Study On Texture Properties Evaluation Of Sweet Potato

Different varieties of sweet potato were used as raw material to be measured through texture ofsweet potato, sensory evaluation, physicochemical index evaluation in our study. Mechanicaldifferences were analyzed at different positions of sweet potato, the correlation between textureproperties index and physicochemical indicators, principal component were tested. Furthermore, thetexture properties indexes of cooked sweet potato were measured in order to build a predictable modelof sensory evaluation. And basic chemical composition, texture, physical property, viscosity of differentdrying methods to sweet potato were characterized by chemical means, texture test, SEM, RVA,respectively.Through TPA study of test analyzer to different part of the Vietnam purple potato, the resultsshowed that texture index (hardness, elasticity, cohesiveness, chewiness) in different part of sweetpotato existed significant differences(p<0.05), and correlation among every texture properties indexdisplayed some difference. Cohesiveness and elasticity were significantly positively correlated (r=0.656)and chewiness (r=0.929), elasticity and cohesiveness were significantly positively correlated (r=0.845).Optimization of texture experiment revealed that: different testing methods had a tremendousinfluence on the results. According to optimizations, the best puncture test condition of sweet potatowas P5probe, speed less than1.5mm/s, depth more than or equal4mm; The shear test of sweet potatowas a half shear, speed less than1.5mm/s; The TPA test of sweet potato was P/75, speed less than1.0mm/s, compression degree less than40%.The analysis of correlation analysis and principal component were carried on12qualitycharacteristics (physicochemical index and texture index) of19sweet potato cultivars. Results showthat there was a significant correlation between physicochemical characters and texture indicators. Fourprincipal components were extracted from the principal component analysis, and their rate ofcumulative variance contribution was84.13%.The sensory evaluation and TPA analysis were performed through cooked sweet potato, exceptsensorial viscosity and sweetness, other each individual index of sensory evaluation could be predictedfrom TPA texture parameters.The effect of different drying methods on quality characteristics were researched, the resultsshowed that the ability of preservation on functional nutrient (such as anthocyanins, beta-carotene andflavonoids) was better, the sun drying resulted in the largest hardness followed by hot air drying,microwave drying and vacuum frozen drying. The results of RVA and SEM displayed that vacuumfrozen drying was best for sweet potato starch, hot drying second.