| Original peach gum is the solid material coming from the peach tree [Prunus persica(L.) Batsch] and it has no good water-solubility. In China it is used as Chinese traditional medicine with no industrial value. Commercial peach gum which is also called prepared peach gum (PPG) can be got from original peach gum by cleaning, hydrolyzing and drying. As a substitute of arabia gum, it has enough water-solubility, proper viscosity, and it has being widely used in many industries. The purpose of this dissertation is to study the preparation, properties and application of peach gum.Firstly, the effect of alkali hydrolyzation, decoloration, removing minerals on the process of PPG was studied. The results showed that in the process of alkali hydrolyzation, 500 nm was observed to have the optimal wavelength when measuring the content of xylose. The optimized process was selected by orthogonal design, at 85~90℃, pH 10~11, 2%~3% of the content of the original peach gum. According to this process, steady and transparent solution could be obtained. The optimum conditions of active carbon decoloration were selected by single factor and central composite rotatable design experiments with discoloration ratio as index, the optimum conditions were: 31℃, pH 4.8, 2% amount of active carbon at 31 min. At those parameters, more than 82.45% of the discoloration ratio was obtained. When the strong acid cation change resin and alkalescent anion change resin were used, the conductance of hydrolyzing solution of peach gum declined to less than 200μs·cm-1. The obtained ratio of PPG was 80.53%, and its technical indexes were up to the standards of JECFA (Joint FAO/WHO Expert Committee on Food Additives), this makes the product to be utilized in the food, medical and chemical industries.Secondly, the rheological properties of PPG were studied. The results showed that the apparent viscosity of the gum solution was greatly influenced by the concentration, temperature and pH. At the same time, it had good frozen-thawing stability, acid-resistance and salt tolerance, it was pseudoplastic fluid. PPG couldn't be induced to form gel by monovalent, divalent and tribasic cations. PPG had better emulsification and emulsion stability than arabia gum.Lastly, rheological properties of dough and qualities of noodle were studied. According to the farinographic analysis, water absorptivity and stable time of dough increased while weak value significantly decreased when the proper amount of PPG was added. This was also verified by SEM and dynamic rheology measurements. The gluten continuous phase of dough with the addition of the proper amount of the PPG appeared to be more dense and uniform than the dough without the PPG. The viscoelastic property of dough was also observed to increase when the proper amount of PPG was added to it, the noodles exhibited higher hardness, gumminess and chewiness than those without the PPG. For the turbidity of soup and solid loss after cooking, they were both reduced. This also makes the PPG to be used in noodle making as an improved agent for wheat flour.
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