**2. Material and methods**

Kiwi fruits (Actinidia deliciosa) in natura were locally purchased. The fruits were washed in a bleach solution, peeled, and cut in half. The juice was extracted by home centrifuge Walita, pre-filtered, centrifuged at 5000 rpm, and filtered. Mineral water was added to 50% volume, and sucrose to reach 16º Brix. It was made an ultra filtration with ceramic membrane of 0.10µm at the pressure of 3bar at 45ºC for clarification, according to Lopes et al. (2005). The drink was kept in 500 mL plastic bottles (PET), and exposed to the following treatments:


Irradiation was conducted in a Cobalt-60 source; model Gammabeam 650, of Nordion Canada, installed in the Center of Nuclear Energy in Agriculture of the University of Sao Paulo – CENA/USP., Piracicaba city, State of São Paulo, Brazil. The dose rate was 0.712 kGy/hour. The analyses were conduced in the Laboratory of Radiobiology and Environment of CENA/USP.

Dosimetry was performed using 5 mm diameter alanine dosimeters (Bruker Instruments, Rheinstetten, Germany), and the free radical signal was measured with Bruker EMS 104 EPR Analyzer. The actual dose was within 0.02 of the target dose. Samples was turned 360 continuously during the irradiation process to achieve uniform target doses and the nonirradiated control was placed outside the irradiation chamber to have the same environmental temperature effect with the irradiating sample.
