14A-2

A. T. CAIXETA¹, R. G. Moreira², and M. E. Castell-Perez¹. (1) Department of Agricultural Engineering, Texas A&M University, 310 Scoates Hall, College Station, TX 77843-2117, (2) Department of Agricultural Engineering, 310 Scoates Hall, 310 Scoates Hall, College Station, TX 77843-2117

Increasing consumer demand for low-fat snack foods requires the study of alternative processes to make savory snacks. Superheated steam impingement drying of foods has proven to provide better energy efficiency and product quality and could be a reliable alternative for production of fat-free potato chips (not-fried).

Our objectives were to determine the effect of drying operating conditions (temperature, convective heat transfer coefficient, h) on the drying rate and quality (texture, density, porosity, shrinkage, and nutritional value) of potato chips.

Potato chips were dried in a lab-size superheated steam impingement dryer. The temperature profile was measured on-line using a data acquisition system. The effect of h (100, 160 W/m2C) and steam temperature (115, 130, 145 °C) was evaluated. Potato chips were dried up to the equilibrium moisture content. Product properties were determined off-line using standard methods.

At 145 °C and 160 W/m2C, particle density and porosity showed an increase from 1.09 to 1.54 g/cm3, and from 0 to 0.779, respectively. However, bulk density decreased from 1.09 to 0.34 g/cm3. Same behavior was observed for all other drying conditions. Particle density did not exhibit significant changes with temperature and h values. Porosity of chips dried at 160 W/m2C was higher than for those dried at 100 W/m2C (0.779 and 0.75, at 145C). During drying, change in thickness was 50% for 155C and 62.5% for 130 and 145 °C drying conditions. Potato chips became crispier as drying time increased. No significant differences in crispness of chips (peak force in Newton) due to drying conditions was observed. However, chips were harder (4.19 N) at 115 °C, 100 W/m2C than the chips dried at higher temperature (145 °C).

Results show the potential of producing a good quality fat-free potato chip using steam impingement drying.