Study On Effects Of Hydrocolloids On Characteristics Of Tapioca Starch And Derivatives

In order to reveal the synergy principle between food gum and starch, four kinds of food gums, xanthan gum, guar gum, sodium alginate, arabic gum, and three kinds of starch, tapioca starch, anionic tapioca starch, cationic tapioca starch were selected/studied in this paper. The effect of food gum on properties of tapioca starch and its derivatives paste was investigated by using Bradender Viscoamylograph, scanning electron microscope and Haake rheometer. Results of the experiment were as follows:The addition of either xanthan gum or guar gum increased peak viscosity and breakdown of tapioca starch, anionic tapioca starch and cationic tapioca starch separately, while arabic gum exhibited opposite trend. Xanthan gum, guar gum, and sodium alginate promoted the swelling of tapioca starch granules. Owing to the electrostatic interactions between moleculars, xanthan with negative group could promote the swelling of anionic tapioca starch granules, but inhibited the swelling of cationic tapioca starch granules. Neutral guar gum had little effect on the swelling of anionic starch and cationic starch.The results of freeze-thaw stability indicated that the addition of xanthan gum, guar gum, sodium alginate decreased syneresis of tapioca starch and anionic tapioca starch paste; the addition of sodium alginate and xanthan gum increased the syneresis of cationic tapioca starch paste and weakened its freeze-thaw stability, even cationic tapioca starch had good freeze-thaw stability itself. Cationic tapioca starch paste had no syneresis when guar gum existed, even after five the freeze-thaw cycles. Xanthan gum, guar gum, sodium alginate made cavities in network formed by tapioca starch gel became larger, and the network membrane became thinner. When more xanthan gum, guar gum was added to replace anionic tapioca starch (5.4/0.6), the syneresis of anionic tapioca starch dropped to low levels since anionic tapioca starch gel cannot fully form network structure. Xanthan gum, sodium alginate could make cationic tapioca starch gel form apparent network structure but guar gum failed to make it.The result of rheological properties indicated in the test range, power law model was observed for starch pastes of tapioca starch/food gum system, anionic tapioca starch/food gum system, cationic tapioca starch/food gum system, and each paste was pseudoplastic fluid. The total starch gels were weak gels, the storage modulus was always higher than the loss modulus. The addition of xanthan gum, guar gum decreased tanδvalue of three kinds of tapioca starch gels, the gels tend to a more solid-like behavior, and the effect of xanthan gum was highly greater than that of guar gum; sodium alginate increased tanδvalue of three kinds of tapioca starch gels, the gels tend to a more fluid-like behavior; Arabic gum had little effect on tanδvalue of three kinds of tapioca starch gels.