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Title: ANALYTICAL PYROLYSIS AS A TOOL TO DETERMINE CHEMICAL CHANGES IN MAIZE STOVERS DURING GROWTH

Author
item GALLETTI, G. - CNR, ITALY
item Reeves Iii, James
item BOCCHINI, P. - CNR, ITALY

Submitted to: Journal of Analytical & Applied Pyrolysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/10/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Pyrolysis is a process in which samples are decomposed by heating to high temperatures in an inert (oxygen free) atmosphere. In this way, the samples break down into materials which are characteristic of the starting material (different starting materials give different products) without the sample burning. The resulting products can then be separated and identified by a technique known as gas chromatography/mass spectrometry. This process was applied to the stalks of five corn varieties grown as feed for cattle. The stalks of the five corn hybrids were harvested at various growth stages, and subsequently subjected to pyrolysis and gas chromatography/mass spectrometry (PY/GC/MS). The materials were also analyzed chemically for fiber and protein. The aim of the experiments was to find pyrolysis products which indicated the growth stage and to determine how well the results of pyrolysis and chemical analysis for fiber rand crude protein agreed. Results found some pyrolysis products which agreed well with chemical analysis for fiber and protein and with stage of growth. In conclusion, PY/GC/MS can monitor chemical changes in the main components of corn stalks during growth with the advantage over the chemical assays of providing more detailed information and of being faster and much simpler.

Technical Abstract: Stovers of five maize hybrids harvested at various growth stages were subjected to pyrolysis/gas chromatography/mass spectrometry (PY/GC/MS) and conventional analyses for fiber and protein, i.e. Van Soest's neutral detergent fiber (NDF) and Kjeldahl crude protein (CP). The aim of the experiments was to find pyrolysis markers of the growth stage and to ascertain what degree of correlation exists between analytical pyrolysis and conventional analyses of fiber and crude protein. Correlation coefficients higher than 0.90 in absolute values were found for some pyrolysis fragments and NDF, CP and growth stage. Such fragments included lignin, carbohydrates and protein thermal decomposition products. In conclusion, PY/GC/MS can monitor chemical changes in the main components of maize stover during maturation with the advantage over the conventional assays NDF and CP of providing molecular information and of being faster and much simpler.