Title of article :
Effect of Red Seaweed Polysaccharides Agar (Gracilaria changii) on Thermal Properties and Microstructure of Wheat Starch
Author/Authors :
KHAIRUL FAIZAL, P. Malaysian Institute of Chemical Bioengineering Technology (MICET) - Department of Food Technology, Malaysia , ROHASMIZAH, H. National University of Malaysia - Faculty of Science and Technology - Centre of Chemical Sciences and Food Technology, Malaysia , ABDUL SALAM, B. National University of Malaysia - Faculty of Science and Technology - Centre of Chemical Sciences and Food Technology, Malaysia , NORRAKIAH, A.S. National University of Malaysia - Faculty of Science and Technology - Centre of Chemical Sciences and Food Technology, Malaysia
Abstract :
This study has been carried out on the mixture of Gracilaria changii agar (0.1%, 0.2%, 0.4% and 0.8%) with wheat starch. Scanning electron microscopy (SEM) was performed for morphology observation, and starch thermal analysis were carried out to determine the properties of gelatinization and retrogradation. Proximate analysis has been determined for isolated wheat starch and agar. Through SEM, interaction was first observed at 64°C for 0.4% agar but at 0.8% of agar, a more extensive bridging was formed which enveloped the starch granules. Differential scanning calorimetric (DSC) result shows that the addition of agar decreased the onset temperature (To) of gelatinization significantly (p 0.05) but increased the gelatinized enthalpy (ΔHgel), gelatinized temperature range (Rg) and Peak Height Index (PHI) significantly (p 0.05). Agar lowered the retrogradation enthalpy (ΔHret), retrogradation range (Rret) and retrogradation percentage (%R) of wheat starch significantly (p 0.05).
Keywords :
Agar , gelatinization , Gracilaria changii , retrogradation , starch granule
