Mechanism of Peptide Changes during Drying Fermented Soybean Meal

To investigate the effect of drying temperature on the fermented soybean meal, we examined the water content, protein solubility, and kinetics and thermodynamics of small peptide elimination. Results showed that the drying process of the fermented soybean meal could reduce the water content to safe level, and higher temperature (>70 degrees C) would shorten the drying time, but at the same time, decrease the protein solubility and the content of small peptides. Kinetic parameters indicated that the highest rate constant k at 90 degrees C was 18.6 times of the lowest k at 50 degrees C and temperature effect was stronger than the time effect in the reaction, as a result, reducing their content. Thermodynamic calculation appeared that there was the chemical endothermic reaction of peptides and higher temperature also accelerated the elimination of the small peptides in this drying system.