Studies On Extraction And Rheological Properties Of Pectin From Tangerine Peel Waste

Tangerine peel is one good kind of pectin resources, whose waste is great and pollute environment. At present 80% domestic pectin depend on import because of their deep color and poor quality. We investigated the extraction of citrus pectin, which has an important meaning to develop China's citrus industry and food additives industry.Pectin's rheological properties play an extremely important role in food processing, and many factor could influence rheology. The subject researches the concentration, temperature, metal ion, pH value and high-speed shear how to affect rheological properties, aiming to provide the theory basis for the development and utilization of pectin in thickening, stability and gelatin etc.(1) Citrus pectin is extracted by using two different processes from tangerine peel waste. Anglicizing the basic physicochemical properties and considering the extracting rate and case, the best process could be established:firstly extract citrus pectin via strongly acidic ion exchange resin and then after predicate pectin via AB-8 type of macro porous adsorption resin column ion, which can solve the problem about deep color and poor quality.(2) Effects of concentration and temperature on rheological property of citrus pectin solutions were studied. The citrus pectin was pseudo plastic fluid. The viscosities increased with the increasing of concentration. When processing temperature rise to 80℃above, viscosity is very low, and pectin tended to Newton fluid.(3) Effects of different metal ion on rheological property of citrus pectin solutions were discussed. Ca2+could increase pectin solution viscosity, while Na+ K+,Mg2+ and Fe2+ all made viscosity decreased. The solution viscosity was 10 times of initial viscosity by adding Ba2+, and "Instantaneous gel" occurred in the addition of Fe3+.(4)Effects of pH value on rheology of pectin solutions were researched through different concentration of acid and alkali. Pectin viscosity gradually reduced with the increase of acid concentration and lowest when H+was 0.01mol/L. Low concentration of alkali could make pectin solution viscosity increasing, and the viscosity increased with the concentration of OH-. When the concentration of OH- was more than 0.007 mol/L, high levels of alkali all could make the viscosity decrease, and the viscosity decreased with the concentration of OH-.(5) The influences of shear treatment on rheological property of pectin extracted from tangerine peel have been studied. It's shown that, the viscosity of citrus pectin solution decreased with the increasing of shearing speed, and pectin solution tended to Newton fluid when the shear speed was 21,500 r/min.