61A-10 |
Detection of guar gum adulteration in locust bean gum with fourier transform infrared spectroscopy (FT-IR) |
B. F. OZEN and L. J. Mauer. Dept. of Food Science, Purdue Univ., 1160 Food Science Bldg., West Lafayette, IN 47907-1160 Guar gums (GG) and locust bean gums (LBG) are used as thickeners and stabilizers in the food industry. Adulteration of LBG with inferior GG for economic gain has been a concern for the food industry due to product quality and consumer safety issues. FT-IR spectroscopy methods are rapid analysis techniques that require minimum sample preparation and have successfully identified the adulteration of several food products. Development of FT-IR methods to detect adulteration in gums would be beneficial for industries using these ingredients. The objective of this study was to identify the adulteration of LBG with GG using FT-IR spectroscopy. The 2% gum solutions were prepared by dissolving gums with various mannose:galactose ratios in water, homogenizing the solutions, and then applying vacuum to remove air bubbles. Adulterated samples were prepared by: 1) blending LBGs with different sugar ratios and then adding GG to the mixture, and 2) adding GG to each individual LBG with a known sugar ratio. Multiple bounce ATR measurements were performed on pure gum solutions as well as on the adulterated samples (2-20% GG in LBG). Data were analyzed by multivariate statistical procedures. Discriminant analysis with three principal components was able to classify the pure samples as GG and LBG based on their spectra with a performance index of 0.97. Adulteration of LBG with GG also was accurately identified for the second method of adulteration. The detection of adulteration depended on the sugar ratio; therefore, detection of adulteration using the first method was questionable. FT-IR spectroscopy is a rapid method for detection of gum adulteration; however, this method has some limitations due to the wide range of sugar ratios in LBGs from different sources. If a single source of LBG with a known mannose:galactose ratio was used, then FT-IR would be a useful detection tool for GG adulteration.
Session 61A, Carbohydrate
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