Development of Healthy Biscuits from Purple Sweet Potato Containing High Resistant Starch

Abstract

The research was aimed to develop high resistant starch - new healthy biscuits from purple sweet potato. The proximate composition of purple sweet potato found 41.58 g/100g carbohydrate, 0.30 g/100g fat, 0.59 g/100g protein, 1.08 g/100g crude fiber, 2.10 g/100g ash and 79 g/100g moisture. The appropriate conditions for processing purple sweet potato starch to have a high starch resistant value were steamed at 100^oC for 30 min, then dried in a hot air tray oven at 70^oC for 9 hours, ground to 100 mesh. The starch was hydrolyzed with two commercial enzymes, α-Amylase (1%w/v) at 70^oC for 2 hours, followed by ß-Amylase (1%w/v) at 55^oC for 2 hours and dried by spray dry. Results found that the 30 minute stremed process of purple sweet potato had antioxidant activity of 160.18 µmol TE/g using DPPH assay and resistant starch (%) at 18.96 with the lightness color of L*= 55.6, red-yellow hue (a*=15.10) and yellow-blue values (b*=-5.50). The purple sweet potato with high resistant starch content can be substituted for all-purpose flour in the basic formulation at the level of 50%. The produced high resistant starch - biscuits from purple sweet potato had sensory liking with overall liking score at moderately (7.45). The physical quality for hardness (Kg) at 0.74, fracturability at 0.76, color L* (18.06), a* (15.27), b* (9.52). This product had quality of total microorganisms, yeasts and molds < 10 est. (cfu/g), which was in the safe standard. The 100 consumer test of developed high resistant starch - new healthy biscuits from purple sweet potato, found that 90% accepted the product and 87% interested in purchasing the product.