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面粉灰分和时间因素对增白剂作用的影响 总被引:3,自引:0,他引:3
讨论了面粉灰分和时间因素对增白剂作用的影响,对不同灰分水平,不同增白剂添加量,以及不同时间情况下面粉白度的变化进行了测定和数据分析。 相似文献
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探讨了纯化工艺对纸浆水抽提液电导率和灰分的影响,同时探讨了纯化工艺对绝缘纸板电气性能和物理性能的影响规律。结果发现:采用蒸馏水洗涤纸浆,可以使纸浆的水抽提液电导率降低至16.1μS/cm。进一步采用酸处理工艺可降低纸浆的灰分,但对水抽提液电导率有负面影响。采用酸处理配合钡盐处理工艺可以进一步降低纸浆水抽提液电导率,但同时也会提高纸浆的灰分含量。将纯化后的纸浆制备成纸板发现,纯化工艺对纸板的电气性能有着重要的影响。 相似文献
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我们知道,面粉灰分的测定是鉴定面粉品质优劣的重要指标之一。它对指导加工、提高面粉品质具有重要意义。过去我们常用550C灼烧法和850C灼烧法。前者适用于结果准确度高的灰分测定,操作方法简便,但测定时间长。850C法适用于快速灰分的测定,准确度差些。在面粉厂,为能及时指导生产,可采取减少试样,增大灼烧容器面积等办法,来加速灰分的测定。现将目前采用的一种快速方法介绍如下,仅供参考。1仪器用品1.140毫升平顶增朗盖(直径约为52毫米去掉盖环,磨平洗净,烘干备用);1.2小毛刷一把;1.3SDX80毫米描图纸一张;其它仪器与8… 相似文献
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原料面粉是影响挂面品质的主要因素,本研究选择了市面上常见的八种面粉作为原料面粉,分别了测定了各自的主要质量指标,然后用同样的工艺加工成挂面,分别进行质构分析、蒸煮试验和感官评价。试验结果表明:面粉中灰分含量高,面条硬度增加、黏度、回复性降低;湿面筋含量高,面条的回复性、拉伸阻力增加。面粉中的灰分含量是影响挂面蒸煮损失的主要原因之一,也是影响挂面感官评价得分的主要因素之一。面条品质包括质构品质、拉伸品质、蒸煮品质和感官品质,这些品质不仅受到原料面粉中灰分、蛋白质、淀粉、油脂成分的影响,而且受到这些高分子物质分子结构及其互相作用的影响,因此研究面粉品质与挂面品质指标之间的关系的科学道路任重道远。 相似文献
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为了探究影响导电纱线及柔性传感器耐久性的因素,本文选取5种典型金属导电纱线,首先分析洗涤次数、热定型温度及氧化时间对其电阻的影响。然后,以77 dtex镀银导电纱线织造不同尺寸的柔性传感器,进行30次洗涤测试,并用活性藏青BF-DB进行染色处理,以此分析洗涤和染色对传感器性能的影响。结果表明:三种因素对铜纤维的导电性能影响最大,而对铜丝和不锈钢导电纱线的导电性能影响最小,其耐洗涤性、耐热性及抗氧化性能良好。锦纶基镀银导电纱线电阻随着热定型温度的增大而减小,长度缩短;洗涤次数增加,其电阻有一定程度增大;氧化处理20 d后导电性能明显减弱。镀银导电纱编织的柔性传感器较耐洗涤,染色处理后其尺寸变小,但能维持稳定的导电性。 相似文献
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燕麦中含有丰富的多酚化合物,具有很强的抗氧化活性。本实验在单因素试验基础上,采用二次回归正交旋转组合设计对燕麦粉中多酚化合物提取工艺进行优化,建立提取温度(X1)、提取时间(X2)、乙醇体积分数(X3)、料液比(X4)4个因素与总多酚得率之间的回归模型:Y=5.2119+0.6358X1+0.1947X2-0.4213X3+0.452X4-0.1016X12- 0.2786X22 - 0.1963X32 - 0.1526X42,得出各因素对燕麦总多酚得率影响的顺序为提取温度>料液比>乙醇体积分数>提取时间。从模型可知,在提取温度60℃、提取时间65.2min、乙醇体积分数50.6%、料液比1:20(g/ml)条件下,燕麦总多酚得率量最高可达6.6717mg/g。验证值为6.3989mg/g,与理论值基本一致。 相似文献
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Antioxidant activity of commercial buckwheat flours and their free and bound phenolic compositions 总被引:5,自引:0,他引:5
Commercial buckwheat flours were investigated for their antioxidant activities, free, and bound phenolic compositions using spectrophotometer, LC–ESI-IT-MS, and LC–ESI-Q-TOF-MS. Farinetta flour contained the highest free and bound phenolic contents, followed by Supreme, whole buckwheat, and Fancy flour, respectively. The 50% ethanol extraction achieved significantly higher free phenolic content compared with water and absolute alcohol. The absolute ethanol extraction contained considerable more bound phenolic and flavonoid compounds. A high extraction temperature increased the phenolic contents. The optimal solvent to solids ratio was 50:1, and the optimal extraction time was 5 h for flavonoids. The spectral method was reproducible for analysing the total flavonoid contents. The LC–ESI-Q-TOF-MS studies on whole buckwheat flour showed that p-coumaric and gallic acids were found in the bound phenolics along with isoquercitrin but were not present in the free phenolic compounds. The free flavonol-glycosides were found in whole buckwheat flour but not in any other buckwheat flours. 相似文献
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Mass transfer models of leaching oil from soybean (Glycine max) flour with hexane after high-pressure process (HPP) treatment were developed. High pressure (450 MPa) was applied to the soybean flour (mean diameter of flour particle: 365 μm) for 30 min before leaching the oil components in the solvent. The ratio of solvent (volume, mL) to soybean flour (mass, g), such as 1:10 and 1:20, was employed to characterize the effect of solvent ratio on the leaching rate in the batch type of extraction process. Ultraviolet absorbance at 300 nm was used to monitor the extraction rate. Saturation solubility (C(AS)) was determined to be 21.73 kg/m3. The mass transfer coefficients (k) were determined based on the 1st- and 2nd-order kinetic models. The 2nd kinetic model showed better fit. The HPP treatment showed a higher extraction rate and yield compared to the control, while the amount of solvent did not affect the extraction rate and yield. The scanning electron microscope showed that HPP-treated soybean particles included more pores than the untreated. The pores observed in the HPP-treated soybean flours might help increase the mass transfer rate of solvent and solute in the solid matrix. PRACTICAL APPLICATION: High-pressure processing can help increase the extraction rate of oil from the soybean flour operated in batch systems. The conventional solid to solvent ratio (1:20) used to extract oil composition from the plant seed did not help increase the amount of oil extracted from the soybean flour. 相似文献
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T.R. GUPTA 《Journal of food process engineering》1993,16(3):227-235
A steady state technique was used to measure thermal conductivity of whole wheat dough (rolled chapati) and baked chapati (round disc prepared mostly from whole wheat flour dough) at various stages of cooking. Based on the experimental data of chapati at various stages of cooking, a linear equation K = -0.5677 + 0.01396 M + 0.005131 T is proposed for conductivity of wheat flour dough and baked chapati at moisture levels (M): 35 < M < 50 and temperature ranges 35 < T < 60 A separate equation K = 0.3204 + 0.0091 M -0.00805 T predicts thermal conductivity of rolled chapati and baked chapati at T > 60C. 相似文献
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采用亚临界丁烷对大豆粉脱油制得豆粕(DSF-B),并与正己烷制备豆粕(DSF-H)比较,对分离蛋白得率及热变性、豆粕残余极性脂和在贮藏过程中蛋白的氧化进行分析。DSF-B的蛋白得率(32.1%)比DSF-H高(约6%),蛋白热变性二者一致,且11S变性温度低于工业白豆片。残余极性脂分析,DSF-B比DSF-H总量低、磷脂含量高,脂肪酸组成有差异。模拟贮藏试验表明,DSF-B在贮藏中蛋白更易被氧化,这可能与极性脂的组成有关。亚临界萃取技术无高温处理、可选溶剂多样,可开发应用于大豆等植物蛋白制品。 相似文献
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以小麦粉为原料,通过β -淀粉酶对面制品进行抗回生处理,研究了加酶量、酶作用时间、酶作用温度对β -淀粉酶抑制面制品回生效果的影响,并在单因素试验基础上,采用响应面分析法对β -淀粉酶抑制面制品回生工艺进行优化,结果表明,β -淀粉酶抑制面制品回生工艺的最佳条件为:酶浓度为45.8 U,酶作用温度为57℃,酶作用时间32.2 min.在此工艺条件下制得的面制品,经4℃下冷藏48 h后测得的硬度为(3299.86±8.32)g,而未经β-淀粉酶抗回生处理的面制品,经4℃下冷藏48 h后测得的硬度为(12950±7.22)g.面制品硬度降低了74.52%. 相似文献