การหาปริมาณไขมันในนมผงโดยวิธีพัลส์เอ็นเอ็มอาร์ / วิชาญ กกกนทา = Determination of fat content in milk powder by the pulsed NMR method / Wicharn Kogkontha
The aim of this research is to study about the determination of fat content in milk powder by the pulsed NMR (nuclear magnetic resonance) method. An instrument called pulsed generator was built to generate square pulses used to induce the resonance. The transverse relaxation time of fat in milk powder was measured and used to determine the suitable delay time and repetition time. The results obtained by using 2.6, 1.3 and 0.65 grammes of milk powder gave the average relaxation time as 22.6 milliseconds. The fat in milk powder was extracted by chloroform. Four samples yielded 0.54, 0.35, 0.24 and 0.13 grammes of fat which was then put into the pulsed NMR system of measure the height of the signals which were subsequently plotted against the fat samples to serve as a calibration curve. The four samples of fat was dissolved by carbontetrachloride to make the same volume for all samples and then measure the height of the signals again as in the first experiment then measure the height of the signals again as in the first experiment then the data was plotted to obtain the second calibration curve. The four samples of milk powder : 2.6, 1.3, 0.65 and 0.33 grammes, were then used to measure the height of the signals and the results were compared with both calibration curves, obtaining the average fat content as 26.60 and 27.58%, respectively. While the manufacturer quote the fat content to be 28%.
