Degumming of crude soybean oil by ultrafiltration using polymeric membranes

In this study, the ability of two ultrafiltration polymeric membranes to perform the degumming of a crude soybean oil/hexane mixture is tested. The performance of both membranes is defined in terms of their permeation flux, permeate color, and rejection of phospholipids. One of the membranes was synthesized in our laboratories from polyvinylidenefluoride (PVDF); the other one is a commercially available membrane made of polyimide. The degumming experiments were done in a stirred dead-end ultrafiltration cell pressurized with N₂. Results show that tested membranes are suitable for removing phospholipids from the crude oil/hexane miscella in the range of temperature and transmembrane pressure utilized in this work. Both membranes have high selectivity regarding phospholipids and produce a moderate reduction in permeate color. The PVDF membrane gives permeate fluxes up to threefold larger than those obtained with polyimide membrane at the same operational conditions, making the former more suitable for use at industrial scale.     

An evaluation of the life cycle cost of rapeseed oil as a straight vegetable oil fuel to replace petroleum diesel in agriculture

The use of straight vegetable oil (SVO) as biofuel has been recognized as a valid substitute of diesel fuel in the agricultural sector under specific circumstances. Its direct use reduces most of the chemical processes involved when converting it into biodiesel, thus lowering harmful emissions. This study presents the economic analysis of a self-supply farming model that uses rapeseed as its fuel base. This model addresses agricultural environmental concerns and can even minimize dependence on the fluctuating costs of diesel fuel. The use of SVO in agriculture can help reduce farmers’ vulnerability to fossil fuel prices. The economic evaluation of the model proposed in this study shows clear economic benefits of introducing rapeseed to the traditional crop rotation of wheat and barley. The key factors analyzed in this model are diesel fuel price, diesel fuel grants and crop aids. The current situation in Spain favors the use of diesel fuel in agriculture rather than rapeseed SVO due to an 8% profit difference. However, results show that changes in key factors slightly affect the profit margin, calculating a difference of only 3.7% for particular factor combinations. Combined environmental-friendly agriculture supporting policies are necessary to cover this slight profit difference to promote this biofuel.     

Effects of high hydrostatic pressure processing and subsequent storage on phenolic contents and antioxidant activity in fruit and vegetable products

Fresh fruits and vegetables have been reported to possess a variety of bioactivities partly due to their high abundance of phenolics. However, traditional thermal pasteurisation during fruit and vegetable processing typically induces a pronounced loss of phenolic compounds. In contrast, nonthermal pasteurisation techniques, especially high hydrostatic pressure (HHP) processing, are beneficial to the retention of phenolics. In addition to more effectively keeping original freshness, flavour and colour of fruit and vegetable products to the greatest extent, in most cases, HHP processing and subsequent storage more effectively sustain the levels of phenolic compounds and antioxidant activity in fruit and vegetable products compared with thermal pasteurisation. Therefore, HHP processing has a huge potential to preserve fruit and vegetable products rich in phenolic compounds.     

Performance of a combined passive/active solar house

The paper describes a residence designed and built to demonstrate that active and passive solar homes could be economically by conventional home builders. The systems were designed for simplicity and cost effectiveness. The home was built in 56 days with conventional building materials and built by labourers with no particular training in energy efficient building techniques. After one season of operation the energy use data shows impressive performance. The auxiliary fuel requirement for the heating season was only 0.035 MJ/m²°C-day (1.72 Btu/ft²°F-day).

Economically the home is equally impressive. An independent appraiser of the home valued the construction at US $67 500. In reality the home cost US $59 000 including contractor's overhead and profit. Subtracting from this the amount US $4000 for the Federal Solar Tax Credit results in an owner cost of US $55 000.

The project demonstrated that given proper consideration for design, construction techniques, and solar systems integration, a solar structure need not cost more than conventional construction.     

Monitoring of the bacterial communities of bamboo shoots (Dendrocalamus latiflorus) during pickling process

The diversity and dynamics of the dominant bacterial communities arising during the pickling process of bamboo shoots (Dendrocalamus latiflorus) were investigated by nested polymerase chain reaction denaturing gradient gel electrophoresis combined with quantitative real‐time polymerase chain reaction. Results showed only several kinds of halophilic bacteria during early sampling time (0?3 days). After pickling for 7 days, Lactococcus lactis significantly increased (P < 0.05, quantities were 6.39 × 10⁵ copies μL^?1) and became the first dominant bacterium. After pickling for 14 days, Weissella sp. bands appeared and quickly became dominant on the 21st day (4.07 × 10⁶ copies μL^?1). As maturation progressed, Lc. lactis decreased in intensity whereas Weissella sp. increased in intensity. Finally, the quantities of Weissella sp. (2.50 × 10⁷ copies μL^?1) became higher than those of Lc. lactis (1.43 × 10⁷ copies μL^?1) after pickling for 56 days. The pickling process was initiated by Lc. lactis, followed by Lc. lactis and Weissella sp., and was finally succeeded by Weissella sp.     

绿色化学和绿色淬火介质

从绿色化学的12条原则出发,分析了绿色淬火介质的生产和使用的重要性.绿色淬火介质是指在满足使用要求的前提下,能被降解且不危害生态环境的淬火介质.矿物油基淬火油在使用中会产生有害物质,且废油难以降解,不属于绿色淬火介质.通过加氢处理、改进添加剂配方及废油再生可以减少矿物油基淬火油对环镜的危害.然而,开发、生产及使用植物油...     

国内外蔬菜工厂化生产的发展

蔬菜工厂化生产是当代世界先进的科学技术。本文介绍蔬菜工厂化生产的主要关键技术——现代化温室群、工厂化育苗和无土栽培的发展状况,并预示我国蔬菜工厂化生产技术的发展趋势。     

改性橡木宛栲胶鞣制牛皮沙发革工艺的探索

探索了用橡Wan栲胶植鞣黄牛皮沙发革的工艺，分析测试了所鞣坯革的物理及感观性能，为植鞣牛皮轻革产品提供了一些理论与实验依据。     

反胶束溶液萃取植物油料中蛋白质的性能研究

对AOT/异辛烷反胶束溶液萃取大豆中的蛋白质的性能进行了研究 .结果表明 :蛋白质的萃取效果取决于反胶束的w0 、水的pH值和KCl浓度 ,且蛋白质是否能进入反胶束内 ,与反胶束的大小无关 ,而主要受极性核内水的性质的影响