‘Green’ technology for production of protein isolate from novel golden pennycress seeds

Authors: Hojilla-Evangelista, Milagros - Mila; Evangelista, Roque

Submitted to: American Oil Chemists' Society Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 2/22/2022
Publication Date: 4/30/2022
Citation: Hojilla-Evangelista, M.P., Evangelista, R.L. 2022. ‘Green’ technology for production of protein isolate from novel golden pennycress seeds. American Oil Chemists' Society Meeting. [abstract].

Interpretive Summary: New field pennycress-derived varieties with enhanced protein properties are being developed as plant-based protein source. Additionally, alternatives to hexane for defatting are being sought due to negative consumer perception on the use of petroleum-based solvents for food processing. This research reports on the evaluation of alcohol (ethanol) defatting of a novel golden pennycress line, TT8, in tandem with saline extraction for protein isolate production, their effects on protein extractability and properties, and how results compare with previous hexane defatting/saline extraction techniques. Alcohol defatting gave a more protein-enriched meal but led to lower protein yield and purity. However, the protein extract from alcohol defatted TT8 meal was generally more soluble across a broad range of aqueous media and had improved foaming and emulsification (blending immiscible liquids like water and oil) properties than protein from hexane defatted meal. Overall, TT8 protein was more soluble than wild pennycress protein and showed better foaming and emulsifying properties. This work demonstrated that proteins with desirable properties can be produced by alcohol defatting/saline extraction from TT8, a new golden pennycress variety.

Technical Abstract: A new field pennycress variety with golden yellow seeds (TT8) was developed to enhance protein properties and for use as alternative plant protein source. The chemical and functional properties of TT8 proteins have not been determined. Additionally, alternatives to hexane for defatting are being sought due to negative consumer perception on the use of petroleum-based solvents for food processing. In this research, alcohol defatting of the TT8 ground seeds and saline extraction (AL-SE) of the protein were evaluated as approaches for protein isolate production and compared with the previous hexane defatting/saline extraction (HX-SE) techniques. Seeds were ground (final particle size 250-350 µ) and then defatted with anhydrous ethanol or hexane (60°C) until residual oil content was around 0.7%. Protein extraction from defatted meal was done using our saline-based method (1: 10 w/v, 0.1 M NaCl, 2 h, 50°C) for wild pennycress. Alcohol defatted meal was more protein-enriched (49% protein) than hexane-defatted meal (39% protein), but its protein yield and extraction efficiency were reduced. AL-SE protein had lower purity (85% protein) than did the HX-SE protein (94%). Solubility (73-98%) of AL-SE protein from pH 2-8.5 was notably greater than those observed for HX-SE protein. Foaming capacity (125-145 mL), foam stability (90-93% remaining foam after 15 min), emulsifying activity index (141-236 m2/g protein), and emulsion stability index (15-26 min) were also improved in the AL-SE protein. Overall, TT8 protein was more soluble than wild pennycress protein from pH 2-7 and showed better foaming and emulsifying properties. This work demonstrated that proteins with desirable properties can be produced by AL-SE from TT8, a new golden pennycress variety.