An integrated storage and seed treatment approach for improving oxidative stability and oil quality of canola seeds

Abstract

Canola (Brassica napus L.) seed quality deteriorates during storage, which leads to elevated free fatty acid value (FAV), oxidative damage, and significant refining losses. This study presents an integrated, three-stage investigation aimed at understanding canola seed degradation mechanisms during storage. The approach further aimed to control lipid hydrolysis, improve oil quality, and storage stability through seed pretreatment techniques. Firstly, the effect of storage temperature (5, 20, and 35°C), relative humidity (35 and 85%), and seed moisture content (4, 8, 14%) on canola seed quality was evaluated. All the conditions resulted in accelerated FAV formation (4-6 fold increase), chlorophyll degradation, and germination loss (50%). Multivariate analysis (PCA and MANOVA) confirmed the strong interactions between storage variables and time, demonstrating the complexity of storage-induced degradation. Secondly, based on the observed increase in FAV during storage, thermal (microwave and infrared) and non-thermal (ultrasound) seed pretreatments were investigated as mitigation strategies. Under optimized conditions, pretreatments increased oil yield up to 32% and reduced FAV by 80%. Microwave and infrared preserved over 90% antioxidant activity, enhanced phenolic content, and maintained peroxide value. As these pretreatments effectively stabilized lipid hydrolysis and improved oil quality, it was essential to evaluate the storage behavior of the pretreated seeds. Finally, optimally pretreated seeds were subject to a storage study to evaluate long-term stability. The pretreated seeds effectively reduced FAV and oxidative deterioration during storage compared to untreated seeds. Safe storage guidelines showed a clear clustering between treated and untreated samples, where IR and MW treated seeds resulted with longer safe storage period. This integrated approach demonstrated a scalable and sustainable pathway for stabilizing canola seed quality, reducing refining losses, and improving industrial oil processing efficiency. Unlike conventional studies, which examine storage or pretreatments individually, this study integrates storage degradation analysis with targeted seed pre-treatment and post-treatment evaluation. Overall, this study established a process-level strategy to stabilize canola seed quality, suppress lipid hydrolysis, and reduce refining losses under industrially relevant conditions.May 202