【作者】 吴玉营；

【导师】 王璋；

【作者基本信息】 江南大学 ， 食品科学， 2004， 硕士

【摘要】 大豆制品作为世界公认的健康食品,已经在世界范围内受到越来越多的关注。传统的东方豆制品也面临着前所未有的机遇和挑战。本论文以无糖速溶豆奶粉为目标产物,既为迎合现在生活快节奏的需求,也为解决当代特殊人群对无糖豆奶粉的需要问题另辟蹊径。首先,以豆奶粉的风味和溶解性为研究对象,确定了大豆的浸泡和热烫条件。在室温下用0.5% NaHCO3水溶液浸泡12hr可以使豆粒充分吸水。在经过对大豆的浸泡、热烫、磨浆、煮浆和喷雾干燥等工艺过程之后,实验制备的豆奶粉口味纯正,无不良风味。在浸泡之后,采用同时蒸馏萃取法提取了经不同条件热烫、打浆及添加还原剂所得豆浆的风味物质;用气相色谱—质谱联用技术分离和鉴定了这些风味物质的组成成分;并以苯甲醇为内标,用峰面积归一化定量了几种对豆腥味有重大贡献化合物(正己醛、正己醇、2-己烯醛、2-戊基呋喃等)的相对含量。结合感官评定,确定大豆最佳处理条件为:浸泡大豆在90℃热烫5分钟,并用90℃热水磨浆,可使所得豆奶粉基本无豆腥味,主要豆腥味成分正己醛含量仅为对照样品的5%(W/W)。其次,论文通过对食品工业中比较常用的蛋白酶(Neutrase中性蛋白酶、AS1.398中性蛋白酶、Alcalase碱性蛋白酶和胰蛋白酶)进行了研究,结果表明Neutrase中性蛋白酶是一种适用于豆奶粉生产的比较理想的蛋白酶。采用Neutrase中性蛋白酶进行水解时,加酶量控制在0.4%左右,加酶温度控制为65℃,水解结束时浆料蛋白质水解度为4.37%,经均质、喷雾干燥后所得到的豆奶粉残余酶活为零。同时又对明胶的脱苦性进行了研究,结果表明:在豆奶浆料水解之前加入明胶与大豆蛋白质一起进行水解,可以有效掩盖大豆蛋白质水解产物带来的苦味。第三,论文以乳化剂和亲水性胶体对豆奶粉速溶性的影响为对象进行研究,结果表明:要使豆奶粉达到速溶的效果,需在豆奶粉中添加乳化剂和亲水性胶体等物质。在豆奶粉中需添加的亲水性胶体为明胶,明胶的添加量应该控制为1.0g/100g固形物,明胶不但可以在豆奶粉颗粒表面形成一层亲水性薄膜,增强豆奶粉的亲水性,而且还可以使豆奶粉复水后的豆奶粘度增加,阻止或推迟豆奶发生分层、沉淀等现象。在豆奶粉中应该添加的乳化剂为亲水性单甘酯和吐温80,亲水性单甘酯可以提高豆奶粉流动性,吐温80极易溶解于水,可以增强豆奶粉的分散性,两种乳化剂从不同的侧面来提高豆奶粉的物理性质。在进行乳化剂种类选择的同时,也确定了两种乳化剂的总添加量和复配比例,两种乳化剂的总添加量为2.0g/100g固形物,复配比例为3:2。<WP=8>最后,论文又对豆奶粉喷雾干燥条件进行了研究,结果表明最佳喷雾干燥条件为:豆奶浆料浓度控制在12.60%左右,喷雾干燥时雾化盘空气压力为0.20MPa,进风温度为185℃,出风温度为85℃。在最佳条件下所得豆奶粉的润湿性98秒,分散性为41秒,溶解性为67.99%。之后,又采用蒸发量为200L/hr的压力式喷雾干燥塔进行了豆奶粉扩大化实验,扩大化实验所生产的豆奶粉品质优良,口味纯正,迎合大众需求。更多还原

【Abstract】 In virtue of its health benefits, soybean is now attracting more and more attention throughout the world. It brings those traditional oriental soybean-based food great chances and challenges. The objective of this dissertation was to prepare instant sugar-free soybean milk powder. We chose it both for catering to the mainstream of modern food industry-“fast food” and for meeting the demands of the special group. Firstly, the dissertation established the soaking and blanching conditions in terms of the flavor and the solubility of soybean milk powder. Soybean could gain sufficient absorption of water when soaked in 0.5% NaHCO3 aqueous solution for about twelve hours under room temperature. After the process of blanching, grinding, preheating and spray-drying, the soybean milk powder thus prepared tasted palatable and had no off-flavor. After the process of soaking, beany flavor of soybean milks prepared with different blanching temperature or at various grinding conditions was extracted by SDE. The constituents of the beany flavor were separated and identified by gas chromatography-mass spectrometry(GC/MS). Based on the NBS standard mass spectral data and by integrating peak area method, the main constituents of beany flavor (hexanal, 1-hexanol, 2-hexenal, 2-pentylfuran) in each sample were quantified. Combined with sensory evaluation, optimal processing parameters were determined as: soaked soybean was blanched at 90℃ for 5 minutes, then grinted with hot water at the same temperature, soy powder thus prepared was almostly beany-free, the content of hexanal was only 1:20 to that of control. Secondly, after research of four kinds of proteinases ( Neutrase、AS1.398、Alcalase and Trypsin) frequently used in food industry, this dissertation found that Neutrase was the ideal proteinase, which was used to hydrolyze protein in soybean milk in production of soybean milk powder. When Neutrase was used, the total quantity of the proteinase added was about 0.4%(Neutrase/soy protein, w/w) and the temperature under which the proteinase was added was 65℃... When hydrolyzing was finished, the degree of hydrolysis of protein in soybean slurry was about 4.37%. After homogenizing and spray-drying, the remaining proteinase activity in soybean milk powder was zero. At the same time, the dissertation also did some research on glutin’s debitterness. The result indicated that glutin could mask the bitterness brought by proteolytic product if the glutin was hydrolyzed together with soybean milk slurry.Thirdly, the dissertation also gave regards to the influence of emulsifier and hydrophilic colloid on instant property of soybean milk powder. The research suggested that the addition of emulsifier and hydrophilic colloid to soybean slurry could benefit the physical aspects of soybean milk powder. The hydrophilic colloid added was glutin, and its quantity was about 1.0%( glutin/ solid in soybean milk, w/w). The glutin could not only bring about a bed of hydrophilic pellicle on the surface of soybean milk powder particles to increase hydrophilicity, but also increase the viscosity of milk to avoid or postpone delaminating and precipitating. The emulsifiers added were Hydrophilic Glycerol Monostearate and Tween-80. Hydrophilic Glycerol Monostearate could increase the flowability of soybean powder, while Tween-80 <WP=10>could increase the soybean powder’s dispersibility because of its strong solubility in water. The two emulsifiers increased the soybean milk powder’s physical properties in different aspects. The total quantity of the two emulsifiers was 2.0%( emulsifiers/solid in soybean milk, w/w) and the proportion of Hydrophilic Glycerol Monostearate to Tween-80 was 3:2.Finally, the dissertation attached great importance to the research of spray-drying conditions. The optimal conditions were: when spray-drying, the concentration of soybean milk was about 12.60%, the air pressure of atomizer was 0.20MPa, and the inlet temperature was 185℃, the outlet temperature was 85℃. The moistability of the soybean milk powder thus prepa更多还原