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巧克力是很多人日常所喜爱的甜蜜美食,也是节日馈赠佳品.巧克力在常温下呈坚硬状态,放入口中却能够迅速融化,给人以丝滑愉悦的感官享受,这主要是由于脂肪(可可脂)在巧克力中形成连续体系使之能够在口中快速且顺滑地融化,从而提供特有的肥腴滑爽的口感.通常而言,巧克力中的脂肪会在约28℃时软化,在32~35℃下完全融化,故品质优良... 相似文献
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A method for identifying refined vegetable fats added to chocolate (cocoa butter equivalents, CBEs) was combined with established quantitative methods for determining the level of vegetable fat added to cocoa butter with the aim of providing improved precision. The identification of fats was based on the analysis of sterol and triterpene alcohol degradation products formed during the processing of the fat. The procedure was able to successfully discriminate between 95% of pairs of fats from a set (33) of CBE-type vegetable fats. Subsequent analysis of 80 mixtures of four CBEs with chocolate successfully identified, on cross-validation, 94% of the samples. Combining the qualitative procedure with established quantitative methodology, based on the analysis of triacylglycerols, improved the method precision from ± 2.1% to ± 0.3% (5% addition of CBE at 95% confidence). Identifying the fat analytically permits the use of quantitative methods for determining the level of added fat in chocolate that have improved precision in comparison with the measurement of an unidentified fat. This may obviate the need to use factory inspection as a means to identify the ingredients of a product and monitor compliance with proposed legislation. 相似文献
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在恒温条件下对大豆蛋白/牛奶酪素蛋白/聚乙烯醇共混纤维(简称双蛋白纤维)进行干热处理,探讨了干热处理温度和时间对双蛋白纤维白度、黄度、质量损失率的影响,并通过染色试验测定了干热处理条件对酸性深蓝5R染色双蛋白纤维性能的影响.研究表明,双蛋白纤维能够耐受一定的高温,随着干热处理温度的升高和时间的延长,纤维的白度逐渐下降而黄度和质量损失率逐渐增大,205℃干热处理2h或220℃干热处理0.5h后,纤维黄度和质量损失率均急剧上升,染色纤维的表观色深K/S值下降明显,220℃干热处理0.5h后再延长处理时间,纤维开始燃烧.干热处理一定温度和时间后,纤维的染色特征值有所变化,纤维的彩度C和色相角H随干热处理温度的升高和时间的延长而降低. 相似文献
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为改善纤维素在氢氧化钠(NaOH)水溶液中的溶解性能,通过醚化改性制备了低取代羟乙基纤维素(HEC),并借助光学显微镜、核磁共振仪、差热扫描量热仪和透射电子显微镜等研究了HEC在质量分数为8%的NaOH水溶液中的溶解行为及溶解机制。结果表明:低温下NaOH溶剂和水分子可结合形成尺寸合适、结构稳定的NaOH水合分子,与HEC大分子上的羟基键合形成HEC-NaOH-H2O缔合结构,切断了HEC大分子间氢键,HEC直接溶解;醚化改性后亲水性侧链的引入减弱了分子间作用力,增强了HEC与NaOH水合分子之间的作用强度,增强了缔合结构稳定性,促进了HEC在NaOH溶剂中的良好溶解;沿纤维长度方向HEC最外层膜溶胀成球形并逐渐破裂溶解,最终以长度为微米级、宽度为10~80 nm的微纤维形式分散在溶剂中。 相似文献
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溶剂法提取油莎豆油的工艺研究 总被引:1,自引:0,他引:1
目的:为油莎豆油的生产、开发与利用提供试验依据。方法:采用溶剂法提取油莎豆油,单因素试验考察提取次数、时间、料液比、温度对油莎豆油得率的影响,正交试验确定油莎豆油的最佳提取工艺。结果:石油醚(60~90℃)作溶剂,油莎豆油得率最高。提取2次以上,油莎豆油得率增加不大。随着提取时间的增加,得率增加,超过3h后得率的增加趋势不明显。料液比为1:10(g/mL)时,得率较大。随着提取温度的升高,油莎豆油得率增大,30~50℃之间增幅较大。各因素对油莎豆油得率的影响主次顺序依次为:提取时间>提取温度>料液比>次数。结论:石油醚(60~90℃)作溶剂时,油莎豆油的最佳提取工艺为:提取时间4h,料液比1:10(g/mL),提取温度40℃,提取3次,该条件下,油莎豆油得率为27.20% 相似文献
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邹燕娣周青燕包李林熊巍林张谦益周双全 《中国油脂》2020,45(1):137-140
通过研究基准豆粕的制作方法和标样、样品前处理影响因素,建立一种能准确测定豆粕中溶剂残留量的方法。结果表明:制作基准豆粕时,加入适量水,有助于残留的有机溶剂充分挥发,得到合格的基准豆粕;标样结果稳定性与加水量关系不大,选择标样与样品的加热平衡温度均为120℃,加热平衡时间均为120 min,加水量均为200μL(3 g豆粕),样品重复性试验的精密度为0~4. 5%。对相同样品,采用本试验方法的测定结果较国标方法的高,更能准确反映豆粕的质量情况。 相似文献
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利用二甲基亚砜(DMSO)溶解纯涤织物及涤/棉混纺织物,并回收利用涤纶(PET)和棉纤维。研究结果表明,DMSO试剂可以回收纯涤织物,尤其当温度在185~194℃时DMSO与纯涤织物溶解反应相对较快,溶解时间为12min。在一定反应时间内DMSO易溶解涤纶而不溶棉纤维,将其用于回收PET和棉纤维。涤/棉织物投入到温度为185~194℃的 DMSO试剂中,溶解60min,将不溶于DMSO试剂的棉纤维在温度为185~194℃的条件下滤出并回收,同时从溶解液中回收聚酯。回收的棉纤维性能稳定,运用领域广泛。再生PET的特性粘度随DMSO试剂回收率的增加而增大。 相似文献
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Cocoa is the primary ingredient in chocolate, and cocoa concentration attributes to the smoothness of the chocolate. Supporting this statement, we assessed the smoothness and melting properties of five chocolates of different cocoa concentration from three brands using the professional sensor evaluation and weight method, respectively. Artificial saliva was added to obtain the mixed chocolate solutions, and their viscosity and coefficient of friction (CoF) were measured for three rubbing pairs. The correlation of chocolate smoothness with their viscosities and average CoF (aCoF) was also discussed. The results indicated that the cocoa concentration significantly affected the smoothness of the chocolates among the three brands. The mixed solution of 50% chocolate could be a representative of oral processing, but their viscosities were not proficient enough to effectively characterize their smoothness. The aCoF of 50% chocolate solution could be rapid and effective to evaluate their smoothness. In addition, the Two-GCTPE rubbing pair was more suitable way to evaluate the smoothness of similar foods in the oral environment. The study results will provide a better insight into characterizing certain attribution of similar foods. 相似文献
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