Preparation And Properties Of Garlic Polysaccharide Octenylsuccinate

To widen the application of garlic polysaccharide(GP),the reaction between GP and octenylsuccinic anhydride(OSA) was investigated in water with alkalescence.The octenylsuccinic garlic polysaccharide(OSA GP) was purified by extracting and dialysing,then obtained by lyophilizing.(1) Analyzed the IR spectrum and ¹³C-NMR of GP and OSA GP.The OSA GP' degree of substitution(DS) was 0.0594.The carbonyl vibrations absorption peaks(C=O 1729.25 cm^-1),the ethylene vibrations absorption peaks(C=C 1576.97cm^-1) were identified by IR spectrum.These results have shown that the OSA GP was created successfully.By comparing and analyzing the differences between the ¹³C-NMR of GP and OSA GP,it can conclude that the esterification main happen at C₃ position of GP,then at C₆ position.(2) Studied the technological condition of OSA GP prepared from GP in aqueous slurry systems.The effects of reaction temperature,reaction time,reaction pH,GP concentration and OSA concentration on the DS of OSA GP were studied.Through the orthogonal test,the suitable parameters for the preparation of OSA GP were determined as follows:concentration of GP 20%, reaction time 7 h,reaction temperature 40℃,pH 9.0～9.5.The influences extend of factors from big to small are concentration of GP,reaction time,reaction temperature,pH of reaction system. Under this condition,the DS of product reached to 0.0239 and as more OSA was added,the DS was mounted up.(3) The emulsification of OSA GP is good and related to the DS.The emulsification increased as the DS did.Sucrose has no effect on emulsification when at low concentration,but it dose worse at high concentration.NaCl has little effect on the emulsification,increase it at low concentration while decrease when exceeds 6%.The OSA GP can keep good emulsification in acidity condition,and become bad after being froze-thaw.Although several times being froze-thaw,it still has some emulsification.(4) OSA GP can stabilize protein.OSA GP make protein in yoghourt more stabilized,than CMC-Na dose.It also can be applied in yoghourt compounding with CMC-Na and trimeric sodium phosphate.And at the best combination CMC-Na 0.4%,trimeric sodium phosphate 0.08%,OSA GPâ…¢0.3%,the centrifugal sedimentation rate is 27.68%.