| Abstract
| - The thermal and rheological properties of sago starch have been studied in the presence of variousconcentrations of locust bean gum and guar gum of various molecular masses. At the concentrationsstudied (<1%) the galactomannans gave rise to only a very slight increase in the gelatinizationtemperature (up to 0.6 °C), and the gelatinization enthalpy remained constant within experimentalerror. For the low molecular mass galactomannans, depending on the concentration, the storagemodulus, G‘, of the mixtures remained constant or actually decreased, and tan δ remained very low(0.01−0.03 at 0.1 Hz), indicating strong elastic gels. For the higher molecular mass samples G‘increased significantly; however, the loss modulus, G‘ ‘, increased proportionally to a greater extent,and at 1% galactomannan tan δ was ∼0.20 at 0.1 Hz, indicating a reduction in elastic character.The systems were shown to undergo phase separation, and the variations in rheological propertieshave been discussed in the context of their phase behavior and the relative rates of the phaseseparation and gelation processes. The presence of galactomannans significantly improved thefreeze−thaw stability. Keywords: Biopolymer; galactomannans; guar gum; locust bean gum; rheological properties; sagopalm; sago starch
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