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Javier A Linarespasten - One of the best experts on this subject based on the ideXlab platform.

  • integrated process for sequential extraction of saponins xylan and Cellulose from quinoa stalks chenopodium quinoa willd
    Industrial Crops and Products, 2018
    Co-Authors: Alicia Gilramirez, Daniel Martin Salasveizaga, Carl Grey, Eva Nordberg Karlsson, Irene Rodriguezmeizoso, Javier A Linarespasten
    Abstract:

    Abstract World quinoa production is increasing due its high nutritional value. As a consequence, large quantities of stalks accumulate as unused byproducts. Here, we verify the presence of saponins in the stalks and present a biorefinery approach with quinoa stalks as feedstock, using an integrated processing scheme to separate saponins, xylan and Cellulose. Saponins were extracted using pressurized hot water extraction (PHWE), optimized by a central composite experimental design (rotatable 22) with temperature and extraction time as factors. Xylan was extracted from the residual solid material after PHWE by an alkaline method using 0.5 M NaOH at 80 °C. Cellulose was purified from the remaining residuals using acetic and nitric acid at 120 °C, which resulted in recovery of white cotton-like Cellulose, showing no need of further bleaching. The saponin yield was significantly increased at temperatures exceeding 110 °C, with highest amounts obtained at 195 °C (15.4 mg/g raw material). The yield in the following xylan extraction (maximum 120 mg/g raw material) was however significantly reduced when preceded by PHWE above 110 °C, indicating degradation of the Polymer. Cellulose recovery (maximum 296 mg/g raw material) was less affected by variations in temperature and time in the preceding PHWE. The results obtained shows that tuning between saponin and xylan extraction is critical. This approach is foreseen to be applicable to the valorisation of residual fiber-rich biomass from various types of crops, besides quinoa.

Daniel Martin Salasveizaga - One of the best experts on this subject based on the ideXlab platform.

  • integrated process for sequential extraction of saponins xylan and Cellulose from quinoa stalks chenopodium quinoa willd
    Industrial Crops and Products, 2018
    Co-Authors: Alicia Gilramirez, Daniel Martin Salasveizaga, Carl Grey, Eva Nordberg Karlsson, Irene Rodriguezmeizoso, Javier A Linarespasten
    Abstract:

    Abstract World quinoa production is increasing due its high nutritional value. As a consequence, large quantities of stalks accumulate as unused byproducts. Here, we verify the presence of saponins in the stalks and present a biorefinery approach with quinoa stalks as feedstock, using an integrated processing scheme to separate saponins, xylan and Cellulose. Saponins were extracted using pressurized hot water extraction (PHWE), optimized by a central composite experimental design (rotatable 22) with temperature and extraction time as factors. Xylan was extracted from the residual solid material after PHWE by an alkaline method using 0.5 M NaOH at 80 °C. Cellulose was purified from the remaining residuals using acetic and nitric acid at 120 °C, which resulted in recovery of white cotton-like Cellulose, showing no need of further bleaching. The saponin yield was significantly increased at temperatures exceeding 110 °C, with highest amounts obtained at 195 °C (15.4 mg/g raw material). The yield in the following xylan extraction (maximum 120 mg/g raw material) was however significantly reduced when preceded by PHWE above 110 °C, indicating degradation of the Polymer. Cellulose recovery (maximum 296 mg/g raw material) was less affected by variations in temperature and time in the preceding PHWE. The results obtained shows that tuning between saponin and xylan extraction is critical. This approach is foreseen to be applicable to the valorisation of residual fiber-rich biomass from various types of crops, besides quinoa.

W A Collier - One of the best experts on this subject based on the ideXlab platform.

  • estimation of lactate in meat extracts by screen printed sensors
    Analytica Chimica Acta, 1999
    Co-Authors: A.l Hart, C Matthews, W A Collier
    Abstract:

    Abstract Various facets of sensor technology: platinum dispersed on carbon, a second “blank” working electrode, Polymer matrices for enzymes and diffusion-limiting membranes, were integrated using screen-printing to produce lactate sensors. The enzyme was lactate oxidase. The Polymer matrices were hydroxyethyl Cellulose, GafQuat/lactitol and hydroxyethyl Cellulose/polyethyleneimine. The outer membrane was of known composition: polyvinyl chloride co-Polymer/Cellulose acetate butyrate. When the sensors were mounted in a flow injection analyser, estimates were obtained of the lactate concentration in simple buffer extracts of cattle meat. The most accurate estimates were obtained from sensors in which the enzyme was embedded in a matrix of GafQuat/lactitol or hydroxyethyl Cellulose/polyethyleneimine.The currents generated by the enzyme in the matrices containing GafQuat or polyethyleneimine were higher than when hydroxyethyl Cellulose alone was used as a matrix. The activity of the sensors under dry storage (over silica gel at 25°C) varied over eight months, but remained at a functional level. Every step in these relatively simple sensors was achieved by screen-printing; the use of a “blank” working electrode avoided the necessity of additional layers or membranes to reject interferents and the flow injection analyser provided a constant hydrodynamic environment for sensor function.

Stanislaw Janicki - One of the best experts on this subject based on the ideXlab platform.

Jedras Z - One of the best experts on this subject based on the ideXlab platform.