Biomedical Engineering Reference
In-Depth Information
method, etc. The accuracy of the optical rotation method is poor, while the
measurement process for GC and liquid chromatography is complex. The 3,5-
dinitro salicylate (DNS) method is widely used because of its high accuracy, its
reproducibility, and especially its suitability for determination of large quantities.
DNS is an oxidizing agent, which could react with a reducing sugar. So, that
nitro group is reduced into an amino group, and the solution becomes orange. The
orange depth is proportional to the concentration of reducing sugar in a certain
range. Therefore, the reducing sugar content could be obtained by the colorimetric
method.
11.1.3.5
Research Method for Content of Non-fiber Cells
The nonfiber cells are all parenchyma cells except the fiber cells [
5
]. The
parenchyma cell content measurement method used here is an approximation
by measuring area. Slice preparation procedures are the same as that for the
length and width measurements. The prepared slice is placed under a 70-100
magnification microscope, and the approximate area of each cell is measured by
eyepiece-measured micrometer (calculated from the average length and width of a
single cell or the average diameter). It is recorded according to different cell types.
On a slice with the cell uniformly distributed, 100 various miscellaneous fiber cells
and associated parenchyma cells are measured. The results are expressed by the
area percentage of each type cell to all cells (the fiber cell is included).
11.1.3.6
Research Methods for Protein Content
Determination of the protein content includes four common methods: nitrogen
determination, double contraction urine method (Biuret method), Folin-phenol
reagent method (Lowry method), and ultraviolet (UV) absorption method. The
Coomassie blue method (Bradford method) is a new rapid method recently used
widely. The sensitivity of the Bradford and Lowry methods is high, and the nitrogen
determination method is complex but more accurate. Nitrogen determination is
taken as a reference by other methods. The Kjeldahl nitrogen determination
method can be found in the national standard method of China, GB/T 5009.
5-2010.
11.1.3.7
Research Method for Wax Content
The substances contained in wax can be analyzed by HPLC as reported, and the
content of waxy substances can be analyzed by GC-MS (mass spectrometry).
