Drying characteristics of bori nuggets, an Indian traditional food, prepared from black gram batter were studied using hot air temperature of 30, 50 and 70 degrees C and air flow rates of 0.6, 1.0 and 1.4 m/s. The drying constants obtained from Lewis equation decreased from 0.457 to 0.139, 0.514 to 0.324 and 0.735 to 0.487 (r >= 0.975; MSE <= 0.0082) for 30, 50 and 70 degrees C, respectively, while the air velocity decreased from 1.4 to 0.6 m/s in each case. The correlation among drying constant, air velocity and air temperature for the drying was found to best described by Arrhenius equation (r = 0.995; MSE = 0.0029). Statistical analysis (ANOVA) revealed that effects of both air temperature and air velocity on yellowness index, hardness and cooking time of the nugget as well as on drying time were significant (p <= 0.01 or 0.05). Response surface methodology was tried for optimization of these two independent variables with respect to the above-mentioned parameters. The superimposed contour plots suggest optimum drying air temperature between 59 and 63 degrees C and air velocity between 0.9 and 1.05 m/s for attaining minimum values of yellowness index (44) hardness (9.0-9.5 N), cooking time (8.0-8.4 min) and drying time (250-275 min). (c) 2006 Elsevier Ltd. All rights reserved.