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Starch modification with stearic acid for ‘clean’ label starches
M. N. EMMAMBUX (1). (1) Univ of Pretoria, Pretoria, South Africa

Starch is widely used in the food industry for thickening, stabilizing and even as a fat replacer. These starches are generally modified with chemicals to produce substituted and cross-linked starches for better functionality and stability. The production of these starches require the use of ‘non-food friendly’ chemicals with legislative limitation and the use of solvents that require disposal. They are also not regarded as ‘clean’ label. This presentation discusses starch modification using lipids as food biomolecules. The objectives are to determine the effects of stearic acid on the pasting and chemistry of maize starches and its application as a fat replacer. When starches (normal and high amylose maize starch) are modified with stearic acid (a lipid molecule) at 1.5% w/w, a biphasic starch paste (two pasting peak viscosity) is obtained. The second pasting peak viscosity is characterised by high viscosity and non-gelling properties. These properties seem to be similar to (i) substituted starches which are non-gelling and (ii) cross-linked starches with high viscosity. The viscosity and freeze thaw stability can be further enhanced when xanthan gum is added in the system, suggesting a starch-xanthan gum interaction. Starch modified with stearic acid can also be used as a fat replacer in mayonnaise type emulsion and mozzarella cheese analogue. The non-gelling and high viscosity of starch modified with stearic acid is due to the production of amylose-lipid complexes as shown by X-ray diffraction and differential scanning calorimetry. The amylose lipid complexes are at nanometer scale and this can also allow for more interaction in the system for higher viscosity. Starch modified with stearic acid may be regarded as ‘clean’ label starch for food applications.

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