EFFECT OF HIGH FREQUENCY ULTRASOUNDS ON LYCOPENE AND TOTAL PHENOLIC CONCENTRATION, ANTIOXIDANT PROPERTIES AND [alpha]-GLUCOSIDASE INHIBITORY ACTIVITY OF TOMATO JUICE

Tomato juice was subjected to high frequency ultrasounds (378 and 583 kHz) at increasing energy densities (up to 250 MJ/[m.sup.3]). Results relevant to the treatments at high frequency providing an energy density of 250 MJ/[m.sup.3] were compared with those obtained at 24 kHz delivering the same energy density. Lycopene and total phenolic concentration, as well as the [alpha]-glucosidase inhibitory activity of tomato juice, were not affected by ultrasound regardless the frequency and energy density. However, the antioxidant properties were negatively affected by high frequency ultrasounds. Keywords: antioxidant properties, [alpha]-glucosidase inhibitory activity, high frequency ultrasounds, tomato juice, total phenolic concentration