Effect of Soy Lysophospholipid on Rheological Properties of Wheat Starch Gel

Abstract

Many fatty acids in soy lysophospholipid (SLPL) prepared from soy phospholipid (SPL) using phospholipase A2 are unsaturated fatty acids such as linoleic acid and oleic acid. The complexing ability of SLPL-99 (99% hydrolysis of SPL) with starch is practically similar to that of glycerol monostearate. The properties of wheat starch gels blended with SLPL-99 using a Brabender Viscograph were analyzed by a differential scanning calorimeter (DSC), a rheometer, a polarizing microscope and a scanning electron microscope. DSC supported that SLPL-99 could form a complex with wheat starch. The rheological properties of the wheat starch gels blended with SLPLs of 48%, 64% and 89% of hydrolysis of SPL were subjected to a compression test. The breaking strength and stress of the wheat starch gels decreased as the degree of hydrolysis of SPL increased. Both parameters of gels with SLPL showed less change during storage compared to those of wheat starch alone gel. In Brabender amylogram, the gelatinization temperature of wheat starch increased as the degree of hydrolysis of SPL increased. The small changes in the above rheological properties of the gels during storage (5°C) and the rise of gelatinization temperature of the starch also suggested a formation of the complex of wheat starch with SLPL. These results suggested that SLPL has an ability to improve the quality of foods made from wheat starch through a complex formation.