A simple procedure for the measurement of wheat germ in the milling products by fluorescence spectroscopy
1999
Lai, H.M.
An L(9) orthogonal array of the Taguchi method was used to establish an optimal assay condition for the measurement of wheat germ in the milling products by fluorescence spectrophotometry. The developed procedures are: 1 mL of 3% sodium tetraborate solution was added to a 1.5 mL Eppendorf tube containing a 0.05 g flour sample. After extraction with tetraborate solution at 35 degrees C for 30 min, the sample was centrifuged at 6,500 x g (12,000 rpm) for 4 min. After appropriate dilution, the fluorescence intensity of the extract was determined in a fluorescence spectrophotometer with excitation wavelength set at 440 nm and emission wavelength at 510 nm. To validate this procedure, germ contamination of the flour samples from 21 millstreams were analyzed. The flour from the C(1) reduction stream was one of the flour streams showing the least germ contamination among the 21 flour samples tested. For better comparison, relative germ content (G(R)) of various samples was calculated by taking the ratio of fluorescence intensity of each sample to the fluorescence intensity of the C(1) reduction flour. Based on the G(R) values, the millstreams with similar degree of germ contamination could be combined to form precisely graded commercial flour products. The determination of G(R) of milling products by this method is an easy way to monitor the milling condition. The G(R) value serves as a good indicator for quality control of milling products.
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