Study On Stability And Rheological Properties Of Oil In Water Emulsions Prepared By Food Grade Pure Gum

Emulsions have an extremely widely used in industry, agriculture, medicine, cosmetics, food and everyday life. In recent years, emulsion as an excellent carrier in food industry, which possess advantages in improving and extending the application of functional ingredients in food products gets more and more food researchers’attention. However, the emulsion system itself does not have the thermodynamic stability, and can be easily layering after standing for sometime. Therefore, it has very important significance that makes an intensive study of the emulsion system loss stability mechanism and caused stability mechanism and emulsion composition as the starting point. In this paper, emulsions are got with pure gum as emulsifier, and by studying the basic characteristics, stability and rheological properties of emulsions to investigated preliminary study of pure gum emulsions loss stability and caused stability mechanism.By studying basic characteristics, such as particle size, particle size distribution, absorbance, absorbance ratio and rheological properties of pure gum emulsions prepared under different homogeneous pressure conditions, with different oil phase, different emulsifier-oil ratio, to investigatd the effect of homogeneous pressure, oil phase and the content of oil phase on the stability of pure gum emulsions. The results showed that with the increase in homogeneous pressure, average particle size of the emulsion is reduced, the particle size distribution narrowed, the absorbance and SRI values decreased, when homogeneous pressure was above250bar, particle size of emulsion was not significantly reduced, SRI value was less than0.3, and showed Newtonian behavior, then the emulsion had good stability; The pure gum emulsion prepared with coconut oil had the smallest particle size, but the lowest absorbance, while emulsion produced with palm oil got excellent basic characteristics and higher apparent viscosity, and the shape of diluted and concentrated showed nothing instability phenomenon after30days, this emulsions got be stable; The emulsifier-oil ratio of1:1could prepare pure gum emulsion with the minimum particle size, As the oil phase content increased, the turbidity of the emulsion augmented, but the emulsion system got more unstable and showed non-Newtonian fluid properties. Overall consideration, pure gum emulsion prepared with250bar homogeneous pressure, palm oil, emulsifer to oil ratio of1:1had good stability in30days.By studying the particle size, stable kinetic parameters, steady and dynamic rheological properties of emulsions prepared by Purity Gum(PG) with different concentrations of xanthan gum (XG) addition, this paper investigated the emulsions’instability and stabilization mechanism, and prepared emulsion with long-term storage stability. The results showed that depletion flocculation was relatively easy to take place for PG emulsions adding0.1wt%and0.2wt%XG. The stability analysis showed that the stability index(SI) of PG emulsion without XG was stable for30d, after90d emulsion’s back scattering intensity reduced, while PG emulsion adding0.5%XG still had better stability within90d; Rheological properties test results showed that with increasing the content of XQ the apparent viscosity of the PG emulsion increased, flow index (n) reduced from0.939to0.414, thixotropic loop became large, the pseudoplastic of the system increased, the storage modulus (G’) of0.5%XG emulsion is greater than the loss modulus (G") and the8value was less than45°, a weak gel structure was formed, and the emulsion had long-term storage stability.The whey protein isolate (WPI) and pure gum (PG) had been prepared secondary emulsion WPI-PQ with the help of microstructure, by the changes of particle size and absorbance with time, the potential value, SRI value, stable kinetic parameters and rheological properties such as viscosity, creep resistance and temperature scan of WPI-PG emulsions prepared under different pH conditions or adding0.1M NaCl, to investigated the structural strength of the emulsion. The results indicated that as pH3WPI-PG comprehensive performance was better than other conditions; compared to Arabic gum (AG), whether adding O.1MNaCl or not, the particle size and SRI values of WPI-PG emulsions were lower than WPI-AG emulsions in the same situation, zeta potential have the opposite results, emulsions after standed at25℃for15d, the emulsions’ kinetic parameters, ABS and SI as follows, ABS were all under8%, SI values were lower than WPI-AG emulsions, therefore, in WPI-PG emulsions, steric stabilization mechanism dominates stability, and the emulsions had stronger tolerance to NaCl, PG was more easily mixed with WPI. Through the study of WPI-PG emulsions’characteristics under the addition of NaCl and different pH conditions, determined that the appropriate additive amount of PG at WPI emulsion was6%-9%.