Carotenoid content and antioxidant capacity of Mediterranean vegetable soup (gazpacho) treated by high-pressure/temperature during refrigerated storage

Abstract

High-pressure (HP) technology is an alternative to heat preservation methods for foods; therefore, it is essential to assess the impact of this technology on bioactive compounds and their properties. Carotenoids and antioxidant activity were measured in Mediterranean vegetable soup, called gazpacho subjected to HP/temperature treatment. The stability of carotenoids and the effect on antioxidant activity was studied during 40 days of refrigerated storage at 4°C. Two treatments that combine HP with temperature were assayed: T0, freshly made vegetable soup (untreated), T1, 150 MPa/60°C/15 min, T2, 350 MPa/60°C/15 min. Fresh and treated samples were kept refrigerated (4°C) for 40 days. After application of HP and during the refrigeration period, the qualitative and quantitative determination of provitamin A carotenoids (β- and γ-carotene), lycopene and the xanthophyll lutein was achieved. In addition, the radical scavenging activity of vegetable soups was assessed. T1 HP treatment (T1, 150 MPa/60°C/15 min) preserved the carotenoid content in vegetable soups better than T2 HP treatment. Moreover, T1 HP treatment retained the antioxidant activity during storage better than T2 HP treatment.