LAUSR

Beef is one of the important red meat, which contains essential nutrients for human growth and development. baking is a popular beef cooking method. Temperature and time play a key role in the final quality of beef. How temperature and time affect the changes of nutrients and the formation of harmful products in beef is not clear. The purpose of this study was to measure the content of water, fat, protein, ash, nitrite, total volatile base nitrogen, advanced glycation end products (AGEs) and its precursors and polycyclic aromatic hydrocarbons (PAHs) at different temperatures (150℃, 190℃, 230℃, 270℃ and 310℃) for 20 min and 190℃ for different times (10 min, 20 min and 30 min), so as to discuss the effect of different temperatures on beef nutrients and harmful products. The results showed that the moisture content of beef decreased with the increase of baking temperature and time, resulting in the increase of the relative content of fat, protein and ash. At the same time, the content of total volatile base nitrogen also increased continuously. Compared with the control group, the content of glyoxal (GO) in beef decreased, while the content of methylglyoxal (MGO), pentosin and fluorescent AGEs increased, indicating the continuous accumulation of AGEs in beef. A total of 13 PAHs were identified by gas chromatography-mass spectrometry (GC-MS). The content of 13 PAHs in beef increased with the increase of baking temperature and time. Among them, BkP and BaP, which are the most carcinogenic to human body, were 0.36 μg/kg in raw meat and 0.35 μg/kg respectively, which was doubled by high temperature and long-time baking. After beef was baked at 270℃ and 310℃ for 20 min, the content of BkP increased to 9.49 μg/kg and 5.66 μg/kg, the content of BaP increased to 5.45 μg/kg and 4.42 μg/kg, respectively. After baking at 190 ℃ for 30 min and 40 min, the content of BkP increased to 4.81 μg/kg and 24.20 μg/kg, content of BaP increased to 3.85 μg/kg and 17.79 μg/kg, respectively.