Response surface optimization for deep eutectic solvents extraction of bamboo shoots proteins

To enhance the protein extraction rate of bamboo shoots, the Response Surface Methodology was utilized to optimize the protein extraction process of Chimonobambusa purpurea Hsueh f. & T.P.Yi (syn. Chimonobambusa neopurpurea T.P.Yi) bamboo shoots. Choline chloride and proline were utilized as hydrogen bond acceptors in a total of eight deep eutectic solvents, whereas glucose, sucrose, glycerol, ethylene glycol, acetylpropionic acid, malic acid, and lactic acid were used as hydrogen bond donors. This work examined the protein extraction from bamboo shoots using deep eutectic solvents. Single-factor experiments were conducted to determine the optimal composition of the deep eutectic solvents, along with the ideal gradients of material-liquid ratio gradients, water content, extraction time, and water bath temperature. The impact and interplay of various variables on the protein extraction rate of bamboo shoots were examined using the Box-Behnken Design and Response Surface Methodology. Both the water bath temperature and the extraction time significantly influenced the protein extraction rate of bamboo shoots. Notably, the interaction between extraction time and water bath temperature had the most substantial effect on the protein extraction rate of bamboo shoots. The quadratic response surface regression equation for the protein extraction rate of bamboo shoots relative to the actual values of each factor was obtained as follows: Protein extraction rate = -193.3275 + 3.8395 A - 18.7075 B + 6.3285 C + 0.2125 AB - 0.0089 AC + 0.024 BC - 0.02885 A2 + 0.685 B2 - 0.06455 C2. Finally, this work predicted optimum extraction parameters for bamboo shoots with choline chloride-sucrose (molar ratio 1:2), a material-liquid ratio of 1:50, a water content of 74%, an extraction time of 4 h, and a water bath temperature of 44℃. Under the optimal conditions, the protein extraction yield was 59.39±0.45%, which aligned with the predicted value from the response surface fitting equation. This indicated that the optimised regression equation may have practical significance. Compared with conventional extraction using a sodium hydroxide (NaOH) solution, deep eutectic solvents extraction of bamboo shoots is more environmentally friendly, non-toxic and harmless. It provides a theoretical and experimental reference for industrial extraction and offers a reference for deep eutectic solvent development in bamboo shoot resource utilization. Key message: To enhance the protein extraction rate of bamboo shoots, the Response Surface Methodology was utilized to optimize the protein extraction process of bamboo shoots.