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红曲霉培养条件对酯化力影响的研究 总被引:3,自引:0,他引:3
以A13、As3.554和As3.972为研究对象,比较了其培养参数米坯的初始水分、培养时间及以葡萄糖和蔗糖为速效碳源及添加量对底物己酸和乙醇转化为脂肪酸酯的酯化力的影响规律.实验结果表明.蒸米坯的初始水分、培养时间对其酯化力均有显著的影响,其最适水分为50%,培养时间为24d,葡萄糖可作为其培养初期的速效碳源,添加量视其菌株性能而存在一定差异.HS-SPME耦联GC-MS剖析不同红曲菌株制成的曲粉所催化得到的产物组分表明,其主要产物与总酯化力之间存在相关性,其酯化物的种类取决于菌株的特性. 相似文献
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《食品与发酵工业》2015,(7):99-103
在单因素试验的基础上,应用BBD响应面法对影响红曲霉曲酯化力的3个主要因素(接种量、培养温度、培养时间)进行了优化,利用"Design-Expert"软件对数据进行处理,结果显示,在试验水平范围内,培养温度对试验结果影响较大,接种量、培养时间对试验结果影响不大。得到纯种红曲霉曲的最佳制备工艺条件为:接种量为0.37%,培养温度32.69℃,培养时间7.06 d,乳酸添加量0.1%。在此条件下红曲霉曲酯化力的预测值为108.64 mg/g,对优化方案进行验证,红曲霉曲的酯化力为(107.85±0.51)mg/g,实际值与预测值基本一致。 相似文献
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通过对FF-6202红曲霉液体菌种在发酵过程中的几个动态参数的研究,分析了还原糖、糖化力、pH值、菌丝量、色价和色调等主要参数在红曲发酵过程中的变化规律。初步确定了在液体种子培养过程中的几个关键控制参数是:还原糖、pH值、菌丝量和色价。 相似文献
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目的:优化酯化红曲霉麸曲的生产工艺,并探究酯化红曲霉麸曲对浓香型白酒的影响。方法:从大曲中筛选出5株红曲霉,采用酯分解法检测菌株产酯化酶能力,选择产酶能力最突出的菌株制备红曲霉麸曲。通过单因素及正交试验优化制曲工艺,并将其应用到白酒生产中。结果:5株菌株中产酯化酶能力最强的是J-3菌株,其在水分50%,菌株接种量4%,pH 4.0,培养温度32 ℃的条件下,可制得酯化酶活力高达77.78 mg/g的麸曲。将该麸曲按接种量不同添加到糟醅中发酵,较未添加麸曲的糟醅,在麸曲接种量为1%时,糟醅中乙酸乙酯含量提高了4.84倍,己酸乙酯含量提高了3.55倍。在接种量为1.5%时,丁酸乙酯含量提高了4.72倍。且添加酯化红曲霉麸曲能够提高酒精度与淀粉的利用率,显著提高糟醅中总酯含量。结论:将红曲霉麸曲按照适宜的接种量添加到糟醅中,能够提高浓香型白酒的质量。 相似文献
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该研究以白酒大曲中筛选出的一株高产酯酶菌株HQ为研究对象,采用分子生物学对其进行菌种鉴定。通过硫酸铵二级沉淀、丁基琼脂糖凝胶柱和Superdex G-200柱对其所产的酯酶进行纯化,并进行N-端序列、质谱和酶学性质分析。结果表明,菌株HQ被鉴定为紫红曲霉(Monascus purpureus),经纯化获得一个分子质量为60 kDa的酯酶,命名为ESM1。酯酶ESM1具有一段酸性蛋白酶的肽段序列,最适温度为60 ℃、最适pH值为7.0,在温度为50 ℃的环境和中性环境中表现出良好的稳定性。Zn2+、Ca2+和Na+对ESM1有促进作用,其中Zn2+促进作用最高,Cu2+、Mg2+、Fe2+和Mn2+有抑制作用,其中Cu2+的抑制作用最强。 相似文献
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C A Meinardi A A Alonso E R Hynes C A Zalazar 《International Journal of Dairy Technology》2002,55(3):139-144
The aim of this work was to study the influence of milk-clotting enzymes on whey starter culture and hard cheesemaking. Four cheeses were prepared simultaneously per cheesemaking day, and the experiment repeated on eight consecutive days. Adult bovine rennet was used in the control cheeses, and three formulations of fermentation-produced chymosin (FPC) in the experimental cheeses. Whey cultures were obtained from the whey of the preceding cheeses, incubated individually for 24 h at 42°C. pH values of the control and experimental whey did not differ significantly before incubation, but after 24 h incubation the pH of the FPC whey was significantly higher than that of the control. Soluble nitrogen content in trichloroacetic acid 2% and 12% and in phosphotungstic acid 2.5% was significantly lower for all experimental whey samples than for control whey. This probably explains the decrease in the acidification rate of the whey cultures when bovine coagulant is replaced by FPC in hard cheesemaking. 相似文献
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本文研究了栅栏技术对毛竹笋采后品质劣变的作用。对毛竹笋贮藏期间纤维素、木质素含量、苯丙氨酸解氨酶(PAL)、多酚氧化酶(PPO)活性、可食率、褐变指数以及腐烂率等生理指标进行检测。结果表明,采用栅栏因子处理能够明显抑制毛笋PAL、PPO酶活性、纤维素、木质素的合成,降低硬度;抑制可食率降低、腐烂率的增加及褐变指数升高,从而有效延长采后毛竹笋的贮藏期,从5 d延长到30 d。 相似文献
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P Prabhasankar D Indrani R Jyotsna G Venkateswara Rao 《Journal of the science of food and agriculture》2004,84(15):2128-2134
Enzymes are used in the baking and milling industries to control dough properties and improve the quality of finished products. The role of enzymes in the baking process of an unleavened Indian flat bread, namely South Indian parotta, was studied. In this connection, comparisons have been made on the effects of different enzymes such as fungal α‐amylase (FA), glucose oxidase (GO), proteinase and xylanase on rheological characteristics and microstructure of parotta dough and its relation to the overall quality characteristics of baked parotta. Addition of GO increased, while FA, xylanase and proteinase decreased farinograph stability. Extensograph resistance to extension increased with GO or xylanase and decreased with FA or proteinase. The extensibility increased with FA, xylanase or proteinase and decreased with GO. The microstructure of parotta dough with different enzymes revealed that the use of proteinase improved the continuous gluten formation compared with the control and the other three enzymes, FA, xylanase and GO. This could be due to the proteinase enzyme breaking larger protein fibrils into smaller fibrils and thus enhancing the continuous gluten film formation. A similar observation was also noted in the microstructure of baked parotta layers. The microstructure of parotta with proteinase enzyme showed a continuous network of protein films compared with a cluster of protein films in parotta with GO. In the case of xylanase‐treated parotta, the starch granules were deformed completely and these deformed starch granules were found sticking to the protein films. In parottas prepared with GO and FA, only a few starch granules with faint outlines were visible. Generally speaking, the overall quality score of parotta decreased to 68 and 64 with the use of FA and, GO respectively, as against the control parotta score of 74. The score increased to 92 and 82 with the addition of proteinase and xylanase, respectively. Copyright © 2004 Society of Chemical Industry 相似文献
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无损检测技术作为一种新兴的检测技术,与传统的检测技术有很大区别。该方法可以在不破坏样品的前提下完成检测,因此在食品分析中得到了广泛的应用,同时也受到了越来越多的科研人员的关注。本文根据其检测机制的不同,概述了目前在生鲜食品品质鉴定中应用广泛的几类无损检测技术,包括光学法、声学及力学法、X射线法、电学法和电磁法以及传感器法。本文简述了这些方法在生鲜食品品质鉴定中的应用,比较了各技术的方法特点。由于技术的多样化,在进行检测时需根据检测目标和目的的不同来选择不同的检测技术以获得最佳检测结果。而随着科技的发展,无损检测技术必将向着简单、微型、便携、专一、高灵敏的方向发展。 相似文献
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不同水稻品种胚芽米加工特性及其品质研究 总被引:1,自引:0,他引:1
以不同品种的水稻为材料,以留胚率为参数进行胚芽米专用水稻品种的筛选,同时进行营养成分(如灰分、蛋白质、氨基酸、直链淀粉、微量元素等)的测定,最后进行品质比较分析,进一步明确不同品种加工成胚芽米的可适性。结果发现,不同品种水稻经加工后留胚率存在较大差异,粳稻的留胚率明显高于籼稻与籼粳杂交稻,三者平均留胚率分别为76.1%、66.83%和64.96%。品质比较结果表明,在相同水稻品种的条件下,由留胚率高的水稻品种加工而成的胚芽米蛋白质、氨基酸、灰分及矿物质含量明显优于留胚率低的水稻品种。综上所述,不同品种均可加工成胚芽米,但胚芽米的品质取决于品种的类型与粒形。因此,以留胚率为指标开展胚芽米加工专用品种的选育对于提高胚芽米的产量与品质是切实可行的。 相似文献