Effect of Extractant and Temperature on Phenolic Compounds and Antioxidant Activity of Selected Spices

Abstract

Ten spices marketed in Jordan, ( Syzygium aromaticum L., Coriadrum sativum L., Cuminum cyminum L., Zingiber officinale Rosc., Elettaria cardamomum , Curcuma longa , Rhus coriaria L., Cinnamomum zeylanicum Blume, Foeniculum vulgare Mill and Laurus nobilis L.) were investigated for their phenolic compounds and antioxidant activity. The influence of different extractants (methanol, ethanol and acetone) at different temperatures (20, 40 and 60&degC) was examined. Results showed at 60&degC using methanol, cloves had the highest level of total phenolics (781.0 mg GAE/100g using acetone). At 40&degC, sumac and cloves had the highest amounts of total phenolics (343.9 mg/100g and 342 mg GAE/100g respectively). At 20&degC, cloves continued to have the highest amount of total phenolics (394.7 mg/100g) using methanol as extactant. Ethanol as extractant, cloves gave the highest level of phenolics (548 mg GAE/100g, 493.4 mg GAE/100g) at 60&degC, while at 20&degC cloves and sumac showed the highest concentrations of phenolics (350.8 mg GAE/100g and 342.8 mg GAE/100g respectively). Acetone as extractant at 60&degC, cloves had the highest levels of phenolics (781 mg GAE/100g) while at 40&degC and at 20&degC, sumac contributed the highest levels of total phenolics (583.2 mg GAE/100g and 754.5 mg GAE/100g). The total phenolics concentration varied significantly among the spices. Their values varied according to the extractant and extracting temperature. IC 50 (radical scavenging activity) reflecting the antioxidant activity was presented. Results showed that cloves had the highest antioxidant activity while the cinnamon, turmeric and sumac had a appreciable level of antioxidant activity. Green cardamom and coriander had the lowest antioxidant activity. Antioxidant activity was positively correlated with total phenolic compounds content of the investigated spices.