Kinetic changes of antioxidant capacity and physical quality of tempe during heating

Tempe is a traditional fermented soyfood from Indonesia which has a short shelf-life. Thermal process destroying microorganisms might be applied to extend the shelf-life of tempe. The study on evaluation of quality changes of tempe during heating is very limited. The main objective of this research was to study the kinetics of antioxidant capacity and physical changes during isothermal heating of tempe at different temperature (75 degrees C, 85 degrees C and 95 degrees C). Tempe was cut and placed in vial tubes with 2% of aqueous salt (NaCl) solution as heating medium. Changes of antioxidant capacity (2,2-diphenyl-1picrylhydrazyl (DPPH) scavenging capacity and total phenolic content (TPC)) and physical quality (texture and color) of tempe during heating were analyzed and modeled as first order kinetic reaction. Thermal process affected on antioxidant capacity and physical quality of tempe. During heating the rate constant of antioxidant capacity and physical quality in samples increased with increase of time and temperature process. The changes of DPPH scavenging capacity had similar trend to TPC indicating that TPC strongly influenced on the antioxidant capacity of tempe. Based on Arrhenius equation, the most heat sensitive parameter was color properties, followed by hardness, TPC and lastly antioxidant capacity. (c) All Rights Reserved