14A-49

R. PURI, Food Science, Rutgers University, 63 Dudley Road, Cook Campus, New Brunswick, NJ 08901 and J. L. Kokini.

Introduction: Non-enzymatic browning is a complex set of pathways to form brown compounds. It often causes quality loss in dehydrated foods and is also responsible for the off flavors; discoloration and nutritional loss in products such as dry milk, whey powders, cereals and cake mixes. The browning reaction follows zero order reaction kinetics. Objective: The objective of this research is to predict the diffusion controlled non-enzymatic browning reaction rates. Method: The model system studied was xylose and lysine in polyvinylpyrrolidone matrix. The diffusion coefficient of Xylose in Poly vinyl pyrrolidone was calculated using free volume theory. The free volume theory uses group contribution data to calculate the jumping unit of Xylose in polyvinylpyrrolidone, which lead us to estimation of diffusion coefficient of Xylose in PVP. The amino group used was amino acid Lysine. The reaction rate constants were obtained for the Xylose-lysine PVP model system as a function of water activity, temperature and glass transition temperature. Results: The observed browning reaction rates were found to be similar to the calculated browning reaction rates for low water activity. The calculated diffusion coefficients from free volume theory are validated with experimental data. These diffusion coefficients will be used to calculate the NEB reaction rates. Significance: The predictive technique will help in determination of diffusion controlled reaction rates needed for estimation of shelf life for food products by characterizing deteriorative reactions such as Non-Enzymatic Browning.