QUANTITATIVE ANALYSIS OF FAT AND MOISTURE IN MAYONNAISE USING FOURIER TRANSFORM INFRARED SPECTROMETER

Figures & data

Figure 1. FTIR spectra of standard 1-propanol solutions containing various know compositions of oil and moisture. Peaks at 1748 and 1650 cm⁻¹ were due to the -C˭O of oil and the bending of H-O-H, respectively.

Figure 2. Calibration curves correlating absorbance at 1748 and 1650 cm⁻¹ with the percentages of oil and moisture, respectively, in mayonnaise samples.

Figure 3. A typical spectrum of a regular mayonnaise sample showing a dominant oil peak at 1748 cm⁻¹.

Figure 4. A typical spectrum of a reduced-fat mayonnaise sample showing a water peak (1650 cm⁻¹) higher than the oil peak (1748 cm⁻¹).

Figure 5. A typical spectrum of a low-fat mayonnaise sample showing a dominant water peak at 1650 cm⁻¹.

Figure 6. An example ‘normalization’ process for obtaining the corrected peak height at 1748 cm⁻¹ of a reduced-fat mayonnaise sample. (a) Matching the height of the water peak with a superimposed, water-only spectrum at 1650 cm⁻¹ (— the original spectrum; ---- the water-only peak); (b) The corrected peak after subtracting the water-only peak from the original spectrum.

Table 1. Verification of the FTIR Results with the Modified Mojonnier Method and the Dehydration Method

	% Fat		% Moisture
Mayonnaise Product	FTIR	Mojonnier	FTIR	Dehydration
Regular	80±1*,^a	80.4±0.6^a	14.6±0.2^d	14.6±0.4^d
Reduced fat	32.3±0.3^b	32.0±0.2^b	62.6±0.1^e	62.1±0.2^e
Low fat	5.97±0.06^c	5.92±0.04^c	86.4±0.3^f	86.3±0.5^f

*Each value is the mean±SD, n=3.

Values bearing the same superscripts are not significantly different (p>0.05).