Effect of the defatting process, acid and alkali extraction on the physicochemical and functional properties of hemp, flax and canola seed cake protein isolates
The effect of the defatting process, acid and alkali extractions on the physicochemical and functional properties of hemp, flax and canola protein isolates was studied. The defatting process enriched the protein content from around 35 to 52–55 % in the defatted oilseed cakes. Further treatment with acid and alkali led to the highest enrichment (P < 0.05) in the protein content (>90 %). The defatting process produced the lightest (P < 0.05) colour compared to the parent oilseed cakes and the protein isolates. Alkali extraction produced protein isolates with the highest (P < 0.05) water holding capacity while the original oilseed cakes had the highest oil holding capacity. Acid and alkali extractions produced protein isolates with the highest emulsifying activity and emulsion stability. The alkaline soluble flax protein isolate and acid hemp protein isolate had the highest (P < 0.05) creaming stability and largest droplet size respectively. Amino acid profiles of protein isolates after acid and alkali extraction were improved, leading to a protein suitable for fortification in food products that meet human nutrition requirements.
KeywordsProtein isolate Hemp Flax Canola Seeds Functional properties
The authors are grateful to the University of Otago for a Doctoral Scholarship (S–S T) and a research grant from the Department of Food Science, University of Otago, for financial support throughout the study. The authors acknowledge the assistance of Department of Biology, Universiti Sains Malaysia for amino acid analysis.
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