Effect of extrusion temperature on characteristic amino acids, fatty acids, organic acids, and phenolics of white quinoa based on metabolomics

Quinoa is considered a "full nutritional food" owing to its high nutrition value. However, the whole grain form of quinoa is not always convenient direct consumption in everyday life. Extrusion is effective viable solution to this issue. In this study, the metabolic characterization of white quinoa (WQ) and extruded white quinoa (EWQ) was performed by investigating the characteristic amino acids, fatty acids, organic acids, and phenolic content of WQ after extrusion. A total of 24 amino acids, 25 organic acids, 32 fatty acids and 50 phenolics were identified in both WQ and EWQ, The results showed that extrusion and extrusion temperature significantly (p < 0.05) affect the content of amino acids, fatty acids, organic acids and phenolics in WQ. For example, the content of glutaconic acid (1231.9 μg/g of EWQ-180 to 1926.4 μg/g of WQ) and L-aspartic acid (115.47 μg/g of EWQ-140 to 643.70 μg/g of WQ) in WQ was significantly decreased, while L-serine (138.01 μg/g of WQ to 201.04 μg/g of EWQ-160) was increased respectively after extrusion. Among the EWQ samples, the highest content of glutaconic acid (1447.9 μg/g), L-aspartic acid (270.32 μg/g), and L-serine (201.04 μg/g) was observed in EWQ-160, EWQ-180 and EWQ-160, respectively. These results indicated extrusion affects the content of various amino acids differently and that the changes are dependent on the extrusion temperature. Similar result was also observed for fatty acids, organic acids, and phenolics. In conclusion, extrusion has potential in the processing of quinoas and the metabolic characterization of amino acids, fatty acids, organic acids, and phenolics in grains could be effectively analyzed using metabolomics.