88-6 |
Yield and stability of flavanolignans from milk thistle seeds |
S. N. WALLACE, Biological Engineering, University of Arkansas, Sunny Wallace, 203 Engineering Hall, Fayetteville, AR 72701, D. J. Carrier, and E. C. Clausen, Chemical Engineering, University of Arkansas, 3202 Bell Engineering Center, Fayetteville, AR 72701. Flavanolignans from milk thistle seeds show symptoms of heat degradation when extracted with boiling solvents. This study examined the yields and stabilities of flavanolignans collectivley called silymarin from whole and defatted milk thistle seeds. 60 °C methanol, ethanol, and water were used to extract both seed types in a water shaker bath for 10 h, and values were compared to previous work done at boiling temperatures. High-pressure liquid chromatography was used to evaluate silymarin yields, and liquid chromatography/mass spectrometry was used to evaluate flavanolignan stability. Water recoveries at 60 °C were low compared to recoveries from boiling water. Methanol recoveries were higher at 60 °C than at boiling for both whole and defatted seeds. Maximum recoveries at 60 °C were 4, 5, 9, and 16 mg of taxifolin, silychristin, silybinin A, and silybinin B, respectively, per g defatted seed. Ethanol extracts at the same temperature were slightly higher than those of methanol, and reached 5 mg taxifolin, 5 mg silychristin, 11 mg silybinin A, and 19 mg silybinin B per g of defatted seed. At lower temperatures, extracts from both seed types approached similar levels. Mass spectrometric analysis showed boiling extractions to yields several isomers of silychristin, whereas 60 °C extracts contained only one isomer of silychristin. Lowering milk thistle extraction temperatures can increase silymarin yields by minimizing compound degradation, and can produce more stable forms of some silymarins.
Session 88, Nutraceuticals & Functional Foods: General
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