Fourier transform infrared spectroscopy investigation of batch pasteurized milk molecules.

Abstract

The study investigated the effects of stirring on the milk molecular arrangements in a batch pasteurized milk. Three variables were considered with 3x3x2 factorial levels. The stirrer shapes considered were anchor, vane and helical; the orientation was single and twice the stirrer shapes while the varied speeds were 30 rpm, 36 rpm and 42 rpm. Standard batch pasteurizing temperature of 63 degree Celsius for 30 minutes was considered. The experimental outcome at 95% significance showed that these treatments did not create new bonds, however, statistically significant changes were observed in few selected bond frequencies for NH, OH and CN. The experiment showed different organic molecules at different frequencies and wavelengths. The raw sample which was used as the first control, gave similar outcome as the second control which was raw milk pasteurized without stirring. The following frequencies were obtained for the raw sample with the other samples showing slight deviations in values after the decimal place; amine group ⸝N– H ⸌ which stretch at frequency (3449.20 cm-1), methylene group, C–H (2920.45 cm-1), methyl, C–H stretch (2853.96 cm-1), terminal alkyne group, C C, (2103.57 cm-1), secondary amine bend (1644.47 cm-1 ) and aromatic ring, C=C–C (1460.83 cm-1). However, methyl, C–H bend of frequency 1365.85 cm-1, is in the wave frequency as aromatic tertiary amine and primary amine, indicating their presence. Also, O–H group was observed at frequency 1248.70 cm-1 with secondary amine, CN stretch at frequency 1156.88 cm-1 .