Study On Processing Technology Of Potato Granules

The potato granules powder is a dehydrated product of fresh potato,which cannot only be preserved for a long time,but also has the similar nutrition,flavor and taste of fresh mashed potato after rehydration.Therefore,it is a good raw material for potato foods processing.In this paper,in order to solve the problems of poor color and broken cells in the process of potato granules powder resulted in serious losses of flavor substances and nutrients,high content of free starch and excessive viscosity,the suited potato assortment and the best technology for preparing potato granules powder were selected.The effects of low temperature blanching and calcium infiltration on the cell walls to reduce the amount of free starch in potato granules powder were also studied in order to obtain a new kind of potato granules powder with good color,integrity,high retention of flavor substances and nutrients and convenient application,the main research contents are as follows:?1?Selection of suitable variety for processing of potato granules powderBased on the collection of 12 potato varieties and according to the quality requirements of the potato granules powder,the preliminary selections of Jizhang 8,Longshu 3,Kexin 14 and Yam 4 were the test varieties,the indexes of dry matter,starch,amylose,vitamin C,reducing sugar,protein,PPO enzyme activity and granules powder yield of raw potato were detected respectively,and the variation coefficient method was used to score the 8 indexes synthetically.The results showed that Longshu 3 had the highest comprehensive score of 11.04,followed by Yam 4 was 9.58,while that of Kexin 14 and Ji Zhang 8were lower by 7.8 and 6.25 respectively,so that Longshu 3 with the highest comprehensive score as a preparation of potato granules powder processing variety.?2?Comparative study on processing technology of potato granules powderAt present,the domestic processing of potato powder granules powder used in the process of backfill process and slicing process,etc.,on this basis scraper process had been proposed,the effects of different processing techniques on physical and chemical properties and sensory characteristics of potato granules powder were also discussed.The results of the study showed that the rate of free starch of granules powder obtained by the scraper process was the lowest?4.81%?through the detection of the rate of free starch,the result showed that the granules powder cells obtained by the scraper process had high completeness and better retention the nutrition and flavor substances contained in the fresh potato;the rate of free starch of granules powder obtained by the slicing process was the highest,it was 7.51%,it showed that a large number of cells were destroyed and more free starch was released,and by detecting the water holding capacity and oil holding capacity of granules powder can also reflect the scraper process of the granules powder had a better quality.From the detection and analysis of the nutritional components of the potato granules powder,the granules powder prepared by the slicing process had a lower content of nutrients than the scraper and backfill processes due to the longer time of heating and drying.From the analysis of sensory evaluation,potato granules powder prepared by scraper had the better color and flavor than the granules prepared by slicing and backfill processes.Even though the process of slicing was relatively simple,the free starch of granules was in a higher rate and poor dispersion,and also there was a group phenomenon which affected the quality of granules powder.?3?Scraper process parameters optimizationThe rate of free starch in potato granules powder was reduced by low temperature blanching and leaching of calcium treatments,the optimum condition of scraping process was in low-temperature preheating?60??,calcium concentration was 150mg/kg and steaming time was 35min,the regression equation was R=4.13-0.85A-0.58B-0.35C+0.67AB+0.35AC+0.60BC+1.37A²+0.82B²+0.57C²,It can also predict the theoretical value of the free starch in granules powder under this condition was 4.32%.?4?Studying on relevant anti-crushing mechanismLow temperature preheating can significantly increase the activity of pectin methyl esterase?PME?and through the detection of anti-fragmentation index found that the value of unbreakable with low temperature preheating of potato tissue was 1.8 times than the raw potato tissue;PME and Ca²⁺can form a bridge to effectively enhance the cell wall strength,PG and?-amylase which can lower the negative influence on potato cell walls strength,thereby reducing the free starch rate.?5?Physical and chemical indexes and application characteristics of potato granules powderThe potato granules powder made by optimized scraper processing was better than that of market-sold potato granules powder,browning degree was low,its color was similar to fresh potatoes,and the free starch rate was low?4.81%?;The physicochemical properties of the self-made granules powder and market-sold granules powder were also determined.The water retention,oil retention,and freeze-thawing stability indexes by self-made potato granules powder were all lower than those of market-sold potato granules powder.The values from the physicochemical properties can also be further demonstrated that the self-made granules powder had a low rate of free starch and better integrity of the cells.These characteristics show the high quality of the potato granules produced by the scraper process,and the flavor and texture of processed products were similar to that of fresh potatoes.