Pulps. Determination of lignin content. Acid hydrolysis method

2020 ◽  
Keyword(s):  
Acid Hydrolysis ◽  
Lignin Content ◽  
Hydrolysis Method

The Composition of Crude Fibre

1935 ◽  
Vol 25 (4) ◽  
pp. 529-540 ◽  
Author(s):  
A. G. Norman
Keyword(s):  
Acid Hydrolysis ◽  
Direct Effect ◽  
Lignin Content ◽  
Alkaline Treatment ◽  
Empirical Method ◽  
Crude Fibre ◽  
Definite Relationship ◽  
Alternative Method ◽  
Made In

The crude-fibre determination is misleading, because the fraction obtained does not bear any definite relationship to the structural constituents of the material. The cellulose is partially attacked, and lignin extensively removed. Considerable variation is found in the lignin content of crude-fibre fractions. Highly lignified materials do not necessarily yield a crude fibre high in lignin.Since the presence of lignin exercises a direct effect on the digestibility of the material, any empirical method should include all the lignin, and alkaline treatment must be avoided. Acid hydrolysis may be a possible alternative method, if a correction for protein be made in the case of materials high in nitrogen, and a determination of the lignin content made.

Determination of Amino Acids in Feeds: Collaborative Study

1994 ◽  
Vol 77 (6) ◽  
pp. 1362-1402 ◽  
Author(s):  
Cynthia R Llames ◽  
Johannes Fontaine
Keyword(s):  
Amino Acids ◽  
Acid Hydrolysis ◽  
Hydrobromic Acid ◽  
Collaborative Study ◽  
Performic Acid ◽  
Acid Oxidation ◽  
Sodium Metabisulfite ◽  
Hydrolysis Method ◽  
Relative Standard

Abstract A total of 28 laboratories (including authors’ laboratories) participated in a collaborative study for determination of amino acids in feeds using 3 complementary procedures. Each collaborator analyzed 5 blind duplicate samples of feed and ingredients used in the poultry industry. The amount of amino acids in these materials ranged from 0.10 to 8.50%. Twenty-three laboratories conducted analyses using performic acid oxidation with acid hydrolysis—sodium metabisulfite method, 16 laboratories performed analyses using performic acid oxidation with acid hydrolysis—hydrobromic acid method, and 15 laboratories used acid hydrolysis method. The repeatability relative standard deviation values for all amino acids for all 3 procedures ranged from 1.1 to 5.6% for broiler finisher feed, 1.1 to 4.73% for starter feed, 1.3 to 9.6% for corn, 0.8 to 3.96% for fishmeal, and 0.8 to 12.7% for poultry meal. The reproducibility relative standard deviation values for all amino acids ranged from 3.71 to 19.80% for broiler finisher feed, 4.1 to 16.93% for starter feed, 4.4 to 28.2% for corn, 3.46 to 18.96% for fishmeal, and 3.73 to 24.1% for poultry meal. The performic acid oxidation with acid hydrolysis—sodium metabisulfite and hydrobromic acid methods, and acid hydrolysis method for determination of amino acids in feeds have been adopted first action by AOAC INTERNATIONAL.

Determination of Fat in Body Tissues and in Food Mixtures

1975 ◽  
Vol 58 (1) ◽  
pp. 23-27 ◽  
Author(s):  
Emily S Conway ◽  
Mildred Adams
Keyword(s):  
Acid Hydrolysis ◽  
Animal Tissues ◽  
Hydrolysis Method ◽  
Body Tissues

Abstract The official final action acid hydrolysis method, 14.019, for the determination of fat in foods was successfully applied, with slight modifications, to the analysis of homogenates of food, feces, and animal tissues as well as dry samples of mixed foods. In samples containing sucrose or fructose, it was necessary to carry out a fermentation procedure before acid hydrolysis to avoid problems encountered when these sugars were present.

Simplified determination of total lignin content in kraft lignin samples and black liquors

Holzforschung ◽  
2011 ◽  
Vol 65 (4) ◽  
Author(s):  
Fredrik Aldaeus ◽  
Hannah Schweinebarth ◽  
Per Törngren ◽  
Anna Jacobs
Keyword(s):  
Acid Hydrolysis ◽  
Standard Method ◽  
Lignin Content ◽  
Kraft Lignin ◽  
Black Liquors ◽  
Total Lignin ◽  
Total Lignin Content

Abstract Determination of total lignin content in lignin samples and black liquors using methods with reduced or omitted acid hydrolysis has been compared to the standard method, and results show that the simplified methods yield equivalent results.

Collaborative Study of the Determination of Fat in Intermediate Moisture Pet Foods

1976 ◽  
Vol 59 (6) ◽  
pp. 1218-1223
Author(s):  
Gustav O Kuhn
Keyword(s):  
Petroleum Ether ◽  
Acid Hydrolysis ◽  
Cross Section ◽  
Collaborative Study ◽  
Pet Food ◽  
Petroleum Ether Extraction ◽  
Hydrolysis Method ◽  
Ether Extraction ◽  
Aoac Method

Abstract Four different semimoist pet food formulations representing a cross section of commercial products were studied collaboratively for fat content by 2 methods. Ten laboratories participated in the study. Direct petroleum ether extraction by AOAC method 7.045 yielded low and variable fat recovery. AOAC acid hydrolysis method 7.047 for fat in baked dog foods was satisfactory for semimoist pet foods. The method, with some editorial changes, was adopted as official first action for this type of pet food.

DETERMINATION OF MICRO-AMOUNTS OF 5β-PREGNAN-3α-OL-20-ONE IN URINE USING INFRARED-SPECTROMETRY

1962 ◽  
Vol 41 (2) ◽  
pp. 234-246 ◽  
Author(s):  
H. J. van der Molen
Keyword(s):  
Infrared Spectrum ◽  
Quantitative Determination ◽  
Acid Hydrolysis ◽  
Chromatographic Separation ◽  
Pure Form ◽  
Infrared Spectrometry ◽  
Hydrolysis Of

ABSTRACT A procedure for the quantitative determination of 5β-pregnan-3α-ol-20-one in urine is described. After acid hydrolysis of the pregnanolone-conjugates in urine, the free steroids are extracted with toluene. Pregnanolone is isolated in a pure form as its acetate; after chromatographic separation of the free steroids on alumina, the fraction containing pregnanolone is acetylated and rechromatographed on alumina. Quantitative determination of the isolated pregnanolone-acetate is carried out with the aid of the infrared spectrum recorded by a micro KBr-wafermethod. The reliability of the method under various conditions is discussed under the headings, specificity, accuracy, precision and sensitivity. It is possible to determine 30–40 μg pregnanolone in a 24-hours urine portion with a precision of 25%.

The impact of acid hydrolysis conditions on carbohydrate determination in lignocellulosic materials: a case study with Eucalyptus globulus bark

Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ricardo Jorge Oliveira ◽  
Bruna Santos ◽  
Maria J. Mota ◽  
Susana R. Pereira ◽  
Pedro C. Branco ◽  
...  
Keyword(s):  
Acid Hydrolysis ◽  
Eucalyptus Globulus ◽  
Industrial Processes ◽  
Lignocellulosic Materials ◽  
Optimal Conditions ◽  
Hydrolysis Conditions ◽  
The Impact ◽  
Eucalyptus Bark

Abstract Lignocellulosic biomass represents a suitable feedstock for production of biofuels and bioproducts. Its chemical composition depends on many aspects (e.g. plant source, pre-processing) and it has impact on productivity of industrial bioprocesses. Numerous methodologies can be applied for biomass characterisation, with acid hydrolysis being a particularly relevant step. This study intended to assess the most suitable procedures for acid hydrolysis, taking Eucalyptus globulus bark as a case study. For that purpose, variation of temperature (90–120 °C) was evaluated over time (0–5 h), through monosaccharides and oligosaccharides contents and degradation. For glucose, the optimal conditions were 100 °C for 2.5 h, reaching a content of 48.6 wt.%. For xylose, the highest content (15.2 wt.%) was achieved at 90 °C for 2 h, or 120 °C for 0.5 h. Maximum concentrations of mannose and galactose (1.0 and 1.7 wt.%, respectively) were achieved at 90 and 100 °C (2–3.5 h) or at 120 °C (0.5–1 h). These results revealed that different hydrolysis conditions should be applied for different sugars. Using this approach, total sugar quantification in eucalyptus bark was increased by 4.3%, which would represent a 5% increase in the ethanol volume produced, considering a hypothetical bioethanol production yield. This reflects the importance of feedstock characterization on determination of economic viability of industrial processes.

Optimisation of microwave-assisted acid hydrolysis for the determination of seleno-amino acids bound to proteins in powdered milk, lyophilized milk and infant formula

2019 ◽  
Vol 79 ◽  
pp. 128-133
Author(s):  
Romina Lopez ◽  
Luis Escudero ◽  
Roberto D’Amato ◽  
Daniela Businelli ◽  
Massimo Trabalza-Marinucci ◽  
...  
Keyword(s):  
Amino Acids ◽  
Acid Hydrolysis ◽  
Infant Formula ◽  
Powdered Milk ◽  
Microwave Assisted
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