Characterization Of Lipu Taro Starch And Effect Of Processing Conditions On Its Emulsification And Application

Lipu taro(Colocasia esculenta)is a characteristic agricultural product of Guangxi.As the main component,Lipu taro starch has a very high value of development and utilization.But for a long time,Lipu taro is limited to the primary processing of meat products as an auxiliary material or used to make fried food,its development and utilization has been in the primary stage.In order to promote the deep processing and application of Lipu taro,the physicochemical properties of Lipu taro starch were systematically characterized in this study,and found that its particle was small,as an emulsifier has a certain application potential.Therefore,the influence of different processing conditions and other factors on the emulsification of Lipu taro starch was further studied in order to do basic research for the development and application of Lipu taro starch-based emulsifier.The main results are as follows:1.Structural and technological characteristics of Lipu taro,japonica rice,corn,wheat and yam starch were characterized by scanning electron microscopy,laser particle size analyzer,X-ray diffraction(XRD),fourier transform infrared spectroscopy(FTIR),solid state nuclear magnetic and high performance gel permeation chromatography(HPGPC)and other methods.The results showed that: Lipu taro starch showed irregular polygons with the smallest average particle size(2.29 μm),which was half of that of japonica rice starch,but significantly different from other starches.Lipu taro starch had the same A-type crystal structure as japonica rice starch and other starches,while yam starch had the C-type crystal structure.The crystallinity of Lipu taro starch was the highest(38.36%),15% higher than that of japonica rice starch,but much higher than that of other starches.The analysis of FTIR and solid state nuclear magnetic were further showed that Lipu taro starch had more ordered structure.HPGPC results showed that Lipu taro starch had the smallest molecular weight and concentrated distribution.The amylose content of Lipu taro starch was the least(17.21%),which was similar to that of japonica rice starch,but significantly different from that of other starches.The iodine absorption curve showed that the absorption peak intensity,average polymerization degree(56)and iodine blue value(0.23)were the least,which indicated that the molecular weight distribution of amylose was larger.Under the influence of amylose content,the solubility and swelling power of Lipu taro starch changed the most,which were1.68～68.86% and 2.86～38.54 g/g,respectively.Lipu taro starch showed the best anticoagulation property,and the syneresis rate was 2.5% after standing for 7days,while the syneresis rate of other starches was higher.Lipu taro starch had the lowest Lipu taro(20.97%)and better freeze-thaw stability than other starches.In addition,Lipu taro starch had the highest oil retention(158.33%)and water retention(136.24%).2.Rheological properties,thermal properties and gelatinization properties of starch were characterized by rheometer,differential scanning calorimeter(DSC)and rapid viscosity analyzer(RVA).The results showed that the hardness and viscosity of gel structure of Lipu taro starch paste was the lowest under certain conditions.The gelatinization temperature of Lipu taro starch was the highest(80.37 ℃),and the viscosity value,regression value and disintegration value were all small,indicating that the particles of Lipu taro starch were easy to expand and break when heated,but had good anti-aging properties.The Lipu taro starch based-emulsion that was prepared under the conditions of 2% starch content in water phase and 50% oil phase volume was stable within 30 days and the droplet size was the smallest(34.64～52.20 μm).Other starches could not stabilize the emulsion,which indicated that Lipu taro starch had certain application potential as emulsifier.3.Lipu taro starch was treated by ultrasonic,freeze-thaw process,complex enzymes(α-amylase and saccharifying enzyme),pullulanase and sulfuric acid,the starch obtained were respectively ULTS,FLTS,ELTS,PLTS and ALTS.PLTS with the smallest average particle size and the best wettability showed the best emulsification ability,with the emulsification index(EI)of 79% and 5%higher than that of ALTS,which was significantly different from other samples.Moreover,PLTS had the smallest droplet size(10.83～23.81 μm)during the30-day storage period.4.The influences of the preparation process of PLTS and the environmental conditions of PLTS-based emulsion on emulsification effect of PLTS were explored.The results showed that the optimal emulsification capacity of PLTS was obtained under the conditions of enzyme concentration of 30 U/g,enzymolysis temperature of 60 ℃,enzymolysis time of 8 h and recrystallization time of 24 h.When the PLTS content in water phase was less than 3%,the oil phase of liquid paraffin,the oil-water ratio of 2:3～3:2,the Na Cl concent of 0～1m M and p H of 3～7,the stability of PLTS-based emulsion was better.5.PLTS was used to replace part of lipidic in the production of salad dressing.The results showed that compared with the commercial salad dressing,the fat of PLTS base salad dressing was reduced by 30.8～42.9%,the energy was reduced by 42～49%,and the carbohydrate was increased by 1.3～10.3%.PLTS base salad dressing was salty and sour,and had uniform texture and less solid characteristics.It was of great practical significance to further explore the application of Lipu taro starch.