compared to the neat PGC hydrogel. Network parameters of PGC and PGCO hydrogels are estimated using Flory-Rehner equation and strong correlation between the cross-link density and swelling behaviour is established. 45.68 % NC loading in the PGCO hydrogel is achieved. Release study in phosphate buffer (PB) of pH 7.4 provided sustained release of NC over a period of 100 h. The release study of NC followed primarily the Korsmeyer-Peppas model with less-Fickian diffusional character (n < 0.5). The average diffusion coefficients of NC and curcumin are found to be 3.52 × 10^-5 cm² s^-1, and 3.43 × 10^-5 cm² s^-1 respectively demonstrating the quick release of NC in early time, which is a pre-requisite in drug delivery. The study provides initial evidence of the usefulness of okra mucilage in green hydrogel development and drug delivery applications.

Extraction of Pectin from Satsuma Mandarin Peel: A Comparison of High Hydrostatic Pressure and Conventional Extractions in Different Acids

Satsuma mandarin peel pectin was extracted by high hydrostatic pressure-assisted citric acid (HHPCP) or hydrochloric acid (HHPHP), and the physiochemical, structural, rheological and emulsifying characteristics were compared to those from conventional citric acid (CCP) and hydrochloric acid (CHP). Results showed that HHP and citric acid could both increase the pectin yield, and HHPCP had the highest yield (18.99%). Structural characterization, including NMR and FTIR, demonstrated that HHPHP showed higher Mw than the other pectins. The viscosity of the pectin treated with HHP was higher than that obtained with the conventional method, with HHPHP exhibiting significantly higher viscosity. Interestingly, all the pectin emulsions showed small particle mean diameters (D_4,3 being 0.2–1.3 μm) and extremely good emulsifying stability with centrifugation and 30-day storage assays, all being 100%. Satsuma mandarin peel could become a highly promising pectin source with good emulsifying properties, and HHP-assisted acid could be a more efficient method for pectin extraction.

Physicochemical and functional characteristics of polysaccharides from okra extracted by using ultrasound at different frequencies

In this study, single- (SFU) and dual-frequency (DFU) ultrasounds were used to extract polysaccharides from okra (Abelmoschus esculentus (L.) Moench) pods (OPSs), and the physicochemical characteristics, functional properties, and in vitro biological activities of the OPSs were comparatively evaluated. Results showed that ultrasonic extractions at different frequencies led to remarkable variations in extraction yields, chemical components, monosaccharide compositions, molecular weights (MWs), surface morphologies, and rheological properties of the OPSs but hardly affected their preliminary structural features and thermal stabilities. The OPS obtained through DFU at 40/60 kHz with the lowest MWs (0.85-14.93 × 10⁵ Da) and highest polyphenol content (7.38%) as well as loosest network structures showed superior antioxidant, cholesterol absorption and nitrite ion absorption capacities than the other OPSs, and the OPS extracted through SFU at 20 kHz with the highest carboxylate content (76.08%), MWs (7.28-32.83 × 10⁵ Da) and degree of esterification (30.7%) exhibited higher bile acid-binding capacity than the other OPSs.

Ultrasound freeze-thawing style pretreatment to improve the efficiency of the vacuum freeze-drying of okra (Abelmoschus esculentus (L.) Moench) and the quality characteristics of the dried product

Vacuum freeze-drying is a new and high technology on agricultural product dehydrating dry, but it faces the high cost problem caused by high energy consumption. This study investigated the effect of ultrasound (US), freeze-thawing (including the freeze-air thawing (AT), freeze-water thawing (WT), freeze-ultrasound thawing (UST), and freeze-air ultrasound thawing (AT + US)) pretreatments on the vacuum freeze-drying efficiency and the quality of dried okra. The results indicated that the application of ultrasound and different freeze-thawing pretreatments reduced the drying time by 25.0%-62.50% and the total energy consumption was 24.28%-62.35% less. The AT pretreatment reduced the time by of okra slices by 62.50% and the total energy consumption was 62.35% less. The significant decrease in drying time was due to a change in the microstructure caused by pretreatment. Besides, the okra pretreated with the US retained most of the quality characteristics (flavor, color, hardness, and frangibility) among all methods, while, AT + US had the most changeable characteristics in quality, which is deprecated in our study. The okra pretreated with the US and AT, separately, had the best dry matter content loss (9.008%, 5.602%), lower chlorophyll degradation (5.05%, 5.44% less), and higher contents of total phenolics, total flavonoids, and pectin, with strong antioxidant capacity, compared to other methods. The pretreatments did not have a large effect on the functional groups and the structure of pectin, but slightly affected the viscosity. It can be concluded that AT and US pretreatment methods are better than others.

Structural Properties, Bioactivities, and Applications of Polysaccharides from Okra [Abelmoschus esculentus (L.) Moench]: A Review

Okra [Abelmoschus esculentus (L.) Moench], as a kind of nutritive vegetable, is rich in flavonoids, polyphenols, polysaccharides, amino acids, and other bioactive substances and has various biological activities. As one of main bioactive components, okra polysaccharides (OPs), mainly comprising pectic polysaccharides, have various biological activities. OPs have been extensively investigated in recent years. Many studies characterized structures of OPs obtained by different extraction methods, which were confirmed to be rhamnogalacturonan-I-type polysaccharides in most cases. OPs have a thick and slimy texture, suggesting that they can be a promising source of texture modifiers for complex food matrices. They have various biological activities, such as antioxidant activity, immunomodulatory activity, hypoglycaemic activity, and improving intestinal function. Therefore, OPs may potentially serve as novel immunomodulators or an adjuvant for diabetic nephropathy. Up to now, there is no specific summary on the research progress of OPs. In this paper, the latest research progress on the extraction, purification, characterization, rheological properties, biological activities, and applications of OPs is reviewed, to provide the reference for the processing and comprehensive utilization of OPs in the future.

Application of Polysaccharide Biopolymer in Petroleum Recovery

Polysaccharide biopolymers are biomacromolecules derived from renewable resources with versatile functions including thickening, crosslinking, adsorption, etc. Possessing high efficiency and low cost, they have brought wide applications in all phases of petroleum recovery, from well drilling to wastewater treatment. The biopolymers are generally utilized as additives of fluids or plugging agents, to correct the fluid properties that affect the performance and cost of petroleum recovery. This review focuses on both the characteristics of biopolymers and their utilization in the petroleum recovery process. Research on the synthesis and characterization of polymers, as well as controlling their structures through modification, aims to develop novel recipes of biopolymer treatment with new application realms. The influences of biopolymer in many petroleum recovery cases were also evaluated to permit establishing the correlations between their physicochemical properties and performances. As their performance is heavily affected by the local environment, screening and testing polymers under controlled conditions is the necessary step to guarantee the efficiency and safety of biopolymer treatments.

Clustering of instrumental methods to characterize the texture and the rheology of slimy okra (Abelmoschus esculentus) suspensions

Okra (Abelmoschus esculentus) is one of the ingredients widely used in African gastronomy because of the unique slimy texture it gives to sauces. However, processing and formulation can affect the textural and rheological properties of these sauces, leading to unacceptable quality for the African consumer. The aim of this study was to select the instrumental measurements best enabling (a) characterization of the rheology and texture of slimy sauces prepared from okra and (b) monitoring its evolution during the preservation process. Thirty-seven slimy suspensions (sauces and purées) were measured with 16 rheological and textural parameters. A principal component analysis revealed that flow consistency index K and flow behavior index n were well correlated with visco-elastic, adhesive, and shear thinning properties, and that stringiness was well correlated with elongational, cohesive, and ductile properties. These two sets of measurement methods are sufficient to characterize their rheological and textural properties, and necessary to discriminate them according to their process and formulation.

Ultrasonic-assisted citrus pectin modification in the bicarbonate-activated hydrogen peroxide system: Chemical and microstructural analysis

The modified pectin (MP) showed the improved functional properties than the native one. The aim of present study was to develop the ultrasonic accelerated bicarbonate-hydrogen peroxide system for pectin modification to generate short fragments with advanced bioactive properties. The depolymerization effects of this system on the physicochemical properties, structural features, and bioactivity of the degraded fragments were studied systematically. The results indicated that the molecular weight of pectin was reduced drastically from 1088 kDa to 33 kDa within 50 min under an optimized condition (M_H2O2-M_NaHCO3 = 1:2.5, 50 °C, and ultrasound intensity = 11.4 W/cm³). The resulting fragments also showed lower degree of methoxylation and rheological viscosity. The investigation on the sample structures and active oxygen species demonstrated that the highly active O₂^- species generated from HCO₄^- of NaHCO₃-H₂O₂ acted preferentially on the GalA backbone in the HG region, while the RG-I region was maintained; and ultrasound enhanced the degradation efficiency via both chemical effects (increasing the transformation of free radicals) and mechanical effects (disaggregating polysaccharide clusters). The atomic force microscope (AFM) imaging directly verified the branched-chain morphology of pectin and the small-strand degradation fragments. Moreover, ultrasound and NaHCO₃-H₂O₂ treatment induced high galactose content in the degraded products, contributing to an improved inhibitory activity against A549 lung cancer cells, as shown by MTT assay.

Synergy of the flow behaviour and disperse phase of cellulose nanoparticles in enhancing oil recovery at reservoir condition

Ascorbic acid was used for the first time to synthesize cellulose nanoparticles (CNP) extracted from okra mucilage. The physical properties of the CNP including their size distribution, and crystalline structures were investigated. The rheological properties of the cellulose nanofluid (CNF) were compared with the bulk okra mucilage and commercial polymer xanthan. The interfacial properties of the CNF at the interface of oil-water (O/W) system were investigated at different concentrations and temperatures. The effects of the interaction between the electrolyte and ultrasonic were determined. Core flooding experiment was conducted at reservoir condition to justify the effect of the flow behaviour and disperse phase behaviour of CNF on additional oil recovery. The performance of the CNF was compared to conventional EOR chemical. The combined method of ultrasonic, weak-acid hydrolysis and nanoprecipitation were effective in producing spherical and polygonal nanoparticles with a mean diameter of 100 nm, increased yield of 51% and preserved crystallinity respectively. The zeta potential result shows that the CNF was stable, and the surface charge signifies long term stability of the fluid when injected into oil field reservoirs. The CNF, okra and xanthan exhibited shear-thinning and pseudoplastic behaviour. The IFT decreased with increase in concentration of CNF, electrolyte and temperature. The pressure drop data confirmed the stability of CNF at 120°C and the formation of oil bank was enough to increase the oil recovery by 20%. CNF was found to be very effective in mobilizing residual oil at high-temperature high-pressure (HTHP) reservoir condition. The energy and cost estimations have shown that investing in ultrasonic-assisted weak-acid hydrolysis is easier, cost-effective, and can reduce energy consumption making the method economically advantageous compared to conventional methods.

Optimization of Alkali Extraction and Properties of Polysaccharides from Ziziphus jujuba cv. Residue

Ziziphus jujuba cv. Muzao is a plant widely cultivated in the Yellow River Basin of China. It has nutritional and healthcare functions, in which polysaccharides are the main components of its bio-functions. In order to make effective use of Ziziphus jujuba cv. Muzao residue resources and explore new functional food ingredients, the polysaccharide (ZJRP) from Ziziphus jujuba cv. Muzao residues were extracted by sodium hydroxide, and the optimal extraction conditions of ZJRP were obtained by the response surface method. The basic composition and antioxidant effects of ZJRP were determined. The results showed that ZJRP has significant antioxidant activity, mainly reflected in the high DPPH radical scavenging rate, which may be related to their high content of galacturonic acid and the extraction method. In addition, the rheological and thermal properties of ZJRP were respectively determined by a rheometer and differential scanning calorimetry (DSC), indicating that they have shear thinning properties and good thermal stability. Results showed that the alkaline extraction method can be used as a potential technique for extracting ZJRP with high antioxidant activity, and ZJRP can be further explored as a functional food ingredient.

Dynamic High-Pressure Microfluidization-Treated Pectin under Different Ethanol Concentrations

We previously reported that dynamic high-pressure microfluidization (DHPM) can degrade pectin in aqueous solution. In this study, we further investigated the effect of DHPM on pectin in water-ethanol systems. In the absence of DHPM treatment, it was found that pectin exhibited increased average particle size and unchanged average molecular weight, but a decline in reducing-sugar-ends content with the increase of ethanol concentrations (0⁻10% v/v). These results indicated that the addition of ethanol induced aggregation of pectin. During DHPM treatment, pectin underwent disaggregation and degradation under all measured ethanol concentrations. Disaggregation was enhanced but degradation was weakened with the increase of ethanol concentration. FT-IR and UV spectra indicated that demethylation but no β-elimination occurred in the water-ethanol system during DHPM. Finally, the mechanism of DHPM-induced disaggregation and degradation of pectin under a water-ethanol system was updated. This work may help us to find a suitable condition for reducing the degradation of pectin during the process of homogenization.

Extensional and shear rheology of okra polysaccharides in the presence of artificial saliva

Extensional and shear viscosities were studied for mixtures comprising artificial saliva and okra mucilage, the latter acting as a model thick-liquid food. These experiments aimed to obtain information on the flow-behavior information of the systems, underpinning the texture sensation of foods as perceived by dysphagic and xerostomic populations. Mixing okra mucilage with artificial saliva dramatically increases the shear viscosity of artificial saliva throughout the studied ranges of concentrations and deformation rates. Particle tracking does not suggest direct interactions between the components of artificial saliva and of okra mucilage. The rheology of the okra polymer (OP)–artificial saliva (AS) mixture is dominated by its extensional viscosity: Trouton ratios are in the order of tens to hundreds, while they decrease with increasing okra-mucilage concentration; this highlighs the dominance of the extensional rheology and the increasing importance of the shear mechanics with increasing okra content. The relaxation times and extensional moduli are also reported for the systems under study. Extensional and shear flows are of equal importance concerning the elastic behavior.

Artificial saliva is usually formulated to help people with dysphagia or xerostomia. Their mouth feels of food textures are largely dependent on the flow behaviors of the food–artificial saliva mixtures. Christos Ritzoulis and coworkers from Zhejiang Gongshang University now studied the rheological and structural properties of artificial saliva when mixed with okra mucilage. They found the shear viscosity and storage modulus of the artificial saliva were much higher in the presence of okra polysaccharide, suggesting the formation of a macromolecular-interacting network. Moreover, it was found the overall rheological behaviors of the mixtures were always dominated by the extensional viscosity, though the shear behavior became more and more obvious with the increasing amount of okra polymer. Together with the data obtained with real saliva, these on artificial saliva could guide the future formulation of artificial saliva.

Upgrading Pectin Production from Apple Pomace by Acetic Acid Extraction

Pectin, as one of the most widely used functional polysaccharide, can be abundantly extracted from apple pomace which is the main by-product of apple juice industry. In the case of 110 min, 10% (w/w) acetic acid (AA), and 100 °C, extraction yield of pectin reached 19.6%. Compared with mineral acid-extracted pectin, the yield, molecular weight, galacturonic acid content, and DE of the AA-extracted pectin were higher while neutral sugars were lower. Furthermore, the AA-extracted pectin solution demonstrated a higher viscosity during the shear rate increased, and a higher G″ modulus than pectin extracted with mineral acid and commercial pectin possibly because of stronger polymer chain interaction, which was reflected in gel textural properties. The green approach for the pectin production, in terms of pectin components was developed from apple pomace using AA that was highly competitive and environmentally friendly process.

Degradation of carboxymethylcellulose using ultrasound and β-glucanase: Pathways, kinetics and hydrolysates' properties

In order to provide an efficient way to degrade carboxymethylcellulose (CMC), three pathways were investigated: enzymolysis, combination of ultrasound pretreatment and enzymolysis, and sonoenzymolysis. Effects of these treatments on enzymatic kinetics, degradation kinetics and properties of degraded CMC were investigated. The degradation degree of CMC was increased by 18.90% and 35.73% with ultrasound pretreatment (at an intensity of 24 W/mL for 30 min) and sonoenzymolysis (at an intensity of 9 W/mL for 50 min), compared with that obtained under the traditional enzymolysis. Analysis of kinetics demonstrated that ultrasound, both pretreatment and combined with β-glucanase, could accelerate CMC degradation. Measurements of rheological properties, molecular weight and structures of CMC hydrolysates revealed that ultrasound broke the glycosidic bond of CMC chains without changing its primary structure. The sonoenzymolysis process was the most efficient method to degrade CMC, with potential to provide a way to obtain CMC with lowest molecular weight or viscosity.

Purification, characterization and anti-fatigue activity of polysaccharide fractions from okra (Abelmoschus esculentus (L.) Moench)

The aim of this study was to investigate the anti-fatigue activity of polysaccharide fractions from Abelmoschus esculentus (L.) Moench (AE) in mice. After crude polysaccharide (CAEP) was extracted from AE and purified by DEAE cellulose-52 column, two polysaccharide fractions (AEP-1 and AEP-2) were obtained. The structural analysis suggested that AEP-1 and AEP-2 were a RG-I polysaccharide and an AG-II polysaccharide, respectively. According to the results of the weight-loaded swimming test, compared with the negative control group, the CAEP, AEP-1 and AEP-2 treatment groups could prolong the swimming time, decrease serum urea nitrogen (SUN) and blood lactic acid (BLA), and increase hepatic glycogen (HG) and muscle glycogen (MG), which indicated that okra polysaccharides have an effective anti-fatigue activity. Furthermore, our study exhibited the anti-fatigue mechanism of okra polysaccharide was correlated with retarding the accumulation of creatine kinase (CK) and lactate dehydrogenase (LDH) in serum, and enhancing succinate dehydrogenase (SDH), adenosine triphosphate (ATP) and adenosine triphosphatase (ATPase) levels. In addition, the anti-fatigue activity of AEP-1 was stronger than that of AEP-2, and significantly better than that of CAEP. Therefore, AEP-1 and AEP-2 may be the main active anti-fatigue functional substances of AE.