MARKET QUALITY OF SWEET-POTATOES AFTER GAMMA-IRRADIATION FOR WEEVIL CONTROL

Roots of sweetpotatoes [Ipomoea batatas (L.) Lam.] were treated with 2 00 to 1000 Gy of ionizing radiation from a Co-60 source. Within this r ange, radiation dosage had no effect on surface injury and decay when roots were evaluated after 1 month of storage at 13C and 90 % relative humidity. During storage, weight loss by irradiated roots was 0.5 % t o 3.3 % over that of nontreated roots, which, in some instances, affec ted root firmness. Changes in peel color were visually imperceptible, but raw medullar tissue of the staple-type, white-fleshed cultivar Pic adito had a more intense yellow hue with increasing irradiation. The g reatest differences were evident after roots had been baked. The hue o f the cooked medullar tissue of the sweet, orange-fleshed cultivar Jew el was not changed by increasing irradiation, although roots were dark er and had a lower color intensity. With baking, the medullar tissue o f irradiated roots of'Picadito' lost some of its yellow tinge, but it also became darker with increased irradiation. Taste panelists reporte d that irradiated roots were sweeter, but these were not preferred to nonirradiated roots, due, in part, to the darkened appearance of treat ed samples.