Studying the Effects of Nucleating Agents on Texture Modification of Puffed Corn-Fish Snack

To improve textural attributes of puffed corn-fish snack, the effects of 1%, 1.5%, and 2% of calcium carbonate, magnesium silicate (talc), sodium bicarbonate as well as 5% and 10% of wheat bran (as the nucleating materials) on textural attributes were studied. Sensory evaluation, bulk density, expansion ratio, maximum force, and count peaks were measured using the Kramer test. The results showed that all of the additives except bran significantly enhanced the texture. Among them, talc at 0.5% was the best to enhance the density and expansion ratio. Effects of using 0.5% talc on puffed corn-fish snack microstructure were studied using scanning electron microscopy. The average cell diameter of 109 48 m and cell numbers per square centimeter of 67.4 for talc-treated products were obtained, while for nontalc-treated extrudates, average cell diameter of 798 +/- 361 m and cell numbers per square centimeter of 13.9 were found. Incorporation of 0.5% w/w of magnesium silicate reduced (7-fold) the average cell diameter while increased (4-fold) the cell number. Practical Application Incorporation of high moisture materials in extrusion feed results in poor texture (low density, high porosity) extrudates. Using 0.5% magnesium silicates in corn-fish composition compensated for the high-moisture content of the extrusion feed. Consequently, the corn-drying stage was eliminated from the process line in commercial production. This was decided upon for reasons of production economy. Doing away with the drying of large amounts of corn grits daily reduced production costs by economizing energy use as well as labor cost. Dryer costs also will be eliminated from fixed investment.