Traditional Hot Water Extraction Research Articles

Optimization of ultrasound-assisted extraction of Imperata cylindrica polysaccharides and evaluation of its anti-oxidant and amelioration of uric acid stimulated cell apoptosis

An efficient, cost-effective and environmentally friendly ultrasound-assisted hot water method for Imperata cylindrica polysaccharide (ICPs) extraction was developed. According to the response surface results, the optimal ultrasonic time was 85 min, ultrasonic power was 192.75 W, temperature was 90.74 °C, liquid–solid ratio was 26.1, and polysaccharide yield was 28.50 %. The polysaccharide mainly consisted of arabinose (Ara), galactose (Gal), and glucose (Glc), with a molecular weight of 62.3 kDa. Ultrasound-assisted extraction of Imperata cylindrica polysaccharide (UICP) exhibited stronger anti-oxidant activity and ability to ameliorate cellular damage due to uric acid stimulation compared with traditional hot water extraction of Imperata cylindrica polysaccharide (ICPC-b). It also exhibited higher thermal stability, indicating its potential value for applications in the food industry.

Synergistic ultrasound pulsed electric field extraction of litchi peel polyphenols and determination of their properties

The effects of pulsed electric field combined with ultrasound (PEF-US) on the recovery of polyphenols from litchi peels were investigated. In addition, the optimal purification parameters for polyphenol extracts and their biological activities were also explored in this study. Single-factor and orthogonal experiments were used to optimize the extraction conditions of polyphenols. After optimization, the total phenol content (TPC) of the sample extracted by PEF-US was 2.30 times higher than that of the sample extracted by traditional hot-water extraction. The mechanism of PEF-US enhancing polyphenol recovery was also revealed by morphological analysis of the powder surface. LX-7 was the best resin by comparing the purification effect of nine macroporous resins. The optimum conditions for purification of litchi peel polyphenols by LX-7 resin were also optimized through adsorption and desorption experiments. UHPLC-MS and HPLC results revealed that gentisic acid, catechin, procyanidin A2 and procyanidin B1 are four main substances in purified samples. The results of bioactivity experiments showed that the purified polyphenol samples had strong antioxidant and antibacterial activity. Overall, PEF-US is an efficient method for recovering polyphenols from litchi peels. Our study also provides a strategy for the comprehensive utilization of fruit processing waste.

Ultrasound-assisted enzyme extraction and properties of Shatian pomelo peel polysaccharide

In this study, Shatian pomelo peel was used as the raw material for extracting polysaccharides using hot water extraction (HW) and ultrasonic-assisted enzyme (UVE) methods, respectively. The optimal parameters for extractingShatian pomelo peel polysaccharides (StPP) using the ultrasound-assisted enzymatic method were determined using response surface methodology (RSM). The optimal conditions for the extraction of StPP were as follows: ultrasound power 350 W, ultrasound time 50 min, enzymatic digestion time 50 min, compound enzyme addition 1.5%, and enzymatic digestion temperature 55 °C. The yield of StPP was found to be 30.1310% under these conditions. Comparing the physicochemical properties and antioxidant activity of StPP extracted using different methods, it was observed that ultrasound-assisted enzyme extraction resulted in higher yield, sugar content and glucuronic acid content of StPP compared to traditional hot water extraction. Additionally, StPP extracted by ultrasound-assisted enzyme extraction showed better antioxidant activity. These results suggest that ultrasound-assisted enzymatic extraction is an effective method to enhance the activity of natural polysaccharides.

Studies of caprolactam and cyclic oligomer content, molecular weight, and thermal properties during melt post-polycondensation of polycaprolactam in the film state

In industrial application of polycaprolactam, the content of caprolactam monomer and oligomers, as well as their average molecular weight are the key factors. In this work, a liquid-chromatography/time-of-flight mass spectrometry (LC-TOF-MS) method and an advanced polymer chromatography/multi-angle laser light scattering/refractive index detector (APC-MALLS-RID) hyphenated technique have been developed as a quantitative analysis method for monomer and cyclic oligomers, and a means of determining the molecular weight of polycaprolactam. The melt post-polycondensation reaction characteristics of polycaprolactam films and the variation in monomers and cyclic oligomers (C2–C7) content have been systematically investigated. The results showed excellent repeatability and stability of quantitative test results on monomers and cyclic oligomers in polycaprolactam. The content of monomers and cyclic oligomers in the polycaprolactam decreased from 10.21% to 1.52% at 260 °C and 50 Pa for 60 min, and the average molecular weight increased from 1.53×104 g/mol to 2.36×104 g/mol. Additionally, the results of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) experiments showed that the thermal stability and crystallization properties of polycaprolactam were improved after the film melt post-polycondensation reaction. Thus, this melt post-polycondensation method can realize the efficient removal of monomers and cyclic oligomers (compared with the traditional hot water extraction method) and afford high-quality polycaprolactam with high average molecular weight.

The anti-aging activity of Lycium barbarum polysaccharide extracted by yeast fermentation: In vivo and in vitro studies

Lycium barbarum polysaccharide (LBP) is an important active substance in Lycium barbarum. In this study, LBP was extracted by the hot water method and yeast fermentation method to obtain products called LBP-W and LBP-Y, respectively. Both LBPs have a strong ability to scavenge DPPH, hydroxyl, and superoxide anion free radicals and have a total antioxidant capacity. Both LBPs prolong the lifespan of C. elegans under normal conditions, oxidative stress and heat stress and do not affect fertility, LBPs could prolong the lifespan of C. elegans by upregulating the expression of daf-16, sod-3 and hsp-16.2 genes, and LBP-Y is more efficacious. The molecular weight of the LBPs was characterized by gel permeation chromatography (GPC), and the results showed that LBP-Y is smaller and more uniform than LBP-W. The skin penetration experiment showed that the absorption effect of LBP-Y is better than that of LBP-W. These lines of evidence suggest that the yeast fermentation extraction of LBP produces better antioxidant and anti-aging effects than those obtained with the traditional hot water extraction, which is more suitable for obtaining raw materials with anti-aging functions that can potentially be used in the food and cosmetic industries.

Exploring the Potential of Icelandic Seaweeds Extracts Produced by Aqueous Pulsed Electric Fields-Assisted Extraction for Cosmetic Applications.

A growing concern for overall health is driving a global market of natural ingredients not only in the food industry but also in the cosmetic field. In this study, a screening on potential cosmetic applications of aqueous extracts from three Icelandic seaweeds produced by pulsed electric fields (PEF) was performed. Produced extracts by PEF from Ulva lactuca, Alaria esculenta and Palmaria palmata were compared with the traditional hot water extraction in terms of polyphenol, flavonoid and carbohydrate content. Moreover, antioxidant properties and enzymatic inhibitory activities were evaluated by using in vitro assays. PEF exhibited similar results to the traditional method, showing several advantages such as its non-thermal nature and shorter extraction time. Amongst the three Icelandic species, Alaria esculenta showed the highest content of phenolic (mean value 8869.7 µg GAE/g dw) and flavonoid (mean value 12,098.7 µg QE/g dw) compounds, also exhibiting the highest antioxidant capacities. Moreover, Alaria esculenta extracts exhibited excellent anti-enzymatic activities (76.9, 72.8, 93.0 and 100% for collagenase, elastase, tyrosinase and hyaluronidase, respectively) for their use in skin whitening and anti-aging products. Thus, our preliminary study suggests that Icelandic Alaria esculenta-based extracts produced by PEF could be used as potential ingredients for natural cosmetic and cosmeceutical formulations.

Physicochemical and Biological Properties of Polysaccharides from Dictyophora indusiata Prepared by Different Extraction Techniques.

In this study, different extraction techniques, including traditional hot water extraction (HWE), microwave-assisted extraction (MAE), pressurized assisted extraction (PAE), and ultrasonic-assisted extraction (UAE), were used to extract Dictyophora indusiata polysaccharides (DFPs), and their physicochemical and biological properties were compared. Results revealed that extraction yields of D. indusiata polysaccharides prepared by different extraction techniques ranged from 5.62% to 6.48%. D. indusiata polysaccharides prepared by different extraction techniques possessed similar chemical compositions and monosaccharide compositions, while exhibited different molecular weights (Mw), apparent viscosities, and molar ratios of constituent monosaccharides. In particularly, D. indusiata polysaccharides prepared by HWE (DFP-H) had the highest Mw and apparent viscosity among all DFPs, while D. indusiata polysaccharides extracted by UAE (DFP-U) possessed the lowest Mw and apparent viscosity. In addition, the in vitro antioxidant effects of D. indusiata polysaccharides prepared by PAE (DFP-P) and DFP-U were significantly higher than that of others. Indeed, both DFP-P and DFP-H exhibited much higher in vitro binding properties, including fat, cholesterol, and bile acid binding properties, and lipase inhibitory effects than that of D. indusiata polysaccharides prepared by MAE (DFP-M) and DFP-U. These findings suggest that the PAE technique has good potential for the preparation of D. indusiata polysaccharides with desirable bioactivities for the application in the functional food industry.

Optimization of ultrasonic-assisted extraction of polysaccharides and triterpenoids from the medicinal mushroom Ganoderma lucidum and evaluation of their in vitro antioxidant capacities.

Ganoderma lucidum (Fr.) Krast, commonly known as "Lingzhi" in Chinese, is a medicinal mushroom that is rich in biologically active substances. Polysaccharides and triterpenoids are the two major components responsible for the bioactivity of this fungus. In the present study, the ultrasonic-assisted co-extraction (UACE) of polysaccharides and triterpenoids from G. lucidum was optimized using response surface methodology with a desirability function, with the equal importance for the two components. Following single factor experiments, the optimal conditions were determine as ultrasonic power of 210 W, extraction temperature of 80C, ratio of liquid to solid of 50 mL/g, and 100 min extraction time, using aqueous ethanol (50%, v/v) as the extracting solvent. Under the optimal conditions, the extraction yields of polysaccharides and triterpenoids reached 0.63% and 0.38%, respectively. On the basis of the scavenging capacity of 2,2-diphenyl-1-picrylhydrazyl and evaluation of reducing power, the antioxidant capacities of the polysaccharides obtained by optimal UACE process were higher than those of polysaccharides extracted using traditional hot water extraction, whereas the triterpenoid-rich extracts showed antioxidant activities similar to those obtained using the ethanol maceration method. The present study is the first report on the simultaneous extraction of polysaccharides and triterpenoids from G. lucidum. The developed UACE process could be useful in preparation of a polysaccharide- and triterpenoid-rich ingredient that holds great promise for application in the Ganoderma industry.

Polysaccharides of Scrophularia ningpoensis Hemsl.: Extraction, Antioxidant, and Anti-Inflammatory Evaluation.

The roots of Scrophularia ningpoensis Hemsl. are a famous traditional Chinese medicinal herb and are also used as health food. However, information about polysaccharides from S. ningpoensis (SNPS) is very limited. We applied the ultrasonic-assisted extraction (UAE) process to extract SNPS. The UAE conditions were optimized using single-factor experiments and response surface analysis. Under the optimized conditions of ultrasonic power of 550 W, extraction time of 26 min, and extraction temperature at 50°C, the highest yield of 13.47% ± 1.63% was obtained, which was in accordance with the predicted value of 13.71%. In comparison with traditional hot water extraction, the optimized UAE method significantly increased the extraction yield with lower extraction temperature and shorter extraction time. Furthermore, the in vitro antioxidant evaluation showed that EC50 values of SNPS were 2.43 ± 0.21, 4.40 ± 0.35, and 0.56 ± 0.062 mg/mL for 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) radical, hydroxyl free radical, and 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging assay, respectively. The anti-inflammatory potential of SNPS was detected in lipopolysaccharide (LPS) induced ICR mice. Real-time reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay showed that SNPS significantly improved LPS-stimulated inflammatory response by decreasing mRNA and protein expression of interleukin (IL)-6 and tumour necrosis factor (TNF)-α in a dose-dependent manner. In conclusion, the extraction process of SNPS established in this study is reliable, and SNPS possesses potential antioxidant and anti-inflammatory activities, which will provide a theoretical basis for guiding the clinical application of S. ningpoensis.

Effects of different extraction methods on the properties of pine cone polysaccharides from Pinus koraiensis

In order to realize the resource utilization of the Pinus koraiensis pine cone, the polysaccharides were obtained by a traditional hot water extraction process, and the optimal extraction process was confirmed. The effects of a traditional hot water, alkali, and ultrasound assisted extraction on the yield and properties of polysaccharides were studied. The structure, monosaccharide composition, and content of polysaccharides obtained by different extraction methods were analyzed by means of Fourier infrared chromatography and liquid chromatography. Effects of polysaccharides extracted by different methods on the antimicrobial activity of Staphylococcus aureus and Escherichia coli were studied. The scavenging effect of DPPH free radicals were also examined. The optimum condition of the hot water extraction was identified as an extraction temperature of 100 °C, a ratio of material to water at 1:16 (w/v), an extraction time of 4 h, and a yield of polysaccharide at 10.2%. In comparison, the yield of the pine cone polysaccharide was improved significantly to 29.1% by using NaOH solution extraction method. The FTIR spectra of polysaccharides showed that the samples possessed the typical chemical structure of a polysaccharide.

Antioxidant activities of Sagittaria sagittifolia L. polysaccharides with subcritical water extraction

In the present study, orthogonal experiment (L9 (3)4) was used to optimize the extraction process of Sagittaria sagittifolia L. polysaccharides (SSP) with subcritical water, and the antioxidant activities of polysaccharides were also investigated. The results showed that the optimum extraction conditions were obtained when pH, extraction temperature, extraction time, and liquid to solid ratio were 7, 170 °C, 16 min and 30:1 (mL/g), respectively. In addition, DPPH/ABTS radical scavenging rate and Fe3+ reducing power of polysaccharides exhibited a certain dose-effect relationship. Furthermore, both yield and antioxidant activities of polysaccharides with subcritical water extraction (SWE) were higher than traditional hot water extraction (HWE). The above results showed that SWE was an effective technique to extract and separate polysaccharides from Sagittaria sagittifolia L., which may be potentially applied in the related polysaccharides extraction.

Effects of non-traditional extraction methods on extracting bioactive compounds from chaga mushroom (Inonotus obliquus) compared with hot water extraction

Chaga mushroom (Inonotus obliquus) is mainly consumed as an extract. Hot water extraction, which is a traditional method preparing chaga mushroom extract, has limitations requiring a large amount of solvent and long extraction time. The objective of this study was to compare non-traditional methods for extracting bioactive compounds in chaga mushroom with traditional hot water extraction. β-Glucans and total phenolic compounds were the highest in high temperature and pressure extract. Enzyme extract contained more β-glucans than hot water extract. Enzyme and ultrasound extracts contained more triterpenoids than the hot water extract.

Effect of multimode ultrasound assisted extraction on the yield of crude polysaccharides from Lycium Barbarum (Goji)

Abstract The goals of this exploration were to find out the optimum conditions of ultrasound assisted extraction (UAE) of L. Barbarum crude polysaccharides. Furthermore, to research the impacts of three multi-frequency ultrasound assisted extraction modes on the yield of L. Barbarum crude polysaccharides. The results showed that by applying the traditional single-frequency UAE mode, the optimum extraction time was 30 min, extraction temperature of 60 °C, and solid/liquid ratio of 20 g/600 mL, at a power density of 300 W/L, and ultrasound frequency of 28 kHz. Secondly; a comparison was carried out between three UAE modes using the optimum extraction conditions obtained previously. The energy aggregation counter flow dual-frequency UAE mode gave the highest yield of 38.93% of crude polysaccharides. Followed by the Opposite-sit dual-frequency UAE mode and the energy aggregation counter flow single-frequency UAE mode with yields of 33.60%, and 26.38% of crude polysaccharides, respectively. As a result the ultrasound assisted extraction with dual-frequency mode is more effective for the extraction of L. Barbarum crude polysaccharides. Furthermore, the yield of crude polysaccharides increased by 73.41% using the dual-frequency ultrasound extraction compared to traditional hot water extraction.

Optimization of microwave assisted extraction, chemical characterization and antitumor activities of polysaccharides from porphyra haitanensis

Microwave assisted extraction (MAE) technology was used to extract polysaccharides from Porphyra Haitanensis (PHP) with water. Polysaccharide yield was used as index to evaluate the extraction process. Effects of ratio of water to raw material (X1), microwave power (X2) and extraction time (X3) on polysaccharide yield were investigated. Based on single factor experiment, MAE process of PHP was optimized using response surface methodology. Chemical characterization of PHP was investigated based on analysis of chemical compositions, monosaccharide and thermal gravimetric. The antitumor activities of PHP in vivo and in vitro were evaluated. The results indicated that the optimal conditions for MAE of PHP were ratio of water to raw material 28.98(mL/g), microwave power 77.84 W and extraction time 14.14 min. MAE was a suitable and efficient technique for PHP extraction compared with traditional hot water extraction. Analysis of chemical characterization showed that PHP contained 75.36 ± 1.48% of total carbohydrates, 24.63 ± 1.69% of uronic acid residue and no proteins with monosaccharides such as rhamnose, arabinose, xylose, mannose, glucose, and galactose in a molar ratio of 10.25:9.38:1:12.45:9.9:11.55. Thermal gravimetric analysis suggested that PHP was relatively stable below 170℃.PHP had obvious effect on inhibiting proliferation, inducing apoptosis of SGC-7901 tumor cells in vitro and antitumor effect on SGC-7901 tumor-bearing mice in vivo. The results suggested that PHP had the potential for clinical use in cancer prevention and treatment.

Response Surface Methodology for Optimizing the Ultrasound-Assisted Extraction of Polysaccharides from Acanthopanax giraldii.

The aim of this study was to investigate and optimize the most important factors affecting the extraction of Acanthopanax giraldii HARMS polysaccharides (AHPs) by ultrasound-assisted extraction (UAE) technology in a systemic manner. The ranges of four factors, including extraction temperature, liquid/solid ratio, extraction time, and ultrasonic power, were first determined by a single-factor experiment, followed by optimization of the UAE conditions using the Box-Behnken design (BBD) for maximum AHPs production. In our study, the models developed from the experimental design predicted the experimental data well and had a high determination coefficient (R2=0.9387). The optimized conditions for AHPs extraction were as follows: extraction temperature, 58°C; liquid/solid ratio, 25 : 1; extraction time, 73 min; and ultrasonic power, 85 W. Under these optimized conditions, the polysaccharide yield was 1.532±0.037% (n=3), being very close to the predicted value of 1.546% by the model. In addition, to investigate whether there was a difference of AHPs content between UAE and traditional hot water extraction (THWE), Fourier-transform (FT) IR spectral analyses was performed. The results showed that the functional groups of the polysaccharides extracted by either UAE or THWE were fundamentally identical. Furthermore, AHPs extracted by UAE could promote macrophage activation, such as enhanced phagocytosis and increased cytokine (interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α)) secretion in RAW264.7 cells. In conclusion, optimization of the UAE conditions by response surface methodology (RSM) was a promising method to improve the extraction yield of AHPs. AHPs extracted by the optimized UAE method can maintain their polysaccharide structure and biological activity.

Enzyme-assisted extraction, chemical characteristics, and immunostimulatory activity of polysaccharides from Korean ginseng (Panax ginseng Meyer)

In this study, enzyme-assisted extraction was used to isolate functional polysaccharides from Korean ginseng (Panax ginseng Meyer) and the physicochemical and biological properties of the extracted polysaccharides were investigated, comparing with those from traditional hot-water extraction (FGWP). In macrophages, their effects on cytokines production could be ordered as FGEP-CA ≥ FGEP-A > FGEP-C > FGWP, suggesting that FGEP-CA (combined cellulase- and α-amylase-extracted polysaccharide) is a potent immunostimulator. In addition, enzymatic digestion led to differences in the monosaccharide profile of the extract. FGWP mainly consisted of rhamnose, arabinose, galactose, galacturonic acid, and glucose in molar percentages of 1.8:10.1:9.2:17.8:60.6, whereas FGEP-CA was 3.2:11.4:16.5:22.3:45.8, respectively, suggesting that enzyme-assisted extraction of ginseng polysaccharides produces a higher proportion of pectin polysaccharides. The HPLC profile of FGEP-CA also showed lower and more heterogeneous molecular weights than FGWP did. In cyclophosphamide-induced immunosuppressed mice, FGEP-CA administration ameliorated decreased spleen and thymus indices (200 mg/kg), lymphocyte proliferation, natural killer cell activity, leukocyte counts, and the serum cytokines, interleukin-2, interleukin-6, and interferon-γ (100 and 200 mg/kg). These results suggest that enzyme-assisted extraction using cellulase and α-amylase is an effective method for the preparation of functional polysaccharides from fresh Korean ginseng, and FGEP-CA could be utilized as a potential immune-stimulatory agent.

Synthesis and application of hydrophilically-modified Fe3O4 nanoparticles in oil sands separation.

Nanoparticles have been reported to be a promising candidate for the separation of heavy oil from its host rock's surface. These nanoparticles (NPs) are often dispersed and stabilized in the solution by some surfactants during the unconventional oil ores processing. Herein, the PEG600–KH560 (PK) has been grafted onto Fe3O4 NP surfaces, obtaining a kind of hydrophilically-modified recyclable nanoparticle. Results show that these NPs (averaged at around 16 nm for single sphere) could be well dispersed in water (no settling in 72 h), forming PK-Fe3O4 nanofluids (NFs) at 0.2 wt%. These PK-Fe3O4 NFs are found to be able to be quickly separated from the dispersions by an external magnetic field, and returning back to stable NFs when the magnetic field disappears and by shaking. The PK-Fe3O4 NFs have been further used for the enhancement of heavy oil recovery from oil sands. The floatation results show that the PK-Fe3O4 NFs could improve oil recovery by at least 12% compared with the traditional hot water extraction process (HWEP). After the extraction, up to 70% of the PK-Fe3O4 NPs could be directly recycled from the solution for further use. The rest of the NPs are left in the oil phase and attached on the residual solid surface. However, the efficiency of the PK-Fe3O4 NPs is found to be decreased when the recycling times exceed 5 due to the adsorption of oil components. A mechanistic study shows that the hydrophilic PK-Fe3O4 NPs could be adsorbed on the mineral surface, making the surface more hydrophilic. The hydrophilic surface and the agitation disturbance helps the liberation process of bitumen from the solid surfaces. On the other hand, when adding the PK-Fe3O4 NPs into the heavy oil–water system, the oil–water interface is found to be highly modified by the NPs, resulting in significant reduction of the oil–water interfacial tension. The above findings suggest that the PK-Fe3O4 NPs combined the surface-active role (surfactant) and the nano-size role (adsorption) together, which facilitates its role in oil sands separation.

Extraction Optimization, Composition Analysis, and Antioxidation Evaluation of Polysaccharides from White Jelly Mushroom, Tremella fuciformis (Tremellomycetes).

We investigated the sonication-assisted extraction (SAE) conditions of Tremella fuciformis polysaccharides. Single-factor experiments showed that the optimal sonication intensity was 6 W/cm2; the other SAE conditions were further optimized using response surface experimental design. A Box-Behnken experiment exhibited that the optimal SAE conditions were temperature, 85°C; ratio of liquid to solid, 46 mL/g; and sonication time, 2 hours. The maximal polysaccharide yield (8.95 g/100 g) was obtained under the optimal extraction conditions. Polysaccharides extracted by sonication or traditional hot water extraction (TWE) were further separated and purified using DEAE-Sepharose and Sephadex G-100 column chromatography. Polysaccharide fractions (SAE-1, SAE-2, TWE-1, and TWE-2) were obtained; their molecular weights were 9.85 × 104, 6.64 × 104, 4.75 × 105, and 2.81 × 105 Da, respectively. The total sugar content of SAE-1 and SAE-2 was lower and the protein and nucleic acid contents were higher than those of TWE-1 and TWE-2. In addition, SAE-1 and SAE-2 showed stronger Fe2+-chelating activities and superoxide radical scavenging activities than TWE-1 and TWE-2. This suggests that polysaccharides extracted by sonication possess high antioxidant activities.

Optimization of Alkali Extraction of Polysaccharides From Foxtail Millet and Its Antioxidant Activities In Vitro

Highlights Extraction of polysaccharides from foxtail millet with alkali solution. Response surface methodology was used. The antioxidant activity of the polysaccharides was investigated in vitro. Model was set up to optimize extraction of polysaccharides. The best extraction conditions were alkali concentration 0.83 mol/L, liquid–solid ratio 20.9:1 mL/g, extraction time 1.1 h and extraction temperature 72.7C. Abstract Response surface methodology was employed to obtain the best possible combination of alkali concentration, liquid–solid ratio, extraction time and extraction temperature for maximum polysaccharide yields in the experiment of alkali extraction of polysaccharides from foxtail millet. The antioxidant activity of the obtained polysaccharides was meanwhile investigated in vitro. The experimental data obtained were fitted to a second-order polynomial equation using multiple regression analysis. The optimum extraction conditions were alkali concentration 0.83 mol/L, liquid–solid ratio 20.9:1 mL/g, extraction time 1.1 h, and extraction temperature 72.7C, the experimental yield was 46.21 mg/g, which was well in close agreement with the model's predicted value (45.60 mg/g). The polysaccharides of foxtail millet have better capacity of radical-scavenging activity on DPPH (1,1-diphenyl-2-picrylhydrazyl) and hydroxyl radical-scavenging activity. The mathematical model had high correlation (P < 0.01) and could be greatly employed to optimize polysaccharide extraction technology. Polysaccharides of foxtail millet can be used as a potential antioxidant agent. Practical Applications This study can be considered as the first report on the extraction of polysaccharides with alkali solution from foxtail millet. Compared with the traditional hot water extraction method, it can improve efficiency, shorten extraction time, reduce extraction temperature and has great potential in large-scale extraction of polysaccharides from foxtail millet.

Optimization of ultrasound extraction of Alisma orientalis polysaccharides by response surface methodology and their antioxidant activities.

Rhizoma alismatis (the rhizome of Alisma orientalis) polysaccharides (RAP) have been reported to have a variety of important biological activities. However, effective extraction of RAP has been an unsolved issue. In this study, we used an ultrasound method for high yield extraction of RAP and optimized the conditions using the response surface methodology (RSM). Following multiple regression analyses of the experimental results, we applied the 3-D response surface and the contour plots to determine the optimal conditions, which were found to be ultrasound treatment at 76.1°C for 75.2 min, and water to material ratio at 30.1 ml/g. Under such conditions, the yield was 6.90% which was much higher than traditional hot water extraction yield (3.41%). The fractionated RAPs following stepwise ethanol precipitation showed strong antioxidant activities. The results indicated that ultrasound extraction was a very effective method for the extraction of RAP and the polysaccharides could be explored as a potential antioxidant agent for use in medicine or functional food.