Mussels increase xenobiotic (azaspiracid) toxicity using a unique bioconversion mechanism

Azaspiracid Poisoning (AZP) is a human toxic syndrome which is associated with the consumption of bivalve shellfish. Unlike other shellfish, mussels contain a large array of azaspiracid analogs, many of which are suspected bioconversion products. These studies were conducted to elucidate the metabolic pathways of azaspiracid (AZA1) in the blue mussel (Mytilus edulis) and revealed that the main biotransformation product was the more toxic demethyl analog, AZA3. To elucidate the mechanism of this C-demethylation, an unprecedented xenobiotic bioconversion step in shellfish, AZA1 was fed to mussels that contained no detectable azaspiracids. Triple quadrupole mass spectrometry (MS) and high resolution Orbitrap MS were used to determine the uptake of AZA1 and the toxin profiles in three tissue compartments of mussels. The second most abundant bioconversion product was identified as AZA17, a carboxyl analog of AZA3, which is a key intermediate in the formation of AZA3. Also, two pairs of isomeric hydroxyl analogs, AZA4/AZA5 and AZA7/AZA8, have been confirmed as bioconversion products for the first time. Ultra high resolution (100 k) MS studies showed that the most probable structural assignment for AZA17 is 22-carboxy-AZA3 and a mechanism for its facile decarboxylation to form AZA3 has been proposed.     

Plate assay for endo-beta-N-acetylglucosaminidase activity using a chromogenic substrate synthesized by transglycosylation with Arthrobacter endo-beta-N-acetylglucosaminidase

The transglycosylation activity of Arthrobacter endo-beta-N-acetylglucosaminidase (Endo-A) was used for the enzymatic synthesis of a novel oligosaccharide, Man6GlcNAc-5-bromo-4-chloro-3-indolyl-beta-glucoside (Man6GlcNAc-Glc-beta-X). Various endo-beta-N-acetylglucosaminidases hydrolyzed this oligosaccharide, producing Man6GlcNAc and Glc-beta-X. The E. coli strains coexpressing Endo-A and beta-glucosidase formed blue colonies in the presence of Man6GlcNAc-Glc-beta-X. Therefore, endo-beta-N-acetylglucosaminidase activity could be directly detected by the plate assay. This simple plate assay is useful for screening microorganisms for endo-beta-N-acetylglucosaminidase activity.     

Involvement of copper in microsomal mixed-function oxidase reactions: a review.

Microsomes from various mammalian tissues contain the components of a short, non-phosphorylating electron transport chain which is an obligatory requirement for numerous mixed function oxidase reactions. Certain of these reactions, in particular Δ9-desaturation of fatty acids and the hydroxylation of drugs, are influenced by dietary copper deficiency. The inhibition of Δ9-desaturase activity by copper chelating agents and the reactivation by copper ions suggest that copper may be involved catalytically in the reaction. Copper also influences Δ6-desaturation of fatty acids, and the synthesis of prostaglandins. Copper-proteins are ideally suited as terminal components of electron transport chains and as such may function in a greater variety of mixed-function oxidase reactions than has hitherto been considered.     

Inactivation of microbes using ultrasound: a review

Alternative methods for pasteurization and sterilization are gaining importance, due to increased consumer demand for new methods of food processing that have a reduced impact on nutritional content and overall food quality. Ultrasound processing or sonication is one of the alternative technologies that has shown promise in the food industry. Sonication alone is not very effective in killing bacteria in food; however, the use of ultrasound coupled with pressure and/or heat is promising. Thermosonic (heat plus sonication), manosonic (pressure plus sonication), and manothermosonic (heat and pressure plus sonication) treatments are likely the best methods to inactivate microbes, as they are more energy-efficient and effective in killing microorganisms. Ultrasonic processing is still in its infancy and requires a great deal of future research in order to develop the technology on an industrial scale, and to more fully elucidate the effect of ultrasound on the properties of foods.     

High pressure-temperature effects on enzymatic activity: Naringin bioconversion

Initially exploited in chemistry and physics, high-pressure technology has gained importance in various fields.     

渥堆黑茶香气和主要功效研究进展

为探究不同种类黑茶香气成分特征,采用顶空固相微萃取和气相色谱-质谱联用技术（Headspace solid-phase microextraction-gas chromatography-mass spectrometry,HS-SPME-GC-MS）结合感官审评对茯砖茶、黑砖、藏茶、六堡茶、天尖等五种主要黑茶样品的香气成分进行分析。结果表明,五种黑茶的香气特征明显。茯砖茶主要香气轮廓为菌花香和陈香,六堡茶具有明显持久的槟榔香与陈香,藏茶具有持久的陈香,黑砖茶香气纯正,天尖具有持久的松烟香。五种黑茶样品的感官审评总分排序为藏茶（91.35）>茯砖茶（90.15）>黑砖（89.05）>六堡茶（88.85）>天尖（86.33）;五种不同的黑茶共含有56个香气成分,不同种类黑茶在香气成分构成与含量上均有差异。五种黑茶样品的香气成分总含量排序为茯砖茶（6355.30 μg/L）>藏茶（5858.73 μg/L）>黑砖（5789.71 μg/L）>天尖（4801.37 μg/L）>六堡茶（3740.14 μg/L）。根据多元统计分析以及香气活性值分析,发现1,2,3-三甲氧基苯对藏茶的陈香具有突出贡献。反,反-2,4-癸二烯醛、反,反-2,4-壬二烯醛、柠檬醛I、柠檬醛II、正己醛和水杨酸甲酯对茯砖茶的菌花香具有突出贡献,而1,2,3-三甲氧基苯则对茯砖茶的陈香具有突出贡献。（+）-雪松醇对六堡茶的槟榔香具有突出贡献。反,反-2,4-癸二烯醛、反,反-2,4-壬二烯醛、正己醛和植醇等对天尖的松烟香有突出贡献。苯乙醇、橙花叔醇II和氧化芳樟醇I等香气成分的综合作用形成了黑砖纯正的香气。本研究为探索不同种类黑茶的香气品质提供了数据参考。     

Cogeneration of cellobiose and glucose from pretreated wood and bioconversion to lactic acid: a kinetic study

Samples of Eucalyptus globulus wood were subjected to sequential treatments of delignification and swelling, and the solid residues were hydrolysed with a cellulase complex deficient in beta-glucosidase activity. In experiments carried out at 45 degrees C, the highest cellulose conversion (61.9%) was achieved in media containing 28 filter paper units/g using a liquor/solid ratio of 30 g/g. Models for the generation of cellobiose and glucose were developed assuming two sequential reactions (conversion of cellulose into cellobiose and hydrolysis of cellobiose to glucose) with end-product that results in competitive inhibition. Selected regression parameters were correlated with the operational conditions by means of empirical models (including linear and interaction terms) and a generalized calculation procedure that allows a close reproduction of data and shows a satisfactory ability for quantitative predictions was developed. Further experiments were carried out to study the bioconversion of hydrolysates by Lactobacillus delbrueckii into lactic acid. The kinetic modelling of the fermentation stage allowed a close interpretation of the experimental data.     

Determination of aminoglycosides and quinolones in food using tandem mass spectrometry: a review

The widespread use of antibiotics in dairy cattle management may result in the presence of antibiotic residues in food. While rapid screening tests are commonly used to detect the presence of antibiotics in food, more accurate chromatographic-mass spectrometric methods combined with tandem mass spectrometry (MS/MS) are required to determine the identity and quantity of the antibiotic present. These methods (HPLC/MS/MS) may have the greatest potential for accomplishing direct multi-residue identifications in complex biological matrices, such as food. This study reviews recent applications of tandem mass spectrometry in the determination of antibiotic residues, such as aminoglycosides and quinolones in food.     

Microencapsulation using starch as wall material: A review

Microencapsulation is a process oriented to protect substances that are susceptible to decomposition or reduction in their functionality due to different degradation reactions (i.e., oxidation, hydrolysis, etc.). Diverse wall materials, including some carbohydrates, preserve substances against adverse temperature, pH, humidity, oxygen, and other components that can react with the protected material. Starch is a wall material that is widely used for microencapsulation purpose. Unmodified and modified starches are increasingly considered for microencapsulation of vitamins, essential oils, flavors, drugs, and microorganisms. Recently, spherical aggregates of starch using small granules (1–3 μm) were developed for encapsulation purposes. Spherical aggregates are produced when small starch granules in the presence of additional bonding agents (e.g., proteins and hydrocolloids) are spray dried. Some studies have reported the application of spherical aggregates, but they neither report the effects of amylose content nor the molecular weight of amylopectin. In this sense, this review focuses on the state of the art of starch spherical aggregates and the perspectives of their applications as encapsulating agents.     

In situ observation of CO2 sequestration reactions using a novel microreaction system

A novel, externally controlled microreaction system has been developed to provide the first in situ observations of the reaction processes that control CO2 sequestration via mineral carbonation. The system offers pressure (to 20 MPa), temperature (to 250 degrees C), and activity control suitable for investigating a variety of fluid-fluid and fluid-solid interactions of environmental interest. Mineral sequestration efforts to date have effectively accelerated carbonation, a natural mineral weathering process, to an industrial timescale. However, the associated reaction mechanisms are poorly understood, limiting further process development. Synchrotron X-ray diffraction and Raman spectroscopy have been used to provide the first in situ insight into the associated supercritical mineral carbonation process. Magnesite was found to form directly under the reaction conditions observed (e.g., 150 degrees C and 15 MPa CO2),facilitating geologically stable sequestration. Thermodynamic analysis of fluid-phase species concentrations in the Na+ buffered H2O-CO2 reaction system found the primary aqueous reactant species to be CO2(aq) and HCO3-, with CO2(aq) more prevalent under the reaction conditions observed. The microreactor provides a powerful new tool for in situ investigation of a broad range of environmentally, fundamentally, and commercially important processes, including the reactions associated with geological carbon dioxide sequestration.     

Recent developments in pasteurising seeds and their products using radio frequency heating: a review

Food-borne or plant diseases mainly rely on the spread of seeds with pathogens. It is vital to eliminate food/seed-borne pathogens of seeds and their products before commercial import/export or circulation. Radio frequency (RF) heating is identified as an effective method with lack of chemical residues, rapid or volumetric heating and large penetration depth, and also validated as a potential physical method to eliminate pests or pathogens in agricultural products or foods. Although, many reviews have summarised the applications of RF treatment during the process of foods, little comprehensive review has been focused on seeds and their products pasteurised by the RF energy. Comprehensive summary about principles and main applications of RF energy for pasteurising seeds and their products was reported in this review. This review also introduced some typical RF heating systems, thermal death kinetics of pathogens, influences of RF heating on germination rate of seeds and some ways for improving uniformity of RF heating. Furthermore, this review recommended the future research directions about treatment of seeds and their products using RF energy, especially for seed industry to control the pathogens in seeds without reducing their quality after RF treatments.     

Phytosterols and their extraction from various plant matrices using supercritical carbon dioxide: a review

Phytosterols provide important health benefits: in particular, the lowering of cholesterol. From environmental and commercial points of view, the most appropriate technique has been searched for extracting phytosterols from plant matrices. As a green technology, supercritical fluid extraction (SFE) using carbon dioxide (CO₂) is widely used to extract bioactive compounds from different plant matrices. Several studies have been performed to extract phytosterols using supercritical CO₂ (SC‐CO₂) and this technology has clearly offered potential advantages over conventional extraction methods. However, the efficiency of SFE technology fully relies on the processing parameters, chemistry of interest compounds, nature of the plant matrices and expertise of handling. This review covers SFE technology with particular reference to phytosterol extraction using SC‐CO₂. Moreover, the chemistry of phytosterols, properties of supercritical fluids (SFs) and the applied experimental designs have been discussed for better understanding of phytosterol solubility in SC‐CO₂. © 2014 Society of Chemical Industry     

Oenological tannins: a review

This review is a state‐of‐the‐art summary of current literature on the commercial oenological tannins that are often added to wine. These tannins can come from different origins, which affect their composition and characteristics. The two main sources of oenological tannins are grapes and oak wood. This review describes methods to quantify and characterise oenological tannins and indicates that these methods also need to be improved. These tannins have different interactions with proteins as well as with wine components such as anthocyanins and other phenolics in wine. The suppliers of commercial tannins often emphasise that these products can stabilise colour in red wine and influence the mouthfeel of the wine, among other things. The literature, however, suggests that the addition of these tannins often does not lead to large differences in the chemical profile of the wine and sometimes even leads to unwanted sensory characters being observed in the wine. More research clearly is needed regarding the role of oenological tannins in wine.     

Lipid shortenings: a review

A critical introduction to lipid shortening systems is provided. The review covers types, formulations, functionality, and processing conditions required for the production of lipid shortening systems. Furthermore, lipid shortenings and their production are placed within the context of recent advances in the areas of crystallization, structural elucidation, and mechanical modeling of fat crystal networks in general. The various unit operations involved in the production of lipid shortenings are examined in light of the evolution of structure (both at the crystalline and microstructural levels) and derived physical functionality.     

Wood-cement composites: a review

This paper reviews the research reported mostly in the last 10 years in the most common journals on the wood-cement composites field. The focused topics include: the problem of the compatibility (or not) between cement and woods, what causes it, ways of overcoming the problem; methods for manufacture and the properties exhibited by common wood-composites; special techniques to accelerate the curing of cement and to improve the properties of wood-cement composites; manufacture of nonwood vegetable raw materials-cement composites; durability against weathering and fungi; and construction materials. A discussion on the state-of-the-art is also presented.     

Basmati rice: a review

India contributes about one-third of the world acreage under rice. Rice is available in over 5000 varieties, of which Basmati rice occupies a prime position on account of its extra long superfine slender grains, pleasant, exquisite aroma, fine cooking quality, sweet taste, soft texture, length-wise elongation with least breadth-wise swelling on cooking and tenderness of cooked rice. This article reviews the quality and aroma traits of Basmati rice, particularly the varieties grown in different parts of India and Pakistan, the agronomy, breeding and physiology of the grain, the trade scenario, Agmark grade designation for export and the US patent of new hybrid strains of Basmati.     

Production of a new pyridine N-oxide by bioconversion with Cunninghamella echinulata var. elegans

A new N-oxide was produced from 3-(N-Boc-aminomethyl)-5-bromopyridine by bioconversion with Cunninghamella echinulata var. elegans ATCC 9245, and its structure was established based on the spectral data. The microbial N-oxidation is efficient and highly selective. The substrate was transformed into the product in 7 days.     

Valorisation of food wastes to produce natural pigments using non-thermal novel extraction methods: a review

Waste or by-products produced during food processing can be used as a potential source of bioactive compounds including natural pigments. Natural pigments/colourants have numerous health benefits whereas the synthetic colourants have many negative effects on human health. Thus, there is a considerable interest worldwide in pigments extraction from natural sources. Conventional extractions such as soxhlet extraction, water distillation, and solvent extraction have many limitations such as large solvent consumption, long extraction time, and low extraction yields. Therefore, novel techniques such as high pressure, ultrasound, negative pressure and electric field have been employed to assist the pigment extraction process. The novel extraction methods are being developed with the primary aim of higher pigment yield, lower solvent consumption, minimised environmental effects and the convenience of extraction. With this perspective, the present review provides recent insights into the recovery of natural pigments from food wastes/by-products and the application of novel non-thermal technologies for their recovery.