Volatile profiles and characteristic odorants in camellia seeds with different heat pretreatments

Heat pretreatment plays a crucial role in affecting the quality, colour and aroma of camellia oil during the extraction process. This study aimed to investigate the effects of steaming, stir-frying, roasting, microwave and infrared treatment on the flavour and physicochemical quality of camellia seeds. The results indicated that, compared with unpretreated samples, the heat-pretreated ones exhibited increased oil content and browning degree, imparting a caramel colour with toasty and nutty flavours. 137 VOCs, including 23 characteristic aroma compounds, were detected by HS-SPME/GC-O-MS analysis. 17 different VOCs were identified by OPLS-DA and 12 key aroma compounds (KACs) were determined by ROAV. Moreover, 6 characteristic flavour substances were obtained through comprehensive analysis. The relationship between physicochemical properties and sensory attributes was elucidated using the Mantel test. This study provided scientific insights into the formation mechanism of camellia seeds flavour and supported further development of processing strategies to enhance camellia seeds flavour.