In situ regeneration of the Ni-based catalytic reformer of a 5 kW PEMFC system

The paper reports the results of on-site regeneration catalytic bed of the natural gas reformer in a 5 kW PEM fuel cell system. The Ni catalyst previously poisoned by sulphur from the available natural gas, could be re-activated by injection of pure water steam, following the method developed for industrial reformers using the same metal catalyst: this method was shown to be perfectly efficient, provided no natural gas was fed during the operation. Results of the tests conducted are presented and discussed in relation to published data on S-sorption on Ni surfaces.     

Lactic acid production from dining‐hall food waste by Lactobacillus plantarum using response surface methodology

BACKGROUND: Food waste generally has a high starch content and is rich in nutritional compounds, including lipids and proteins. It therefore represents a potential renewable resource. In this study, dining‐hall food waste was used as a substrate for lactic acid production, and response surface methodology was employed to optimise the fermentation conditions. RESULTS: Lactic acid biosynthesis was significantly affected by the interaction of protease and temperature. Protease, temperature and CaCO₃ had significant linear effects on lactic acid production, while α‐amylase and yeast extract had insignificant effects. The optimal conditions were found to be an α‐amylase activity of 13.86 U g^?1 dried food waste, a protease activity of 2.12 U g^?1 dried food waste, a temperature of 29.31 °C and a CaCO₃ concentration of 62.67 g L^?1, which resulted in a maximum lactic acid concentration of 98.51 g L^?1 (88.75% yield). An increase in inoculum size would be appropriate for accelerating the depletion of initial soluble carbohydrate to enhance the efficiency of α‐amylase in dining‐hall food waste fermentation. CONCLUSION: A suitable regression model for lactic acid production was developed based on the experimental results. Dining‐hall food waste was found to be a good substrate for lactic acid fermentation with high product yield and without nutrient supplementation. Copyright © 2008 Society of Chemical Industry     

Establishing a System for Food Recalls to Protect Food Quality and Safety in China

There are no explicit laws concerning food recalls in China; moreover, some related regulations have weaknesses. China should first create a system of laws and regulations governing food recalls, establish a system to recall defective food, and strengthen administrative and legal remedial mechanisms related to consumer rights.     

Determination of the content of wax esters in some sea foods and their molecular composition. A comparison with ω-3 enriched wax esters

Wax esters enriched in ω-3 fatty acids have been recently shown to be readily absorbed by rats after dietary supplementation. Wax esters are less prone to oxidation and can be better formulated than liquid ω-3 derivatives. All these characteristics suggest a possible use of wax esters enriched in ω-3 as food supplements. However, some naturally occurring wax esters are defined as scarcely digestible (jojoba oil, spermaceti). On the other hand, wax esters have been found in several sources of marine origin, which can enter normal foodstuff. In order to better understand the digestibility of wax esters, we have analysed some foods from marine sources. The content of triglycerides and wax esters of the foods has been determined. Moreover, wax esters have been analysed for their composition in alcohols and fatty acids. Wax esters have been shown to be a part of the neutral lipid extract of the foods analysed. Their content, if compared with the content in triglycerides, shows striking differences. In the case of two botargo preparations, it has been shown that wax esters are more than 90% of the total neutral lipid extract. The content of fatty acids and alcohols found in the foods analysed is consistent with published data.     

GC–MS characterization of oligomers in polyadipates used as plasticizers for PVC in food contact

Fourteen commercial polyadipates and a polysebacate were analysed for their components of a molecular mass below 1000 Da, primarily with the aim of generating the background data for measuring the migration of this type of polymeric additives from plasticized PVC (e.g. cling films and gaskets of lids) into foods or food simulants. Since the composition of the material <1000 Da varies between the polyadipates, the main components must be identified to enable a correct quantification. Polyadipates differ in the diol used as linker, their termination (acid or alcohol) and in the end‐capping (free alcohols, acetylation, acylation with fatty acids, esterification with octanol/decanol). Gas chromatography (GC) provides good separation, but the material remaining in the column up to high temperatures decomposes and forms a hump in the rear part of the chromatogram. Examples of mass spectra are shown, the most indicative fragments pointed out and spectra of 159 components listed. The polyadipates and the sebacate are characterized by their structure, the main components <1000 Da and the fraction of material <1000 Da. Copyright © 2006 John Wiley & Sons, Ltd.     

微电热新技术及其在食品加工领域中的应用前景

ＤＺＲ是新型微电热材料的简称，其发明人是孔德凯先生，该材料已先后获美国、澳大利亚、英国、法国、意大利、瑞典、日本等国专利。发明人的杰出贡献在于不仅找到了ＤＺＲ材料的制造方法，而且实现了元件和部件的系列化和标准化，并提出了微球理论，创立了孔氏面电阻定律、面热材料功率计算定律、寿命计算定律，引起了各国的极大关注。本文阐述了国内外电热材料研究概况及国际发明专利ＤＺＲ技术特点及其在食品加工领域中应用前景。     

Taste recognition threshold concentrations of styrene in oil-in-water emulsions and yoghurts

Taste recognition threshold concentrations (TRTC) of styrene were determined in samples of oil-in-water emulsions (30–300 g kg^?1 oil) and yoghurts (1–30 g kg^?1 fat), spiked with styrene. The observed TRTC increased linearly with increasing fat content and ranged from 0–3 to 2–1 mg kg^?1 for the emulsions and from 36 to 171 g kg^?1 for the yoghurts. Styrene equilibrium partition coefficients between emulsions and their respective vapour phases were determined. The concentrations of styrene in the continuous aqueous phase of the emulsions and yoghurts were calculated at the TRTC. The styrene concentrations in the continuous phase had constant values of about 15 g kg^?1 indicating that perception of styrene for oil-in–water emulsions is determined by the aqueous phase of the emulsion. The concentrations of styrene in the vapor phases above the emulsions and yoghurts were also calculated and were found to be constant at the TRTC. This relationship probably resulted from the equilibrium of distribution of styrene between the respective phases. Commercial yoghurt packed in polystyrene beakers contained styrene levels in the range 2–11 g kg^?1, much lower then the TRTC reported.     

The geographies of a more just food system: Building landscapes for social reproduction

Within the lifetime of a generation of people now involved in work in the cattle and beef industry in South Dakota, the landscapes of social reproduction that support and give shape to life for people there have been rearranged. Many of the social and physical relationships that developed to support smaller-scale, diverse farms and their surrounding communities are being made redundant by a new system of beef production and retailing. The costs of these redundancies are felt in dwindling small towns and an ever sparser rural population. Considering these changes as parts of landscapes of social reproduction is a means to connect the political and corporate logic driving our food systems to the spatial production of difference in the conditions for livelihood, as well as the spatial production of livelihood itself for both producers and consumers. Such an analysis is necessary in order to address the injustices inherent within our current food system.     

meso-四-(4-甲氧基-3-磺酸苯基)卟啉在测定痕量金属的应用—锌的分光光度法测定

本文研究了在咪唑存在下 meso—四—(4—甲氧基—3—磺酸苯基)卟啉(TMPPS_4)与锌显色反应的最佳条件,建立了测定锌的新方法,灵敏度高,锌量在0—1.2μg/10mL 范围内遵守比耳定律,用于测定粮食中的锌时结果满意     

静脉产业园餐厨垃圾处理厂与焚烧厂协同处理运行实例和经济性分析

以广西某静脉产业园内餐厨垃圾处理厂为例,介绍了以"预处理+油脂提取+厌氧发酵+沼气净化利用"为主体的餐厨垃圾处理工艺,并对该厂与生活垃圾焚烧厂协同处理进行了经济性分析。结果表明,与餐厨厂独立运营相比,与焚烧厂协同处理年节省成本达94.83万元。