共查询到19条相似文献,搜索用时 140 毫秒
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《食品与发酵工业》2014,(2):60-65
从生姜中分离得到具有凝乳活力的生姜蛋白酶,采用Urea SDS-PAGE、RP-HPLC和MALDI-TOF/MS等方法分析生姜蛋白酶对酪蛋白单体和脱脂乳中酪蛋白的水解作用。结果表明,生姜蛋白酶水解κ-酪蛋白生成的主要产物比较稳定,不会被进一步水解。温度高于60℃时生成κ-CN(f 1-90)和κ-CN(f 1-102)两个末端疏水性肽段,其次为κ-CN(f 1-121),温度较低时,还生成大量分子量高于κ-CN(f 1-121)的产物。在脱脂乳体系中,生姜蛋白酶水解脱脂乳的κ-酪蛋白,而对αS1-、αS2-和β-酪蛋白没有显著的水解作用。主要裂解κ-酪蛋白的Thr121-Ile122键,生成疏水性N末端肽段κ-CN(f 1-121)。这一结果表明生姜蛋白酶凝乳的主要机理是水解κ-酪蛋白Thr121-Ile122肽键,破坏了酪蛋白微粒的稳定性,促使酪蛋白形成凝胶。 相似文献
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沙湾姜埋奶制作原理初探 总被引:3,自引:0,他引:3
对姜埋奶的制作原理以及影响姜埋奶凝固的主要因素进行初步研究 ,结果表明 ,能使牛奶凝固主要是蛋白酶的作用 ,而温度、pH值、乳酸钙含量等因素均对姜埋奶凝固时间有影响 ;同时 ,作者用木瓜蛋白酶代替生姜蛋白酶 ,对影响姜埋奶凝固的主要因素还进行了更进一步的探索。 相似文献
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Hou‐Pin Su Mei‐Ju Huang Han‐Tsung Wang 《Journal of the science of food and agriculture》2009,89(7):1178-1185
BACKGROUND: Ginger rhizome (Zingiber officinale Roscoe) contains ginger proteases and has proteolytic activity. Ginger proteases have been used for tenderizing meat but rarely for milk clotting. The purpose of this study was to purify ginger proteases and to research their biochemical characteristics. RESULTS: The milk clotting activity (MCA) and proteolytic activity (PA) of the proteases was stable after storage at 4 °C for 24 h. The MCA and PA of fresh ginger juice with 0.2% L ‐ascorbic acid remained stable for 6 days at 4 °C. When under storage at ?80 °C for 2 months, the MCA and PA of the fresh ginger juice and acetone precipitate were still high. Two peaks with protease activity were purified from a DEAE FF ion‐exchange column; the specific activity (units mg?1 protein) of the MCA (MCSA) and PA (PSA) for the first peak was significantly higher than the second peak (P < 0.05). The protease activity of the ginger proteases was significantly inhibited by E‐64, leupeptin, and iodoacetic acid. Zymography results showed that two protease fractions purified from ginger juice with 62 and 82 kDa had a higher PA against α‐ and β‐casein than against κ‐casein. CONCLUSION: The ascorbic acid addition significantly stabilized the MCA and PA of ginger proteases. The protease inhibition test suggested that ginger proteases belonged to the cysteine type. The biochemical characteristics of ginger protease described in this paper can provide useful information for making new milk curd products. Copyright © 2009 Society of Chemical Industry 相似文献
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生姜蛋白酶是从生姜中发现的一种植物蛋白酶,属于木瓜蛋白酶类,与木瓜蛋白酶、菠萝蛋白酶及猕猴桃蛋白酶共同组成4种重要植物蛋白酶。生姜蛋白酶的提取方法主要有沉淀法中的有机溶剂法、结合有机溶剂的盐法、单宁法,以及超滤法。生姜蛋白酶的嫩肉、澄清和凝乳等作用在食品领域已被广泛研究及应用,其酶学性质、相对分子质量分布及结构也进行了检测分析和研究。近期的部分研究还表明生姜蛋白酶的一些生物活性有潜在医药价值、具有广阔的应用前景。本文对生姜蛋白酶的提取分离与纯化、酶活性及分析检测、生物活性及应用等研究现状进行了概述,并对今后应重点加强的研究方向进行展望。 相似文献
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利用气相色谱-质谱联用(gas chromatography-mass spectrometry,GC-MS)技术分析经超临界二氧化碳流体萃取(supercritical fluid extraction-CO2,SFE-CO2)及水蒸气蒸馏(steam distillation,SD)提取的山东大(黄)姜精油的挥发性香气成分,结合感官评价对两种方法萃取的精油的香气性能进行对比分析。结果表明:SFE法提取的姜精油辛辣味浓郁饱满,果甜香柔和,具较好的柑橘香,香气性能较优。 相似文献
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Ginger proteases are used as milk coagulants in making a Chinese traditional milk product (Jiangzhinai or Jiangzhuangnai), suggesting their potential as a source of rennet substitute that might be applicable in the modern dairy industry. In this study, ginger proteases were extracted from fresh ginger rhizome by using phosphate buffer and subsequently purified by ion exchange chromatography. Ginger proteases, all with a molecular weight around 31 kDa, were found to exist in 3 forms with isoelectric point values around 5.58, 5.40, and 5.22, respectively. These enzymes had very similar biochemical behavior, exhibiting optimal proteolytic activity from 40 to 60°C and maximum milk clotting activity at 70°C. They were capable of hydrolyzing isolated αS1-, β-, and κ-casein, of which αS1-casein was most susceptible to the enzyme; κ-casein was hydrolyzed with a higher specificity than αS1- and β-casein. In addition, the ginger proteases exhibited a similar affinity for κ-casein and higher specificity with increasing temperature. Gel electrophoresis and mass spectra indicated that Ala90-Glu91 and His102-Leu103 of κ-casein were the preferred target bonds of ginger proteases. The milk clotting activity, affinity, and specificity toward κ-casein showed that ginger protease is a promising rennet-like protease that could be used in manufacturing cheese and oriental-style dairy foods. 相似文献
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研究目的主要是针对不同提取方法得到的生姜提取物挥发性组分分析方法进行创新性探索,并确定生姜不同提取物中的挥发性组分和含量。本论文采用热脱附(TD)-气质联用法(GC-MS)对不同提取方法(水蒸气蒸馏、冷榨、超临界萃取、溶剂萃取)获得的生姜提取物中的挥发性成分进行分析和比较。采用保留指数(RI)辅助定性。研究过程中,成功分离分析出水蒸气蒸馏生姜提取物挥发性成分61个、冷榨生姜提取物67个、超临界生姜萃取物61个、溶剂生姜提取物65个、超临界姜油树脂53个。实验结果表明,热脱附-气质联用法可以避免生姜提取物中不挥发性物质对实验结果的影响。不同生姜提取物挥发性成分的含量和组成均在差异,水蒸气蒸馏得到的姜油轻挥发性组分的含量相对较高。 相似文献
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多种生姜有效成分联合提取工艺 总被引:1,自引:1,他引:0
为了研究生姜中有效成分姜辣素、姜黄素以及生姜蛋白酶同步提取的方法,文中使用乙醇溶剂法结合旋蒸确定了生姜中3种有效成分同步提取的工艺条件,即生姜与无水乙醇料液比1∶3(g∶mL),生姜蛋白酶提取中缓冲液pH值为6.5,冰浴时间7 h;姜辣素、姜黄素旋转蒸发最佳温度为60℃,转速为16 r/min。在此优化条件下,生姜中姜辣素、姜黄素的提取率分别为0.3143%、0.3889%;生姜蛋白酶的得率为1.376%,比活力达到4 465 U/mg。此工艺能够同步提取姜辣素、姜黄素以及生姜蛋白酶3种有效成分,减少了原材料的消耗,降低生产成本,更适合产业化生产。 相似文献