Purification Of Inulin From Jerusalem Artichoke And Its Application In Whipped Cream

The extraction and purification technique of inulin from Jerusalem Artichoke and its application in whipped cream as fat substitute was studied in this paper.Inulin is formed with some fructose connected by the bondβ(1→2) which terminal is the unit of glucose.The degree of polymerization is from 2 to 60,Generally,the average degree is 10.Inulin is rich in tuber undergrounds of Jerusalem Artichoke.Inulin has many excellent functions and has been successfully applied in food industry as textural improver,stabilizer,antifreezer or anti-ageinger.Firstly,the extraction of inulin was studied to find the optimum method to produce inulin in large scale.The optimal conditions were as follows:temperature at 70℃,extracting time for 90 min,the ratio of material to water 1:15,times of continual extraction 2,the extraction rate was 97.65%.Secondly,the purification of inulin and its characters was studied.On the purification of the juice, Ca(OH)₂ was added to adjust pH 12,keeping in water at temperature 80℃for 1h,then adjusted pH 8 by adding phosphoric acid;the rate of wiping off protein was 65.28%.Then the solution was deposited by alcohol,stored overnight and centrifuged.A clear and colorless solution was obtained after treaded by D218 ion exchange resin.The rate of wiping off protein was 98.10%.Finally,the inulin was frozen dried and the purity was 96.23%.HPLCanalysis revealed that the MW of inulin was 2098 Da and its DP value was 13.Finally,the feasibility of taking inulin as fat substitute in whipped cream was studied.The overrun and foam stability decreased as inulin substituted more fat.When inulin substituted less than 50%fat,the overrun and foam stability time was similar with that of the whole fat sample.The melting point of whole fat and low fat samples were determined by DSC,which indicated that both could be melted in the mouth. The yield stress and thixotropy were determined by Rheometer.The yield stress and thixotropy-loop area decreased as inulin substituted more fat.When inulin substituted less than 50%fat,the yield stress was similar with that of the whole fat sample,thus it had good stability and daubility.When substituted less than 60%fat,the thixotropy-loop area was similar with that of the whole fat sample,thus the sample coule hold its shape.By measuring the G′,G″and tgδ,it revealed that the whipped cream belonged to elasticity system. The whole module of samples substituted less than 50%fat was similar with that of the whole fat sample, thus the system was stable and its intensity was big.The hardness was determined by texture analyzer.The sample substituted less than 50%fat could fashion fine veins,such as the whole fat samples.The sensory assessment indicated that the whipped cream substituted less than 50%fat could be accepted by consumers like the whole fat samples.Therefore inulin couldn't substitute more than 50%fat in whipped cream to get a sample like the whole fat ones.