Application Study On Milk Quality Detection And Control By Using Spectroscopic Technique

The fluorescence spectroscopy, three-dimensional fluorescence spectroscopy and polarizationfluorescence spectroscopy of milk products are studied on experiment in this paper. After summing uptheir changing patterns and characteristics, the spectrum phenomena is analyzed theoretically and areasonable conclusion is made at last.Three kind of milk product by YiLi and MengNiu is studied in this thesis. They are pure milk,milk with high calcium, milk with high calcium but low fat. With exchange the water, they are madeinto solution. After determine their emission spectrum under different excitation wavelength. Andgauss decomposition method is used to disintegrate the spectrum after smoothing and filtering, then5basic gauss peaks appeared. After analysis and conclude, it is found that the peak position of everybasic gauss peak is much the same under same excitation wavelength, and all basic gauss peaks arered shifted along with the stimulation wavelength growth. Under the long stimulation wave length;each element gauss peak of milk with high calcium but low fat is stronger than the others. Milkdensity plays an unimportant role to the total fluorescence spectrum. The reasons for these areanalyzed briefly.Three dimensional fluorescence spectrums of aforementioned three kinds of milk and pure milkthat expired about10days are measured. It is showed that the fluorescence intensity of expired milk isstronger under certain stimulation wave length, which is less than310nm or bigger than330nm, thenthe reason is analyzed preliminary.The polarized fluorescence spectrums of them are also studied. Three dimensional polarizedfluorescence spectrums are measured when the orientation of excitation Polaroid and emissionPolaroid is parallel or vertical. We found that under longer polarized excitation wavelength, thefluorescence strength of milk with high calcium but low fat is higher than that of milk with highcalcium and pure milk when the orientation of excitation Polaroid and emission Polaroid is parallel.But when the orientation is vertical, the launch fluorescence intensity of them is much the same.Angle between stimulate dipole and launch dipole of that three kinds of milk equivalent dipole isestimate by fluorescence polarization theory. And the reasonable explanation is provided by thisestimation at last.