Gas Chromatographic-Olfactometric Aroma Profile and Quantitative Analysis of Volatile Carbonyls of Grilled Beef from Different Finishing Feed Systems

In this study, the important odor impact volatiles generated in the meat of grilled beef loin muscle were characterized. Animals were finished in 4 different diet systems: T-1, pasture (a mixture of Medicago sativa, Trifolium repens, and Festuca arundinacea); T-2, pasture supplemented with cracked corn grain (offered at 0.6% live weight, LW); T-3, pasture supplemented with cracked corn grain (offered at 1.2% LW); and T-4, concentrate (pellets with 85% corn and 12.8% sunflower, on a dry-matter basis) plus alfalfa hay (both ad libitum). Aroma compounds were assessed by dynamic headspace-solid phase extraction (DHS-SPE) and gas chromatographic-olfactometric (GC-O) analysis. Most odorants were carbonyl compounds, some of them reaching high GC-O scores, especially 1-octen-3-one, (E)-2-octenal, methional, and hexanal. A specific quantitative analysis of ketones and aldehydes was conducted through their derivatization with o-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine hydrochloride directly on the headspace trap and analyzed by GC-MS, with the purpose of studying the effect of finishing diet systems. From the 23 carbonyl compounds quantified, 2 were especially affected by the diet system; methional was higher in the treatment based on concentrates, whereas (E,E)-2,4-heptadienal was higher in the treatment based only in pastures. The results are discussed considering previous published productive and quality traits.