Optimization of microwave-assisted extraction of perilla meal protein by single-factor test and response surface methodology

This study adopted single-factor tests integrated with response surface methodology (RSM) based on Box-Behnken design (BBD) to improve and optimize the microwave-assisted extraction (MAE) technique for protein extraction from perilla meal. Four major parameters (material-liquid ratio, extraction pH, microwave power, microwave time) were screened and evaluated in preliminary trials, and their favorable ranges were determined as 1:15, 8-10, 400 W and 120 s, respectively. On this basis, BBD was employed to further refine three core variables: extraction pH, microwave power, and microwave time, and a quadratic regression model was constructed. Analysis of variance verified the model was statistically significant and highly reliable (F = 30.48, p < 0.0001), with a satisfactory goodness-of-fit. A distinct synergistic interaction between extraction pH and microwave power toward protein yield was detected, whereas interactive impacts between microwave time and the other two variables were not significant. The magnitude of influence on protein yield followed: microwave time > microwave power > extraction pH. The model predicted a peak protein yield of 31.3276% under the optimized conditions: pH 10.02, 398.63 W, 115.45 s. Validation experiments yielded an actual yield of 30.9309 ± 0.1036% (n = 3), which closely matched the predicted value, confirming the precision and industrial applicability of the model. This work established a high-efficiency MAE protocol for perilla meal protein and supplied a scientifically sound and scalable technical foundation for industrial application and high-value valorization of this underused plant protein resource.