Drying kinetics and thermal degradation of phenolic compounds and vitamin C in full fat germinated soy flours

Abstract

The effects of temperature on drying kinetics, thermal degradation of phytonutrients and quality of full fat germinated soy flours were investigated. The drying process was conducted in the oven drier at the temperatures of 40, 50 and 60°C and the moisture contents of final products were lower than 5%. The first order equation was used for analysis drying kinetic and thermal degradation of total phenolic content (TPC), vitamin C and antioxidant activity expressed as DPPH radical scavenging percentage. Kinetic parameters k of each model showed high dependence on temperature and were evaluated by determination coefficient (R2) that was calculated for goodness of fit. Arrhenius type equation was applied to determine the activation energy of moisture loss and degradation of vitamin C, TPC and antioxidant activity. These values were 53.14±1.77, 42.03±1.40, 33.44 ± 1.15 and 43.62±1.45 kJ/mol, respectively. Full fat germinated soy flour dried at 50oC remained highest vitamin C, TPC, antioxidant activity as well as sensory quality.