Effects Of NaCl, Sucrose And PH On Gelatinization And Aging Characteristics Of Millet Starch And Millet

Millet is rich in nutrition, it is often be viewed as a kind of diet therapy health food. It is notthe main food, though appears in people’s daily life widely. In addition to being the raw materialsof millet porridge in daily life. The development of convenient food and functional has becomean inevitable trend of the new millet product. In order to explore the effects of the gelatinizationand aging characteristics of millet starch and millet flour which added NaCl、sucrose and pH.With the method of alkali process to extract the starch from millet in this experiment and refine it.Use the millet starch and millet flour as the materials in this experiment. Research the effects ofgelatinization and aging characteristics of millet starch and millet flour.Millet starch has different shapes and different sizes, the granule of starch presents oval andpolygon under the Scanning Electron microscope (SEM). Using the Laser Pariticle DistributionInstrument to test the particle distribution of millet starch, the result showes that, the average size(D50) of millet starch particle is10.20μm. The material of this experiment is Tuo-Gu milletwhich plants in Zhao Zhou, the content of amylose is (20.53±0.13)%, and the content of solubleamylose is (9.98±0.09)%. Added different mass fractions of NaCl、sucrose into the millet starchand millet flour, or adjust the pH by citric acid and sodium hydrogen carbonate, research theretrogradation, transparency, solubility, swelling properties and textural characteristics. Theresults showed that NaCl promotes the millet starch paste to retrogradate and reduces thepellucidity; Sucrose restrains the millet starch paste to retrogradate and increases the pellucidity;The citric acid promotes the retrogradation characteristics of millet starch paste and reduces thelight transmission rate; Adding Sodium Hydrogen Carbonate inhibites millet starch paste toretrogradate, and enhance the transparency of starch paste; Adding NaCl makes the hardness andcohesiveness of millet starch paste and millet flour paste increase, but reduces the viscosity andrecovery; Adding the sucrose into the system, the elastic, cohesiveness and restoration areincreased, but the hardness is decreased; Adding Citric Acid reduces elasticity, cohesiveness andrestoration, enhance the hardness of them; Adding Sodium Hydrogen Carbonate increases theelasticity, cohesiveness and restoration of millet starch paste and millet flour, reduces thehardness of the systerm. Research the gelatinization characteristics of millet starch and millet flour by usingdifferential scanning calorimeter (DSC). The results showed that: under the same conditions, thegelatinization temperature(including initial gelatinization temperature T0, peak gelatinizationtemperature Tpand pasting termination temperature Tc) of millet starch is2.65±0.87℃lowerthan millet flour’s; the gelatinization enthalpy (△H) is2.51±0.32J·g-1higher than millet flour’s.The gelatinization temperature of millet starch and millet flour is reduced which added NaCl andsucrose. The gelatinization temperature of millet starch and millet flour added NaCl is4.30±1.24℃higher than the ones of which added sucrose; The citric acid inhibits the starch and flourgelatinization, and the sodium hydrogen carbonate accelerates this process.Research the aging characteristics of millet starch and millet flour by using rapid viscoanalyzer (RVA). The results showed that: under the same testing conditions, the viscosity ofmillet sharch is（3200±296）cp higher than millet flour’s; The setback value of millet starch andmillet flour which adds NaCl is（1366±422.06）cp higher than those adds sucrose. The citric acidpromotes the system aging, but the sodium hydrogen carbonate inhibits the system aging. Put themillet starch paste and millet flour paste at4℃, in the first3days, the aging rate is rise fastest,when the time of storage more than25days, the aging of syetem is tend to placid, has no obviouschange.