【作者】 王军；

【导师】 陈山；

【作者基本信息】 广西大学 ， 制糖工程， 2008， 硕士

【摘要】 影响成品糖色泽和色值的因素有很多,包括原料甘蔗本身带来的色素和生产过程中生成的有色物质,其中铁对制糖过程有色物质的生成有很大的影响。然而,目前尚无有关糖厂中间汁色值与铁质相互作用的深入研究。本文在综述了蔗汁色值研究现状、铁离子的测定方法及其化学性质、物质显色机理和蔗汁及白糖中铁作用机理的基础上,进行蔗汁中铁离子测定方法及不同价态铁对蔗汁色值影响的研究。其主要研究内容及结果如下:(1)采用膜分离技术对初压汁进行预处理,经处理的料液其浊度、色值、锤度分别降低了99.70%、84.23%、9.69%。可见,微滤可去除糖厂初压汁中大部分悬浮物、蔗屑、果胶和其他胶体等杂质。但是在微虑过程中,初压汁对膜组件的污染程度比较大,膜通量降低比较显著。(2)采用湿法消解、干法消解、微波消解方法处理制糖过程中间汁(各工艺段蔗汁),并利用火焰原子吸收光谱法测定了经不同方式消解后的蔗汁中的铁含量。结果表明:消解方法对铁元素的测定损失程度依次为:干法＞湿法＞微波消解法;试剂用量:湿法＞微波消解法＞干法;耗时:湿法＞干法＞微波消解法。同时,研究发现从初压汁到糖浆,蔗汁中铁含量的波动幅度很大。(3)采用原子吸收光谱法、邻菲啰啉法、EDTA络合滴定法所测得的初压汁中铁含量分别为:36.16μg╱g、35.73μg/g、35.50μg╱g。通过对试验数据的系统误差、精密度、准确度估计进行分析,得出原子吸收光谱法、邻菲啰啉法优于EDTA滴定法。(4)对系列浓度梯度的铁—水溶液、铁—蔗汁溶液的吸光度进行了研究。结果表明,随着铁含量的增加,吸光度增加显著;基于吸光度曲线分析,二价态较三价态铁对蔗汁吸光度的影响程度较低;通过单因素实验得出,温度、pH值、处理时间都可不同程度的影响蔗汁和加铁蔗汁的色值,并分析了各因素下料液色值的变化趋势。(5)采用Box—Behnken模型,设计正交试验,探讨了不同条件(温度、pH值、处理时间)下,蔗汁、“二价态铁—蔗汁”、“三价态铁—蔗汁”体系色值的变化规律;通过二次回归分析得到了温度、pH值、处理时间与色值关系的回归方程;通过响应曲面分析各因素对色值的影响程度和显著性。更多还原

【Abstract】 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.更多还原