			Home About us Contact

Alkaline Extraction (alkaline + extraction)

Distribution by Scientific Domains

Life Sciences	83%

Selected Abstracts

DECREASE IN DYNAMIC VISCOSITY AND AVERAGE MOLECULAR WEIGHT OF ALGINATE FROM LAMINARIA DIGITATA DURING ALKALINE EXTRACTION,

JOURNAL OF PHYCOLOGY, Issue 2 2008
Peggy Vauchel
Alginates are natural polysaccharides that are extracted from brown seaweeds and widely used for their rheological properties. The central step in the extraction protocol used in the alginate industry is the alkaline extraction, which requires several hours. In this study, a significant decrease in alginate dynamic viscosity was observed after 2 h of alkaline treatment. Intrinsic viscosity and average molecular weight of alginates from alkaline extractions 1,4 h in duration were determined, indicating depolymerization of alginates: average molecular weight decreased significantly during the extraction, falling by a factor of 5 between 1 and 4 h of extraction. These results suggested that reducing extraction time could enable preserving the rheological properties of the extracted alginates. [source]

Ultrasonic assisted alkali extraction of protein from defatted rice bran and properties of the protein concentrates

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 9 2009
Thutiyaporn Chittapalo
Summary Alkaline extraction for the preparation of protein concentrate from rice bran was compared with a range of ultrasonic treatments. Results revealed that the extraction time decreased, and the reaction rate constant increased, with increasing ultrasonic power. The reaction rate constants were 0.0065, 0.0130, 0.0237 and 0.0924 at 40, 60, 80 and 100 W respectively. The defatted rice bran protein concentrate (DRBPC) using ultrasonication (100 W for 5 min) and conventional methods showed no significant difference in bulk densities (P > 0.05) but it had higher yield (%) and was lighter brown using ultrasonication (P , 0.05). The SEM showed that the residual rice bran after extracting protein using ultrasonication exhibited more damage than the conventional method. The functional properties of both samples were not significantly different (P > 0.05) in terms of foam and emulsifying stability. However, the water and oil absorption, foam capacity and emulsion activity were significantly different (P , 0.05). The nitrogen solubility index of both DRBPC samples gave similar profiles with the lowest solubility at pH 4,6. [source]

High-efficiency protein extraction from polyacrylamide gels for molecular mass measurement by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry

ELECTROPHORESIS, Issue 6 2005
Ya Jin
Abstract A simple and fast method of protein extraction from Coomassie Brilliant Blue (CBB)-stained polyacrylamide gels suited for molecular mass measurement of proteins by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS) is reported. Proteins in CBB-stained gel pieces were extracted by a 10-min soaking in 0.1,M NaOH at 25°C. The recovery of this one-step extraction method was 34,73% for proteins <67,kDa. CBB adduction to proteins during mass spectrometric analysis was avoided by a destaining step before the alkaline extraction. The molecular mass values of the extracted proteins coincided with those of purified proteins within ±0.01,0.10% deviation for all the proteins <36,kDa. Because of the high extraction recovery, mass measurement was possible for the proteins extracted from CBB-stained gels with loaded protein quantities as little as 34,ng for cytochrome,c, ,-lactalbumin, myoglobin, ,-lactoglobulin, trypsinogen, and carbonic anhydrase (12.4,29.0,kDa), 340,ng for glyceraldehyde-3-phosphate dehydrogenase (35.6,kDa) and albumin (66.3,kDa). This method provides a highly efficient approach to utilize CBB-stained one- or two-dimensional gels for whole protein analysis using MALDI-TOF-MS. [source]

DECREASE IN DYNAMIC VISCOSITY AND AVERAGE MOLECULAR WEIGHT OF ALGINATE FROM LAMINARIA DIGITATA DURING ALKALINE EXTRACTION,

Standard assays do not predict the efficiency of commercial cellulase preparations towards plant materials

BIOTECHNOLOGY & BIOENGINEERING, Issue 1 2006
Mirjam A. Kabel
Abstract Commercial cellulase preparations are potentially effective for processing biomass feedstocks in order to obtain bioethanol. In plant cell walls, cellulose fibrils occur in close association with xylans (monocotyls) or xyloglucans (dicotyls). The enzymatic conversion of cellulose/xylans is a complex process involving the concerted action of exo/endocellulases and cellobiases yielding glucose and xylanases yielding xylooligomers and xylose. An overview of commonly measured cellulase-, cellobiase-, and xylanase-activity, using respectively filter paper, cellobiose, and AZCL-dyed xylan as a substrate of 14 commercially available enzyme preparations from several suppliers is presented. In addition to these standardized tests, the enzyme-efficiency of degrading native substrates was studied. Grass and wheat bran were fractionated into a water unsoluble fraction (WUS), which was free of oligosaccharides and starch. Additionally, cellulose- and xylan-rich fractions were prepared by alkaline extraction of the WUS and were enzymatically digested. Hereby, the capability of cellulose and xylan conversion of the commercial enzyme preparations tested was measured. The results obtained showed that there was a large difference in the performance of the fourteen enzyme samples. Comparing all results, it was concluded that the choice of an enzyme preparation is more dependent on the characteristics of the substrate rather than on standard enzyme-activities measured. © 2005 Wiley Periodicals, Inc. [source]