Suitable extraction conditions for determination of total anti-oxidant capacity and phenolic compounds in Ruspolia differens Serville

Abstract

Recent research on edible insects’ composition has placed more emphasis on the quantity and quality of macro- and micro- nutrients and less emphasis on their bio-active components. This study aimed at assessing the effect of four factors, namely: defatting, solvent type (ethanol, methanol and acetone), solvent concentration (50, 75 and 100%) and extraction time (15, 30, 45 and 60 minutes) on the extraction efficiency, the total anti-oxidant activity and the amount of total phenolics and total flavonoids of Ruspolia differens. It was not known if the removal of fat (defatting) would influence the total anti-oxidant activity, and the distribution of anti-oxidant compounds in the R. differens matrix. Non-defatting use of acetone and sonication for 60 minutes are associated with high anti-oxidant activity and high amounts of bio-active compounds extracted. Aqueous acetone (50%) extracts had the highest average anti-oxidant activity (87.00±2.59% RSA) while 100% acetone extracts had the highest average total phenolics (11.14±0.18 GAE/g) and average total flavonoids (3.02±0.21 QE/g) content, indicating the presence of other, possibly highly polar, bio-active compounds in R. differens.