【作者】 吴姣；

【导师】 郑为完；

【作者基本信息】 南昌大学 ， 粮食油脂与植物蛋白工程， 2007， 硕士

【摘要】 本文以大米糖化制造淀粉糖生产中产生的大量副产物—米渣为原料，探讨采用酶法和美拉德反应法这两种蛋白改性方法制备乳化性能高的米渣蛋白改性产品，并将自制得到的高乳化性能的改性产品应用于微胶囊粉末油脂。1．对米渣中理化指标（水分、灰分、蛋白质、脂肪、碳水化合物、金属元素、氨基酸）进行测定，结果表明米渣蛋白含量极高、营养丰富、氨基酸配比合理，可以作为保健品、功能型食品开发的原料。采用碱溶酸沉法；蛋白酶法；碱蛋白酶两步法；排杂法；淀粉酶、纤维素酶结合酶解法五种不同的提取方法对米渣中的蛋白进行提取，结果表明，采用排杂法和淀粉酶纤维素酶酶解法两种方法联用提取的效果最佳，得到的米渣蛋白中的蛋白质含量近84％，蛋白质得率近82％。2．探讨了木瓜蛋白酶、Alcalase、Protamex和Flavourzyme四种蛋白酶对米渣蛋白进行水解过程中，水解度（DH）、水解产物乳化活性及乳化稳定性的变化，确定了米渣酶解过程的最佳用酶为Alcalase 2.4L FG酶。确定了Alcalase水解米渣蛋白的工艺条件为：酶浓度为0.003mL·g^-1，底物浓度=10％，T=60℃，pH=9.0。根据pH—state法，通过控制反应加碱量为0mL、9mL、18mL、27mL、63mL，可以得到水解度依次为2.89％，3.89％、4.89％、5.89％和9.89％的有限酶解米渣蛋白，为了方便记录，将水解度数值取整，即得到水解度分别为3、4、5、6、10的有限酶解米渣蛋白。3．对不同DH的有限酶解米渣蛋白性能：乳化性、乳化稳定性、溶解性、表面张力、粘度进行表征。结果表明，DH=4的有限酶解米渣蛋白的乳化功能特性最佳；与酪朊酸钠进行比较，结果显示DH=4的有限酶解米渣蛋白的乳化性、表面张力更优，但乳化稳定性和溶解性不及酪软酸钠佳。通过对不同DH的有限酶解米渣蛋白乳状液的粒度与酪朊酸钠的粒度进行测定，只有有限酶解米渣蛋白（DH=4）和酪朊酸钠的乳状液粒度分布呈正态高斯分布，但前者平均粒径会随着时间的增加而增大，这是导致它的乳化稳定性不如酪软酸钠的原因。4．对不同DH的有限酶解米渣蛋白的分子量分布进行测定，有限酶解米渣蛋白的分子量分布范围在80Da—15KDa，随着水解度的提高，米渣蛋白的分子量向低分子量移动：当DH=10时，产物的分子量集中Mw=692Da处，且其分布所占面积比例达到94.76％，可见此时酶解产物中小分子肽或氨基酸成分为主，分子量低，柔韧性差，乳化性能不高，再次证明了要想得到乳化性能较佳的米渣蛋白有限酶解产物，水解度必须要控制10以内，即（DH＜10）；由有限酶解米渣蛋白的乳化性能表征，可以看出DH=4的有限酶解米渣蛋白的分子量分布（43.17％的Mw=2233Da和50.17％Mw=441Da的分布）是有利于乳化性能的提高。5．通过二次回归通用旋转正交试验设计，应用响应面分析法对有限酶解米渣蛋白—麦芽糊精Maillard反应过程中的各反应条件进行分析，建立数学模型，优化反应条件参数，根据SAS脊岭分析结果，结合实际的操作条件，在58℃，采用水解度（DH=6）的有限酶解米渣蛋白，保持其与麦芽糊精的比例为8∶1，pH为6.5，反应3天可以得到乳化活性（EAI）为0.3170的反应共聚物，比国外进口的酪朊酸钠（EAI=0.2695）还要好。6．对制备的有限酶解米渣蛋白—麦芽糊精Maillard反应共聚物进行红外光谱扫描，结果表明美拉德反应后产物的红外光谱既具有蛋白的酰胺化合物的吸收带特征峰，又具有糖的特征吸收峰，而且在3400cm^-1左右吸收峰的强度增大，这是由于新物质共价交联反应出现了新的N—H键，1660cm^-1处蛋白中的C=O的伸缩振动明显减弱，1456—1369cm^-1处糖的C—O—H中O—H的弯曲振动也明显减弱，说明反应发生在这两个基团上。7．将自制的DH=4有限酶解米渣蛋白作为乳化剂用于微胶囊粉末油脂制备是可行的，DH=4有限酶解米渣蛋白∶阿拉伯胶比例为7∶3时，所得到的产品油脂包埋率最大，达到92.5％。而自制的有限酶解米渣蛋白—麦芽糊精美拉德反应物相对要差，有限酶解米渣蛋白—麦芽糊精美拉德反应物∶阿拉伯胶为6∶4时，制成产品的油脂包埋率最大，值达83.3％。测定了用DH=4有限酶解米渣蛋白∶阿拉伯胶（7∶3）做乳化剂制备的微胶囊产品的各项指标，结果表明，感官指标、理化指标、复原乳状液指标均符合要求。更多还原

【Abstract】 Rice residue, the by-product during producing starch sugar, was used to prepare high emulsibility production by two modification methods, including enzymatic hydrolysis and Maillard’s reaction. The high emulsibility production was successfully used in microcapsule powder oil.1. Determined the content of rice residue, such as moisture content, ash content, protein, fats, carbohydrate, metal elements and amino acids. It is indicated that rice residue was abundant of protein, metal elements and amino acid, and it was a good raw material for functional foods. Many methods were studied to extract protein in rice residue, the best method was using amylase and cellulose enzymatic hydrolyse carbohydrate after the fats were removed by hexane. By this means, the loss percentage was only 18%, the purified rice residue contained protein 84%, we can call it rice residue protein.2. Investigated effects of papain, alcalase,protamex and flavourzyme to hydrolysis degree, emulsification activity and emulsification stability of enzymatic hydrolyzed rice residues protein. It was clearly found that alcalase 2.4L FG was much better than the other three. The hydrolysis characters of rice residue protein were studied with Alcalase 2.4L FG in light hydrolysis degree and with the results as follows, pH was 9.0, the hydrolytic time was 30min, temperature was 60℃, the substrate concentration was 10 g·100ml^-1water, the enzyme concentration was 0.03 mL·g^-1 water（the enzyme was diluted to 10% concentration ）.According to pH-state, limited enzymatic hydrolyzed rice residues protein with different hydrolysis degree could be prepared by controlling the added NaOH volume. When the volume was 0mL,9mL,18 mL,27 mL,63 mL, the limited enzymatic hydrolyzed rice residues protein with different hydrolysis degree （DH=2.89%,3.89%,4.89%,5.89%,9.89%） could be gotten. In order to record conveniently, DH was recorded as 3,4,5,6,10 instead of DH=2.89% ,3.89 % ,4.89 % ,5.89 % ,9.89 %.3. Emulsification characteristics such as emulsification activities, emulsification stabilities, dissolution characters, surface tension, consideration and granularity gaussian distribution was studied with the Rice Residues Protein DH 3,4,5,6,10 which was limited enzymatic hydrolyzed by Alcalase 2.4L FG It could be easily seen from the investigation result that rice residues protein with limited enzymatic hydrolyzed had much better emulsification characteristics than rice residues protein. And the emulsification activity of the rice residues protein DH 4 was better than sodium casein, but the emulsification stability a little worse than it. In a word, the rice residues protein DH 4 had a very good emulsification characteristic.4.Determined molecular weight distribution of limited enzymatic hydrolyzed rice residues protein with different DH, distribution range was from 80Da to 15KDa. While the hydrolysis degree increasing, more low molecular weight appeared. While DH=10, the molecular weight was mainly at 692Da, the ratio reached 94.76%. Because there were chiefly micromolecule peptide or amino acid in DH10, and lower molecular was with worse flexibility , yet the hydrolysis production of DH10 was with low emulsification properties. The highest emulsification hydrolysis production of DH4 possesed a molecular distribution range with 43.17% at Mw=2233 Da and 50.17% at Mw=441Da.5.The factors such as limited enzymatic hydrolyzed rice residues protein of different DH, different substrate ratio to the malt dextrin, reaction temperature, reaction pH and reaction time which affect the Maillard’s reaction kinetics were discussed. Response surface methodology was used to optimize Maillard’s reaction factors, in order to get the Maillard conjugation with the highest emulsification activities. The results indicated that: the DH 6, the weight ratio of RRHP to MD 8:1, temperature 58℃, pH 6.5, and reaction time 3 days were the optimum reaction conditions. Within these conditions, the actual emulsification activities value （EAI=0.3170） was higher than sodium casein （EAI=0.2695） .6.The spectra of limited enzymatic hydrolyzed rice residues protein -malt dextrin Maillard conjugation was determined by FTIR spectrometry. The absorption peaks of the spectra were analyzed. Results from the comparison of the three spectra showed the spectra of Maillard conjugation possessed not only amide characteristic absorption peaks in limited enzymatic hydrolyzed rice residues protein, but also C— O-C characteristic absorption peaks in malt dextrin. Some differences in the intensity and the shape of absorption peaks of their FTIR spectra could be found,especially at 3400cm^-1, 1660 cm^-1 and in the range of 1456-1369 cm^-1, which mainly reflected the substituent nature of C=O and O-H. So FTIR spectra could be used for the identification of Maillard conjugation.7.Used the self-made high emulsification activity products, DH4 limited enzymatic hydrolyzed rice residues protein and limited enzymatic hydrolyzed rice residues protein -malt dextrin Maillard conjugation to embed oil for preparing microencapsulation powder oil. It could be told from the results that self-made DH4 limited enzymatic hydrolyzed rice residues protein could be used to substitute sodium casein, when the ratio of DH4 enzymatic hydrolyzed rice residues protein to gum Senegal was 7:3, the microencapsulation production embedding ratio could reach 92.5%, and the production could get to request. But the self-made Maillard conjugation could relatively get a lower embedding ratio 83.3%, when it was combinated with gum Senegal at the ratio of 6:4.更多还原