Effect Of Microwave Preparation Of Dough And Heated-air Drying On The Quality Of Potato Starch Instant Vermicelli

Vermicelli facilitates the gradual rise of a convenience food in recent years, because ofits high value nutrition, good elastic toughness and flavor. It gradually likes by consumers ofall ages. Potato starch has high yield, good quality, unique properties, which is suitable formaking vermicelli. Microwave is a new type of heating technology. Microwave starchvermicelli has a better bomb toughness, not easy breaks off and cooking time is shortened,which provides a solid theoretical foundation for potato vermicelli study. In the process ofproducing vermicelli, drying method is the key to the production. Hot air drying is the maindrying method of vermicelli, whose application is simple and low cost. This paper studiedmicrowave processing potato starch to improve its dough glutinous, and thus facilitated thequality of vermicelli to ensure that potato starch vermicelli achieve better bomb toughness.This paper studied the β starch of vermicelli and the retrogradation properties of instantvermicelli, which provided guidance for the production practice.The potato starch dough was prepared using microwave treatment. The optimum processparameters were optimized when potato quality and water content and microwave power andmicrowave treatment time were as variable by response surface Box-Benhnken. The qualityof potato starch vermicelli was controlled and evaluated on the basic of comprehensivesensory evaluation.The results showed the best quality of starch vermicelli when potatoquality was5.47g, the moisture content of potato starch was54.34%and microwave powerwas426.98w and microwave processing time of microwave was15.23s.Instant vermicelli was dried in hot air drying method. With the increasing of hot airdrying temperature, the rehydration time of instant vermicelli was decreasing and therehydration rate of instant vermicelli was increasing. With the increasing of hot air dryingtemperature, the elasticity of instant vermicelli got bigger before they were smaller. When hotair drying temperature was50°Cand60°C, the elasticity of instant vermicelli was best. Withthe increasing of hot air drying temperature, the hardness of instant vermicelli has been toreduce, instant vermicelli was easier rehydration. The quality of instant vermicelli and theirinternal microstructure had the close relation. When drying temperature is30°Cand40°C, thestructure of the instant vermicelli is close and strong, less holes. When the drying temperaturewas50°C、60°C, the reconstitution properties of instant vermicelli was better. When thedrying temperature was70°C、80°C, instant vermicelli had a lot of holes. Instant vermicelli was full of the water so rapidly that elasticity and hardness of instant vermicelli became bad.In the meanwhile, instant vermicelli became paste soup and broke easily.Without the hot air drying and drying temperature30°C,40°C,50°C,60°C,70°C,80°Cof instant vermicelli heat enthalpy, in turn, was0.3530J/g、0.7223J/g、0.5812J/g、0.4036J/g、0.3973J/g、0.03799J/g、0J/g. The heat enthalpy of instant vermicelli reducedwith the increase of hot air drying temperature. Since starch crystal remelted which needabsorb heat reducing with the increasing of hot air drying temperature. The degree of β starchin instant vermicelli always declined, instant vermicelli was easier rehydration.Potato starch showed diffraction peak in2theta5.6°and17.33°and22.25°and23.99°,which was a typical type B diffraction pattern. Potato starch in microwave showed Adiffraction peak characteristics in2theta17.18°and23.89°. The instant vermicelli under hotair drying30°C,40°C and50°C showed V diffraction peak characteristics in2theta19.5°around, the crystal type of the instant vermicelli under hot air drying30°C,40°C and50°Cwas from the type A to V, the degree of β starch in instant vermicelli was larger. The instantvermicelli under hot air drying60°C,70°C also showed A diffraction peak characteristics, thedegree of β starch in instant vermicelli was smaller. The results shown that the degree of βstarch in instant vermicelli from high to low was the vermicelli which was made under30℃、40℃、50℃、60℃、70℃、80℃. This showed that the degree of β starch in instantvermicelli was smaller with the higher the drying temperature. The instant vermicelli kept thehigher the degree of α starch and easier rehydration.The results of DSC and X-ray diffraction were accordance, which showed the degree ofβ starch in instant vermicelli was bigger as hot air drying temperature was low. The degree ofβ starch in instant vermicelli was smaller as hot air drying temperature was high. When hot airdrying temperature was high, instant vermicelli can keep the higher the degree of α starchwell and easier rehydration.