Effect of thermal packaging temperature on Chinese steamed bread quality during room temperature storage

In order to investigate the influence of different packaging temperature on thermal-vacuum packaged Chinese steamed bread (CSB) quality under room temperature storage, the packaging temperatures of 50 °C, 70 °C and 90 °C were set respectively to study the effect on the packaging vacuum degree (VD) and starch retrogradation properties. The VD and moisture content of thermal-vacuum packaged CSB significantly increased with the increase of the packaging temperature from 50 °C to 90 °C, while the hardness of CSB decreased, and there was no significant difference in moisture migration during room temperature storage. The results of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and small angle X-ray scattering (SAXS) indicated that CSB packaged at different temperatures formed B-type crystals, leading to an enhanced the ordered and dense state of starch structure, and the semi-crystalline growth ring structure disappeared during storage. The influence of different packaging temperatures on VD of CSB could effectively hinder the formation of ordered and dense state of CSB starch, consequently delaying the crystallization of amylopectin and inhibiting the progress of staling. The result of this study is of great significance for improving the quality of starchy foods and guiding the industrial development of Chinese steamed bread.     

提高切花真空预冷效果的技术措施

由小型试验到大型中试，探讨了真空预冷中各种花材的降温特点及提高预冷效果的技术措施。结果表明，在给定的相同真空预冷处理条件下，北京和昆明生产的同一种花材降温速度差异较小；但是相同地域栽培的不同花材降温速度差异较大。喷水和吸水处理有效地提高了预冷速度，其中，吸水处理使４种花材在相近短时间内达到了很好的预冷效果。研究结果不仅为提高切花真空预冷效果提供了一项技术措施，也为制订真空预冷处理花材规范化程序提供了依据     

竹-MMA复合材的制备及性能研究

采用真空注入法,将单体MMA注入竹材,然后以偶氮二异丁腈为催化剂,采用催化加热法聚合处理,制得竹-MMA复合材,测其力学性能和物理性能.结果表明:所制备的竹-MMA复合材比未经处理的素材,力学性能和物理性能都有明显提高.而且在本试验条件下,不同因素对竹-MMA复合材的制备及特定物理力学性能有着不同程度的影响.     

真空冷冻干燥技术原理及其在食用菌加工方面的应用

介绍了真空冷冻干燥技术的原理、设备和干制品特点,以及食用菌真空冷冻干燥的加工要点,并对真空冷冻干燥技术在食用菌加工方面的应用前景进行了展望。     

Dough and bread made from high- and low-protein flours by vacuum mixing: Part 2. Yeast activity,dough proofing and bread quality

The combined effects of reduced mixer headspace pressure and mixing duration on the yeast activity, proofing and quality of dough and bread made from both high-protein flour (HPF) and low-protein flour (LPF) were addressed in this study. Rheofermentometer analysis showed that a reduction in mixer headspace pressure up to 0.08 MPa did not affect the overall gassing power of yeast in either of the two dough matrices. An increase in mixing duration sped up the mass transfer rate of CO₂ at the initial stage of fermentation, leading to a faster expansion of dough volume at the beginning. Moreover, an increase in mixing time promoted dough development and gas inclusion, which resulted in a increased volume of dough and bread, as well as a softer texture of both baked bread and steamed bread. In general, reduced headspace pressure produced baked bread of smaller volume, denser structure and harder texture. On the other hand, vacuum mixing produced steamed bread with softer texture without significantly changing the bread’s volume and porosity.     

微波真空干燥膨化苹果脆片的研究

研究了一种微波真空干燥膨化果蔬脆片的加工方法。对微波功率、压力、物料厚度、预处理后苹果片初始含水率与其干燥特性、膨化率的关系进行了试验，得出了较佳的工艺参数，在微波功率为12．0w／g、压力为15kPa、苹果片厚度为8mm、预处理后苹果片初始含水率为37．5％的条件下，可干燥膨化高品质的苹果脆片，干燥时间为4min时膨化率最大达到321％。     

魔芋甘露聚糖真空冷冻干燥技术研究

确定了魔芋甘露聚糖湿品的冻结温度即三相点温度,提出了魔芋甘露聚糖真空冷冻干燥工艺的真空度参数和搁板温度参数。为大批量魔芋甘露聚糖真空冷冻干燥生产提供了参考依据     

散烟收购前置增湿机的设计

针对烟站散烟在收购过程中水分散失很快,烟叶造碎率较高问题,同时为实现散烟收购线的全面自动化、降低分级难度、营造洁净的分级环境、保证烟叶质量等,设计开发了散烟收购前置增湿机。该增湿机利用真空泵抽吸真空箱体内的空气,使回潮箱内形成真空,然后由加湿系统对烟叶进行快速增湿回潮。该增湿机可以根据烟叶品种、堆积密度、工艺要求等,实现连续多次抽空加潮。该增湿机主要由回潮箱体、抽真空系统、门系统、控制系统、加潮系统、物流系统组成。试验结果表明,经回潮后的烟叶水分增加2%~5%,无破碎现象,作业质量符合工艺要求;机具结构设计合理,为烟站的烟叶快速增湿提供了技术支持。     

香蕉真空冷冻干燥工艺的试验研究

以香蕉为试验材料,用基于电阻法交流电路装置测定了其共晶点和共熔点;采用正交试验法对香蕉冷冻干燥工艺过程参数进行了试验,得出了香蕉冷冻干燥工艺过程参数的最佳组合,并分析了香蕉冻干工艺曲线和含水率的变化情况,为果蔬的冷冻干燥工艺设计和过程控制提供了参考。     

真空冷冻干燥法制备松多酚微胶囊工艺研究

[目的]利用微胶囊技术保护松多酚的有效成分,使松多酚的产品化得以实现.[方法]采用真空冷冻干燥法制备红松球果种麟多酚微胶囊.以包埋率为评价指标,研究不同因素对微胶囊制备效果的影响,并采用响应面法进行优化.[结果]壁、芯比为2.52∶1,乳化剂用量占芯材量的7.64％,总固形物量为1.79％,在该条件下制得的微胶囊包埋率可达93.81％,扫描电镜下观察包埋结果理想.[结论]采用真空冷冻干燥法制备松多酚微胶囊工艺方法可行,且包埋率较高,具有广阔的工业应用前景.