橄榄二酯油烘焙苏打饼干中3-氯丙醇酯、缩水甘油酯产生规律及其质构分析

以橄榄甘油二酯油为原料,制作苏打饼干,考察甘油二酯（diglycerides,DAG）含量、烘焙温度、盐添加量、烘焙时间对饼干中3-氯丙醇酯（3-monochloropropane-1,2-diol esters,3-MCPDE）和缩水甘油酯（glycidyl esters,GE）及饼干硬度和黏度的影响。结果表明,苏打饼干中3-MCPDE和GE的最高含量分别为1.05 mg/kg和0.37 mg/kg,且烘焙过程中3-MCPDE含量与烘焙温度和盐添加量呈正相关,在170 ℃以上时GE含量随烘焙温度升高而增加。但烘焙时间和DAG质量分数对3-MCPDE和GE的产生无显著影响（P＞0.05）。综上,橄榄甘油二酯油应用于烘焙苏打饼干具有良好的安全性和改善产品质构的效果,同时控制烘焙温度和盐添加量能在一定程度降低苏打饼干中3-MCPDE和GE的含量。     

宁夏电网动态安全评估系统一体化功能设计

为使宁夏电网输配电网全景仿真实验室动态安全评估系统实现对调度生产运行的在线支撑,通过调控中心-实验室在线-离线一体化的功能设计,实现了系统对运行电网安全稳定性进行全方位、多场景、多角度的评估。调控中心在线系统接入电网在线运行数据,运用高性能计算机群并行计算分析,实验室离线支持系统对关键断面进行扩展分析。应用结果表明:动态安全评估系统的实施,深度支撑了电网调度生产运行,同时也验证了设计方案的科学性和合理性。     

Breadmaking and Storage of Various Wheat Fractions Affect Vitamin E

The vitamin E loss during baking of two types of industrially baked breads was studied. Neither scalding nor fermentation reduced the vitamin E content. However, the sour dough preparation and dough-making resulted in 20-60% reduction in the content of tocopherols and tocotrienols. In addition the vitamin E yield in the doughs and the French bread when using two different extraction methods were compared. The two methods showed similar results for flours and doughs, but indicated differences after the baking stage. Storage stability of wholemeal flour, white flour, bran and germ of wheat were also investigated. Storage at 20°C for 12 mo decreased vitamin E activity of the various wheat fractions by 28-40%.     

升温速率对活体硅藻壳提纯的影响

选用一种舟形藻作为实验材料,研究了不同升温速率下硅藻壳的形态和成分变化。首先,对从该种硅藻得到的细胞壳进行酸洗处理,以去除金属离子和其它无机盐;之后,分别以1,3,5 和7℃/min的速率将硅藻壳升温至600℃,并保温2 h。然后,使用扫描电子显微镜、能量色散X射线分析和傅里叶变换红外分析3种手段对不同阶段和不同处理条件下的硅藻壳进行分析表征。实验显示：生物SiO₂的含量随着升温速率的降低而升高,以1℃/min升温到600℃并保温2 h的硅藻壳的SiO₂含量最高,其质量分数可达到90%,并且该硅藻壳能保持完整的原始形态。结果表明：由于硅藻的生物SiO₂结构具有较好的隔热性,热传导速度慢,故较快的升温速率很难使生物有机质充分分解,而过高的温度或保温时间又会对硅藻壳形态造成新的威胁。所以,较为缓慢的升温速率有益于有机质的充分去除和保证硅藻壳外观的完整性。     

熟阳极炭块铣削力建模及预测

利用正交实验,建立了以切削速度v、切削深度ae、走刀量f为影响因素的阳极炭块切削力与铣削温度预测模型。采用方差分析技术对回归模型的显著性进行检验。检验结果表明,铣削力与铣削温度回归方程呈高度显著性。经验证所建立的预测模型与实验数据拟合得较好,完全可以用于三面刃高速钢槽铣刀铣削熟阳极炭块,并为进一步设计适合在线开槽刀具提供理论依据。     

真菌降落数值与烘焙效果的关系

对添加不同剂量α-淀粉酶的小麦粉样品进行降落数值(FN)、真菌降落数值(FFN)、糊化和烘焙面包的分析检验,通过分析实验数据的对应关系,确定烘焙效果较好时的真菌降落数值范围。从而在面包粉生产的重要环节———添加剂添加过程中,能利用真菌降落数值来控制α-淀粉酶的添加量,避免添加不足影响面包粉质量,也避免过量添加增加生产成本,造成浪费。实验表明:FFN值的范围在91~158 s时,烘焙效果较好,FFN值91 s时,综合烘焙效果达到最佳。     

Cu含量对Al—Mg—Si合金析出及烤漆硬化行为的影响

采用DSC、硬度测试及TEM研究A16016铝合金中Cu含量对淬火及淬火预时效样品的人工时效析出和硬化行为的影响。结果表明,微量Cu有利于形成较大且稳定性较好的GPI,能在随后的人工时效过程中进一步向GPII转化,从而提高合金的烤漆硬化能力。但是,当Cu含量为0．3％时,烤漆硬化能力没有得到显著增加。对于含Cu合金,预时效热处理也能有效地抑制合金的自然时效行为。     

Partial Evaluation of the Euclidean Algorithm, Revisited

The usual formulation of the Euclidean Algorithm is not well-suited to be specialized with respect to one of its arguments, at least when using offline partial evaluation. This has led Danvy and Goldberg to reformulate it using bounded recursion. In this article, we show how The Trick can be used to obtain a formulation of the Euclidean Algorithm with good binding-time separation. This formulation of the Euclidean Algorithm specializes effectively using standard offline partial evaluation.     

烘烤条件对鸡肉糜脯品质影响的研究

以鸡肉为原料,研究鸡肉糜脯工艺中的烘烤环节对终产品色泽、硬度和感官等品质的影响。通过正交实验,确定了鸡肉糜脯烘烤的最佳工艺条件是烘制温度为60℃,烘制结束水分为42%,烤制温度为120℃,烤制结束水分含量为25%。通过极差分析可知:最终水分含量对色泽、硬度和感官结果的影响都是最大的。     

Determination of siloxanes in silicone products and potential migration to milk,formula and liquid simulants

A pressurised solvent extraction procedure coupled with a gas chromatography–mass spectrometry–selective ion monitoring (GC–MS–SIM) method was developed to determine three cyclic siloxanes, octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), dodecamethylcyclohexasiloxane (D6) and three linear siloxanes, octamethyltrisiloxane (L3), decamethyltetrasiloxane (L4), dodecamethylpentasiloxane (L5), in silicone products. Additionally, two different extraction methods were developed to measure these siloxanes migrating into milk, infant formula and liquid simulants (50 and 95% ethanol in water). The limits of quantification (LOQs) of the six siloxanes ranged from 6?ng/g (L3) to 15?ng/g (D6). Silicone nipples and silicone bakewares were extracted using pressurised solvent extraction (PSE) and analysed using the GC–MS–SIM method. No linear siloxanes were detected in the silicone nipple samples analysed. The three cyclic siloxanes (D4, D5 and D6) were detected in all silicone nipple samples with concentrations ranging from 0.5 to 269?µg/g. In the bakeware samples, except for L3, the other five siloxanes were detected with concentrations ranging from 0.2?µg/g (L4) to 7030?µg/g (D6). To investigate the potential migration of the six siloxanes from silicone nipples to milk and infant formula, a liquid extraction and dispersive clean-up procedure was developed for the two matrices. The procedure used a mix of hexane and ethyl acetate (1?:?1, v/v) as extraction solvent and C₁₈ powder as the dispersive clean-up sorbent. For the liquid simulants, extraction of the siloxanes was achieved using hexane without any salting out or clean-up procedures. The recoveries of the six siloxanes from the milk, infant formula and simulants fortified at 50, 100, 200, 500 and 1000?µg/l ranged from 70 to 120% with a relative standard derivation (RSD) of less than 15% (n?=?4). Migration tests were performed by exposing milk, infant formula and the liquid simulants to silicone baking sheets with known concentrations of the six siloxanes at 40°C. No siloxanes were detected in milk or infant formula after 6?h of direct contact with the silicone baking sheet plaques, indicating insignificant migration of the siloxanes to milk or infant formula. Migration tests in the two simulants lasted up to 72?h and the three cyclic siloxanes were detected in 50% ethanol after an 8-h exposure and after 2?h in 95% ethanol. The highest detected concentrations of D4, D5 and D6 were 42, 36 and 155?ng/ml, respectively, indicating very limited migration of D4, D5 or D6 into the two simulants.