Ultrasound‐Assisted Extraction and Functional Properties of Perilla Meal Protein

ABSTRACT This study aimed to optimize the ultrasound‐assisted extraction of protein from defatted perilla meal and comprehensively evaluate the functional properties of the extracted protein under varied environmental conditions. Single‐factor experiments and Box–Behnken design (BBD) of response surface methodology (RSM) were employed for extraction optimization, with triplicate experiments and ANOVA for statistical analysis. Amino acid profiling and functional property assays (solubility, water/oil holding capacity, emulsifying/foaming properties) were performed to characterize the protein. Defatted perilla meal contained 36.68% crude protein, and the optimal extraction conditions (45°C, 30 kHz, 85 min) yielded 32.95% protein (consistent with the predicted 33.86%). The protein contained 18 amino acids (including 8 essential ones) with abundant sulfur‐containing amino acids, and its functional properties were dependent on pH, temperature, NaCl, and sucrose. Specifically, it showed minimum solubility at the isoelectric point (pI 4.4) and maximum solubility at 60°C with 0.05 mol/L NaCl; the maximum water holding capacity (5.93 g/g) was achieved at pH 10 with ≤ 7% sucrose; oil holding capacity decreased with increasing temperature; emulsifying properties were optimal at 1.6% protein, pH 10, 0.05 mol/L NaCl, and 1.5% sucrose; and maximum foaming capacity (290%) with 100% stability at 60 min was observed at 9% protein, pH 10, and 0.05 mol/L NaCl (with sucrose enhancing stability). This study verified defatted perilla meal as a high‐quality plant protein source, and the optimized ultrasonic extraction process efficiently obtained perilla meal protein with excellent functional properties, providing technical and theoretical support for its high‐value utilization and application as a novel plant protein in the food industry.