Study On Preparation Processing And Properties Of Sweetpotato Resistant Starches

As a new kind of food additives, experts has great interest on the area of resistant starch. In thisstudy, taking sweetpotato starch as raw material, handling it with pullulan enzyme,microwave-enzymatic, pressure heat combined with enzymatic treatment to make sweetpotato resistantstarch and work out its optimum conditions. By studying the particle morphology, crystallinityproperties,pasting viscosity,swelling properties in vitro of sweet potato resistant starch, analyze therelationship between structure and anti-peptic.1.According to the results of single factor experiment and the orthogonal test(L934). The optimumconditions are as follows: pullulan enzyme dosage320ASPU/g-A, debranching time72h-B,retrogradation temperature-20℃-C,coagulation time48h-D,under this condition,the maximumproduction of RS reached to36.23%.After variance analysis, it was concluded that four factors impacton the yield of RS were very significant, from large to small was: B> C> A> D.2. Using microwave-enzymatic, on the basis of single factor test, by selecting microwave time(A),starch concentration (B) and pullulan enzyme dosage (C) three factors experiment design, it wasconcluded that the theoretical optimal conditions that microwave time303.08s, starch milkconcentration11.01%, pullulan enzyme dosage77.9ASPU/g,and the theoretical value of RS was31.6595%under the condition. The model P value0.0064showed significantly difference (P<0.01)andprediction regression equation that Y/%=31.06-0.71A+0.93B+0.80C+0.78AB+0.38AC+0.96BC-1.78A2-0.81B2-1.66C2.3.Using pressure heat enzymatic processing,(A)pressure heat time,(B)enzyme adding amount,(C)debranching time and (D)pressure heat-cooling cycles were chose into L934orthogonal test. The bestcombination: A2B2C2D3, namely pressure heat time30min, adding amount80ASPU/g, enzymedebranching time20h, pressure heat-cooling cycle four times, starch concentration10%, and repeated5times test under this condition, sweetpotato RS average yield was35.77%.4.Comparing and analyzing physicochemical properties of sweetpotato resistant starch with threedifferent fabrication processes. Scanning electron microscope(SEM) results showed that all processingsamples broken into irregular fragments,and particles morphology were subjected severe damage.X-raydiffraction analysis results revealed that most samples crystallinity increased except a few low RS sample of pressure-heat. The native C-type was transformed to A-type by water bath heating, afterabove three kinds of treatment, starch type from A to B+V. P value decreases in treatment samples.Takefinal glucose content as reference index in vitro digestion test.And it concluded that: all processingstarch final product were less than original starch, difference between them increased with RS growth.In addition, compared different process of corresponding six samples: pressure heat-enzymetreatment<microwave-enzyme<debranching enzyme processing.To sum up, through above three kinds of process, content of sweetpotato resistant starch wereincreased greatly, each process had its own advantage. Enzyme process is the best on the base of RSyield. From the standpoint of starch crystallization stability and digestive performance, pressureheat-enzyme process was optimal. If considered the time of obtaining RS sample, microwave-enzymeprocess was better. Therefore, best conditions’ selecting should according to the specific situation.