The Effects of Donkey Meay Cooking Processes on Vitamins and Minerals Content

Meat is an important source of minerals and vitamins, and for this reason largely contributes to the daily intakes of these micronutrients in human diet. Meat cooking techniques showed significant effects on vitamin and trace element contents, with important losses of B-vitamins. Losses in minerals after cooking occur, too, so the amounts of these nutrients really ingested with meat intake could vary greatly. Donkey meat minerals level has been previously determined, while vitamins content has never been evaluated in this kind of red meat. The aim of the present study was to detect minerals and vitamins B-complex content in raw donkey meat and to analyze the influence of cooking process on the level of these micronutrients. Twelve male entire crossbred donkeys born and reared in the same farm were slaughtered at 20 months of age, with an average final body weight of 246±20 kg. After slaughtering four samples of 600 g were taken from the muscle Longissimus thoracis (LT). Two samples of LT were used for raw meat chemical analysis, the other two LT samples were cooked in an oven at 170 °C for 45 min. B-vitamins were quantified by HPLC, while macro (Ca, K, Mg, Na, P) and microelements (Cu, Mn, Fe, Zn) were determined by means of atomic absorption spectroscopy. Data were analysed by the method of least squares using the GLM procedure. Niacin content was the most abundant vitamin determined in raw meat, 6.9±0.27 mg/100 g, followed by pantothenic acid, 1.13 mg/100 g, vitamin B6, 0.61±0.12 mg/100 g, then riboflavin, 0.22±0.07 mg/100 g. Thiamine content was 0.09±0.01 mg/100 g, vitamin B12 content was 1.8±0.15 μg/100 g. Cooking procedure decreased B-vitamins complex content, mainly thiamine, that resulted significantly reduced (trace) by thermal degradation. Niacin content showed a significant (5.22±0.16 mg/100 g) decrease after cooking; riboflavin resulted more stable to heat. Vitamin B12 showed a significant (1.10±0.04 mg/100 g) decrease in cooked donkey meat. Potassium is the most abundant mineral in raw donkey meat (375±23.4 mg/100 g), followed by phosphorus (261±14.4 mg/100 g) and sodium (44.7±2.11 mg/100 g). Considering the microelements, in raw meat iron content was 2.87±0.28 mg/100 g, while zinc was 5.60±1.01 mg/100 g. Cooked donkey meat did not show significant decrease in iron and zinc content compared to raw meat. Copper remained quite stable after cooking process, and the other minerals did not show significant differences.