【作者】 鲁晶晶；

【导师】 郑喜群；

【作者基本信息】 齐齐哈尔大学 ， 农产品加工及贮藏工程， 2011， 硕士

【摘要】 玉米浸泡水是玉米湿法生产淀粉时产生的有机废水,其中含有3 ~ 4 %的蛋白质。玉米浸泡水蛋白具有增强人体免疫力、抗氧化等生理活性特点,是目前尚未充分开发利用的蛋白资源。如果能将玉米浸泡水中蛋白质提取出来,不但可以提高工厂的经济效益,解决环境污染的问题,同时还可以开发新的蛋白资源。本文以玉米浸泡水粗蛋白为原料,经硫酸铵盐析提纯后,初步研究其性质。根据其性质,研究采用醇洗及碱溶酸沉两种方法进一步纯化玉米浸泡水粗蛋白的工艺条件,然后研究提纯后的玉米浸泡水浓缩蛋白的功能性质,最后将其添加到火腿肠中,研究其添加量对火腿肠质构特性的影响。采用40 %饱和硫酸铵盐析,分离提纯玉米浸泡水粗蛋白,纯度达到84.57 % (w/w),达到了玉米浸泡水浓缩蛋白的水平,经透析除盐后,研究其基本组成及性质。结果表明:玉米浸泡水蛋白中含有较多的疏水性氨基酸和酸性氨基酸,且脯氨酸含量最高;同时,由于疏水性氨基酸含量的增加使其具有较好的热稳定性;SDS-PAGE电泳和Sephadex-G50凝胶层析表明玉米浸泡水浓缩蛋白的分子量主要分布在10000 Da以下。采用乙醇醇洗和碱溶酸沉两种方法对玉米浸泡水粗蛋白进行提纯。实验结果表明:醇洗方法不适用于提纯玉米浸泡水粗蛋白;实验范围内,碱溶酸沉法提纯玉米浸泡水粗蛋白的适宜条件为:温度25℃,碱溶阶段pH 12,浸提时间20 min,料液比(W:V)l:35,酸沉阶段pH 5.5。经提纯后玉米浸泡水蛋白的得率为70.06 %,纯度可达到91.84 %。因此,选用碱溶酸沉法提纯玉米浸泡水粗蛋白。以大豆分离蛋白做对照,对玉米浸泡水浓缩蛋白功能性质进行了评价,结果表明:CSWPC的乳化稳定性、起泡性及其稳定性、吸油性以及凝胶形成性都优于大豆分离蛋白;CSWPC在NaCl浓度为0.15 mol/L、温度为70℃、远离等电点的偏碱环境中有良好的溶解性;其持水性随着pH逐渐增加而增大,随着温度和NaCl浓度的增加而减小,在60℃,NaCl浓度0.15 mol/L、pH为10时持水性最好;在温度为80℃,蛋白浓度为2 %的偏酸环境中CSWPC溶液的黏度较低。在火腿肠中添加玉米浸泡水浓缩蛋白,使火腿肠得率提高了14.4 %,且对火腿肠的色泽和质构特性都有影响。当蛋白添加量在0.5 ~ 1 %的范围内火腿肠的外观肠体干爽,无粘液,不破损,颜色均匀一致,组织致密,有弹性。更多还原

【Abstract】 Corn steep liquor, the organic wastewater of corn wet milling, contained approximately 3~4 % (w/w) protein. Corn steep liquor protein had biological activity such as strengthening the human body immunity and antioxidation, which wasn’t fully exploited and used recently. So if corn steep liquor protein can be extracted and purified, it’s not only can improve the factory economic efficiency and solve the present environmental problems, but also can develop new protein resources.In this research, the crude protein from corn steep liquor was used as the raw material.Its properties was studied after preliminary purified by ammonium sulfate precipitation .The technological conditions were determined when corn steep liquor protein was purified by alcohol washing, alkali-solution and acid-isolation two different methods. Then the functional properties of protein concentrate from corn steep liquor after purified were studied. Finally the effects of protein concentrate addition on sausage texture characteristics were researched.The purity of crude protein was 84.57 % under the condition of 40 % saturated ammonium sulfate, and it was up to the level of protein concentrate after dialysised. The basic compositions and properties of protein concentrate were preliminary studied after purified. The results showed that the protein concentrate contained more kinds of essential amino-acids, non-essential amino acids was equalized. The thermal stability of protein concentrate was better because it contained more hydrophobic amino acids. SDS-PAGE electrophoresis and Sephadex-G50 gel chromatography indicated that protein concentrate molecular weight was less than 10000 Da.Corn steep liquor protein was purified by alcohol washing, alkali-solution and acid-isolation. The results showed that alcohol washing was not applicable to purified crude protein. The optimum conditions of crude protein with alkali-solution and acid-isolation in the range of experiments were alkali soluble pH value 12, solid-liquid ratio (W:V)1:35 and acid subside pH 5.5 at 25℃for 20 min. Under the best conditions, the yield of protein was 70.06 % and the protein purity was 91.84% after purification. The best way of purfied crude protein was the alkali-solution and acid-isolation.Comparing with soybean protein isolate (SPI), the functional properties of protein concentrate were evaluated. The results showed that the emulsifying stability, foaming property and stability, oil absorption and gelation of protein concentrate were better than that of SPI, the protein concentrate showed higher solubility under NaCl concentration of 0.15 mol/L and far away isoelectric point in alkali environment at 70℃. The water holding capacity was increased with the increment of pH value, decreased with the increment of temperature and NaCl concentration. The WHC showed better under the conditions of pH value 10 and NaCl concentration of 0.15 mol/L at 60℃. The lowest viscosity was observed under protein concentration of 2 % and far away acidic environment at 70℃.Adding protein concentrate could influence the tincture and texture characteristics of sausage and the yield of sausage was increased by 14.4 %. When adding amount of protein concentrate ranged from 0.5-1 %, the sauage showed dry appearance, no mucus, no breakage, uniform color, compact structure and good elasticity.更多还原