Optimisation of accelerated solvent extraction for screening of the health benefits of plant food materials

Abstract

The development of a rapid, robust and reliable method for extracting plant food materials is important for screening a wide range of plant bioactives for their health benefits. In this study, extractions of bioactive polyphenolic com-pounds from fruits and vegetables were per-formed using a pressurised solvent extraction technique. Variables including solvent, extrac-tion temperature and time, and number of ex-traction cycles, were optimised to develop a rapid and efficient extraction protocol. The re-sulting extracts were then analysed for antioxi-dant capacity, total phenolic content and com-position. The optimal parameters found were 19:1 methanol/water (95% methanol) as solvent and three extraction cycles, of 10 minutes at 40ºC or 2 minutes at 100ºC. High performance liquid chromatography mass spectrometry did not detect any difference in extract composition between low and high temperatures. Extraction at 100°C generally gave a moderately higher yield of polyphenolics for some fruit and vege-table extracts but appeared to reduce the anti-oxidant activity particularly for turnip leaf, el-derberry and sour cherry extracts as measured by oxygen radical absorbance capacity assay. We found that all 40°C extracts were better at protecting cells from H2O2-induced cellular damage than their 100°C counterparts. The 40°C apple puree and elderberry extracts were about 2 fold and 1.7 fold more effective, respectively, than extracts prepared at 100°C. Our results demonstrated that pressurised solvent extrac-tion technique with careful parameter selection can be used as a quick method for screening the health benefits of plant food materials.