Open Access Original

Biorefinery process for protein extraction from oriental mustard (Brassica juncea (L.) Czern.) using ethanol stillage

Kornsulee Ratanapariyanuch1, Robert T Tyler1, Youn Young Shim2* and Martin JT Reaney2*

Author Affiliations

1 Department of Food and Bioproduct Sciences, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada

2 Department of Plant Sciences, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada

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AMB Express 2012, 2:5  doi:10.1186/2191-0855-2-5

Published: 12 January 2012

Abstract

Large volumes of treated process water are required for protein extraction. Evaporation of this water contributes greatly to the energy consumed in enriching protein products. Thin stillage remaining from ethanol production is available in large volumes and may be suitable for extracting protein rich materials. In this work protein was extracted from ground defatted oriental mustard (Brassica juncea (L.) Czern.) meal using thin stillage. Protein extraction efficiency was studied at pHs between 7.6 and 10.4 and salt concentrations between 3.4 × 10-2 and 1.2 M. The optimum extraction efficiency was pH 10.0 and 1.0 M NaCl. Napin and cruciferin were the most prevalent proteins in the isolate. The isolate exhibited high in vitro digestibility (74.9 ± 0.80%) and lysine content (5.2 ± 0.2 g/100 g of protein). No differences in the efficiency of extraction, SDS-PAGE profile, digestibility, lysine availability, or amino acid composition were observed between protein extracted with thin stillage and that extracted with NaCl solution. The use of thin stillage, in lieu of water, for protein extraction would decrease the energy requirements and waste disposal costs of the protein isolation and biofuel production processes.

Keywords:
Biorefinery; Protein extraction; Thin stillage Mustard; Salt concentration; Ethanol