Establishment of a Generalizable Industrial Crop Model for Microwave Extraction of Unsaturated Fatty Acids

To explore the relationship between unsaturated fatty acid (UFA) content and parameters for microwave extraction, multimaterial and multiparameter testing was conducted in which five kinds of materials with different UFA contents (potato, wheat, corn, soybean, and peanut) were selected for the experiment. Four factors, namely, extraction temperature (X ₁), extraction time (X ₂), proportional volume of acetone (X ₃), and liquid-to-solid ratio (X ₄), were screened for their significant effects by using Prob > |T| values from the Plackett-Burman experiment. A microwave extraction orthogonal experiment with four factors and five levels was designed separately using Design-Expert 8.05 software and them concentrated. Microwave-accelerated methyl esterification was then performed, and the UFA content was determined via gas chromatography (flame ionization detector). The optimal extraction conditions (X ₁, X ₂, X ₃, X ₄) and the optimal UFA content of potato were 80.68°C, 10.74 min, 0.80, 3.25 mL × g^-1, 1.08%; wheat: 80.81°C, 10.54 min, 0.80, 20.91 mL × g^-1, 2.26%; corn: 81.18°C, 9.93 min, 0.80, 50.94 mL × g^-1, 6.89%; soybean: 82.07°C, 9.07 min, 0.80, 93.87 mL × g^-1, 15.81%; and peanut: 83.12°C, 8.11 min, 0.80, 168.70 mL × g^-1, 33.07%. Then, the optimization results for the five kinds of materials were synthesized by Origin 8.0 software, the fitting degree of the cubic model with the four extraction factors was the highest, the determination coefficients were 0.9984, 0.9991, 0.8953, and 0.9989, the residual sums of squares were 0.2888, 0.1587, 0.8265, and 0.1864, and the correlation coefficients are ideal. The stability and accuracy of the model were verified by the orthogonal experiment of UFA extraction from rice, and the correlation coefficient between the predicted value and the actual value of the orthogonal experiment was 0.9998. This study systematically collates the optimal parameters for microwave extraction of UFA content in different crops from the perspective of multimaterial and multiparameter, which can provide a large amount of detailed basic data for microwave extraction technology.