【摘要】： 隨著科學技術的發(fā)展,物理方法在變性淀粉制備中的地位越來越重要。通過物理方法處理的淀粉,不含化學試劑的殘留,其產(chǎn)品的理化性質(zhì)得到明顯改善,產(chǎn)品應用范圍和附加值也大大提高。微波處理具有加熱速度快、加熱均勻性好、易于瞬時控制、選擇性吸收以及加熱頻率高等基本特性,目前作為一種方便、節(jié)時的加熱能源廣泛應用到食品和化工領域。 本論文以玉米原淀粉為原料,分別用過氧化氫和混合磷酸鹽為氧化劑和酯化劑,采用微波作為加熱介質(zhì)制備了氧化淀粉磷酸酯�？疾炝宋⒉üβ�,催化劑用量,反應溫度,反應時間和pH值對氧化淀粉性能的影響;在此基礎上,以制備的氧化淀粉為材料,進而考察了微波功率、磷酸鹽配比、尿素添加量、反應溫度和反應時間對氧化淀粉磷酸酯性能的影響,并確定了氧化淀粉磷酸酯較佳的制備工藝參數(shù);氧化反應條件為:微波功率為500W,催化劑用量為0.08%,反應溫度為45℃,氧化時間為30 min,pH值為3.5左右;酯化反應條件為:微波功率為800W,NaH2PO4/Na2HPO4比例為2:1,尿素用量為4%,反應溫度為140℃,反應時間為30min。 通過紅外光譜(FTIR)、X-射線衍射儀(XRD)、差示掃描量熱儀(DSC)、偏光顯微鏡(PLM)、、掃描電子顯微鏡(SEM)及旋轉(zhuǎn)式粘度計等檢測儀器,分析了改性前后淀粉的分子結(jié)構(gòu)、結(jié)晶結(jié)構(gòu)、顆粒形貌和糊的性質(zhì);分析表明:微波法所制備的最終產(chǎn)物為氧化淀粉磷酸酯,對原淀粉進行氧化和酯化改性后并沒有徹底改變淀粉顆粒的結(jié)晶結(jié)構(gòu),但對其結(jié)晶結(jié)構(gòu)產(chǎn)生了一定程度上的破壞,使其熔融溫度下降、熔融過程延長;改性后的淀粉顆粒表面發(fā)生了非常明顯的變化,不僅棱角變鈍,而且表面出現(xiàn)了孔洞,說明改性不僅發(fā)生在顆粒的表面,而且進入了顆粒的內(nèi)部;改性后淀粉的糊化溫度有所降低,氧化淀粉磷酸酯糊的粘度較氧化淀粉大,但穩(wěn)定性增強。 為了實現(xiàn)淀粉對膠乳的部分或全部替代,探討了實驗制備的不同氧化淀粉磷酸酯樣品及其添加量對涂布紙性能的影響,并對涂料流變性能和保水性能進行了研究。本實驗制備的氧化淀粉磷酸酯的涂布紙性較好,其與膠乳的較佳配比為4:10或3:10,最佳干燥溫度應控制在85℃為宜;氧化淀粉磷酸酯的涂布紙綜合性能優(yōu)于氧化淀粉和市售的3S涂布淀粉;氧化淀粉磷酸酯的添加并沒有改變涂料的剪切稀化特性,但使涂料的表現(xiàn)粘度提高;涂料粘彈性能測試表明:氧化淀粉磷酸酯的添加使涂料組分間相互作用增強,但添加量不宜太大;與純膠乳配方涂料相比,添加氧化淀粉磷酸酯的涂料的失水量明顯下降,由108.32g/m2下降到最小的63.86g/m2,下降幅度約為41%,說明涂料中添加一定量氧化淀粉磷酸酯能明顯提高涂料的保水性能。
[Abstract]:With the development of science and technology, physical methods play a more and more important role in the preparation of modified starch. The physical and chemical properties of starch treated by physical method without the residue of chemical reagent were obviously improved, and the application range and added value of the product were also greatly improved. Microwave treatment has many basic characteristics, such as fast heating speed, good heating uniformity, easy instantaneous control, selective absorption and high heating frequency. At present, as a convenient and time-saving heating energy, it is widely used in the field of food and chemical industry. In this paper, oxidized starch phosphate was prepared by using raw corn starch as raw material, hydrogen peroxide and mixed phosphate as oxidant and esterification agent, microwave as heating medium. The effects of microwave power, catalyst dosage, reaction temperature, reaction time and pH value on the properties of oxidized starch were investigated. On this basis, the effects of microwave power, phosphate ratio, urea addition, reaction temperature and reaction time on the properties of oxidized starch phosphate were investigated. The optimum preparation parameters of oxidized starch phosphate were determined. The oxidation conditions are as follows: microwave power 500W, catalyst dosage 0.08%, reaction temperature 45 鈩，

本文編號：2495069