Cereal Chem 59:142 - 148.  |  VIEW ARTICLE
Kinetics of Protein Quality Change in Egg Noodles Stored Under Constant and Fluctuating Temperatures.

T. P. Labuza, K. Bohnsack, and M. N. Kim. Copyright 1982 by the American Association of Cereal Chemists, Inc. 

Loss of protein quality, measured by available lysine and extent of nonenzymatic browning, was studied in pasta. Pasta was stored for 48 weeks under constant conditions of 25, 35, 45, and 55 C and water activity (aw) levels of 0.44, 0.52, 0.65, and 0.75. In addition, pasta at each aw level was stored under a square wave temperature profile of 3 1/2-day periods at 35 and 55 C. Data from the constant conditions were used to test the applicability of equations for predicting losses under the fluctuating condition. As expected, browning rate and loss of protein quality increased with increased temperature and aw. The Q10 for browing and lysine loss ranged between 2 and 4. At 25 C, about 25% of the lysine was lost in 40-50 weeks, whereas at 45 C, the same loss occurred in 6-12 weeks. The amount of loss for the fluctuating condition was greater than that occurring at the mean temperature of 45 C. The Arrhenius relationship equations gave variable results in predicting the extent of change using steady-state data, although the absolute error was generally less than four weeks.