Sunflower Seed Meal Protein Analysis

The SDS-PAGE was conducted using the Mini-PROTEAN^® System (Bio-Rad, Hercules, CA, USA). The sunflower seed meal protein samples (2 mg) were dissolved in 0.5 mL of sample buffer (0.08 M Tris-HCl buffer, pH 6.8), 1% (w/v) SDS, 2% (v/v) 2-β-mercaptoethanol, 5% (v/v) glycerol, and 0.025% (w/v) bromophenol blue and mixed well [27 (link)]. The protein was subjected to SDS-PAGE analysis using a 5% concentrating gel and a 12% separating gel. A marker with a molecular weight range of 11~180 kDa (Sigma-Aldrich Co., St. Louis, MO, USA) was employed. 4 μL samples of supernatant were applied to the stacking gel slot and 1 L of electrode buffer was added. Electrophoresis was conducted initially at 30 V for 1.5 h, followed by a change to 60 V for an additional 2 h. After electrophoresis, the gel was stained with Coomassie brilliant blue R250. The decolorization was achieved using a methanol-ice acetic acid solution, and the photographic analysis was performed after decolorization. The images were finally taken using a Bio-Rad gel imaging system. Image Studio Lite (version 5.2, LI-COR Biosciences, Lincoln, NE, USA) The intensity of the stained bands is analyzed by Image Studio Lite to determine the relative ratio of specific proteins to the total protein content, providing an indication of the component purity of the sample.