Market Quality of Sweetpotatoes after Gamma-irradiation for Weevil Control

Abstract

Roots of sweetpotatoes [Ipomoea batatas (L.) Lam.] were treated with 200 to 1000 Gy of ionizing radiation from a 60Co source. Within this range, 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% to 3.3% over that of nontreated roots, which, in some instances, affected root firmness. Changes in peel color were visually imperceptible, but raw medullar tissue of the staple-type, white-fleshed cultivar Picadito had a more intense yellow hue with increasing irradiation. The greatest differences were evident after roots had been baked. The hue of the cooked medullar tissue of the sweet, orange-fleshed cultivar Jewel was not changed by increasing irradiation, although roots were darker and had a lower color intensity. With baking, the medullar tissue of irradiated roots of `Picadito' lost some of its yellow tinge, but it also became darker with increased irradiation. Taste panelists reported that irradiated roots were sweeter, but these were not preferred to nonirradiated roots, due, in part, to the darkened appearance of treated samples.