共查询到20条相似文献,搜索用时 93 毫秒
1.
2.
3.
4.
5.
6.
7.
目的 分析番茄红素原料和胶束中的番茄红素在不同温度下的构型变化规律。方法 通过YMC Carotenoid C30-HPLC 高效液相色谱法对其构型变化情况进行研究。结果 各异构体降解速率常数(k)的绝对值会随着温度的升高而变大,表明其降解速率加快,结构越不稳定。通过对比显示,四种番茄红素异构体,稳定性由高到低依次为:5Z> All-E> 9Z>13Z。番茄红素原料中13Z、9Z、ALL-E和5Z的活化能分别为22.0 kJ/mol、23.4 kJ/mol、26.5 kJ/mol、27.6 kJ/mol,而番茄红素胶束中13Z、9Z、ALL-E和5Z的活化能均高于番茄红素原料,分别为25.8 kJ/mol、26.0 kJ/mol、31.5 kJ/mol、31.9 kJ/mol。结论 将番茄红素包载于聚合物胶束中,可以降低其降解速率,提高稳定性。 相似文献
8.
9.
采用RVA快速黏度仪研究了食盐、蔗糖和植脂末等配料对普通和高支链玉米淀粉的峰值粘度和糊化温度的影响。结果表明,对于NaCl和蔗糖来说,随着其质量分数的升高,普通和高支链淀粉的峰值黏度和糊化温度均增大;而对于植脂末,普通淀粉在其质量分数小于6%时,其峰值黏度升高,糊化温度基本不变,大于6%时,峰值黏度和糊化温度均降低。高支链玉米淀粉在植脂末质量分数小于4%时峰值黏度和糊化温度均略微降低,而大于4%时均升高。研究结果有助于阐明玉米淀粉糊化的规律,以及为其它谷物淀粉糊化工艺提供借鉴。 相似文献
10.
11.
采用德国产HAAKEROTOVISICORV12型黏度测定仪 ,对黏性和非黏性酸乳的流变学特性进行了测定 ,分析了影响酸乳流变特性的因素 ,结果表明 :在 2~ 3 5℃的范围内 ,黏性和非黏性酸乳都是触变性流体 ;在配料和工艺相同的条件下 ,由产黏菌株形成的酸乳在大多数情况下表观黏度比非产黏菌株酸乳大 ,但有时反而小 ,初步分析这是由其微观结构的不同造成的 ;配料中无脂乳固体 (SNF)和乳脂肪的含量对酸乳的表观黏度具有强烈的影响 ,在一定条件下 ,后者影响力稍大于前者 相似文献
12.
13.
用自制的高温落球黏度计测试两种低熔点共聚酰胺的零切黏度,获得零切黏度与熔体温度的关系,为相应的理论研究打下了基础。从零切黏度的测试结果求出两种原料的黏流活化能。所测试的两种原料中原料2的黏流活化能较小,在同样温降范围内其黏度降也较小,即不容易发生热降解,因此更适合于熔喷生产。 相似文献
14.
15.
选用高温大曲在30 ℃、37 ℃、40 ℃、43 ℃和53 ℃不同温度条件下液体培养,对培养过程中微生物菌群结构和代谢产物的变化进行了分析。结果表明,较低的培养温度有利于酵母菌和乳酸菌的生长,而较高的培养温度有利于耐高温细菌和霉菌的生长。其中,酵母菌在37 ℃培养60 h数量最多,霉菌在53 ℃培养48 h数量最多,乳酸菌在37 ℃培养24 h数量最多,总细菌在40 ℃培养24 h数量最多。从代谢产物的分析结果看,酒精度和总酸含量在37 ℃时含量最高,乙酸乙酯、总酯含量在30 ℃时最高,α-氨基酸态氮含量在53 ℃时最高。可根据增强发酵活力、提高酒度和酯含量等需求,延长不同培养温度范围的保持时间。 相似文献
16.
M. Spanghero P. Berzaghi F. Masoero C. Zanfi A. Gallo J.C. Ferlito 《Journal of dairy science》2010,93(10):4855-191
The objective of this study was to test the precision and agreement with in situ data (accuracy) of neutral detergent fiber degradability (NDFD) obtained with the rotating jar in vitro system (DaisyII incubator, Ankom Technology, Fairport, NY). Moreover, the precision of the chemical assays requested by the National Research Council (2001) for feed energy calculations and the estimated net energy of lactation contents were evaluated. Precision was measured as standard deviation (SD) of reproducibility (SR) and repeatability (Sr) (between- and within-laboratory variability, respectively), which were expressed as coefficients of variation (SD/mean × 100, SR and Sr, respectively). Ten fibrous feed samples (alfalfa dehydrated, alfalfa hay, corn cob, corn silage, distillers grains, meadow hay, ryegrass hay, soy hulls, wheat bran, and wheat straw) were analyzed by 5 laboratories. Analyses of dry matter (DM), ash, crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) had satisfactory Sr, from 0.4 to 2.9%, and SR, from 0.7 to 6.2%, with the exception of ether extract (EE) and CP bound to NDF or ADF. Extending the fermentation time from 30 to 48 h increased the NDFD values (from 42 to 54% on average across all tested feeds) and improved the NDFD precision, in terms of both Sr (12 and 7% for 30 and 48 h, respectively) and SR (17 and 10% for 30 and 48 h, respectively). The net energy for lactation (NEL) predicted from 48-h incubation NDFD data approximated well the tabulated National Research Council (2001) values for several feeds, and the improvement in NDFD precision given by longer incubations (48 vs. 30 h) also improved precision of the NEL estimates from 11 to 8%. Data obtained from the rotating jar in vitro technique compared well with in situ data. In conclusion, the adoption of a 48-h period of incubation improves repeatability and reproducibility of NDFD and accuracy and reproducibility of the associated calculated NEL. Because the in vitro rotating jar technique is a simple apparatus, further improvement would probably be obtained by reducing the laboratory differences in rumen collection procedures and type of animal donors, which, however, reflect practical conditions. 相似文献
17.
18.
为优化金枪鱼鱼肉匀浆的黏度测试条件,本文研究了不同均质时间、稳定时间、鱼肉匀浆浓度、NaCl浓度、pH及测试温度对鱼肉匀浆黏度的影响。研究结果表明:当均质1 min,稳定60 min,加溶液量(mL):肉(g)为9:1,Na l为1.2 mol/L,pH为7.5,测试温度为5℃时,可获得较稳定的鱼肉匀浆黏度测定结果,为建立通过金枪鱼鱼肉匀浆黏度测量方法评价冻藏金枪鱼品质奠定基础。 相似文献
19.
20.
目的以低温豆粕为原料,采用微波-超声波协同技术提取了水溶性大豆多糖(water-soluble soybean polysaccharide,SSPS),并对大豆多糖的部分理化性质,包括单糖组成、相对分子质量以及粘度性质等进行深入研究。方法分别采用气相色谱与高效凝胶色谱方法对SSPS的单糖组成、相对分子质量进行了测定,采用旋转式粘度计分析了大豆多糖质量浓度、离子强度、温度、pH对SSPS溶液粘度的影响。结果 SSPS的单糖组成主要为半乳糖,其次为葡萄糖、甘露糖、氨基半乳糖、阿拉伯糖等;SSPS的重均相对分子质量约274.752 k;SSPS的粘度随其质量浓度增加而显著增大,随温度、pH值的增加而减小,金属离子(Na+、Ca2+、K+)浓度的变化对其粘度的影响很小。结论本研究将为SSPS的潜在应用提供理论指导。 相似文献