三种食品添加剂对粉圆抗老化特性的研究

煮熟的粉圆在储藏过程中容易发生老化。为延缓粉圆老化,保证粉圆在储藏过程中的口感,本实验将通过测定粉圆的质构硬度和感官评分来研究三种食品添加剂的添加量对粉圆老化特性及品质的影响。本实验将羟丙基二淀粉磷酸酯、海藻糖、β-环状糊精三种食品添加剂添加到粉圆中,以质构硬度的增加率和感官评分作为评价指标,通过单因素实验和正交试验确定粉圆的最佳抗老化配方。在单因素分析中,粉圆的感官评分随羟丙基二淀粉磷酸酯与木薯淀粉的比例、海藻糖添加量以及β-环状糊精添加量的增加呈先增加后降低的趋势;粉圆的硬度增加率随羟丙基二淀粉磷酸酯与木薯淀粉比例、海藻糖添加量增加而逐渐减小,随β-环状糊精添加量的增加呈先减小后增大的趋势。以硬度增加率为评价指标,通过正交试验优化粉圆抗老化工艺。最佳抗老化配方:羟丙基二淀粉磷酸酯和木薯淀粉以5∶5比例复配,以淀粉总质量计,添加35%的海藻糖和0.3%的β-环状糊精。按照最佳抗老化配方制得的粉圆在常温下放置6 h后,其质构硬度、感官品质与煮熟冷却后的新鲜粉圆相比变化较小,即粉圆的老化得到抑制。

Elastoplastic response of functionally graded cemented carbides due to thermal loading

Finite dement formulations are used to simulate the evolution of the elastoplastic response of functionally graded cemented carbides （FGCC） due to thermal loading. The geometry of specimens is an axisymmetric solid cylinder with a two-dimensional gradient. The elastoplastic constitutive relationship is developed by constraint factors. Numerical results show that compressive stresses occur in the surface zone and tensile stresses in the cobalt rich zone when the temperature drops from the initial stress-free temperature of 800 to 0℃. The maximum value of the surface compressive stress is 254 MPa and the maximum value of the tensile stress is 252 MPa in the cobalt rich zones. When the cobalt concentration difference in the specimens is equal to or greater than 0.3, there is pronounced plastic flow in cobalt rich zone. When the temperature heats up from 0 to 800 ℃, the total plastic strain reaches 0.001 4. Plastic flow has a significant effect on the reduction of thermal stress concentration.

Structure design of gradient hard coatings on YG8 and their residual stress analysis by ANSYS

A structure of gradient hard coatings( Ti,TiN,TiCN and TiAlN) is designed,and residual stress is simulated by a finite element method with ANSYS. The influence of the realistic situation including load and temperature on the residual stress of the coatings is investigated. Simulated results show that the realistic situation strongly affects the residual stress. To be specific,i) The main residual stress concentrates on the coatings prepared on YG8 substrate,and the residual stress and its gradient of the coatings are bigger than that of the substrate; ii) TiAlN and TiCN coatings have better resistance compression than that of TiN coatings in the same condition; iii) The improved multilayer structure of the gradient hard coatings produces weaker residual stress but higher anti-pressure of the substrate.

Hardness Genetic Analysis of Pink Hard-fruit Tomato

Hardness genetic laws of pink hard-fruit tomato were studied for breeding new varieties of pink hard-fruit tomato. The change of hardness degree and heredi- tary characters of tomato were studied using the texture analyzer, with female parents P27, male parents P31 and tomato F1 combination 15# as the test materials. The result showed that transverse hardness was the lowest, followed by longitudinal hardness, and the hardness of fruit shoulder was the highest. The average hardness at green fruit stage was higher, the hardness at turning-color period and red ripe stage decreased significantly. The average hardness of P27, P31, F1 combination 15# at red ripe fruit was 13.27, 10.88, 12.28 N, respectively. The hardness at red fruit stage and green fruit stage had significantly positive correlation. Fruit shape index of F1 combinations 15#at red ripe stage was 0.87. The fruit shape was round with 5-6 locules. The pericarp thickness was 0.7-0.8 cm. The single fruit weight was 258 g. It was the ideal bred variety for pink hard-tomato fruit. There was no necessary connection among fruit hardness and fruit size, pericarp thickness, ventricle numbers, single fruit weight. Fruit shape index could be used as indirect selection index of the hardness of tomato.

油煮菠菜的质构、感官和Vc保存率分析

探究了不同加油、加盐量的煮制方法对菠菜感官接受度和Vc保存率的影响。采用质构仪和感官评价法分别测量样品的质构硬度和感官接受性。以质构硬度作为自变量,感官硬度作为因变量进行逐步回归分析,得到具有统计显著性的预测公式。结果表明影响硬度的主要因素是烹调时间,其次是添加油量,而加盐量的影响较小。添加盐对Vc保存率有不利影响。烹煮2min、盐量0.5%、油量2.5%时,感官接受度最佳,Vc保存率高达81.5%。