Optimization of preliminary purification conditions for protein extraction from tea residues

Q.Y. Cui, X.H. Ni, L. Zeng, Z. Tu, J. Li, K. Sun, X. Chen, X.H. Li
To optimize the enzymatic method for extracting proteins from tea residue, the effect of conditions on the protein extraction rate from tea residue was investigated through single factors experiment: extraction temperatures (30-80°C), extraction times (20-80 min), pH values (1.0-13.0) and liquid-solid ratios (20:1-70:1). On the basis of the results of single factors experiment, the protein extraction conditions were optimized through an orthogonal test. The results showed an optimum condition where the extraction temperature was 70°C, the extraction time 60 min, the pH value 12, and the liquid-solid ratio was 50:1. The protein extraction rate reached 29.71% under these conditions. In addition, isoelectric point precipitation, ammonium sulfate precipitation and isoelectric point plus ammonium sulfate precipitation were performed to find a better method for tea protein precipitation in this paper. The precipitation rate of tea protein was about 82.88% using isoelectric point plus ammonium sulfate method. Furthermore, powdered activated carbon was chosen as the most suitable decolorant for decoloration of the extracted proteins. Finally, the yellow grey proteins with a purity of 88.53% were obtained.
Cui, Q.Y., Ni, X.H., Zeng, L., Tu, Z., Li, J., Sun, K., Chen, X. and Li, X.H. (2018). Optimization of preliminary purification conditions for protein extraction from tea residues. Acta Hortic. 1208, 455-462
DOI: 10.17660/ActaHortic.2018.1208.63
tea leaves, protein extraction, isoelectric plus salt method, powdered activated carbon, optimization

Acta Horticulturae