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1.
以新鲜牛乳为原料、细菌凝乳酶作凝固剂,先采用单因素试验研究了凝乳温度、pH值、CaCl2添加量和凝乳酶添加量4个因素对凝乳效果的影响,然后通过Box-Benhnken设计进一步优化了细菌凝乳酶干酪素生产工艺参数。根据试验结果,采用逐步回归的方法进行二次回归分析,得到相应的回归方程式,模型的R2值为0.98%,说明回归方程的拟合程度良好。采用Design-Expert软件预测得到干酪素得率的最大估计值为3.534%,此时因素X1、X2、X3的对应值分别为0.306、0.216、0.342,3个因素的对应水平为：温度36.53℃、pH值6.216、凝乳酶添加量为0.368 mL。采用上述优化条件进行验证试验时将温度设定为36.5℃、pH值设定为6.2、凝乳酶添加量设定为0.37 mL。验证试验结果表明,在此条件下凝乳酶干酪素的得率为3.527%±0.02%,与理论预测值相比,相对误差为0.19%。分别测定了细菌凝乳酶干酪素和小牛皱胃酶干酪素的水分、灰分和蛋白质等理化指标,结果表明细菌凝乳酶干酪素所含水分、灰分和蛋白质含量比小牛皱胃酶干酪素高,但差异不显著（P>0.05）,而脂肪含量比小牛皱胃酶干酪素低,差异也不显著（P>0.05）。将2种凝乳酶干酪素进行红外光谱扫描,发现小牛皱胃酶干酪素和细菌凝乳酶干酪素的特征峰基本一致。以上结果表明,2种凝乳酶干酪素品质差异不显著,说明细菌凝乳酶可作为小牛皱胃酶的替代品用于凝乳酶干酪素的生产。研究结果可为细菌凝乳酶的应用提供技术依据。 相似文献
2.
利用自主分离的芽孢杆菌菌株TS01和15种芽孢杆菌(地衣芽孢杆菌,枯草芽孢杆菌,短小芽孢杆菌,巨大芽孢杆菌,凝结芽孢杆菌,蜡状芽孢杆菌,迟缓芽孢杆菌,苏云金芽孢杆菌,嗜热脂肪芽孢杆菌,解淀粉芽孢杆菌,环状芽孢杆菌,球形芽孢杆菌,侧孢短芽孢杆菌,多粘类芽孢杆菌,泛酸枝芽孢杆菌)模式菌种进行ARDRA分析。采用16S rDNA通用引物16S-27和16S-1525进行PCR扩增,16S rDNA扩增片段经六种限制性酶（Alu I、Taq I、Mse I、Bst UI、Hha I和Tsp509 I）酶切电泳,获得了TS01菌株的特征性ARDRA指纹图谱。ARDRA图谱通过GelcomparⅡ软件进行聚类分析(UPGMA),结果表明菌株TS01和地衣芽孢杆菌处于同一分支,亲缘关系最近。ARDRA分析鉴定结果与实验室前期菌株TS01形态、生化鉴定和16S rDNA序列分析结果一致,TS01是一株地衣芽孢杆菌菌株,从而证明ARDRA技术在菌种水平上对芽孢杆菌TS01进行鉴别具有可靠性。 相似文献
3.
本文对33株枯草芽孢杆菌群菌株进行β-甘露聚糖酶活性筛选,其中的32株具有β-甘露聚糖酶活性,只有1株无β-甘露聚糖酶活性。通过基因克隆测序的方法获得33株枯草芽孢杆菌群菌株β-甘露聚糖酶基因编码区全序列,对酶基因进行同源性分析并构建系统发育树;在β-甘露聚糖酶基因系统发育树中,33株枯草芽孢杆菌群菌株聚为3个分支,分别是枯草芽孢杆菌分支、地衣芽孢杆菌分支和解淀粉芽孢杆菌分支;枯草芽孢杆菌、地衣芽孢杆菌和解淀粉芽孢杆菌β-甘露聚糖酶基因种内同源性大于91％,而种间同源性为60％～69％。 相似文献
4.
研究TGase、CaCl2、凝乳酶复合对Mozzarella干酪硬度的影响,以优化工艺参数。采用三因素二次正交回归设计确定TGase、CaCl2、凝乳酶的添加量水平,通过SAS软件RSREG过程,分析三因素主效应、单因子效应及其交互效应对成熟10d的干酪硬度的影响。结果表明,三因素对硬度的影响符合Y=B0+∑BjXj+∑BijXiXj+∑BjjX2的三元二次回归模型,其关键参数主效应为TGase(P<0.01)>CaCl2(P<0.05)>凝乳酶(P>0.05);单因子效应均为开口向下的抛物线型,符合报酬递减规律,且以TGase的边际效应较大;TGase和CaCl2对干酪硬度有明显的交互作用。最优工艺参数为:TGase0.952%,凝乳酶0.977%,CaCl20.095g/L,硬度值29.08N。 相似文献
5.
为弄清水产养殖中常用的有益菌——地衣芽孢杆菌和3种常见的浮游微藻的相互关系,本文采用陈海水配制的无机培养液和对虾养殖池水,分别研究了地衣芽孢杆菌对微绿球藻、隐藻和颤藻的影响以及这几种微藻对地衣芽孢杆菌的反作用。以通径分析法分析微绿球藻、隐藻和地衣芽孢杆菌对颤藻直接和间接影响力的大小。结果发现,地衣芽孢杆菌对微绿球藻有一定的抑制作用,对隐藻的促进作用明显,而对颤藻的作用效果不明显;在与微绿球藻和隐藻混合培养时,地衣芽孢杆菌生长正常,仅在藻细胞密度较大时受到一定程度的抑制;在与颤藻混合培养时,地衣芽孢杆菌受到明显的抑制作用。通径分析结果发现,地衣芽孢杆菌与微绿球藻协同对颤藻产生抑制作用,而隐藻对颤藻的作用较弱。 相似文献
6.
该文目的在于为干酪功能特性、含水率和产率的控制提供理论依据,使用标准化原料乳经低温巴氏杀菌,采用无盐渍新工艺生产Mozzarella干酪,从添加发酵剂开始,到制成新鲜干酪,测定各阶段干酪凝块的温度、水分含量、pH值和滴定酸度及各阶段乳清和凝块的蛋白和脂肪含量,计算Mozzarella干酪的效能和产率。试验结果表明：在排乳清和粉碎加盐阶段,干酪凝块中的水分含量变化幅度最大,排出乳清中的蛋白和脂肪数量明显增加;干酪的脂肪回收率达到92.22%,实际测得的乳清中脂肪的损失率为7.62%;乳蛋白的回收率达到83.60%,仅有16.72%的蛋白质损失于乳清中;在堆酿阶段pH值有一个从6.3(干酪凝块5.5)至5.25的快速下降过程。Mozzarella干酪的实际产率达到12.38%,达到了同类型干酪的产率要求。Mozzarella干酪的理化指标达到了美国全脂Mozzarella干酪的标准。 相似文献
7.
通过单因素试验对地衣芽孢杆菌发酵培养基配方及条件进行优化。结果表明,该菌菌株培养基最佳配比为蛋白胨1%、酵母提取物0.5%、氯化钠1%,最佳培养条件是初始pH值8.5、温度37 ℃、时间36 h、三角瓶装液量125 mL、接种量4%、转速200 r·min~(-1)。该研究为地衣芽孢杆菌的大规模工业化发酵培养提供了有益借鉴。 相似文献
8.
为控制干酪的质量,对Mozzarella干酪成熟过程中蛋白质的水解(测定SDS凝胶电泳和可溶性氮)和未融化干酪的质构变化以及融化干酪功能特性变化进行了研究,干酪成熟过程中由于凝乳酶和乳酸菌酶的作用使蛋白水解,从而使pH 4.6可溶性氮(SN)和12% TCA SN逐渐增加;凝乳酶主要影响酪蛋白的水解范围,乳酸菌及其酶,不但影响酪蛋白的水解范围,而且主要影响酪蛋白的水解深度。干酪中的残留凝乳酶和乳酸菌酶使酪蛋白水解为大分子量的肽段,而乳酸菌酶还可将大分子量的肽段进一步降解为小分子量的肽段和游离氨基酸。由于酪蛋白的水解,使干酪的硬度和弹性下降,融化性和油脂析出性增加,随着小分子量肽和游离氨基酸的增加,干酪的褐变性提高。 相似文献
9.
从自然发酵鸡粪中分离筛选出2株(编号JS4、JS8)高温蛋白分解菌,能产较高活性的中性蛋白酶。对JS4、JS8菌株的形态、培养特征和生理生化特性进行鉴定,JS4、JS8菌株分别属于枯草芽孢杆菌和地衣芽孢杆菌。将2菌株复合接种发酵鸡粪,以中性蛋白酶活性作检测指标,研究鸡粪发酵条件。结果表明,最佳发酵条件为含水量为50%、接种量为1%、添加辅料为麸皮、pH值为7.0。 相似文献
10.
枯草芽孢杆菌是一种广泛存在于土壤中的产酶细菌,在环境领域也具有广阔的应用前景。本文以一株产高温蛋白酶枯草芽孢杆菌BY25为研究对象,比较添加不同有机氮源的产酶培养基进行发酵时,各处理中枯草芽孢杆菌胞外蛋白酶的组成和产量的差异;并对不同培养基发酵液的粗酶液组分进行酶学性质分析和明胶酶谱检测。结果表明,枯草芽孢杆菌BY25在不同培养基条件下会出现差异性产酶,产酶培养基中添加麸皮有利于中性金属蛋白酶（(Npr）)的产生,而添加豆饼粉则有利于枯草菌素（(Apr）)的产生。 相似文献
11.
凝乳是干酪加工的关键环节,对奶油干酪的品质具有重要影响。通过对奶油干酪理化成分、产率、涂抹性的测定,比较了酶凝、酸凝、酸-酶互作凝乳3种方式对奶油干酪涂抹性的影响。结果表明,随着酸化程度的加深,奶油干酪的脂肪含量和蛋白质含量逐渐减少,含水率显著增加,校正产率、脂肪回收率和酪蛋白回收率降低。有酶高酸组(RHA)涂抹性最佳,其剪切功、屈服应力都分别为最小(19.23N·s、195.67Pa),与传统酸凝型奶油干酪(NR)相比,RHA的剪切功和屈服应力分别降低了17.04%和27.88%,干酪涂抹性得到明显改善。这为涂抹型奶油干酪的研发提供了技术基础。 相似文献
12.
为探究减轻杏果实采后黑斑病的方法,以赛买提杏果实为试验材料,经3.0 mg·L -1 2,4-表油菜素内酯(EBR)结合2%氯化钙(CaCl 2)减压渗透处理后,于温度1.0±1℃、相对湿度90%~95%条件下放置48 h后,进行交孢链格孢( Alternaria alternata)损伤接种,并进行 A. alternata离体抑菌试验。结果表明,3.0 mg·L -1 EBR结合2% CaCl 2对 A. alternata的菌落直径和孢子萌发没有直接抑制作用。EBR结合CaCl 2处理可通过诱导苯丙氨酸解氨酶(PAL)、肉桂酸-4-羟化酶(C4H)、香豆酸辅酶A连接酶(4CL)活性上升,增加总酚、类黄酮和木质素含量来抑制杏果实接种发病率与病斑直径的上升。综上,EBR结合氯化钙处理可通过诱导苯丙烷代谢途径来增强杏果实对黑斑病的抗性。本研究结果可为减轻杏果实采后黑斑病提供技术参考与理论依据。 相似文献
13.
为明确大气CO 2浓度升高及氮肥施用对薏苡( Coix lacryma-jobi L.)苗期营养元素吸收运输的影响,本研究以兴仁白壳薏苡为试验材料,采用盆栽控制试验,通过人工气候箱模拟CO 2浓度升高,探究薏苡各器官中营养元素对CO 2浓度升高和施用氮肥的响应。结果表明,CO 2浓度升高使薏苡根中TOC含量显著增加15.82%;叶、茎中TP含量显著增加18.98%、29.41%( P<0.05);叶、根中N含量显著减少8.15%、8.31%( P<0.05);叶、茎、根中K含量无显著差异。施氮使薏苡叶、茎、根中N含量显著增加19.52%、28.42%、23.29%;叶、茎中TP含量显著增加14.60%、51.96%( P<0.05);根中K含量显著减少22.57%( P<0.05);叶、茎、根中TOC含量无显著差异。两者交互作用下,薏苡茎、根中N含量显著增加6.49%、8.99%;叶中TP含量显著增加15.33%( P<0.05);叶中N含量显著减少4.22%;叶、茎中K含量显著减少18.47%、33.25%( P<0.05);叶、茎、根中TOC含量无显著差异。在CO 2浓度升高条件下,薏苡叶片中中量元素S和微量元素Cu、Zn、Ni含量,分别显著减少18.06%、54.01%、37.96%、50.99( P<0.05);而茎中Mn、Cu、Zn、Ni含量,分别显著增加90.20%、70.55%、46.80%、149.50%( P<0.05)。CO 2浓度升高能促进Mg、S根向茎的运输以及Zn、Mn茎向叶的运输,施用氮肥能促进Fe茎向叶的运输。综上所述,CO 2浓度升高和氮肥施用会影响薏苡不同器官矿质离子的吸收及选择性运输能力,从而维持植物体内营养元素平衡。本研究结果可为深入认识未来大气环境变化下,薏苡对营养元素的需求变化特征,以及薏苡栽培中施肥策略的选择提供科学依据。 相似文献
14.
Puddling as well as no-puddling for growing transplanted and direct seeded rice, respectively, have their disadvantages as well as advantages on the physical condition of the soil and yield of rice. The soil that is more susceptible to changes in structure is easy to puddle. However, what should be the extent of puddling is not well established. Generally, farmers have a tendency to create a very fine puddle that actually may not be required. Keeping in view the current global emphasis on conservation of resources as well as reduction of the production cost to improve the economic gain of farmers, this study attempted to find out the influence of varying intensities of puddling on the soil physical condition and rice yield (cv. IR 36) in a Vertisol of central India. The study was conducted over two cropping seasons during year 2000 and 2001. Three puddling intensities i.e. no-puddling ( P0), and puddling by four ( P1) and eight ( P2) passes of a 5 hp power tiller were evaluated. The aggregate mean weight diameter (AMWD) of soil (0–15 cm depth) for P0 remained almost unchanged till harvest. At 15 days after puddling, AMWD in P1 and P2 compared to P0 was less by 45 and 59% in the first year and by 60 and 69% in the second year, respectively. These values at harvest changed to 22 and 46% in the year 2000 and 28 and 43% in the year 2001, respectively. Soil bulk density (BD) and penetration resistance (PR) increased significantly from transplanting to harvest in puddled soil, but in unpuddled soil significant increase in PR only at the surface 0–7 cm layer was observed. Higher intensity of puddling favoured more soil wetness at harvest, as the puddled soil maintained 25% more water than P0. Compared to P1, P2 showed an increase of 4.3, 10.3 and 7.7% in length, width and depth of cracks, respectively, while the increase in P1 over P0 in the same order was 35, 23.5 and 13.3%, respectively. Thus, crack dimensions (length, width and depth) were larger under high intensity of puddling. Water loss through seepage plus percolation was significantly higher in P0 as compared to P1 and P2 and the higher intensity of puddling reduced the losses more. The grain yield of P2 was slightly higher than P1 but both were significantly above P0. Higher grain yield resulted in 46 and 49% more water use efficiency under P1 and P2 than P0, respectively. This 2-year study has shown that puddling beyond P1 i.e., four passes of a 5 hp power tiller may not be required to obtain higher yield or other benefits in Vertisols having similar hydrology to that reported here. Puddling only to the required level will also deteriorate less the soil physical condition as compared to more intense puddling. The unpuddled direct seeded rice maintained the soil in a better physical condition but the yield was significantly lower in relation to the puddled ones. 相似文献
15.
在模拟中等水分亏缺条件下(0.3M甘露醇溶液相当于-7.3巴,土壤含水量7-8%),研究了氯化钙(Ca)和赤霉素(GA)浸种对提高糜子成苗的作用.结果表明:Ca和GA处理种子促进了幼根、幼芽的伸长,提高了出苗率和幼苗的抗旱力.经初步研究,Ca和GA促进成苗的机理有所不同.对这一技术在实际生产中的应用价值作了评价. 相似文献
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为探究葛根素(PUE)对小白菜镉(Cd)损伤的保护效果,采取外源添加不同葛根素处理,将小白菜植株随机分为7组,即对照组(CK)、PUE30组(葛根素30μmol·L -1)、Cd4组(镉4 mg·L -1)、Cd与PUE共处理组(4+15、4+30、4+45、4+60)。处理30 d后,观察小白菜植株生长状况、测定Cd富集量及抗胁迫生理活性物质,包括叶绿素、抗氧化酶(SOD、APX、CAT、POD)活性及过氧化氢(H 2O 2)、丙二醛(MDA)Vc、可溶性蛋白含量,并用实时荧光定量PCR(qRT-PCR)技术检测抗氧化酶基因(SOD、POD、APX及CAT)表达量。结果表明,与CK组相比,Cd4组小白菜根中Cd含量、H 2O 2和MDA含量显著升高,而地下部鲜重、地上部鲜重、抗氧化酶(SOD、POD和APX)活性和叶绿素含量整体显著降低(P<0.05)。与Cd4组相比,Cd+PUE共处理组小白菜氧化损伤程度减轻,H 2O 2 相似文献
17.
Rice–wheat productivity in irrigated tract of the Indo-Gangetic plains is constrained by water and energy limitations. In order to minimize unproductive soil water evaporation and percolation loss at a field scale, management practices include soil puddling, water-economizing irrigation schedule, and matching growth cycle with periods of low evaporative demand. This 3-year field study examines combined effects of these options on rice–wheat productivity and water-use efficiency (WUE) and energy-use efficiency (EUE) on a sandy loam soil in an irrigated semi-arid sub-tropical environment. Treatments included combinations of three puddling intensities, viz., one ( P1), two ( P2), and four ( P4) runs of a tine cultivator in ponded water after a common pre-puddling tillage; with two irrigation regimes, viz., continuous submergence ( I1) throughout the growing season, and intermittent submergence ( I2) with continuous submergence for 2 weeks after transplanting followed by 2-day interval between successive irrigations, and two transplanting dates, viz., first fortnight of June ( D1) and end June ( D2) to impose variation in seasonal evaporative demand. Residual effect of puddling in rice on succeeding wheat was also evaluated during the 3 years. Intensive puddling and water-economizing schedule caused a significant reduction in seasonal percolation loss primarily due to puddling-induced changes in soil bulk density and hydraulic behavior. Increasing puddling intensity from P1 to P2 enhanced mean rice yield by 0.2–0.3 Mg ha−1, but additional puddling did not improve yield significantly. Mean grain yield increase with I1 over I2 ranged between 0.3 and 0.6 Mg ha−1. Interaction effect between puddling and irrigation indicate that yield benefit with I1 over I2 was greatest in P1 regime (0.6 Mg ha−1), and the effect decreased with increase in puddling intensity. Delayed transplanting caused a decline of 0.3–0.5 Mg ha−1 in rice yield. Although maximum yield was realized with combination of P2 or P4 regime with I1 regime, but water-use efficiency was greater with I2 compared to I1 regime by 1.1 kg ha−1 mm−1 in 2000 and by 0.3 kg ha−1 mm−1 in 2001. It indicates that yield gain with additional irrigation were not commensurate with additional water input. Energy analysis also showed that energy-use efficiency was 6.8, 7.2, and 6.6 kg kWh−1 for P1, P2, and P4 regimes suggesting that yield gain with P4 did not match energy input for additional puddling. Further, there was a greater risk of yield reduction of succeeding wheat with P4 (by 0.2–0.3 Mg ha−1) compared to P1 or P2 regime. 相似文献
18.
为研究青贮玉米(Zea mays L.)产量和品质与气象因素的关系,于2018—2019年在通辽市农业科学研究院试验基地,以北农青贮368、东科301、京科青贮516及京科968为材料,设置D1(4月24日)、D2(5月1日)、D3(5月8日)和D4(5月15日)4个播期,比较不同播期条件下青贮玉米产量和品质的变化,分析青贮玉米产量和品质形成与气象因素的关系。结果表明,随着播期的推迟,各品种青贮玉米生育期缩短,株高和茎粗均呈增加趋势,绿叶数变化不大,D2播期的穗位较高。各品种在D2播期的平均生物产量最高(35.2～40.2 t·hm -2)。随着播期推迟,中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)含量呈增加趋势,粗蛋白含量变化不明显,D2播期淀粉含量较高。生育期日照时数(R 2=0.381,P=0.031)和吐丝后日照时数(R 2=0.507,P=0.003)与干物质产量呈负相关,生育期降雨量(R 2=0.591,P<0.001)和吐丝后降雨量(R 2=0.367,P=0.03... 相似文献
19.
为探究不同解冻方式对羊肉理化品质和微观结构的影响,本研究将冻结的羊半膜肌及背最长肌分别采用室温空气解冻、静水解冻、冷藏解冻、超声波解冻及微波解冻5种方式进行解冻,通过测定相关品质指标,分析各解冻方式对肌肉品质的影响。结果表明,冷藏解冻后羊半膜肌及背最长肌的解冻损失(1.08%、3.10%)、蒸煮损失(21.18%、21.97%)、高铁肌红蛋白含量(36.1%、43.6%)及挥发性盐基氮值(7.02、7.45 mg·100g -1)均显著低于其他解冻方式( P<0.05),微观结构破坏程度较小;超声波解冻、微波解冻后半膜肌与背最长肌的解冻损失(3.34%、7.01%及7.63%、9.59%)、蒸煮损失(25.54%、26.17%及26.45%、28.46%)高于其他解冻方式( P<0.05);室温空气解冻、静水解冻后两种肌肉的挥发性盐基氮(27.5、21.4及21、23.51 mg·100g -1)、菌落总数[3.52、3.89及3.46、3.9 lg(CFU·mL -1)]显著高于其他解冻方式( P<0.05);微波解冻后肌肉纤维发生严重卷曲和断裂。综上,冷藏解冻的羊肉品质较好,这为实际生产中冻结羊肉的解冻方式选择提供了理论依据。 相似文献
20.
A recombinant cyprosin from the cardoon (Cynara cardunculus L.) was assayed and compared with calf rennet in batches of ewes' milk cheese by determining different chemical, biochemical, and microbiological parameters over 4 months of ripening. There were no differences between the two types of coagulants in most chemical parameters, a(w), and pH. Proteolysis was more marked and rapid in cheese containing recombinant cyprosin as coagulant, the soluble nitrogen content of which was significantly higher (p < 0.01) than that of the cheese obtained with animal rennet; at the end of ripening the nonprotein nitrogen of cheese produced with recombinant cyprosin was slightly higher (p > 0.05) as compared with that in cheeses obtained with animal rennet. Microbial counts in the milk used for making cheese were high in most of the groups analyzed. Despite slight differences in counts, the main microbial groups analyzed were similar in cheese produced with both types of coagulants throughout ripening. 相似文献
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