In various embodiments, methods of concentrating apolipoprotein A-I mimetic peptide activity in transgenic plant material expressing such peptides are provided. In certain embodiments the methods involve providing a tissue of a transgenic plant where the tissue contains a heterologous ApoA-I mimetic peptide expressed by the plant, and where the tissue is provided as a substantially dry powder； mixing the powder with a solution comprising ethyl acetate and acetic acid or with a solution comprising ethyl lactate and lactic acid, to form an extraction mixture； and collecting the liquid phase of said mixture and drying said liquid phase to provide a concentrated dry powder extract that displays the biological activity of the apoA-I mimetic peptide.
