Effects Of Inorganic Salt Ions On The Gelatinization Of Corn Starch

Starch is a natural,renewable and degradable carbohydrate and is widely used in food and other industries.Starch gelatinization is a common phenomenon in starch applications and dramatically affects starch utilization.As a common additive in food industry,salt has various influences on the interactions between bio-macromolecules,such as protein and starch.Which can improve the performance of starch and meet the production needs.This paper mainly explores the interactions of various salt ions and corn starch in the gelatinization process,which provides a certain theoretical reference for the production of starch.The main research contents and results are as follows:(1)First,the cross polarization characteristics of the crystals were used to monitor the swelling of the starch granules at different temperatures and the equilibrium state reached in real time.The effects of the type and concentration of inorganic salts on the starch gelatinization process were investigated.The results show that different types of salt have different swelling ratios,which are mainly determined by the structure and ionic strength of the salt.The higher the general polarization phenomenon,the more obvious the inhibition effect of salt.And the higher the salt concentration,the lower the starch swelling rate.The addition of salt will change the thermodynamic angle parameters of starch gelatinization,which can reduce the enthalpy change and entropy change of the chemical reaction and inhibit the spontaneity of the reaction.The addition of salt will also affect the kinetics of starch gelatinization.The activation energy of the original starch solution is 221.04 kJ / mol,and the activation energy of the reaction is increased after the addition of salt.This indicates that the addition of inorganic salts will ionize the salt ions to bind with water molecules,so that starch gelatinization requires higher energy to overcome the hydrogen bonding of water molecules and salt ions,and increase the activation energy.The higher the salt concentration,the higher the activation energy.(2)The effects of different kinds and concentrations of salt on the properties of gelatinized starch were studied by infrared spectroscopy,X-ray diffraction and static rheology.The results show that the addition of salt increases the crystallinity and solubility of the starch granules,and causes unevenness of the starch gel and improves the stability of the starch gel.In addition,the higher the salt concentration,the higher the crystallinity and solubility of starch granules.(3)The micro-rheological technology was used to detect the change of the movement state of the starch system,and the mechanism of the effect of inorganic salts on starch gelatinization was explained from a microscopic perspective through the change of Brownian motion of starch particles.The experimental results show that the addition of salt will affect the micro rheological properties of the starch system.When the salt concentration is high,the salt associates with the starch granules to decelerate the starch diffusion.In addition,concentrated salt induces viscoelasticity reduction of aqueous solutions dispersed with starch particles,which may contribute to inhibit the gel formation.