VOLUME EXPANSION DURING HOT AIR PUFFING OF A FAT-FREE STARCH-BASED SNACK

Puffed volume and puffing uniformity of a fat-free snack were investigated. Strips of drum-dried sweet potato-tapioca pastes were puffed 15 sec at 200 degrees C in a fluidized bed. Puffed product specific volume (SV) was related to starch gelatinization, soluble solids content, initial moisture and method of half-product preparation. SV was maximum (490% increase) and most uniform (3.94% coef. of variation) when 70% moisture paste was drum-dried at 100 degrees C and 1 rpm to produce the half-product, Starch was 93% gelatinized in this process. Soluble solids reduced puffing by reducing starch gelatinization, Half-product produced by sheeting dough containing pregelatinized starch had puffed volumes which significantly correlated with starch gelatinization.