Estabilidade de géis de amido de milho normal, ceroso e com alto teor de amilose adicionados de gomas guar e xantana durante os processos de congelamento e descongelamento

the objective of the present work was to study the effects of guar and xanthan gums on the stability of normal, waxy and high amylose corn starch gels, submitted to freeze-thaw processes. the gels of these starches with a total solids content of 10% and added gums (0.15;0.50;0.85and1%), were submitted to 5 freezing (20 hours, -18 °c) and thawing (4 hours, 25 °c) cycles, with exception of the high amylose gels that were submitted to only 1 cycle. syneresis (% water released) was determined by the difference between the initial and final masses of the samples. the normal corn starch gel released 74.45% water and the addition of 1% xanthan gum significantly reduced syneresis to 66.43%. the incorporation of 0.85 and 1% xanthan gum also reduced syneresis of waxy starch gels. the lowest level of syneresis was reached with the use of 1% xanthan gum in the high amylose corn starch gel, demonstrating the cryo-protective action of the gum.