Synergistic Effect And Mechanism Of Corn Starch And Different Hydrocolloids

Starch is widely used in the food industry, either as a main ingredient of staple foods or as a food additive. For a wide range of starch applications properties of native starches do not meet industrial needs, functional properties of starches available on the commercial market are often modified to meet the needs of applications. In contrast to single starch system, starch and hydrocolloids mixed system generally exhibit unique properties. Many investigations have been carried out so far, using mixtures of starches and hydrocolloids to obtain desired properties or to replace modified starches. Starches and hydrocolloids are often used together in food systems to provide proper texture, control moisture and water mobility, improve overall product quality and stability, reduce costs, and facilitate processing. It is, therefore, important to understand interactions between starches and hydrocolloids that are critical to the functionalities they impart to food productes.This paper investigated the pasting and rheological properties of corn starch and different hydrocolloids (arabic gum, guar gum, xanthan gum) mixed systems. The results showed that the mixture pastes added with xanthan gum and guar gum exhibited a more significant thickening effect and superior viscoelastic properties. The synergistic interaction was much more pronounced in corn starch/guar gum mixed systems. The peak viscosities , final viscosities, K, modulus of corn starch were increased in present of guar gum. The arabic gum have opposite effect on the properties of corn starch. The peak viscosities and final viscosities of corn starch were decreased in present of arabic gum. An increase in the pasting temperature corn starch/guar gum or corn starch/xanthan gum mixed systems has been attributed to interactions between the hydrocolloids molecules and amylose molecules. The SEM images showed the starch/guar gum mixed systems presented a more uniform and tight network.This paper further investigated the effect of hydrocolloids on starch granule swelling, microstructure, and starch polymer leaching, and the mobility of the water molecule. The results showed that in the presence of xanthan gum or guar gum, most swollen granules had preserved their shape, and the starch granules appear prominently coated with gum. the addition of xanthan gum and guar gum causes T₂ to decrease, the mobility of the water molecule, as well as the degree of freedom was decreased by adding hydrcolloids. The starch granules became less swollen when heated in xanthan gum or guar gum solution. The xanthan gum and guar gum were found decreased the leaching of amylose from starch granules. The T_O,T_P,T_C,T_C-T_O were increased by adding hydrocolloid, butâ–³H decreased. The effect was much more pronounced in corn starch/xanthan gum mixed systems. After arabic gum is added, the pattern of the change in T₂ with temperature is similar to that of native starch. The segregative phase behavior of starch/arabic gum mixtures may occur because of thermodynamic incompatibility.This work presented the usefulness of combining multiple analytical techniques to better understand the retrogradatioon process of starch affected by different gums. The resulted showed the xanthan gum molecules exerted intermolecular interactions with the amylose molecules by hydrogen bond. The short-term retrogradation of amylose was prolonged and restricted by the present of xanthan gum. Compared to corn starch, the increase of G′was delay by adding hydrocolloid after 2h. The mixed gels were soft. Phase behavior of corn starch and hydrocolloids were studied. The phase separation behavior of corn starch/xanthan gum or corn/guar gum was not observed. The mixed system had the higher stability.The effect of the mixture containning corn starch and hycrolloids on the stability of chili tomato sauce was studied. The results showed that the sauce had better stability when corn starch and xanthan gum were mixed at a ratio of 9.5:0.5. During the storage stage, the hydrocolloids can protect the starch from the degradation by acid. Compared with the modified starch, the system can maintain the good viscosity and the higher consistency. Use of corn starch and xanthan gum as a thickener can reduce the dosage of starch and the total calorie of food system, and its actual production can replace or partly replace used modified starch in the food systems.