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The production of xanthan gum, an industrially important microbial exopolysaccharide, was enhanced by using Xanthomonas campestris cells adsorbed to cotton fibers. However, the function of xanthan polymers during cell adsorption has not been elucidated. Polyethylenimine (PEI), a cationic polyelectrolyte, was employed to investigate respective effects of fiber surface properties and xanthan polymers during cell adsorption. Adsorption of X. campestris cells to fiber was independent of fiber roughness and hairiness, and the effect of electrostatic interactions between cells and fiber was insignificant. Fiber hydrophilicity was critical in initiating cell-fiber contacts, whereas xanthan polymers enhanced retention of cells on fiber surface. The untreated cotton showed the highest immobilization efficiency and xanthan production.

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A rapid method for quantitative determination of fat and moisture in a variety of mayonnaise products (regular, reduced-and low-fat) was developed using Fourier Transform Infrared (FTIR) spectroscopy. Both the fat and moisture contents could be effectively solvated out of the soluble solids using 1-propanol without sonication. A load cell assembly with a 100 mm Teflon spacer gave sufficient separation under 2 cm À1 resolution using 100 scans. Two distinct peaks were obtained on the ratioed sample spectra of regular mayonnaise: 1748 cm À1 and 1650 cm À1 for C¼O stretching of oil and H-O-H bending of water, respectively. Data was then normalized using the Window-based software that acquired spectra information seamlessly from the instrument. The experimental measurements of the fat and moisture contents were in excellent agreement with those using the modified Mojonnier and the *Corresponding author. Current address: 3304 Marie Mount Hall,

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