教学课程资源库 更多>>

关键词： Hexagonal and orthorhombic structures   C-type starch   Lamellae   Mineral composition   Isolation process  

摘要： This work focused on studying the effect of lamellae presence on the pasting profile of isolated avocado starch (C-type) obtained by a combined mechanical and ultrasonic process. Inductively Couple Plasma indicates that this starch is rich in P, K, Na, and Ca. This starch exhibits the most crystalline structure reported so far. The correlation between the morphological and structural properties throughout its pasting profile explains its apparent viscosity behavior. Granules exhibit a non-conventional irregular morphology with sizes ranging from 35 to 40 um in their long side. DSC reveals endothermal transitions at 68 degrees C and 119 degrees C associated with the nanocrystals solvation and amylose-lipid complex, respectively. After gelatinization, the presence of lamellae originated from the partial fragmentation of the crystals. The pasting end exhibited a combined behavior between custard and hydrogel. This correlation could be considered a new methodology to understand the pasting behaviors in any starch.

关键词： Chickpea flour   Biscuits   In vitro starch digestibility   Physicochemical properties  

摘要： As the effect of chickpea flour (CF) incorporation on the physicochemical properties and starch hydrolysis of biscuits were unclarified, CF was used to replace wheat flou r with a ratio of 10%, 20%, 30%, and 40% to prepare biscuits. The pasting properties, thermal properties, microstructure, in vitro starch digestibility and qualit y properties were investigated. The addition of CF in wheat flou r increased the water solubility and reduced the swelling power of the mixed powder. Elevated incorporation levels increased the content of slowly digestible and resistant starch of biscuits, increased the gelatinization onset temperatu r e and reduced its gelatinization enthalpy and viscosity. The microstructure indicated that the addition of CF also increased the protein and fat content of the biscuits and enhanced the entrapment effect of the starch, which reduced the sensitivity of starch to digestive enzymes. Our finding revealed that the incorporation of 30% CF in biscuits could be an effective w a y to develop a nutritious and low-digestibility biscuit with desirable quality properties.

关键词： 应用技术型人才   物理化学   项目导向式教学方法   线上线下混合式   任务驱动式  

摘要： 面对社会对应用技术型人才的需求,物理化学的教学需要改革。物理化学的教学改革实践表明,线上线下混合式教学方法的应用,高效的利用了学生的课余时间,配合任务驱动式、项目导向式的教学方法,激发了学生学习物理化学的兴趣,培养了学生的实际操作能力,提高了学生的逆商,帮助学生较快的形成工程伦理意识,让学生通过物理化学的学习掌握一些技能,帮助学生早日成为应用技术型人才。

关键词： 物理化学   PYX   耐热炸药   介稳区宽度   二甲亚砜   结晶热力学   重结晶  

摘要： 为了重塑2,6-二苦氨基-3,5-二硝基吡啶(PYX)的晶体形貌,改善PYX的晶体品质,采用激光动态法测定了PYX在二甲亚砜(DMSO)中的溶解度,建立了溶解度模型,估算了溶解过程的热力学参数;测定了不同条件下PYX在DMSO中的介稳区宽度,揭示了介稳区宽度的影响因素及规律,计算了成核级数;在此基础上采用降温法对PYX进行重结晶,对比分析了重结晶前后的晶体形貌和热性能。结果表明,PYX在DMSO中的溶解度随温度的升高而增大,Apelblat模型对溶解度的拟合结果较好,更适合预测溶解度;介稳区宽度随降温速率的增大而增大,随饱和浓度和搅拌速率的增大而减小,结合介稳区变化规律得到适宜的结晶条件为:饱和浓度(摩尔分数)0.016~0.022、降温速率1~2℃/min、搅拌速率250~500 r/min;当饱和浓度从0.0148增至0.0224时,受降温速率影响的成核级数(m)由3.7010增至4.7461,受搅拌速率影响的成核级数(n)由0.3601增至0.6284。PYX在DMSO中经降温重结晶能够得到表面光滑度良好、无明显缺陷的块状晶体,重结晶后PYX的DSC热分解峰温提高了11.9℃,热爆炸临界温度提高了9.8℃,说明通过重结晶能够优化PYX的热稳定性。

关键词： QCM-D   Mucin   Aspartame   Reb A   Sucrose  

摘要： Plagued with unpleasant aftertastes, bitterness, and mouth-puckering astringency, the utilization of sweeteners as regular sugar replacements has met with limited success. In this paper, we investigated mucin-sweetener interactions as a potential cause of the limitation of several popular sweeteners. We employed a QCM-D technique and rheological measurements to quantify the real-time interactions of Reb A, aspartame, sucralose, and sucrose with bovine submaxillary mucin (BSM) at normal oral pH of 7.0 and at pH 3.0, the average pH of typical carbonated beverages. At pH 7.0, the administration of sweetener solutions resulted in a subtle loss of the BSM layer. However, at pH 3.0, the injection of sweetener solutions caused an increase in adsorbed mass. Reb A's adsorbed mass was found to be the largest, 4-5 times that of sucrose and aspartame. The measured rheological properties suggest that the presence of sweeteners could cause a greater change in the BSM's elasticity and viscosity at pH 3.0, which could affect the sweetener-BSM interactions.

关键词： 物理化学   氮团簇   铁氮团簇   钴氮团簇   镍氮团簇   激光溅射   激光光解  

摘要： 为了制备新型高氮含量的原子簇材料,分别将金属铁、钴和镍粉末与氮化硼制成的底物,经波长532nm激光溅射生成了杂氮团簇FeN^(+)_(n)、CoN^(+)_(n)和NiN^(+)_(n),并采用波长266nm激光进行了光解。结果表明,不同底物生成的金属杂氮团簇具有不同特点:3种金属杂氮团簇最高含氮原子数分别为8、12和8;铁杂氮团簇有2种偶数氮原子团簇,其中FeN^(+)_(8)离子峰强度较高;钴杂氮团簇有4种偶数氮原子团簇,团簇离子峰相对强度从6到8随氮原子数增加而提高、从8到12随氮原子数增加而降低,其中CoN^(+)_(8)离子峰强度最高;镍杂氮团簇有2种偶数氮原子团簇NiN+6和NiN^(+)_(8),其离子峰相对强度随氮原子数增加而增高;FeN^(+)_(8)、CoN^(+)_(8)和NiN^(+)_(8)光解通道分别为1个、1个和2个,对应的光解产物分别为Fe^(+)、Co^(+)及Ni^(+)和NiN^(+)_(2)。

关键词： 物理化学   超星平台   多元化教学模式  

摘要： 物理化学是理工科专业重要的必修课程,具有公式多、逻辑性强、课程难度大等特点,传统的教学模式无法满足学生多元化的需求。在疫情防控常态化的背景下,将线下课堂与线上教学平台有机融合,是一种有效的方法。本文以莆田学院的物理化学课程为例,基于超星平台对课程教学进行改革,构建多元化的教学模式。利用线下课堂和超星平台相结合,优势互补,充分发挥学生的主观能动性,激发学生的学习积极性,提升学生的综合素质。

ISBN: (纸本)9787122400642

关键词： Acanthophyllum laxiusculum   Saponin   Foam stability   Antioxidation   phenolic compounds  

摘要： Aqueous Extract of Acanthophyllum laxiusculum root (AE) exhibited remarkable foaming profile, emulsification properties and antifungal activity due to the presence of high concentration of total saponins. Total phenolic compounds, another main component, accounted for the AE antioxidant activity. Spray drying of AE, as a thermal process, did not affect the foaming indices of A. laxiusculum Spray-dried Extract (SE) and is a recommended alternate for convenient application in food industry. Addition of SE to the malt extract at accepted levels of total saponin daily intake (below 50 mg/kg) showed positive attribution of malt and carbonation on the foaming quality of SE. Meanwhile, antioxidant activity of commercial malt beverage was enhanced by addition of phenolic compounds containing SE. The 20-60% antifungal inhibitory ratio of the SE developed here is within the applied range of total saponin that supports its application to inhibit the growth of Saccharomyces cerevisiae after malt beverage production. The bitter taste of SE was not sensed in malt beverage at 30 mg/kg total saponin content and suggested A. laxiusculum root extract as a natural additive in malt industry.

关键词： Balangu   Lallemantia peltata   Seed oil   Fatty acids   Cold-press   Tocopherols   Storage  

摘要： The present research studied the oil content of Lallemantia peltata (Balangu) extracted by cold pressing method. Before extraction, the moisture contents of the seeds were adjusted to 0, 2.5, 5, 7.5 and 10 % to evaluate its effect on the oil yield and its quality. Moreover, the physicochemical characteristics were measured during storage for up to 90 days. The optimum moisture content which gave the highest oil yield (33.5 %) was 7.5 %. Increasing of seed moisture content increased acid value, peroxide value and total tocopherols, whereas decreased total chlorophyll and camtenoid as well as oxidative stability. During storage, a significant increase (p < 0.05) was observed in the acid and peroxide values and gamma-tocopherol content, while the alpha-tocopheml, delta-tocopherol, chlorophyll and carotenoid contents decreased. However, fatty acids and phytosterol composition did not significantly change by increasing moisture content and storage. Taken together, this study shows that the moisture content has a crucial influence on the oil yield and the quality of Balangu oil. Also, Balangu oil is rich in n-3 and n-6 acids and its nutritional profile is excellent and would be a good source of edible vegetable oil.