Evaluation of leaf protein extraction methods from Wedelia trilobata

ObjectiveThe leaf protein extraction method and conditions from Wedelia trilobata were selected and op-timized, which provided technical support for the exploitation and utilization of W. trilobata as protein feed resources.MethodUsing orthogonal experiment,four leaf protein extraction methods including acid heating method,alkali heating method, salting out method and organic solvent method were optimized and extraction results were compared.Hence the optimal extraction conditions from W. trilobata were determined. ResultAccording to the extracting leaf crude protein content from W. trilobata,the four methods were ranked as follows:salting out method (15.18 mg/g)>acid heating method(9.97 mg/g)>alkaline heating method(9.79 mg/g)>organic solvent method(7.21 mg/g). The optimum extraction conditions for salting out method were as follows:concentration of sodium chloride solution was 30%,flocculation time was 10 min. For acid heating method,the optimum extraction conditions were flocculation temperature 60 ℃,pH 3 and floccula-tion time 2 min. The optimum conditions for alkaline heating method were flocculation temperature 25 ℃,pH 7 and floccu-lation time 2 min. The optimum conditions for organic solvent method were 20% ethanol volume fraction and 10 min for flocculation. Flocculation temperature had significant effect on extraction efficiency for acid heating method and alkali heat-ing method(P<0.05),and concentration of extracting solution had extremely significant effect on extraction efficiency for salting out method and organic solvent method(P<0.01). ConclusionBy comparing the four methods,salting out method was determined as the optimal method for extracting leaf protein from W. trilibata because of its high extraction efficiency, simple operation,high protein activity which enabling it suitable for laboratory extraction and industrial production.