Studies On The Cell Anti-Broken And The Thick-slurry Food Of Sweet Potato Granules

Sweet potato is the fourth largest crop in China. Sweet potato granule is an important industrial material for food industry, which could not only solve the storage and long distance transport problems of sweet potato but also promoted the value increase of food processing. Strengthening research on sweet potato granule and its food be of important significance to sweet potato industry upgrade and new rural construction.In this study, the optimal conditions for preparing sweet potato granule with high cell integrity was investigated using red sweet potato as raw material and adopting the relative rupture rate of cell as evaluation index. The explore of sweet potato thick-slurry food and the research on its viscosity and stability was carried out using the prepared sweet potato granule as a main material . Further investigation has been done on the effect of sodium sulfite on the molecular structure, pasting and gelatinization characteristics of sweet potato starch.Main research results:1. The optimal technology conditions that prepared the sweet potato granule with highest anti-broken ability of cell were as follows: preheated temperature was 60℃, preheated time was 10min, steaming time was 15min, and drying temperature was 60℃. At the condition of preheated temperature and steaming time, there was a significant negative correlation between BVI and WAI of sweet potato granule.2. The intrinsic viscosity was used to investigate molecular degradation of sweet potato starch caused by sodium sulfite or pasting temperature and time. According to free radical degradation mechanism of starch, the greatest degradation happened when the concentration of sodium sulfite was 0.04% at 95℃, which means that the oxidative reductive degredation of free radical has occured completely. The results also showed that the intrinsic viscosity of starch with sodium sulfite was lower than native starch at certain high temperature. Pasting temperature and time would effect the dissolution of starch molecules and the thermal degradation, which resulted in the changes of intrinsic viscosity. Thus, the lower pasting temperature need the longer time for thermal degradation.3. DSC and RVA results indicated that with the increase of sodium sulfite in sweet potato starch, the pasting and gelatinization characteristics of starch has been changed. The pasting temperature was elevated, the hot past viscosity was more stable, but the cold past viscosity would be more instabe and the starch was easy to aging. We could adopt appropriate addition of sodium sulfite according to actual processing requirement.4. Using the Ratio Coefficient of Amino Acid (RC) and Chemical Score (CS) as criteria, the optimal mixing rate of sweet potato granule and whole-milk powder was identified as 8:2. The mixing product was named sweet potato thick-slurry food, the nutritional index (NI) of the food increased from 3.52 to 6.39. The order of additives in affecting the stability of the food was Xanthan> CMC> sucrose> Glycerin monostearate.