Study And Application Of Determination Metod For Suspension Index Of High Acyl Gellan Gum

High acyl gellan gum(HA)is a microbial polysaccharide produced by Sphingomonas elodea under aerobic conditions.It is widely used in the food industry due to its good suspension ability.The lack of quick suspension capacity determination restricts the application of gellan gum.Therefore,it is of great significance to establish a rapid and accurate method to determine the suspension capacity of gellan gum for the product modification and application promotion.In this paper,the effects of different factors on the stability of the cocoa suspension system were investigated by using Turbiscan Lab,and the effect of sterilization temperature on gellan gum solutions was also studied by the rheological tests.Then the relationship between the stability index and the rheological parameters of the suspension system was established by the mathematical model.And the purple potato suspension system was constructed for the further verification.The main contents and conclusions were listed as follows:The effects of gel concentration,pH,ionic type,ionic strength and sterilization temperature on the stability of cocoa suspension system were studied.With the increase of the concentration of high acyl gellan gum,the stability of suspension system was enhanced.When the amount of gellan gum up to 0.030%,the stability of the system was the best.In the range of pH 4.5 ? 6.5,the stability of suspension system was good.However,the suspension system became unstable when the pH value was lower than 3.5.Low addition of sodium ion and calcium ion changed the stability of suspension system little,but system became quite unstable when the sodium ion concentration exceeds 0.15% or the calcium ion concentration exceeds 0.06%.When the sterilization temperature was in the range of 85-100 ?,the suspension system was stable.While the temperature reached to 116 ?,the stability of the suspension system dropped sharply.The effect of sterilization temperature on the suspension ability of gellan gum was further investigated.The results showed that the sterilization temperature had no significant effect on the molecular structure of HA,but had a great effect on the rheological properties of the suspension system.With the increase of sterilization temperature,the elastic modulus of the system decreased,indicating that the sterilization temperature affected HA's ability to form network structures when it cooled down.The effects of gel concentration,pH,ionic type,ionic strength and sterilization temperature on the rheological properties of cocoa suspension were investigated by using a rotary rheometer.The results showed that the elastic modulus of the suspension system could sensitively reflected the stability of beverage system.Based on the lowest stability index of the system,the relationship between the stability index and the elastic modulus was established by using the Allometricl model,and the curve fitted well.Finally,the determination method was further verified by constructing a new floating system(purple potato beverage).The elastic modulus of 4 different kinds of gellan gum samples were measured to be used to convert the suspension capacity,and the particle size distribution,suspension stability,centrifugal precipitation and stability index of each sample were investigated.It was found that the intensity of HA suspension capacity was consistent with the stability of purple potato beverage,indicating that the method could accurately judge the suspension capacity of the gellan gum.