Development of a rapid and simple protocol for oil quantification of small (mg) mass oil seed samples

Background: Efficient and accurate determination of oil content is useful for small mass oilseeds and analysis of single seed chips. Results: This study evaluated twelve different methods of seed oil extraction and quantification, including methods that have not previously been applied to oilseeds. The aim of the study was to evaluate and develop efficient and inexpensive techniques that reliably work with small mass amounts of seeds. The Soxhlet method was used as a standard control. Twelve oilseed samples (eleven soybean and one chia) covering an oil content range of 15.5–32.7% (dry weight) were used. The Folch technique provided a higher percentage of oil extraction compared to Bligh and Dyer and hexane-isopropanol techniques. There was not a significant difference (P > 0.05) between the Folch and Soxhlet technique. A supercritical fluid extraction method yielded significantly lower amounts of oil extraction compared to the Soxhlet method. A direct transesterification (DT) method yielded significantly higher oil levels in seeds that contained low moisture content. Together, our results show that bead beating extraction (BBE) developed in this study was highly correlated with the Soxhlet method (R² = 0.88). This involves direct pulverization, extraction and transesterification of glycerolipids in 2 mL tubes processed in a bead beater for 40 s followed by gas chromatography. Conclusions: This BBE method was the simplest, fastest and least expensive.