Study On Determination Of The Color Value In The Process Of Sugar And Total Sugar Of Sugar Products

In order to provide a theoretical basis for the actual production of sugar factory, thedetermination of dry solids concentration and effect of reducing sugar on the measuring thetotal sugar of liquid sugar, and the color value of white granulated sugar were researched, aswell as mathematical models between the color value of white granulated sugar andabsorbance of intermediate material in UV-visible wave band were established in theexperimental base of sugar factory. The content and results of the research were as follows:1. Determination of dry solids concentration of liquid sugar was studied, results showedthat: result of dry solids concentration of liquid sugar measured in the ways of refractive waslarger than that in vacuum drying and the larger concentration was, the smaller D-value was.In the same concentration, the D-values of three types of liquids sugar were: syrup＞firstmolasses＞second molasses. When the dry solids concentration was higher than30%, theD-values reduced to be neglected, which meant that the ways of refractive could be used tomeasure dry solids concentration of liquid sugar under concentration higher than30%, and thedeviation need to be considered when concentration lower than30%and should use the waysof vacuum drying or regulating the results measured in the ways of refractive.2. Effect of reducing sugar on the measuring of the total sugar of liquid sugar wasstudied, results showed that: when the total sugar of liquid sugar was measured according toQB/T4093-2010, the invert sugar and reducing sugar such as fructose and glucose had effectson the sucrose proportion using once polarimetric method, the glucose made the result largerthan the actual value, and the F42, F55fructose made the result less, both of the effectincreased with the increase of the content of these reducing sugars. For the sucrose invertsyrup, the calibration relationship of effect was y=0.393x-0.100, which made the content oftotal sugar meet the requirement of being more than99.5%, reaching the requirements of totalsugar required in the QB/T4093-2010" Liquid Sugar",by using the sucrose hydrolysis to testand verify.3. Measuring of the color value of white granulated sugar was studied, results showed that:"the color values "of second-class, first-class, superior and refined granulated sugarincreased with the increase of pH, and significant exponential relationships were shown in thefirst three: y=5.996e^0.4955x, y=1.154e^0.6528xand y=8.9288e^0.2859x,"the color values " ofrefined granulated sugar increased by0.6with pH increasing by0.1. As the relationships of"the color values " and the second-class, first-class, superior granulated sugar show good, itcould be used in measuring of the color value without buffer system. Linear regressionsimulation analysis was made between the color value of superior and refined granulatedsugar and absorbance of their40%（w/w） concentration of sugar solution in the220nm,240nm,260nm,280nm,300nm wavelength, the mathematical model with best correlationwas: C=60.334A₂₂₀+16.657A₂₄₀-69.062A₂₆₀-20.220A₂₈₀+47.662A₃₀₀-50.207, R=0.965, ofwhich the prediction accuracy and robustness were good.4. Mathematical relation between the color value of refined white granulated sugar andabsorbance of intermediate material in UV-visible wave band was studied, results showed that:the mathematical models with best correlation in three stages of boiling sugar and hybridmodel established in the ways of Unitary Linear Regression（ULR） were: C₁=70.47A₃₀₀+9.12,R=0.813; C₂=32.70A₂₈₀+11.65, R=0.962; C₃=39.16A₂₈₀+3.18, R=0.912; C₄=1.09-0.17C₁+1.13C₂, R=0.965, the hybrid model had best prediction accuracy when predicting thecolor values of products using these models. Similarly, the models established in the ways ofMultiple Linear Regression （MLR） were: C₁=5.74+119.12A₂₂₀-204.34A₂₄₀-189.31A₂₆₀+286.89A₂₈₀-73.10A₃₀₀+171.89A₄₀₀, R=0.854; C₂=8.28+33.15A₂₂₀-83.29A₂₄₀+79.38A₂₆₀-30.93A₂₈₀+34.12A₃₀₀-9.29A₄₀₀,R=0.981; C₃=-15.56+103.31A₂₂₀-271.99A₂₄₀+160.01A₂₆₀-26.50A₂₈₀+49.25A₃₀₀+73.99A₄₀₀, R=0.912; C₄=-1.20+0.16C₁+0.89C₂, R=0.984, the hybrid modelhad best prediction accuracy when predicting the color values of products using these models.Last, the models established in the ways of Stepwise Regression Analysis （SRA） were:C₁=70.47A₃₀₀+9.12, R=0.813; C₂=12.60A₂₂₀+12.49A₃₀₀+12.35, R=0.970; C₃=39.16A₃₀₀+3.18, R=0.912; C₄=-0.42+0.05C₁+0.96C₂, R=0.970, the hybrid model had still the bestprediction accuracy. The results of three methods were compared comprehensively, althoughcorrelation and prediction accuracy of the hybrid model were the best, the workload of using it to predict the color value of product was also the largest for big amount of data involved, sothe model of intermediate stage using SRA, C=12.60A₂₂₀+12.49A₃₀₀+12.35, was consideredto be most appropriate when factors of workload, correlation and prediction accuracy weretaken into account, which could be considered using in the actual production process.