Comprehensive Evaluation of Germinated Rapeseed Oil Under Different Roasting Temperatures: Physicochemical and Flavor Profiles

ABSTRACT With consumers' increasing demand for higher nutritional quality in edible oils, this study aimed to investigate whether the combination of germination and roasting could further enhance the nutritional value of rapeseed oil. This study systematically investigated the effects of roasting temperature (120°C–200°C) on the physicochemical properties, bioactive compounds, antioxidant capacity, and volatile flavor profiles of germinated rapeseed oil (GRO). The results demonstrated that roasting significantly enhanced the contents of total phenols, total flavonoids, chlorophyll, carotenoids, and phytosterols, with maximum levels observed at 200°C. These improvements were accompanied by a marked increase in antioxidant capacity, as measured by the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging and the 2,2′‐azino‐bis (3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS) radical cation scavenging assays. In addition, roasting promoted the formation of volatile compounds, particularly heterocyclics and glucosinolate degradation products, contributing to a more intense roasted aroma. However, higher temperatures also led to undesirable effects, including darker oil color and elevated acid value. Multivariate analysis revealed strong positive correlations between roasting temperature and key bioactive components. In conclusion, based on a comprehensive evaluation of nutritional, flavor, and visual attributes, a roasting temperature of 160°C was identified as optimal for producing high‐quality GRO. Practical applications : The findings of this study provide practical guidance for the industrial production of germinated rapeseed oil with enhanced nutritional and sensory qualities. By adopting a roasting temperature of 160°C, manufacturers can achieve an optimal balance between bioactive compound retention, antioxidant activity, and desirable flavor profile, while minimizing negative impacts on oil color and acidity. This temperature regime is recommended for the development of premium rapeseed oil products with improved health benefits and consumer appeal, such as functional cooking oils or specialty lipid ingredients for the food and nutraceutical industries.