scholarly journals Microwave-assisted Enzymatic Hydrolysis to Produce Xylooligosaccharides from Rice Husk Alkali- soluble Arabinoxylan

2021 ◽  
Author(s):  
Wannaporn Klangpetch ◽  
Alisa Pattarapisitporn ◽  
Suphat Phongthai ◽  
Pannapapol Jaichakan
Keyword(s):  
Enzymatic Hydrolysis ◽  
Sodium Hydroxide ◽  
Microwave Heating ◽  
Rice Husk ◽  
Sugar Content ◽  
Microwave Treatment ◽  
Heating Process ◽  
Microwave Pretreatment ◽  
Microwave Assisted ◽  
Pretreatment Time

Abstract This study aimed to produce xylooligosaccharide (XOS) and arabino-xylooligosaccharide (AXOS) from rice husk (RH) using microwave treatment combined with enzymatic hydrolysis and evaluate their prebiotic properties. The RH was pretreated by a microwave heating process at 140, 160 and 180°C for 5, 10, and 15 min to obtain crude arabinoxylan (AX). The results emphasized that increasing microwave pretreatment time increased sugar content. The crude AX was then extracted with 2% (w/v) sodium hydroxide at 25°C for 24 h. The obtained AX was then used as a substrate for XOS production by commercial xylanases. The results showed that the oligosaccharide produced by Pentopan Mono BG and Ultraflo Max provided xylobiose and xylotriose as the main products. Interestingly, AXOS was also present in the oligosaccharide product. Furthermore, the oligosaccharides obtained were able to promote the growth of Lactobacillus spp. and to resist degradation more than 70% after exposure to simulated human digestion.

scholarly journals Microwave-assisted enzymatic hydrolysis to produce xylooligosaccharides from rice husk alkali-soluble arabinoxylan

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Wannaporn Klangpetch ◽  
Alisa Pattarapisitporn ◽  
Suphat Phongthai ◽  
Niramon Utama-ang ◽  
Thunnop Laokuldilok ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Sodium Hydroxide ◽  
Rice Husk ◽  
Sugar Content ◽  
Microwave Treatment ◽  
Microwave Pretreatment ◽  
Microwave Assisted ◽  
Pretreatment Time

AbstractThe prebiotic properties of xylooligosaccharides (XOS) and arabino-xylooligosaccharides (AXOS) produced from rice husk (RH) using microwave treatment combined with enzymatic hydrolysis were evaluated. The RH was subjected to microwave pretreatment at 140, 160 and 180 °C for 5, 10 and 15 min to obtain crude arabinoxylan (AX). Increasing microwave pretreatment time increased sugar content. Crude AX was extracted with 2% (w/v) sodium hydroxide at 25 °C for 24 h and used as a substrate for XOS production by commercial xylanases. Results showed that oligosaccharides produced by Pentopan Mono BG and Ultraflo Max provided xylobiose and xylotriose as the main products. AXOS was also present in the oligosaccharides that promoted growth of Lactobacillus spp. and resisted degradation by over 70% after exposure to simulated human digestion.

scholarly journals Production of Xyloligosaccharides from Rice Straw by Microwave-assisted Enzymatic Hydrolysis and Evaluation of Their Prebiotic Properties

2021 ◽  
Vol 20 (2) ◽  
Author(s):  
Alisa Pattarapisitporn ◽  
Nonglak Thiangthong ◽  
Pakorn Inthajak ◽  
Pannapapol Jaichakan ◽  
Wantana Panpa ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Rice Straw ◽  
Sugar Content ◽  
Lactobacillus Brevis ◽  
Enzyme Concentration ◽  
Reducing Sugar ◽  
Total Sugar ◽  
Microwave Pretreatment ◽  
Pretreatment Time ◽  
Layer Chromatography

Rice straw (RS) is a by-product from rice production process. It is rich in cellulose, hemicellulose and lignin. RS hemicellulose mainly composes of arabinoxylan (AX). This research aimed to investigate the potential of microwave-pretreatment in AX extraction from RS and substrate to produce xylooligosaccharides (XOS) via enzymatic hydrolysis. The extractive-free RS was pretreated by microwave process at 160°C for 5-15 min, then the AX was extracted with 4% sodium hydroxide. The total sugar and reducing sugar content of AX exhibited that increasing microwave-pretreatment time increased the yield of AX. The highest AX content was found at 160°C for 10 min as 7.73%, reducing sugar content of 11.89 mg/g, and total sugar of 165.85 mg/g. The crude AX obtained by microwave-pretreatment was then used as a substrate for XOS production by two commercial xylanases of Pentopan mono BG (BG) and Ultraflo Max (UM), at the enzyme concentration of 50-300 U/g AX (50°C, pH 6.0) for 24 h.The reducing sugar content and sugar profiles were monitored by DNS assay,and thin layer chromatography (TLC) which revealed that BG 50 U/g at 12 h andUM 50 U/g at 24 h showed the promising reducing sugar of 16.4 and 25.44 mg/g,respectively. The composition of XOS derived from RS (RS-XOS) prepared by BGwas xylobiose (X2), xylotriose (X3), xylotretraose (X4), and xylopentaose (X5)while by UM was xylobiose (X2), xylotriose (X3) and xylotretraose (X5). Moreover,XOS produced by BG contained very low amount of xylose (X1). In addition, theRS-XOS could the growth of Lactobacillus brevis greater than commercial XOS.

Experimental Study on Microwave Pretreatment with some Refractory Flotation Gold Concentrate

2010 ◽  
Vol 158 ◽  
pp. 71-75 ◽  
Author(s):  
Xiu Juan Su ◽  
Wei Mo ◽  
Shao Jian Ma ◽  
Jin Lin Yang ◽  
Mei Qun Lin
Keyword(s):  
Experimental Study ◽  
Microwave Heating ◽  
Heating Time ◽  
Gold Recovery ◽  
Heating Process ◽  
Leaching Rate ◽  
Microwave Pretreatment ◽  
Refractory Gold ◽  
Better Than

The microwave pretreatment of a typically refractory flotation gold concentrate was investigated. The results demonstrated that a maximum gold recovery of 97% was achieved, and that gold recoveries of the refractory gold concentrate quickly increased to the maximum with microwave heating time. Adding additives during microwave heating process was helpful to improve the leaching rate of gold, and the effect of microwave heating with single NaOH on the leaching rate of gold is not better than that of NaOH combined with other additives.

Decomposition mechanism of a mixed rare earth concentrate with sodium hydroxide in the microwave heating process

2019 ◽  
Vol 132 ◽  
pp. 220-227 ◽  
Author(s):  
Yukun Huang ◽  
Ting-an Zhang ◽  
Zhihe Dou ◽  
Guihong Han ◽  
Yijun Cao ◽  
...  
Keyword(s):  
Rare Earth ◽  
Sodium Hydroxide ◽  
Microwave Heating ◽  
Decomposition Mechanism ◽  
Heating Process

Microwave-assisted enzymatic hydrolysis of starch

2009 ◽  
Author(s):  
Marcin Lukasiewicz ◽  
Anna Osowiec ◽  
Magdalena Marciniak
Keyword(s):  
Enzymatic Hydrolysis ◽  
Microwave Assisted ◽  
Hydrolysis Of

Usefulness of Foundry Tooling Materials in Microwave Heating Process

2013 ◽  
Vol 58 (3) ◽  
pp. 919-922 ◽  
Author(s):  
K. Granat ◽  
B. Opyd ◽  
D. Nowak ◽  
M. Stachowicz ◽  
G. Jaworski
Keyword(s):  
Electromagnetic Field ◽  
Microwave Heating ◽  
Loss Factor ◽  
Perturbation Technique ◽  
Resonant Cavity ◽  
Precise Determination ◽  
Heating Process ◽  
Basic Criterion ◽  
Measurement Results ◽  
Heating Technology

Abstract The paper describes preliminary examinations on establishing usefulness criteria of foundry tooling materials in the microwave heating technology. Presented are measurement results of permittivity and loss tangent that determine behaviour of the materials in electromagnetic field. The measurements were carried-out in a waveguide resonant cavity that permits precise determination the above-mentioned parameters by perturbation technique. Examined were five different materials designed for use in foundry tooling. Determined was the loss factor that permits evaluating usefulness of materials in microwave heating technology. It was demonstrated that the selected plastics meet the basic criterion that is transparency for electromagnetic radiation.

Microwave Pretreatment of Vegetable Materials to Increase the Extraction Yield of Natural Products

2018 ◽  
Vol 69 (8) ◽  
pp. 1976-1979
Author(s):  
Ioana Asofiei ◽  
Ioan Calinescu ◽  
Adina Ionuta Gavrila ◽  
Daniel Ighigeanu ◽  
Diana Martin
Keyword(s):  
Natural Products ◽  
Chemical Composition ◽  
Phenolic Compounds ◽  
Total Phenolic Content ◽  
Phenolic Content ◽  
Extraction Yield ◽  
Total Phenolic ◽  
Microwave Pretreatment ◽  
Pretreatment Time ◽  
Conventional Extraction

It was designed and built a laboratory experimental installation (LEI) for the microwave pretreatment of vegetable materials. To study the influence of microwave pretreatment on the total phenolic content (TPC), a conventional extraction of polyphenols from treated and untreated fresh sea buckthorn leaves was performed. For short extraction times, the amount of phenolic compounds was higher for the extracts obtained from treated leaves, but a long pretreatment time (28 s) led to a decrease in TPC. The qualitative analysis showed that the chemical composition is not affected by the microwave pretreatment.

Nitrogen and Sulfur Co-doped Fluorescent Carbon Dots for the Detection of Morin and Cell Imaging

2018 ◽  
Vol 15 (1) ◽  
pp. 47-55
Author(s):  
Xuebing Li ◽  
Haifen Yang ◽  
Ning Wang ◽  
Tijian Sun ◽  
Wei Bian ◽  
...  
Keyword(s):  
Microwave Heating ◽  
Fluorescent Probe ◽  
Fluorescence Intensity ◽  
Carbon Dots ◽  
Cell Imaging ◽  
Water Soluble ◽  
Heating Process ◽  
X Ray ◽  
Doped Carbon Dots ◽  
Co Doped

Background: Morin has many pharmacological functions including antioxidant, anticancer, anti-inflammatory, and antibacterial effects. It is commonly used in the treatment of antiviral infection, gastropathy, coronary heart disease and hepatitis B in clinic. However, researches have shown that morin is likely to show prooxidative effects on the cells when the amount of treatment is at high dose, leading to the decrease of intracellular ATP levels and the increase of necrosis process. Therefore, it is necessary to determine the concentration of morin in biologic samples. Method: Novel water-soluble and green nitrogen and sulfur co-doped carbon dots (NSCDs) were prepared by a microwave heating process with citric acid and L-cysteine. The fluorescence spectra were collected at an excitation wavelength of 350 nm when solutions of NSCDs were mixed with various concentrations of morin. Results: The as-prepared NSCDs were characterized by transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The fluorescence intensity of NSCDs decreased significantly with the increase of morin concentration. The fluorescence intensity of NSCDs displayed a linear response to morin in the concentration 0.10-30 μM with a low detection limit of 56 nM. The proposed fluorescent probe was applied to analysis of morin in human body fluids with recoveries of 98.0-102%. Conclusion: NSCDs were prepared by a microwave heating process. The present analytical method is sensitive to morin. The quenching process between NSCDs and morin is attributed to the static quenching. In addition, the cellular toxicity on HeLa cells indicated that the as-prepared NSCDs fluorescent probe does not show obvious cytotoxicity in cell imaging. Our proposed method possibly opens up a rapid and nontoxic way for preparing heteroatom doped carbon dots with a broad application prospect.

scholarly journals Preparation and application of carbon and hollow TiO2 microspheres by microwave heating at a low temperature

e-Polymers ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 200-209
Author(s):  
Caiyun Zhang ◽  
Chunhong Li ◽  
Bolin Ji ◽  
Zhaohui Jiang
Keyword(s):  
Low Temperature ◽  
Microwave Heating ◽  
Raw Material ◽  
Carbon Microspheres ◽  
Microwave Assisted ◽  
The Core ◽  
Good Crystallinity ◽  
Carbon Core ◽  
Microwave Assisted Method ◽  
Uniform Particle Size

Abstract A fast, simple, and energy-saving microwave-assisted approach was successfully developed to prepare carbon microspheres. The carbon microspheres with a uniform particle size and good dispersity were prepared using glucose as the raw material and HCl as the dehydrating agent at low temperature (90°C) in an open system with the assistance of microwave heating. The carbon microspheres were characterized by elemental analysis, XRD, SEM, FTIR, TG, and Raman. The results showed that the carbon microspheres prepared under the condition of 18.5% (v/v) HCl and heating for 30 min by microwave had a narrow size distribution. The core–shell structure of the carbon core and TiO2 shell was prepared with (NH4)2TiF6, H3BO3 using the microwave-assisted method. The hollow TiO2 microspheres with good crystallinity and high photocatalytic properties were successfully prepared by sacrificing the carbon microspheres.

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