萌发玉米淀粉的糊化特性及其对面包品质的影响

研究了萌发玉米淀粉的糊化特性及对面包品质的影响。结果表明,与原淀粉相比,萌发玉米淀粉的糊化温度有所降低,糊化时间有所缩短。5种面包样品的仪器测定和消费者实验表明,添加适量的萌发玉米淀粉能够有效提高面包质地特性和总体接受程度、口感、外观、气味等特征。     

Instrumental evaluation of defective texture in dry-cured hams

In the first experiment, the effect of the stress relaxation time on texture evaluation of biceps femoris (BF) muscle from dry-cured hams was studied. The specimens were compressed to 25% of their original height and the crosshead speed was 5mm/s. The force decay versus time was recorded and Peleg's model was fitted with different relaxation times. Whatever relaxation time was used, Peleg's model did not describe simultaneously the initial fall of force and the asymptotic tendency of force decay correctly. The initial force and force decay at 2s and at 90s are proposed to assess texture in dry-cured ham. In the second experiment, stress relaxation (SR) and texture profile analysis (TPA) tests were performed on BF and semimembranosus (SM) muscles of 10 hams with abnormal softness and 10 hams with normal texture, at different assay conditions: sample temperature (4°C or 20°C); compression crosshead speed (1mm/s or 10mm/s). The instrumental texture test and the assay conditions that detected defective textures better depended on the muscle considered: for BF muscle the SR test at 4°C and at 1mm/s and for SM muscle the TPA test at 10mm/s at both 4°C or 20°C.     

食品质地及其TPA测试

随着中国食品工业日新月异的发展，尤其质量认证体系在全社会范围的推广与深刻的影响，业内人士越来越希望在面对食品业中大量模糊的感官概念时，能获得一套准确的量值表述，真正实现对传统食品行业的数字化、科技化变革。本文全面介绍了食品质地概念及其多面剖析法和一种客观评价方法-TPA测试。对食品质地评价研究所面临的问题提出了自己的看法。     

膨化高粱粉在面包中的应用

将膨化的高粱粉替代一部分小麦粉,按照快速发酵法生产面包的流程制作有独特风味的高粱面包。采用单因素试验和响应面法进行配方优化,确定最佳配方:膨化高粱粉200.0g,面粉800.0g,谷朊粉26.0g,酵母9.9g,面包改良剂10.0g。用质构仪TPA(质构剖面分析法)进一步验证响应模型,测量优化后制成的高粱面包的质构,并与白面包比较,二者品质差异不大。     

红曲米粉应用于猪冷鲜肉的保鲜效果

采用不同添加量的红曲米粉(100g肉样中含有红曲米粉0,0.0625g,0.125g、0.25g、0.5g、1g)应用于冷鲜肉,随冷藏天数(0,1,2,3,4,5,7,9d)的延长,测其pH及高铁肌红蛋白的变化。对其感官指标和理化指标进行测定,根据结果评价红曲米粉应用于猪肉的保鲜作用。结果显示添加量为0.125g/100g肉样和0.25g/100g肉样的实验组,不仅感官评价、理化指标等较好,保鲜效果也比较优异,相对于空白组,可以有效地将保存期延长3～5d。     

广式月饼感官评分与TPA参数的相关性

针对目前我国月饼品质缺乏客观性评价标准的问题,通过分析测试条件对月饼TPA参数的影响,确定月饼TPA测试的最佳条件为,测试速度5 mm/s、压缩程度75%、停留时间0.5 s、触发力5 g、半圆形样品形状;采用感官评定中的质地多面剖析方法,制定蓉沙类广式月饼感官评分细则,包括最初值、咀嚼中和剩余质地3个阶段中的外形、色泽、硬度、脆性、弹性、粘性、舌对形状的感受、破碎速率、破碎情况、水分吸收和口腔感觉共11个量化指标;通过分析感官评分和TPA参数的相关性,发现月饼的硬度、凝聚性和回复性均与其感官评分呈显著负相关(P<0.05)。由此提出以硬度、凝聚性和回复性3个TPA参数来客观评价月饼品质。     

Textural and viscoelastic properties of pork frankfurters containing canola-olive oils, rice bran, and walnut

Textural, rheological and microstructural properties of frankfurters made with 20% pork backfat, 20% canola or 20% canola-olive (3:1) oils, including rice bran (RB) and walnut extract (WE) as macronutrients (2.5%) were investigated. Textural parameters, including hardness, gumminess and rupture-force, were highly (P<0.05) influenced by the fat-oil composition. Addition of RB or WE in vegetable oil emulsions improved textural consistency (P<0.05). However, RB addition reduced gelling capacity, suggesting antagonistic interactions between fiber and oil droplets. Vegetable oil addition favored gel network formation, and, when combined with WE, showed the highest improvement of gel elasticity. These textural and gelling properties were corroborated by frankfurter micrographs, which revealed interactions between vegetable oils, RB, or WE with protein matrix and fat globules affecting these parameters. The results suggest that functional plant-derived ingredients can be valuable to the modification of frankfurter formulations for improved nutrition and as well as textural quality.     

Copolycondensation of IPA/TPA,BPA, and 4,4′‐dihydroxydipehnylsulfone and 4,4′‐dicarboxydiphenylsulfone

Copolycondensations of IPA, TPA, bisphenol A (BPA), and several cimonomers were carried out to improve thermal properties, such as, the glass transition temperature (T_g) of the IPA/TPA (50/50)–BPA polyester. Among the comonomers examined, 4,4′‐Dihydroxydiphenylsulfone (BPS) and 4,4′‐Dicarboxydiphenylsulfone (DCDPS) having a strongly dipolar sulfonyl group in the chain were significantly effective. The favorable effect upon the T_gs was studied by varying the amounts of BPS and DCDPS incorporated into the copolymers. In the copolycondensation with BPS, two‐stage copolycondensation of BPA first and then BPS, the reverse order of reaction, and their spontaneous addition were examined to investigate the effect of distribution of the BPS unit segments in the copolymer upon the T_gs of the resulted copolymers. The distribution was briefly studied from distribution of the IPA/TPA‐BPA oligomers in the initial reaction using GPC. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 875–879, 2000     

组件技术在嵌入式系统中的应用

研究了提出了通用组件模型不能嵌入式系统中应用的本质原因,对嵌入式组件模型进行分类以及层次化分析. 并对于嵌入式系统的非功能属性进行分析,总结了常见嵌入式组件模型对这些非功能属性的支持情况. 然后介绍了组件库的设计,以及组件模型的未来研究方向.     

Multi-level Modeling of Silica–Template Interactions During Initial Stages of Zeolite Synthesis

Zeolite synthesis is driven by structure-directing agents, such as tetrapropyl ammonium ions (TPA⁺) for Silicalite-1 and ZSM-5. However, the guiding role of these organic templates in the complex assembly to highly ordered frameworks remains unclear, limiting the prospects for advanced material synthesis. In this work, both static ab initio and dynamic classical modeling techniques are employed to provide insight into the interactions between TPA⁺ and Silicalite-1 precursors. We find that as soon as the typical straight 10-ring channel of Silicalite-1 or ZSM-5 is formed from smaller oligomers, the TPA⁺ template is partially squeezed out of the resulting cavity. Partial retention of the template in the cavity is, however, indispensable to prevent collapse of the channel and subsequent hydrolysis.