Effects Of Maltodextrin Addition On The State Diagram And Enthalpy Relaxation Of Mango Powder

Mango is rich in nutrients,but fresh mangoes have high moisture content and are not easy to preserve.Mango is usually processed into mango powder in industrial production.However,the freeze-dried mango powder forms a non-equilibrium amorphous state that is hygroscopic.Therefore,maltodextrin is added to improve the storage stability of the mango powder.In addition,the mango powder may also undergo quality deterioration during the glassy storage,which is the occurrence of enthalpy relaxation.Therefore,the enthalpy relaxation behavior of with and without maltodextrin of mango powder during glassy storage will be further studied,in order to further reveal the mechanism of maltodextrin to improve the stability of mango powder.At present,there is little research on the quality stability of mango powder in glassy state during storage.Therefore,it is of great theoretical and practical significance to deeply explore the storage stability of glassy mango powder.In this paper,the effects of maltodextrin on the state diagram and the enthalpy relaxation behavior of mango powder were studied.The adsorption isotherm and glass transition temperature curves of mango powder at 25°C were obtained by static weighing method and differential scanning calorimetry(DSC).The effect of maltodextrin on the storage stability of mango powder was determined by the combined analysis of the two methods.The lost energy of the sample during aging was analyzed by DSC,and the non-exponential analysis of enthalpy relaxation was further carried out by using the KWW equation to study the enthalpy relaxation behavior of the mango system.By classifying the brittleness of mango powder,the enthalpy relaxation behavior during aging is further revealed.The main findings are as follows:(1)The adsorption characteristics of the adsorption isotherms of with and without maltodextrin mango powder are consistent with type III,and the addition of maltodextrin can significantly inhibit the hygroscopicity of mango powder.According to the fitting parameters of the GAB model,the monolayer moisture content of the mango powder was significantly reduced after the addition of maltodextrin.The T_g of mango powder decreases with increasing water content,but the addition of maltodextrin can increase the T_g of mango powder at the same water content.After adding maltodextrin,the critical moisture content(CWC)and critical water activity(CWA)of mango powder increased by 27.66%and380.65%at 25°C,respectively,which improved the storage stability of mango powder.(2)The physical aging of mango powder at 5,10 and 15°C under T_g has a significant effect on the T_g of freeze-dried mango powder.The lower the aging temperature,the higher the corresponding T_g.The non-exponential enthalpy relaxation of mango powder was studied.At the glass transition temperature,the average molecular relaxation time(?)of mango powder at lower temperature was greater than that of?at higher temperature.Finally,the mango powder is predicted to be strong system by the fragile index(m)of mango powder.However,its thermodynamic brittleness predicts that mango powder is a fragile system.(3)The mango powder with maltodextrin was aged at 5,10 and 15°C under T_g.Different aging temperatures had a significant effect on the T_g of maltodextrin added mango powder.The higher the aging temperature,the lower the T_g.The addition of maltodextrin can increase the T_g of mango powder.The average molecular relaxation time of the mango powder increased after the addition of maltodextrin.In predicting the fragile and strong of the added maltodextrin mango powder,there is a difference in the prediction of the fragile of the maltodextrin-added mango powder between the selected methods.However,the addition of maltodextrin reduced the dynamic fragile and thermodynamic fragile(?C_p)of mango powder.