Studies On Preparation Of Potato Granules And Its Application

Potato granule was made from fresh potato. The processes included cleaning, peeling, slicing, boiling, breaking, drying and so on. Owing to its low water content, the potato granule could be stored for a long time and kept the flavor and nutrition of fresh potatoes. This research mainly studied the methods of browning inhibition of potato granules, the preparation of potato granules and the technologies of baking potato granules cookie.Taking catechol as the substrate, the optimum pH of the potato polyphenoloxidase (PPO) was6.0and the optimum temperature was25℃. The inhibition effect of Sulfite, Ascorbic acid, Phytic, Citric acid and L-cysteine on potato granules was better than other color fixatives. The best conditions were blanching time2min, solution temperature70℃and color preventing time20min. When the concentration of sulfite was higher than0.35%, the effects were no longer significant. The residue of sulfur dioxide exceeded the standard. Through the single factor and orthogonal experiment, the results showed that the best conditions were Ascorbic acid for0.10%, the concentration of Phytic for0.30%,Citric acid for0.40%,and L-cysteine for0.35%. This result could effectively restrain browning of potato granules.The potato slices were dried under50℃、60℃、70℃、80℃and90℃. The results showed that along with the elevation of temperature, the drying rate of potato dried by hot-air was bigger. The thicknesses of potato slices were respectively0.1cm、0.3cm、0.5cm. The results showed that along with the increase of thickness, the drying rate of potato dried by hot-air was smaller. In order to reduce the drying time and obtain potato granules of high quality, the potato which was smaller than0.3cm was dried at50-60℃by hot-air for6-8h. Dried by microwave, the drying time was shorter than hot-air drying, from few hours to several minutes.The results showed that cooked potato granules were different from raw potato granules in phy-chemical properties and function properties. The raw potato granules’ gelatinization was more difficult than raw potato granules. The contents of starch, reductive sugar and ash were different, while the contents of protein and fat were close. The cooked potato granules had a higher water absorbing ability than raw potato granules, but the oil absorption ability, foaming quality and foam stability were lower.After adding potato granules into flour, the cookies would have crisp taste and good quality. The results showed that the best conditions of developing cookies were potato granules40%, sugar40%, grease30%and loosen agent0.8%. The best technologies were200℃and8min.