Papers by Author: Yan Ping Li

Abstract: Guar gum is a highly viscous water soluble heteropolysaccharide obtained from guar seed endosperm portion. Partially hydrolyzed guar gum (PHGG) is low in viscosity and has the healthy benefits as the dietary fiber. In this study, the effect of amount of acidolysis agent, ethanol content, acidolysis temperature and time on the acidolysis degree of guar gum was investigated by using the solvent method. The thermal properties were characterized by the idifferential scanning calorimeter and thermogravimetric analyzer, respectively. It was showed that the better conditions for preparing PHGG were: acidolysis temperature 40°C, acidolysis time 4h, ethanol mass concentration 61%, respectively. The freeze-thaw stability, expansion capability decreased after guar gum was partially hydrolized by hydrochloric acid. The onset temperature, end temperature and peak temperature of PHGG all increased, but its melting enthalpy and thermal stability were reduced, compared with those of guar gum.

Abstract: The properties of the acid modified kudzu starch such as the thermal stability of viscosity, swelling power, transparency, freeze-thaw stability, blue value, acid and alkali resistance, salt resistance and retrogradation was studied in order to enlarge its application in this paper. The thermal properties were analyzed by means of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The results indicated that the swelling power, transparency, freeze-thaw, acid resistance, alkali resistance, blue value increased with increasing the degree of acidolysis of kudzu starch. Compared with kudzu starch, acid hydrolysis increased the decomposition temperature, but reduced the enthalpy change from the thermal analysis.

Abstract: In order to improve the property of pueraria lobata starch, and enlarge application fields of pueraria lobata starch, this study involved in the optimization of determining parameters in hydroxyropylation conditions and the property of acid-modified hydroxypropyl pueraria lobata starch with low substitution degree (DS).Characterizations were carried out by analyzing the spectrum of the thermograms of differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The fludity was used for characterizing the degree of acid hydrolysis. The substitution degree was measured by the spectrophotometric method. The optimized hydroxyropylation conditions were as follows: reaction temperature 40°C, reaction time 18h, amount of sodium hydroxide 1.2%, amount of anhydrous sodium sulfate 12%, respectively. The properties such as the transparency, freeze-thaw stability, blue value, swelling power, retrogradation, acid and alkali resistance of acid-modified hydroxypropyl pueraria lobata starch were compared with those of pueraria lobata starch and acid-modified pueraria lobata starch. It was shown that acid hydrolysis and hydroxyropylation increased the decomposition temperature, but reduced the enthalpy value from the thermal analysis.