Compositional Differentiation of Maize Hybrid Stovers Using Analytical Pyrolysis and High-Performance Liquid Chromatography

Pyrolysis/gas chromatography/mass spectrometry (PY/GC/MS) and high-performance liquid chromatography with electrochemical detection (HPLC−ED) were carried out on stover samples from ten commercial maize hybrids grown in northern Italy. The objective was to check whether the composition of the cell wall lignin and polysaccharides, as obtained by PY/GC/MS, and the phenolic acid content, as determined by HPLC−ED, were significantly different in the various hybrids. Neutral detergent fiber (NDF) and crude protein content were also determined. Thirty pyrolysis fragments were identified mainly deriving from polysaccharides and lignin. Vanillic, p-coumaric, and ferulic acids were quantified by HPLC−ED. Analysis of variance and the Waller−Duncan test showed significant differences in all the examined parameters. Correlations were also found among NDF, PY/GC/MS lignin markers, p-coumaric, and ferulic acids and among vanillic acid, p-coumaric acid, and PY/GC/MS lignin markers. Keywords: Maize stover; lignin; phenolic; pyrolysis/gas chromatography/mass spectrometry; liquid chromatography