Changes of Composition and Angiotensin I-Converting Enzyme-Inhibitory Activity During Douchi Fermentation

Douchi is a fermented soybean food, which is popular in China. Composition and angiotensin I-converting enzyme-inhibitory activity of Douchi fermented with Mucor wutungkiao were studied in this work. The results showed that the nutritional potency of protein, fat, and soluble polysaccharide was improved in Douchi fermentation. The angiotensin I-converting enzyme-inhibitory activity of Douchi that ripening for 2 weeks showed the highest angiotensin I-converting enzyme-inhibitory activity. Then this sample was purified with Sephadex G-25 gel chromatography, and the amino acids and angiotensin I-converting enzyme-inhibitory activity of the purified fractions were studied. The results suggested that hydrophobic amino acids were assumed to cause the main increase of the angiotensin I-converting enzyme-inhibitory activity in Douchi.     

Concentration and survey of phthalic acid esters in edible vegetable oils and oilseeds by gas chromatography-mass spectrometry in China

Now, there is a lack of information regarding the occurrence and the content of phthalic acid esters (PAEs) contamination in edible vegetable oils and oilseeds used for oil production in China. In this study, a method for determination of five PAEs was developed based on gas chromatography-mass spectrometry. Method recoveries for oils and oilseeds were 72.4–103.0% and 77.2–98.8%, respectively. RSDs of five analytes in oils and oilseeds were ranging from 1.22 to 8.64% and 0.62–9.37%, respectively. The LODs and LOQs were ranging from 0.10 to 0.79 and 0.33–2.60 μg/kg, respectively. Based on the established method, PAE concentrations in thirty-four edible oils and twenty-eight oilseeds were evaluated. Five and thirteen oil samples exceeded the upper limits 1.5 and 0.3 mg/kg set for di(2-ethtlhexyl) phthalate and dibutyl phthalate in China, respectively. The results obtained indicated that more concern and comprehensive legislation are still needed and mulriple issues should be considered when it comes to the PAEs contamination in edible vegetable oils.     

Detection of Salmonella enteritidis and Salmonella typhimurium in foods using a rapid,multiplex real-time recombinase polymerase amplification assay

Salmonella has been recognized as a major foodborne pathogen for humans and animals. In this study, a multiplex real-time recombinase polymerase amplification (RPA) was developed for simultaneous detection of Salmonella enterica serovars, Salmonella enteritidis and Salmonella typhimurium, from chicken, eggs, lettuce, and papaya. The reaction was performed for 20 min at 35°C, and the detection limit of the assay was 10² CFU/ml for pure culture. In food application, the limit of detection (LOD) of S. enteritidis and S. typhimurium using multiplex real-time RPA without enrichment procedure was 10² CFU/25 g, respectively. After enrichment, the LOD of S. enteritidis and S. typhimurium was 10 CFU/25 g. Moreover, the result for Salmonella spp. was not significantly different from those obtained using a culture-based method. Additionally, the assay has a lower cross-reactivity with other pathogenic microorganisms and a good stability performance. Thus, the developed multiplex RPA assay could be used as a rapid tool for the detection of S. enteritidis and S. typhimurium in food.     

Flexible open caching for the Web

Caching plays a vital role in the performance of any large-scale distributed system and, as the variety and number of Web applications grows, is becoming an increasingly important research topic within the Web community. Existing caching mechanisms are largely transparent to their users and cater for resources which are primarily read-only, offering little support for customisable or complex caching strategies. In this paper we examine the deficiencies in these mechanisms with regard to applications with requirements for shared access to data where clients may require a variety of consistency guarantees. We present “open” caching within an object-oriented framework, an approach to solving these problems which, instead of offering caching transparency makes the caching mechanism highly visible allowing great flexibility in caching choices. Our implementation is built upon the W3Objects infrastructure and allows clients to make caching decisions for individual resources with minimal impact upon other resources which do not support our mechanisms.     

Solid-phase extraction and HPLC determination of patulin in apple juice concentrate

Solid-phase extraction (SPE) pretreatment method was used to determine the patulin in apple juice concentrate. Undiluted apple juice concentrate was treated by C₁₈-SPE cartridge and analyzed by high-performance liquid chromatography (HPLC) using UV detector. The recovery rates and the coefficient variations were 96.4–114.1% and 1.62–4.82%, the minimum detectable level is 0.005 mg/kg. The method is fast, easy, reliable, and inexpensive; it is applicable to the analysis and control patulin in the course of apple juice concentrate processing and its commercial products.     

生物传感器在有机磷农药残留量检测中的 应用研究进展

有机磷农药是我国使用最广泛的农药,具有广谱、高效等特点,但对人类的健康和环境安全存在潜在威胁。因此,发展快速、简易、准确测定有机磷农药残留量的方法具有重要意义。生物传感器具有简单、灵敏、低成本、便于携带,可实现现场监控等优点,已成为有机磷农药残留量速测技术中的研究热点。本文综述了近年来国内外生物传感器技术在有机磷农药测定中的应用情况,主要介绍了酶生物传感器、免疫生物传感器。最后本文对生物传感器在有机磷农药残留检测中应用的未来发展进行展望。     

Metal–organic framework for the extraction and detection of pesticides from food commodities

Pesticide residues in food matrices, threatening the survival and development of humanity, is one of the critical challenges worldwide. Metal–organic frameworks (MOFs) possess excellent properties, which include excellent adsorption capacity, tailorable shape and size, hierarchical structure, numerous surface-active sites, high specific surface areas, high chemical stabilities, and ease of modification and functionalization. These promising properties render MOFs as advantageous porous materials for the extraction and detection of pesticides in food samples. This review is based on a brief introduction of MOFs and highlights recent advances in pesticide extraction and detection through MOFs. Furthermore, the challenges and prospects in this field are also described.     

The challenge of managing water and material balances in relation to eutrophication

Eutrophication is the result of overfertilisation of the aquatic environment. In other words, the detrimental effects derived from increased anthropogenic release of nutrients to the environment. By modern concepts of environmental abatement this is no longer only a question of identifying and purifying discharges. It is a question of keeping track of the system of nutrient mining, utilisation, recycle, transport, conversion, containment and release in the modern society - in effect, the total balance of nutrients in society. In Denmark, the point sources of nutrient release have been reduced by an order of magnitude. That has contributed to some improvements, but the diffuse sources have turned out to be more significant than originally expected. They are harder to reduce. That is why more integrated approaches have to be analysed. Four approaches will be analysed: the DPSIR-approach, the 5-options approach, the cause-effect relationship and the material balance analysis.