Determination of seed kernel oil content and fatty acid composition
Each plant’s seeds weighed about 10g, and calibration samples of pureA. truncatum oil with known oil content were taken. The oil content of the calibration samples was quickly determined by utilizing the SPEC-PMR pulsed nuclear magnetic resonance instrument oil and water analyzer, and each copy was repeated three times[16, 17].
The fatty acid fraction of A. truncatum seed kernel was determined based on the external standard method specified in GB 5009.168-2016. After methyl esterification of A. truncatum seed oil samples in sulfuric acid medium, the supernatant was obtained, and the fatty acid standard assay solution and the sample to be measured were separately determined on the machine, and then the chromatograms were obtained by GC analysis. GC/MS conditions: DA-2560 capillary column (100 m × Ф0.25 mm × 0.2 μm); high purity nitrogen carrier gas; inlet temperature of the injector is 270 ℃, the Detector temperature was 280 ℃; the initial column temperature was 100 ℃ (lasted 13 min), 100~180 ℃ (heating rate 10 ℃/min, lasted 6 min), 180~200 ℃ (heating rate 1 ℃/min, lasted 20 min), 200~230 ℃ (heating rate 4 ℃/min, lasted 10.5 min). The fatty acid content was obtained by peak area normalization[18-20], and the composition obtained from the determination is shown in Table 2.
Table 2 Fatty acid composition of samples