Maximum Polysaccharide Yield Research Articles

Extraction Optimization of Polysaccharides from Wet Red Microalga Porphyridium purpureum Using Response Surface Methodology

Porphyridium is a unicellular marine microalga that is rich in polysaccharides and has excellent biological activities. Optimizing the extraction of polysaccharides can significantly improve the value of Porphyridium biomass. In the present study, response surface methodology was employed to optimize the extraction conditions of polysaccharides, including extraction time, extraction temperature, and biomass-to-water ratio. Furthermore, microwave-assisted extraction was used to improve the yield of polysaccharides further. The results showed that increasing the extraction temperature and extraction time could enhance the yield of polysaccharides. The multiple regression analysis of RSM indicated that the model could be employed to optimize the extraction of polysaccharides. The optimal extraction time, extraction temperature, and biomass-to-water ratio were 45 min, 87 °C, and 1:63 g mL−1, respectively. Under these optimal conditions, the maximum yield of polysaccharides was 23.66% DW, which well matched the predicted yield. The results indicated that the extraction temperature was the most significant condition affecting the yield of polysaccharides. The microwave-assisted extraction could further improve the yield of polysaccharides to 25.48% DW. In conclusion, hot water with microwave-assisted extraction was effective for polysaccharide extraction in P. purpureum.

Extraction of chitin-glucan complex from shiitake (Lentinula edodes) fruiting bodies using natural deep eutectic solvents and its prebiotic potential

Chitin-glucan complex (CGC) is an emerging novel prebiotic with numerous physiological activities in amelioration of clinical manifestations. In the present work, natural deep eutectic solvent (NADES), ultrasonication, and submerged fermentation using probiotic microorganisms were deployed for the extraction of CGC from Shiitake fruiting bodies. CGC obtained through non-ultrasonication assisted fermentation employing Lactiplantibacillus plantarum exhibited maximum polysaccharide yield (27.86 ± 0.82 % w/w). However, based on antioxidant potential, NADES combination of urea: glycerol (1:1 M ratio) was selected for further characterization. The rheological behavior of CGC under optimized conditions showed shear thinning property in both 0.1 M NaCl and salt-free solution. FTIR, 1H-(1D), and 2D 1H1H Homonuclear NMR spectra displayed distinctive patterns associated with β-glycosidic linkage and β-d-glucopyranose sugar moiety. XRD profiles of CGC exhibited characteristic peaks at 2θ = 23°, 25°, and 28° with corresponding hkl values of (220), (101), and (130) lattice planes, respectively. Enhanced radical scavenging activities were noticed due to the triple helical structure and anionic nature of CGC. CGC exhibited potential prebiotic activity (prebiotic score 118–134 %) and short chain fatty acids liberation (maximum 9.99 ± 0.41 mM by Lactobacillus delbrueckii). Simulated static in-vitro digestion demonstrated that CGC withstands acidic environment of gastric phase, which indicated its suitability for use as a prebiotic in nutraceutical-enriched food products.

Obtaining the Biopolymer Films from Macroalgae Wastes

An analysis of the resource potential of macroalgae wash-outs onto the Baltic Sea coast has been performed. A critical review of the applications of polysaccharides extracted from Furcellaria lumbricalis macroalgae wastes washed ashore is presented. Optimal extraction conditions have been established to ensure maximum yield of polysaccharides. It is recommended to use alkaline hydrolysis with potassium hydroxide 0.1 M, process time is 60 minutes. Recipes of biopolymer films with the necessary physical, mechanical and antibacterial properties have been determined. It was concluded that the production of biofilms with antibacterial properties with the addition of vegetable oils is promising. Their use with application directly to the product will provide a longer shelf life without significant changes in organoleptic properties.

Optimization of Aqueous Two‐Phase Extraction of Polysaccharides from Hawthorn by Response Surface Methodology Coupled with Genetic Algorithm and Its Antioxidant Activity

AbstractHawthorn (Crataegus pinnatifida Bge.) contains various active components including polysaccharides, polyphenols, vitamin, phenolic acid, etc. Polysaccharides are one of the most critical active components in hawthorn, which exhibits different biological activities such as immunomodulatory antioxidant, anti‐inflammatory, hypoglycemic, and other activities. Hence, the main purpose of this paper is to optimize the aqueous two‐phase extraction (UTPE) of polysaccharides from hawthorn via a response surface methodology coupled genetic algorithm (RSM‐GA) and then evaluate its antioxidant activity through free radicals scavenging experiments. The results show that the optimal extraction conditions to achieve the maximum polysaccharides yield (6.42 ± 0.08)% from hawthorn by UTPE is obtained under the mass fraction of ammonium sulfate of 11%, extraction temperature of 57 °C, liquid‐to‐solid ratio of 33 mL g−1, ethanol concentration of 26%, and extraction time of 30 min, and the relative error between the experimental value and the theoretical value is 4.56%. The antioxidant capacity is enhanced with the increase of hawthorn polysaccharides (HPs) concentration. However, the antioxidant activity of HPs is weaker than that of ascorbic acid. The results of this study provide a critical material basis for promoting the further research of HPs, and have certain significance for the deep processing and product development of hawthorn.

Screening of medicinal mushroom strains with antimicrobial activity and polysaccharides production

AbstractObjectivesThis study aimed to determine the antimicrobial activity of culture fluid and mycelial mass of selectedHericiumstrains from the IBK Mushroom Culture Collection (Kyiv, Ukraine) against bacteria and fungi, as well as to evaluate the potential of these mushrooms for biomass and extracellular polysaccharides production.MethodsThe antimicrobial activity of ethyl acetate extracts of culture fluid and aqueous-ethyl extracts of mycelial mass for threeHericiumspecies:Hericium cirrhatumIBK 2393,Hericium coralloidesIBK 2332, andHericium erinaceusIBK 2530 against Gram-positiveBacillus subtilis,Staphylococcus aureus, and Gram-negativeEscherichia coli,Klebsiella pneumoniae,Pseudomonas aureginosabacteria as well asAspergillus niger,Penicillium polonicum, andMucor globosusfungi by the disk diffusion method was conducted. Analysis of the minimum inhibitory concentration was carried out according to the broth dilution method.ResultsHigh antimicrobial activity of culture fluid extracts ofHericiummushroom species againstS. aureuswas established after 14–21 days of cultivation. No effects ofHericiumextracts againstA. niger,P. polonicum, andM. globosuswere observed. On the 7th day of submerged cultivation, the studied strains produced the maximum yield of extracellular polysaccharides. The most promising extracellular polysaccharide (EPS) producers were strains ofH. coralloidesIBK 2332 (1.89 g/L) andH. erinaceusIBK 2530 (1.90 g/L). The maximal value of biomass was produced byH. cirrhatumIBK 2393 on the 21st day of submerged cultivation (17.45 g/L).ConclusionsHericiummushrooms have significant potential for the development of new drugs with health benefits properties.

Composition and Structure of Aspen (Pópulus trémula) Hemicelluloses Obtained by Oxidative Delignification.

In this study, hemicelluloses of aspen wood (Pópulus trémula) were obtained by oxidative delignification in an acetic acid-water-hydrogen peroxide medium at temperatures of 70-100 °C and a process time of 1-4 h. The maximum polysaccharide yield of up to 9.68 wt% was reported. The composition and structure of the hemicelluloses were studied using a complex of physicochemical methods: gas and gel permeation chromatography, Fourier-transform infrared spectroscopy, 2D nuclear magnetic resonance spectroscopy, and thermogravimetric analysis. The xylose, mannose, galactose, and glucose monomer units were identified in the hemicelluloses by gas chromatography. The weight average molecular weight Mw of the products determined by gel permeation chromatography was found to range within 8932-33,142 g/mol. The reported Fourier-transform spectra of the hemicelluloses contain all the bands characteristic of heteropolysaccharides; a weak lignin absorption signal in the spectra at 1500-1510 cm-1 is attributed to a minor content of phenolic fragments in the structure of the obtained hemicelluloses. The use of thermogravimetric analysis established that the hemicelluloses isolated from aspen wood are resistant against heating to temperatures of up to 90-100 °C and, upon further heating up to 400 °C, start destructing at an increasing rate. The antioxidant activity of the hemicelluloses was examined using the compounds that mimic free radicals (1,1-diphenyl-2-picrylhydrazyl) and hydroxyl radicals (salicylic acid). It was found that the activity of all polysaccharides in neutralizing DPPH and hydroxyl radicals is lower than the absorption capacity of vitamin C at all the tested concentrations (0.5, 2, and 5 mg/mL) and attains 81.7 and 82.9%, respectively.

Purification and Characterization of Fractions Containing Polysaccharides from Talinum triangulare and Their Immunomodulatory Effects

Previous studies identified that extracts of Talinum triangulare rich in flavonoids and phenolic acids showed antioxidative and immunomodulatory activities. In this study, the L9 orthogonal array was used to determine the optimal extraction conditions for water-extracted polysaccharides of T. triangulare (TTP) by hot reflux extraction and ultrasonic assisted extraction (UAE) methods. Results showed that while both extraction methods obtained a maximum polysaccharide yield of 3.1%, the optimal conditions for obtaining TTP was by UAE method. TTP was separated into large (LTTP) and small (STTP) molecular weights by dialysis. Since LTTP showed better effects than STTP in inducing macrophages to produce nitric oxide (NO) and indirectly inhibiting human cervical cancer HeLa cells, six different LTTP fractions were separated using anion-exchange chromatography. Contents of polysaccharides, triterpenoids, polyphenols, and proteins and molecular weights of major polysaccharide in each fraction were analyzed. The F1 fraction of LTTP, which showed the highest inducing ability of mouse RAW264.7 macrophages to secrete NO and tumor necrosis factor-α, showed the most significant indirect inhibitory effect of human colon cancer SW620 cells. These results suggest that LTTP, especially the F1 fraction, of T. triangulare may be used in health foods or Chinese medicine for its immunomodulatory potential.

Ganoderma sessile is a fast polysaccharide producer among Ganoderma species

ABSTRACT The selection of fast-growing and high-yield-producing strains is required to satisfy the market demand on fungal food supplements. To that aim, three strains deposited in our collection as G. lucidum and G. oregonense were screened for polysaccharide production and biomass yield. Ganoderma strains deposited as G. lucidum were identified as G. sessile and G. lingzhi by nuc rDNA internal transcribed spacer ITS1-5.8S-ITS2 (ITS) and translation elongation factor 1-α (TEF1-α) phylogenies. The identity of G. oregonense was confirmed by molecular phylogeny and biogeography. Additionally, mycelial antagonism confirmed species differentiation, and strains were further distinguished by morphology and protein profiles. Biomass and polysaccharide yields of G. sessile were clearly different from those of G. lingzhi and G. oregonense in both liquid culture and solid-state fermentation. The maximum polysaccharide yield (4.52 ± 0.83 g L−1) for G. sessile was obtained from submerged cultures at day 9. G. sessile also achieved the highest linear growth in lignocellulosic solid substrates. Consequently, basidiomata were successfully obtained by solid-state fermentation in polypropylene bags, whereas G. lingzhi and G. oregonense mushrooms were not produced in artificial solid substrates. G. sessile, a species frequently collected in America, showed to be a promising polysaccharide producer for the manufacture of dietary supplements.

Polysaccharides from pineapple core as a canning by-product: Extraction optimization, chemical structure, antioxidant and functional properties

Ultrasonic-assisted extraction (UAE) technique has been investigated to extract polysaccharides from pineapple core as a by-product using response surface methodology. A Box–Behnken design was employed to optimize the conditions for the maximum extraction yield of polysaccharides. The results demonstrated that the optimum extraction conditions were as follows: water/solid material ratio of 29.5 mL/g, extraction temperature of 66.3 °C and extraction time of 46.7 min. Under these conditions, the extraction yield of pineapple core polysaccharides (PCPs) was 16.7%. The structure of PCPs was analyzed by Fourier transform-infrared spectroscopy (FT-IR) analysis, X-ray diffractometry (XRD), SEM (scanning electron microscope) and gas chromatography–mass spectrometry (GC–MS). The results of thermogravimetric analysis indicated that the PCPs had a good thermal stability at temperatures below 250 °C. The extracted polysaccharides had a porous structure with rough surface. The extracted polysaccharides had strong scavenging activities on DPPH and hydroxyl radicals. Furthermore, they demonstrated interesting water-holding and fat-binding capacities (3.11 and 4.25 g/g, respectively). The results revealed that polysaccharides displayed good emulsifying and foaming properties. Overall, the findings suggest that PCPs are a promising source of antioxidants and may have potential applications in functional food industries.

Quantitative determination of water-soluble polysaccharides in the aerial part of <i>Potentilla anserina L.</i>

The article presents the gravimetric technique which was developed for the quantitative determination of water-soluble polysaccharides (WSPS) in the aerial part of Potentilla goose (Potentilla anserina).
 The purpose of the work was to develop the method of the quantitative determination of WSPS and the determination of their content in the aerial part of Potentilla anserina L., collected in various regions of Siberian federal district.
 Materials and methods. The object of the study was the aerial part of Potentilla anserina L, collected in June during flowering. To develop the method for the quantitative determination of the WSPS, herb mixtures collected in 2016 in vil. Verkhneussinskoe of Ermakovsky district, Krasnoyarsk Territory were studied. The amount of WSPS was determined in the above-ground part of Potentilla anserina L., collected during flowering in June 2017 in the Krasnoyarsk Territory (vil. Sliznevo), Tomsk Region (Tomsk Region), and the Republic of Buryatia (Zaigraevsky District, vil. Staraya Bryan). The above-ground parts were air dried in the shade. Determination of water-soluble polysaccharides was carried out gravimetrically in order to determine the optimal conditions for the maximum yield of water-soluble polysaccharides There was some variety in the degree of grinding of raw material, raw material / extractant index, extraction ratio, the ratio of extraction and ethyl alcohol 95%.
 Results. The greatest amount of water-soluble polysaccharides was extracted in the following conditions: the degree of grinding of raw material of 0.5-1.0 mm; the ratio of raw material and extractant was 1 : 10; the extraction rate was 5; the ratio of extraction and ethyl alcohol 95% was 1 : 4. The content of water-soluble polysaccharides was 7.55 0.36%, the analysis error did not exceed 5%.
 Conclusion. A gravimetric technique for the quantitative determination of water-soluble polysaccharides in the aerial part of P. anserina L has been developed. The content of water-soluble polysaccharides in the aerial part of P. anserina L. collected in various regions of the Siberian Federal District ranges from 5.95% (Krasnoyarsk Region) to 10.25% (Republic of Buryatia), the analysis error does not exceed 5%.

Optimization of extraction with salicylic acid, rheological behavior and antiproliferative activity of pectin from Citrus sinensis peels

A Box-Behnken design was used to optimize extraction temperature, extraction time and concentration of the salicylic acid to obtain a maximum polysaccharide yield from Citrus sinensis peels. The optimal settings were: extraction time 3 h, extraction temperature 80 °C and concentration of the salicylic acid 1.5%. Under these conditions, the experimental yield and uronic acid content were 11.74% and 66.9% respectively. Preliminary characterization was performed via FT-IR, SEC/MALS/VD/DRI and GC–MS after hydrolysis. SEC analysis showed that the extracted polysaccharide had a weight average molar mass of 350 kDa and an intrinsic viscosity of 640 mL/g. The GC–MS results revealed that the extracted polysaccharide was composed of arabinose 56.7%, galactose 17.8%, xylose 13.8%, rhamnose 5.1%, mannose 2.5% and glucose 1.5% suggested a rhamnogalacturonan pectin type I with a degree of esterification of 50.9% (IRTF). The flow curve and the dynamic frequency sweep were obtained at 10, 20, 30 and 40 g/L in water and at 30 g/L in presence of CaCl2 or NaCl at 1 mol/L. The solutions showed shear-thinning behavior fitted with Ostwald-De Waele model, except 10 g/L with a Newtonian behavior. The apparent viscosity and, the G’ and G” moduli increase with PACO concentration in agreement with a slow-down of the dynamic chain. In the presence of CaCl2 or NaCl the reduction of electrostatic repulsions between pectin chains decreases the rheological parameters. The effect is less sensitive with CaCl2 due to intermolecular interactions. The antiproliferative activity of the extracted pectin on human Caco-2 and Hep-2 cells was very interesting with an IC50 1.4 and 1.8 μg/mL respectively.

Box-Behnken design-based optimization for deproteinization of crude polysaccharides in Lycium barbarum berry residue using the Sevag method

Deproteinization of crude polysaccharides in the residue from Lycium barbarum berries (LBBs) was conducted using the Sevag method. A Box-Behnken design based on single-factor experiments was employed to optimize the deproteinization technology. The results showed that the deproteinization conditions had significant effects on the extraction yield of polysaccharides and the residual protein content in Lycium barbarum polysaccharides (LBP). The experimental data were fitted to a second-order polynomial equation, using multiple regression analysis with a high coefficient of determination (R2) value. The optimal conditions were as follows: a ratio of raw material to water extract concentrate from the residual LBBs of 0.15 g/mL; a ratio of chloroform to n-butyl alcohol of 2.17 mL/mL; and a ratio of water extract concentrate from residual LBBs to Sevag reagent of 0.50 mL/mL; with a maximum polysaccharide yield of 0.49% and minimum residual protein content of 0.087%. The results were confirmed through validation experiments. GPC analysis indicated that deproteinized LBP molecules became much more homogeneous. X-ray diffraction indicated that the hydrogen bonding of deproteinized LBP was weakened. This optimization of LBP should be a useful method for purification of crude LBP.

Ultrasound-assisted extraction and antioxidant activity of polysaccharides from Acanthus ilicifolius

In the present study, ultrasound-assisted extraction of water-soluble polysaccharides from the Acanthus ilicifolius was optimized by using one-factor-at-a-time and Box–Behnken designs. A maximum polysaccharide yield of 2.46% was obtained under the optimized conditions of ultrasonic power of 150 W, temperature of 53 °C, extraction time of 50 min, and liquid to solid ratio of 35 mL/g. Results of UV, FTIR and molecular weights indicated that there were significant differences in structures of polysaccharides extracted with ultrasound assistance (UAE-ACI) and hot-water extraction (HWE-ACI) including monosaccharide compositions and ratios, and molecular weight distributions. Further analysis showed that UAE-ACI had a higher antioxidant activity in vitro than that of HWE-ACI possibly due to lower molecular weight and higher content of phenolics and protein fractions.

Extraction and preliminary purification of polysaccharides from Camellia oleifera Abel. seed cake using a thermoseparating aqueous two-phase system based on EOPO copolymer and deep eutectic solvents

A thermoseparating aqueous two-phase system (ATPS) based on ethylene oxide-propylene oxide (EOPO) copolymer and deep eutectic solvents (DES) was developed for the extraction and preliminary purification of polysaccharides in Camellia oleifera Abel. seed cake. DESs were used as the extraction media for obtaining the crude extract. The maximum extraction yield (Y) of polysaccharides was 152.37 mg/g in the crude extract. Then the crude polysaccharides were extracted and preliminary purified by EOPO/DES ATPS. The maximum extraction efficiency (E.E.) of polysaccharides was 86.91% in EOPO-rich phase by the first ATPS extraction. The EOPO-rich phase was separated and the polysaccharides were recovered by temperature-induced phase separation. The maximum recovery efficiency (R.E.) was 84.92% in aqueous phase by the second ATPS extraction. This thermoseparating ATPS possesses the merits of good environment-friendlies, simple operation, and easy recovery of components, which can be used as an efficient method for the extraction and separation of polysaccharides.

Continuous extraction optimization, molecular structures and antioxidant activities of polysaccharide from Gracilariopsis lemaneiformis using liquid-phase pulsed discharge

The optimization of continuous extraction, molecular structures and antioxidant activities of polysaccharide from Gracilariopsis lemaneiformis using liquid-phase pulsed discharge (LPD) were investigated and compared with maceration extraction (ME). The maximum polysaccharide yield of LPD (147.94 ± 2.95 mg/g) was obtained with 79 min using the single-factor experiments under the optimum conditions: Electric-field strength of 80 kV/cm, ratio of water to solid of 40 mL/g and flow velocity of 14 mL/min, which was more than that of ME (140.19 ± 1.23 mg/g) with 300 min. The structural characteristics of GLPLPD and GLPME such as the carbohydrate, protein and sulfuric radical contents, monosaccharide composition, molecular weight, FT-IR spectra, NMR spectra were determined, and their antioxidant activities were also studied by the assay of scavenging ability of hydroxyl radical and DPPH radical. The results indicated that the structural characteristics of GLP were not affected by LPD and GLPLPD had the better antioxidant activities than GLPME. This study showed that LPD could be considered an alternative way to improve the yields of active ingredients and antioxidant activities of extracts.

Extraction, purification, characterization and antioxidant activities of polysaccharides from Zizyphus jujuba cv. Linzexiaozao

The extraction process, purification and characterization analyses of polysaccharides (LZJP) in Ziziphus jujuba planted in Linze County, Gansu Province were investigated, respectively. The results showed a maximum polysaccharide yield of 5.72% was achieved at a solid/liquid ratio of 1:20 g/mL for 90 min at 80 °C. Two homogenous acidic polysaccharides (LZJP3 and LZJP4) were purified successively by DEAE-52 cellulose and Sephadex G-100 column chromatography. LZJP3 is composed of one polymer with galactose while LZJP4 is made up of two different kinds of polymers with xylose and glucose by size-exclusion chromatograph combined with multi-angle laser photometer (HPSEC-LLS) and gas chromatography (GC) analysis. LZJP3 and LZJP4 were β-pyran polysaccharides with a large number of molecular globular aggregates by FT-IR (Fourier-transform infrared) and AFM (Atomic force microscopy) analysis, and the surface morphology exhibited smooth and filamentous staggered extension in the form of rod-like aggregation with SEM (Scanning electron microscopy) determination. Meanwhile, LZJP3 and LZJP4 exhibited antioxidant activities against DPPH, hydroxyl radical, hydrogen peroxide, superoxide radical and stronger reducing power in vitro with the concentration increasing. The results indicated that LZJPs were worthy of being developed further as a natural antioxidant in food and medicine industries.

Ultrasound-Assisted Extraction of Polysaccharides from Volvariella volvacea: Process Optimization and Structural Characterization.

The aims of the present study were to optimize the operational parameters to maximize the yield of ultrasound-assisted polysaccharide extraction from Volvariella volvacea (straw mushroom) fruiting bodies by using for the first time one-factor-at-a-time and three-level Box-Behnken factorial designs. A maximum polysaccharide yield of 8.28 ± 0.23% was obtained under the optimized conditions of ultrasound power of 175 W, extraction temperature of 57 °C, extraction time of 33 min, and the ratio of liquid to raw material of 25:1, respectively. Compared to the hot-water extraction, the ultrasound-assistance favored the extraction of polysaccharides from V. volvacea for its higher polysaccharide yield and efficiency. Further preliminary polysaccharide structural characterization indicated that ultrasound treatment affected the monosaccharide compositions and ratios, and molecular weight range of polysaccharides extracted from V. volvacea.

Extraction, characterization and biological activity of sulfated polysaccharides from seaweed Dictyopteris divaricata

Dictyopteris divaricata is a kind of important brown algae with many biological activities. It has been receiving more and more attention, yet there are rarely studies done on its polysaccharides. In this study, the optimum extraction and biological activity of seaweed polysaccharides from Dictyopteris divaricata (DDSP) were investigated. Response surface methodology (RSM), based on a three-level, three-variable Box-Behnken design (BBD), was employed to obtain the best possible combinations for maximum polysaccharides yield. The optimum extraction conditions were as follows: liquid-solid ratio of 110 mL/g, extraction time of 6 h and extraction temperature of 100 °C. Under these conditions, the experimental yield was 3.05%, which was in close agreement with the predicted value of 3.15%. The average molecular weight of DDSP was 58.05 kDa. Gas chromatograph (GC) results showed that DDSP was composed of fucose, xylose, mannose, glucose and galactose with the corresponding molar ratio of 4.45:2.74:1.00:2.94:1.35. Biological activity showed that DDSP exhibited strong antioxidant activity in vitro and possessed the potential on stimulating immune response of RAW264.7 cells. So DDSP can be used as a natural ingredient in functional foods.

Identification of polysaccharides extracted from pea pod by-products and evaluation of their biological and functional properties

A three-variable Box-Behnken design was employed to obtain the best possible combination of extraction time, ratio (raw material/water) and extraction temperature to allow maximum extraction yield of polysaccharides from pea pod (PPP). The preferred extraction conditions were: extraction time 195 min, extraction temperature 70 °C and ratio of raw material/water 1/40. Under these conditions, the experimental yield was 16.21 ± 1.12%, which is in close agreement with the value predicted by response surface methodology model yield (16.08 ± 0.95%). The molecular weight distribution of PPP showed two peaks with MW of 5217 kDa and 50 kDa, respectively. The main monosaccharides in PPP were galactose, xylose and arabinose, whereas the major functional groups identified from FT-IR spectrum included CO, OH and CH. In addition, PPP had high 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity and a moderate reducing power. The antibacterial activity of PPP was also observed against the tested microorganisms and at 50 mg/mL PPP could inhibit the growth of the Gram-negative and Gram-positive bacteria. Generally, these results suggest that the PPP has significant antioxidant activity and good antibacterial activity and can potentially be used as additive in food, pharmaceutical and cosmetic preparations.

Optimized microwave extraction, characterization and antioxidant capacity of biological polysaccharides from Eucommia ulmoides Oliver leaf

Microwave-induced technique was combined with response surface methodology for optimizing the isolation of polysaccharides from Eucommia ulmoides Oliver leaf. The maximum polysaccharides yield of 12.31% was achieved by microwave extraction at 74 °C for 15 min with a solid to liquid ratio of 1:29 g/mL, which agreed with the predicted value and was 2.9-fold higher than that of the conventional heat-reflux extraction method. The dominant bioactive constituent in extracts was chlorogenic acid (1.3–1.9%), followed by geniposidic acid (1.0–1.7%). The polysaccharides from the optimized extraction had a high molecular weight and polydispersity (Mw 38,830 g/mol, Mw/Mn 2.19), as compared to the fraction prepared in the absence of microwave (Mw 12,055 g/mol, Mw/Mn 1.26). Glucose was the dominant sugar component (38.2–39.1%) of heterogeneous polysaccharides which belonged to a structure of β-type acidic heteropolysaccharides with a glucan group and highly branched degree. The polysaccharides showed a higher DPPH radical scavenging index (0.87–1.22) than BHT (0.41) but lower than BHA (3.56), which can act as a favorable antioxidant in functional food.