Preparation And Plant Design Of Hydroxypropyl Maltodextrin

The technology and physic-chemical properties of hydroxypropyl maltodextrin fromboth maltodextrin and corn starch were investigated and the plant was preliminarily designed.In the following sections, detailed processes and results of the study were presented.The preparation technology of hydroxypropyl maltodextrin from maltodextrin wereinvestigated and the results showed that the reaction temperature acted as the most importantinfluence on degree of substitution affected the maximum, the reaction time followed, thenthe amount of propylene oxide was the third one, sodium hydroxide (NaOH) dosage had aminimal effect on the reaction. The optimum process conditions were: the reactiontemperature was35℃, the reaction time was18h, the amount of propylene oxide was12%,NaOH dosage was1%.The physico-chemical properties of different DE of hydroxypropyl maltodextrinprepared by direct method were studied systematically. The results showed that comparedwith unmodified maltodextrin, the hydroxypropyl maltodextrins’ transparency, transparentstability, freeze-thaw stability all increased, which were more obvious with the decrease ofDE; but the retrogradation reduced and this phenomenon was more clear as the DE decreased;the hygroscopicity increased and the absorbent rate of the hydroxypropyl maltodextrin werehigher with the increase of DE; whereas, its relative molecular mass and viscosity had littlechange.The preparation technology of hydroxypropyl maltodextrin from corn starch wereinvestigated and the results showed that the amount of enzyme had the maximum influence onthe enzymatic reaction, the reaction time followed, and then the reaction temperature had aminimal effect on the reaction. The best conditions of enzymatic hydrolysis of HPMD200、HPMD150、HPMD100and HPMD50were: the reaction temperature were all90℃, thereaction time were all35min, the amount of enzyme were120U/g,60U/g,30U/g and12U/g respectively.The physico-chemical properties of different degrees of substitution and different DE ofhydroxypropyl maltodextrin prepared by indirect method were studied systematically. Theresults showed that compared with unmodified maltodextrin, the hydroxypropylmaltodextrins’ transparency, transparent stability, freeze-thaw stability all increased, and the effects were more obvious as the degrees of substitution increased and the DE decreased; butthe retrogradation reduced, which was more chear with the increase of degrees of substitutionand the decrease of the DE; the hygroscopicity increased and the absorbent rate of thehydroxypropyl maltodextrin were higher with the increase of the degrees of substitution andDE; however, its relative molecular mass had little change.In consideration of technology and cost, maltodextrin and propylene oxide both werewater soluble and difficult to separate during the preparation process by direct method, so itneed plenty of ethanol to wash unreacted propylene oxide, but the indirect method didn’t havethe problem because it was easy to separate and wash. Therefore, to take all aspects intoaccount, the indirect method was better than the direct one.In this paper, hydroxypropyl maltodextrin prepared by indirect method was used toindustrial design including material equation and heat equation about hydroxypropylmaltodextrin, flow chart and floor plan. It provided the basis for a large-scale industrialproduction.