【作者】 高韩玉；

【导师】 姜绍通；

【作者基本信息】 合肥工业大学 ， 农产品加工及贮藏工程， 2006， 硕士

【摘要】 本研究以苋菜为原料,分析研究其脱水过程中预处理各因素对苋菜干燥速率、外观色泽、苋菜红色素、抗坏血酸以及粗蛋白的影响,得到了脱水苋菜在不同情况下的变化规律;同时还对脱水苋菜进行了复水学试验研究,初步确定了脱水苋菜的复水特性。 苋菜中的过氧化物酶在80℃,85℃和90℃条件下,分别需要漂烫90s,45s和30s即可灭活;漂烫温度越高,苋菜干燥速率显著加快;漂烫1.5min时苋菜干燥速率最快:提高预处理漂烫液的蔗糖浓度的会导致苋菜干燥速率的下降;食盐浓度为1%时苋菜干燥速率最大;预处理液的pH=11时,苋菜的干燥速率最快。 随着漂烫温度的增加,脱水苋菜的外观色泽变差,脱水苋菜中苋菜红色素的含量降低;延长漂烫时间会使脱水苋菜的外观色泽变差,脱水苋菜中苋菜红色素的含量也随之减少;蔗糖浓度10%时外观色泽最好,但此时对苋菜红色素有轻微的不利影响:预处理液食盐浓度在0.5%时产品色泽较好,苋菜红色素的含量随着食盐浓度的提高而减少;漂烫液的pH=9.0时,脱水苋菜的外观色泽较好,pH值在5.0～7.0范围内,苋菜红色素的稳定性较好。 随着漂烫温度的升高,苋菜中Vc的保存率降低,其粗蛋白含量也不断减少;延长漂烫时间,得到同样的变化趋势;pH值越小,Vc的保存率越高;粗蛋白含量在pH=7时最大,酸性和碱性条件都会造成粗蛋白的损失;提高食盐浓度可以更好的保存Vc,但会引起粗蛋白的损失;蔗糖可提高Vc的保存率,但是浓度低于1.0%的蔗糖溶液会导致粗蛋白的损失,浓度高于1.0%的蔗糖溶液可提高粗蛋白的含量:Zn²⁺和Ca²⁺可较好的保存苋菜中的Vc,Mg²⁺对Vc的影响不大,Cu²⁺会导致Vc大量损失。Zn²⁺、Mg²⁺、Ca²⁺和Cu²⁺都会引起苋菜中粗蛋白的损失,其中Mg²⁺和Cu²⁺造成的损失相对较大。 脱水苋菜的最佳复水条件是在90℃蒸馏水中浸泡60min,当处理液中糊精、蔗糖和食盐的浓度分别为15%,15%和10%时能得到较佳的复原率。更多还原

【Abstract】 Amaranth was used as material in this subject, and the effects of several blanching factors on dehydrated speed, color, pigment, vitamin C and crude protein were analyzed, then the variety rules of dehydrated amaranth under different conditions were obtained. At the same time, through some experiments on the rehydration of dehydrated amaranth, elementary conclusions for the characteristic of rehydration was obtained.The processing of dehydration first showed a short accelerated processing, then a constant processing, and finally a slowdown processing. Dry velocity of the amaranth was highly related to blanching temperature, and the temperature was higher, the velocity was faster. The influence of blanching time to dry velocity of the amaranth was not distinct. The increase of the concentrations of sugar solution induced the decline of dry velocity. The dry velocity would be the fastest when the concentration of salt solution was 1%. The pH of blanching solutions was higher, the dry velocity was faster.The blanching temperature was higher, the color of dehydrated amaranth was worse, and the content of amaranth pigment in dehydrated amaranth was lower. Extending blanching time would make the color of dehydrated amaranth become worse, and the content of amaranth pigment in dehydrated amaranth was concomitant decrease, which was less comparatively. The concentration of sugar was higher, the color was better. Sugar solution had slight bad effect on amaranth pigment. The color of product was better when the concentration of salt solution was between 0.5% and 1.0%, and the increase of the concentration of salt solution was concomitant with the decrease of the content of amaranth pigment, but the influence was tiny when the concentrations of salt exceed 1.0%. Better color of dehydrated amaranth was obtained when the pH of blanching solution was 4.0 and 9.0. Amaranth pigment was steadier between pH 4.0 to 7.0.Along with the increasing of the blanching temperature, the preserve rate of Vc and the content of crude protein were decreased. Extending blanching time, the same trend was obtained. Vc could be preserved better under acidic than alkaline, but acidic and alkaline conditions induced the loss of crude protein. Increasing the concentrations of salt could preserve Vc better, but the content of crude protein decreased at the sametime. Sucrose could heighten the preserve rate of Vc. Sucrose solutions which concentrations were lower than 1.0% induced losses of crude protein. Zn2+ and Ca2+ preserved Vc better, and Mg2+ had slightly effect on Vc , while Cu2+ induced heavy losses. Zn^ Mg2\ Ca2+ and Cu2+could induce loss of crude protein.The optimum rehydration condition that dehydrated amaranth was immersed in water was 90 "C for 60 minutes. Disposed with the mixture of dextrine-sugar-salt, which had a concentration ratio of 3:3:2, better reversion rate could be obtained, in addition, the concentration of dextrine was 15%.更多还原