Occurrence of volatile organic compounds in sugarcane silages

Abstract

The main objective of this study was to describe the occurrence of VOC in sugarcane silages. Thirty-three samples of sugarcane silage were collected from farm-scale (n=25) and laboratory-scale silos (n=8). From the total, 11 silages were prepared without additives, 17 were treated with sodium benzoate and 5 were inoculated with Lactobacillus buchneri. Water extracts were prepared and analyzed for 18 fermentation end-products using HPLC and special GC techniques. The functional relationships among the fermentation end-products were established using principal component analysis. In addition to high contents of ethanol, acetic acid, and lactic acid, significant concentrations of 1,2-propanediol, ethyl lactate, acetone, 2,3-butanediol, propionic acid, n-butyric acid, ethyl acetate, 2-butanol, methanol, propanol, and iso-butyric acid were found. Ethanol was negatively associated with acetic acid and 2,3-butanediol but positively correlated with lactic acid and esters. Dry matter content determined by oven drying (DMoven) and ethanol concentration explained 0.98 of the variation in the dry matter content corrected for volatile compounds [DMcorr (g/kg as fed)=42.81+0.916 × DMoven (g/kg as fed)+0.141 × Ethanol (g/kg DMoven)], because silages with high contents of ethanol frequently also contained significant amounts of other volatile substances.