Application of analytical pyrolysis to gain insights into proteins of condensed corn distillers solubles from selective milling technology

Abstract

Present study evaluates the analytical pyrolysis to unravel the pyrolysate compounds (PyCs), protein & glycosylation indicators in a protein fraction (PF) from condensed corn distillers solubles (CCDS) of novel selective milling technology. Besides, quadratic and linear correlations using protein content (%) by Dumas method, toluene signature PyC, and elemental nitrogen (%) were developed. Pyrolysis was performed at temperature of 400 °C, where most of the PyCs released from proteins in a lignin-free PF instead of other constituents. The p-cresol and methyl 9,12-octadecadienoate were found with the highest area% of 3.2 and 19.3 in PF and CCDS, respectively. Protein derived PyCs such as nitrogen heterocyclics, amines & amides and nitriles were examined 63.93%, 61.90% and 70% greater in PF than CCDS. Moreover, the indicators of protein were toluene, p-cresol, phenol, phenylacetonitrile, 4-vinylphenol, whereas that of glycosylated protein were methyl mercaptan, furan derivatives, and hexahydro-3-(phenylmethyl) pyrrolo [1, 2 a] pyrazine-1,4-dione. The absence of diketopiperazines provided evidence of crosslinking and aggregation of protein. The values of the protein content obtained from the quadratic model and Dumas method were found to be statistically non-significant (p < 0.05) imply the model validity. The results would aid in bioconversion of CCDS to future value-added products.