云南普洱茶保健功效的研究

简单介绍了普洱茶的品质特征，对普洱茶的保健功效在国内外的历史记载进行综述，分析了对普洱茶保健功效的影响因素。     

益生菌的安全性评价

过去几十年，益生菌被广泛应用于食品和医药等领域.选择和应用益生菌时，不仅要考虑益生菌的功能特性，安全性也是必须要考虑的方面.随着科学的不断发展，对益生菌的安全性认识也在发生变化，传统益生菌的安全性需要重新评价，新的益生菌菌种也不断地开发， 这些新菌种在使用前也应进行安全性评价.目前我国需要完善对这些新菌种进行系统的安全性评价的程序.本文综述了益生菌潜在的危险因素、转基因益生菌的安全性，安全性评价程序和国外如美国、欧盟、德国等国对益生菌的评价体系。     

Influence of water activity and temperature on growth and mycotoxin production by Alternaria alternata on irradiated soya beans

The aim of this study was to determine the effects of water activity (a_w) (0.99-0.90), temperature (15, 25 and 30 °C) and their interactions on growth and alternariol (AOH) and alternariol monomethyl ether (AME) production by Alternaria alternata on irradiated soya beans. Maximum growth rates were obtained at 0.980 a_w and 25 °C. Minimum a_w level for growth was dependent on temperature. Both strains were able to grow at the lowest a_w assayed (0.90). Maximum amount of AOH was produced at 0.98 a_w but at different temperatures, 15 and 25 °C, for the strains RC 21 and RC 39 respectively. Maximum AME production was obtained at 0.98 a_w and 30 °C for both strains. The concentration range of both toxins varied considerably depending on a_w and temperature interactions. The two metabolites were produced over the temperature range 15 to 30 °C and a_w range 0.99 to 0.96. The limiting a_w for detectable mycotoxin production is slightly greater than that for growth. Two-dimensional profiles of a_w × temperature were developed from these data to identify areas where conditions indicate a significant risk from AOH and AME accumulation on soya bean. Knowledge of AOH and AME production under marginal or sub-optimal temperature and a_w conditions for growth can be important since improper storage conditions accompanied by elevated temperature and moisture content in the grain can favour further mycotoxin production and lead to reduction in grain quality. This could present a hazard if the grain is used for human consumption or animal feedstuff.     

Shrinkage, density, porosity and shape changes during dehydration of pumpkin (Cucurbita pepo L.) fruits

The aim of this work was to study the changes in volume, density, porosity and shape factors of pumpkin tissue during osmotic dehydration (OD) and air drying (AD). Pumpkin cylinders with length/diameter ratio of 5/3 were used. OD experiments were carried out with solutions of sucrose, sodium chloride and mixtures of both solutes at different temperatures. AD experiments were conducted at 70 °C. Volume of samples decreased linearly with weight reduction (WR). Bulk density varied in a restricted range (5-13%) during dehydration and for all the methods maximum values were found. Particle density increased during both processes. Porosity increased at advanced degrees of dehydration, showing a minimum value at the beginning of OD and AD. The proposed models to evaluate shrinkage, bulk and particle densities and porosity from WR were satisfactorily applied. Image analysis showed that shrinkage of samples during OD was isotropic. Pumpkin cylinders increased elongation and decreased roundness and compactness during osmotic dehydration.     

大豆异黄酮抗氧化稳定性研究

利用铁氰化钾还原法测定样品的还原力,研究不同的光照条件、温度、食品成分、金属离子及防腐剂对大豆异黄酮的抗氧化稳定性的影响,比较其影响度的大小,对大豆异黄酮的抗氧化稳定性做出综合评价。结果表明,大豆异黄酮的总抗氧化能力随着温度的提高和加热时间的延长而下降;在避光﹑自然光和光照（日光灯昼夜照射）三种条件下,光照和自然光对大豆异黄酮抗氧化能力影响较大,抗氧化能力随着光照时间的延长呈下降趋势;氯化钠、蔗糖、葡萄糖等食品成分、5种金属离子（K＋、Ca2＋、Mg2＋、Zn2＋、Cu2＋）和防腐剂山梨酸对大豆异黄酮抗氧化能力均有不同程度的影响,因此大豆异黄酮在制备和使用过程中应注意避光和低温保存,同时要注意避免与一些高浓度金属离子的接触。     

铬革屑酶解因素研究

选用1398蛋白酶对铬鞣革屑进行水解,从酶促反应动力学角度出发,研究了酶浓度、底物浓度、温度因素对酶解反应的影响,并通过正交试验,考察了各酶解条件的综合影响。结果表明:酶浓度和底物浓度超过一定范围时,表现为混合级反应,酶促反应受到抑制;反应温度在蛋白酶最适温度范围内时,酶活是影响反应速率的主要因素,反应温度超出最适范围很高时,温度成为影响反应速率的主要因素;1398蛋白酶最佳酶解条件为:底物浓度2%,反应温度60℃,酶浓度2%,氮收率达到60%左右。     

醇解技术在制备皮革加脂剂方面的研究进展

本文介绍了醇解反应的动力学、影响醇解反应收率的因素以及醇解反应在合成加脂剂方面的应用。     

电位滴定法测定食品过氧化值影响因素分析

用电位滴定法测定食品中过氧化值,总结出影响检测食品中过氧化值的因素和应注意的事项,包括食品中油脂提取、检测方法、试剂及其用量、反应条件、滴定速度,并得出结论:在检测时有效控制好这些因素,就可以得到准确可靠的过氧化值检测结果。     

服装色彩偏好研究评述

概述了人对服装色彩偏好的影响因素,探讨其相关研究的不足,并进行了展望。     

磁疗功能保健纺织品及其开发现状

简述了磁性纤维的加工方法,分析了影响磁疗功能保健织物磁感应强度的因素,综述了磁疗功能保健纺织品的开发情况,展望了磁疗保健纺织品的发展方向。