Functional properties of arrowroot starch in cassava and sweet potato composite starches

Abstract

Root and tuber composite flours and/or starches can meet industrial requirements of carbohydrate-based food products since they gelatinize at relative low temperatures with rapid and uniform swelling of granules, and they exhibit a high viscosity profile compared to cereal starches. Arrowroot starch (10, 20, 30, and 40%, respectively) was mixed in cassava and sweet potato starches and their resulting composite gels were investigated for their gelatinization enthalpies, pasting, and freeze-thaw properties. Peak viscosities of composite starches significantly increased (P < 0.05) from 224.45 to 360.25 RVU in cassava mix, to 306.65–580.25 RVU in sweet potato mix. The gelatinization enthalpies of sweet potato and cassava composite starches were significantly affected, which suggested that the thermal energy during gelatinization to break the structural element in starch granular packing was substantially altered with increasing increments of AS. This meant that granular intermolecular bond increased, whereas granule swelling decreased. The addition of AS minimized freeze-thaw damage by reducing the available water to form ice crystals in cassava and sweet potato gel pastes after the first freeze-thaw cycle. This confirmed that partial substitution of cassava and sweet potato starches with AS formed a paste with improved freeze-thaw stability. Addition of arrowroot starch to cassava and sweet potato starches apparently improved gel stability and may find use in modulating gelling properties of these starches in commercial products.