Multistage counter-current and cross-current processes for antioxidant and phenolic components extraction from Rosmarinous Officinalis (Rosmary) plant at pilot plant scale

Multistage cross-current and counter-current extraction processes to extract antioxidant and phenolic components from Rosmarinous Officinalis (rosemary) plant have been performed for the first time, in this paper. The experiments include three stages cross-current extraction using acetone and ethanol solvents, and three stages counter-current extraction using ethanol solvent. Process conditions include rosemary plant weight, 2.5 kg, solvent to plant ratio, 12 lit/kg, and process time, 90 min. The results show that total extract yields are 37.27%, 95.45%, and 93.18%, total phenolic contents (based on dry plant weight) (TPC-DP) are 2662.75, 8627.44, 8378.32 mg (GAE)/100g (DP), total phenolic contents (based on dry extract weight) (TPC-DE) are 16344.4, 17861.69, 21147.07 mg (GAE) /100g (DE), DPPH free radical scavenging of the extracts are 70.72%, 77.09%, 84.1%, for three stages crosscurrent extraction using acetone solvent, three stages cross-current extraction using ethanol solvent, three stages counter-current extraction using ethanol solvent, respectively. The antioxidant activities of the products have been compared with those of two standard antioxidants of BHA and BHT, and the desired results have been achieved. Considering that the amount of consumed solvent is 90 lit and 30 lit for cross and counter-current processes, respectively, the results indicates a significant saving in solvent, energy, and time consumption in counter-current extraction process.