Effect of modifier on the composition and antioxidant activity of carotenoid extracts from pumpkin (Cucurbita maxima) by supercritical CO2

The effects of different modifiers and processing conditions on the compositions, yield, and antioxidant activity of carotenoid by supercritical CO2 (SC-CO2) extraction were studied. Increasing the percentage of modifier would increase the yield, but no significant changes were observed on the antioxidant properties of carotenoids extracted at 50 °C with low concentration (5%) of single modifier. As single modifier, the oil showed the pronounced effects on the yield and antioxidant activity of extracts compared to the effects of water and ethanol. The combination of ethanol and water, or ethanol and oil, or water and oil in SC-CO2 extraction showed that the yields of carotenoids were higher than for the single modifier with equal amount. The modifier and operating temperature of SC-CO2 notably influenced the selectivity of carotenoids, especially the ratio of cis-β-carotene/total carotenoids. The antioxidant activity didn’t show a liner correlation with the total yield of carotenoids. The antioxidant activities of unit mass carotenoid extract were decreased after adding modifiers at both 50 °C and 80 °C. At lower concentrations of water (5% and 10%), the antioxidant activity of unit mass carotenoid extracts was higher at 50 °C. The highest antioxidant activity of unit mass carotenoid extract was found at 80 °C with both single and combined modifiers.

► The antioxidant activity did not show a linear correlation with the total yield of carotenoid extracts.
► Olive oil showed more pronounced effects on the yield of carotenoid extracts among single modifiers.
► The highest yield was obtained at 50 °C with the modifier of 10% ethanol + 10% oil.
►  5% or 10% water significantly enhanced the antioxidant activity of unit mass of the concentrated carotenoid extracts.