Optimization of Soybean Protein Extraction with Ammonium Hydroxide (NH₄OH) Using Response Surface Methodology

Area of Science:

• Biotechnology
• Food Science
• Sustainable Chemistry

Background:

• Plant proteins are valuable renewable resources, but their extraction is hindered by rigid cell walls.
• Conventional methods use harsh, non-reusable alkalis, often causing protein denaturation.

Purpose of the Study:

• To develop an efficient and sustainable method for soy protein extraction.
• To optimize extraction conditions using ammonium hydroxide (NH4OH), a weak, recoverable alkali.
• To minimize protein denaturation during extraction.

Main Methods:

• Response Surface Methodology (RSM) with a Central Composite Design (CCD) was employed.
• Investigated variables included temperature, NH4OH concentration, extraction time, and solvent ratio.
• Response variables were protein yield and amine concentration (indicating hydrolysis).

Main Results:

• Optimized conditions yielded 65.66% protein with minimal amine concentration (0.14 mM).
• Optimal parameters: 0.5% NH4OH, 12h extraction, 1:10 solvent ratio, at 52.5°C.
• RSM model predicted 64.89% yield and 0.19 mM amine concentration.

Conclusions:

• Ammonium hydroxide (NH4OH) is effective for extracting soybean protein.
• The developed method offers high yield and preserves protein integrity.
• This approach provides a sustainable and eco-friendly alternative for plant protein extraction.