Rheological And Textural Properties Of Kudzu Starch

Kudzu,belongs tothe root of legume plantPueraria lobata,is rich in starch and distributed widely in China,contains high value both in food and medicine.The flowing regulation properties of Kudzu starch paste have an important effect on its processing design as well as process management.The texture properties of Kudzu starchgel are important indicators for food quality.In this study,Kudzu starch were used as raw material to research the physical and chemical properties such as particle morphology,crystal properties and thermodynamic properties.Then the effect of four factors: starch concentration,the addition of sodium chloride,sucrose and maltodextrin on rheological properties,texture andthe effect ofstarch concentration on microstructure were studieddeeply,and the regulation and internal changes were analyzed.The main conclusions are as follows:1.The morphology,particle size and crystal characteristics of Kudzu starch showed that:(1)The surface of Kudzu starch granules is smooth,sector,irregular polygon.(2)X-ray diffraction pattern of Kudzu starch is a typical C-type diffraction pattern.Furthermore,the crystallinity of Kudzu starch is 17.50%.(3)The pasting temperature To of the starch is(57.27± 0.04)℃,the peak temperature Tp is(69.06 ± 0.03)℃,the end gelatinization temperature Tc is(78.45 ± 0.06)℃,the enthalpy of gelatinization ΔH is(3.53 ± 0.02)J/g.2.Therheological properties of Kudzu starch paste showed that:Kudzu starch paste is a typical shear-thinning non-Newtonian fluid,and the storage modulus(G’),loss modulus(G’’)and apparent viscosity(η)of Kudzu starch paste are influenced by the four factors.Dynamic rheological properties research showed that G’ and G’’ were positively correlated with the concentrations of starch;in a specific range,as the increasing of the amounts of sodium chloride,sucrose and maltodextrin,G’ and G’’ were first increased and thendecreased.The result of steady-state rheological properties showed that on the same shear rate,η was positively related with the concentrations of starch and negatively correlated with the adding amounts of maltodextrin;in particular range,as the increasing of the amounts of sodium chloride and sucrose,η was first increased and thendecreased.3.CharacteristicKudzu starchtexture showed that:(1)TPA measurement results showed that as the starch concentrationincreasing,thehardness,springiness,cohesiveness and gumminessof gel were all rised.And they were first increased and thendecreased with the increasing of the amounts ofsucrose and maltodextrin.With the increase of the addition of sodiumchloride,thehardnessand springinessof gel were first increased and thendecreased,and reached a maximum at the concentration of1.0% sodium chloride.(2)The results of gel strength measurementshowed that gel strength rised with the increasing of Kudzu starch concentration.Gel strength first rised then dropedwith the increasing of the additionof sodium chloride,sucrose and maltodextrin,and reached a maximum with concentration of 0.5% sodium chloride,8%sucrose and 1.0% maltodextrin respectively.4.Kudzu starch gel microstructure showed that: The higher the concentration of starch,kudzu starch gel’s three-dimensional network structure is more compact,more uniform,the hole size is relatively uniform.