Study On Iron Ionic Mensuration Of Cane Juice And Its Effect On Icumsa Colour Of Cane Juice

Many factors can effect the lustre and color value of commercial sugar, including the pigments from raw material and production process. Among these factors, iron makes a great different to the formation of colored substance. However, there are still no deep research on the interaction between iron and color value of cane juice during the processing at present. This paper reviewed the current researches ,which contained the current research situation on color value of cane juice,the mensuration methods of iron ionic and its chemical properties, the mechanism for colour development in substances and the effect mechanism of iron with white sugar and cane juice. By studing the methods to determine the iron ionic of cane juice ande the effect of different iron ionic on color value of cane juice, primary research subjects and conclusions were summarized as follow:(1)The first expressed juice was pretreated by membrane separation technology. Its turbidity was reduced by 99.70%, colour value was reduced by 84.23%, brix was reduced by 9.69%. It showed that membrane separation was efficient to remove most suspension, bagasse, pectin and other colloid. However, the first expressed juice polluted microfiltration (MF) membrane seriously, and the flux of MF membrane reduced a lot.(2)Three sample digestive methods—dry digetion, wet digetion and microwave heating digetion procedures were used to digest the middle juice of sugar industrial process and the amounts of iron was determined by flame atomic aborption spectrophotometry(FAAS). The results showed: the loss level of iron determined by digestive methods were: dry digetion > wet digetion > microwave heating digetion; reagent dosage: wet digetion > microwave heating digetion > dry digetion; time consuming: wet digetion > dry digetion > microwave heating digetion; From the first expressed juice to the thick juice, the fluctuations of iron content of cane juice were great.(3)The iron content of first expressed juice was measured by flame atomic aborption spectrophotometry(FAAS), O—phenanthroline Photometry and EDTA titration. and the result were 36.16μg/g, 35.73μg/g and 35.50μg/g respectively. By analysis of the data obtained from systematic error,precision and accuracy estimations of the experiments,flame atomic aborption spectrophotometry(FAAS) and O—phenanthroline Photometry were superior to EDTA titration.(4)The absorbency of iron—water liquor and iron—canejuice of serial concentration gradients were studied: the absorbency was increased rapidly with increasing of iron content; Based on curve of the absorbency, the effect of Fe²⁺ was lower than Fe³⁺ to the absorbency of cane juice; The result from single experiments indicated that the colour value of cane juice and iron—canejuice was effected in different degree by temperature,pH value and dispose time. And the change trend were estimated.(5)By designing orthogonal tests base on Box—Behnken model, the variation law of colour value with cane juice, "Fe²⁺—canejuice" "Fe³⁺—canejuice" were observed on different conditions. The relational expression between temperature, pH value and dispose time were obtained by quadratic regression analysis. The degrees and significant of the effected of colour value were estimated by response surface analysis.