Biomedical Engineering Reference
In-Depth Information
Acid detergent could further decompose each component in NDF. For plant
feed, the part dissolved in acid detergent is called the acidic detergent solubles
(ADS), including NDS and hemicelluloses. The remaining residue is called the
acid detergent fiber (ADF) and contains cellulose, lignin, and silicate. In addition,
the difference between the value of NDF and ADF is the hemicellulose content in
the raw materials. ADF is digested by 72 % sulfuric acid to dissolve cellulose. The
residue is lignin and silicates. So, 72 % sulfuric acid digestion residue is subtracted
from the value of ADF; then, the content of cellulose is obtained. Seventy-two
percent of the sulfuric acid digestion residue is then ashed. Ash is the content
of silicate in raw material, and the escaping portion in the ashing process is the
acid detergent lignin (ADL) content. Wang Yuwan [
5
] improved these methods by
changing neutral detergent to 2 M HCl. Other steps are as the same presented.
Cellulose can be divided into
'
-cellulose,
“
-cellulose, and
”
-cellulose according
to their solubility [
7
].
-Cellulose is the cellulosic portion dissolved in 17.5 or 18 %
NaOH solution at 20
ı
C. The extract alkali solution is precipitated by acid, and the
precipitation is
'
“
-cellulose. The residue in a neutral solution without precipitating
is called
-cellulose. If a viscosity method is used to measure the DP of three
celluloses, the DP of
”
'
-cellulose is greater than 200,
“
-cellulose is 10-200, and
”
-cellulose is less than 10.
If cellulose materials are processed as a feed, traditional leaching, ANKOM
(ANKOM Technology Corporation, USA) bag and CAU (made by Chinese
Agricultural University) filter bag technology could be used to determine the NDF,
ADF, and permanganate lignin (PL) contents [
9
]. By comparison, it was found
that three methods have no differences in determining NDF, ADF, and PL content
when measuring the major components of feed. The CAU filter bag technique has
advantages, including a low cost, convenient ordering, and suitability for laboratory
applications.
11.1.3.2
Research Methods for Hemicellulose Content
Methods introduced in Sect.
11.1.3.1
can be applied.
11.1.3.3
Research Methods for Lignin Content
Methods introduced in Sect.
11.1.3.1
can be applied. According to the properties
of lignin, lignin can be determined [
10
] directly by the concentrated sulfuric acid
hydrolysis separation method [
10
,
11
], spectrophotometry method [
12
,
13
], infrared
spectroscopy method [
14
], redox reactions titration method [
10
], and so on.
11.1.3.4
Research Methods of Reducing Sugar Content
There is variety of methods to determine the reducing sugar content [
15
], such as the
optical rotation method, gas chromatographic (GC) method, liquid chromatographic
