Effects of Ageing on Donkey Meat Chemical Composition, Fatty Acid Profile and Volatile Compounds

Donkey meat samples obtained from muscle Longissimus Thoracis Lumborum (LTL) taken from 14 entire donkey males slaughtered at 20 months and aged for 1, 8 and 15 days were analysed with the aim of determining the chemical composition, physical attributes, fatty acid profile and volatile compounds. Ageing did not significantly affect the chemical composition and colour parameters, while cooking loss was significantly (p < 0.05) higher at 8 and 15 days of ageing. Thiobarbituric acid reactive substances (TBARS) content significantly (p < 0.01) increased during ageing, while shear force values significantly (p < 0.01) decreased. Ageing significantly (p < 0.05) increased polyunsaturated fatty acids (PUFAs) determined both at 8 and 15 days after slaughter. Volatile compounds were analysed using solid-phase microextraction (SPME) and gas chromatography–mass spectrometry (GC–MS). Among 109 volatile compounds determined in donkey meat, hydrocarbons were the most common molecules detected. Ageing affected 21 of the detected volatile compounds; both total aldehydes and total ketones contents were significantly (p < 0.05) higher 15 days after slaughter. Total furans and total alcohols were significantly (p < 0.01) higher 15 days after slaughter, as well. Significant modifications of donkey meat volatile compounds can be attributed to ageing periods longer than 7 days.