2.4.2. Total Protein Content
The total protein content was analyzed with the Dumas technique at the Soil Testing Laboratory, Kansas State University. The oleoresins (0.15 ±0.01 g) were combusted, and the nitrogen content was measured on weight percent basis by using a LECO TruSpec CN Combustion Analyzer (TrueSpec Micro, LECO, St. Joseph, MI, USA). EDTA was used as the calibration protein, and the total protein content of samples was calculated by multiplying the total combustion nitrogen with a factor of 6.25.