Denitrification and aerobic respiration, hybrid electron transport chains and co-evolution

Analytical and Bioanalytical Chemistry - Plasma Spectrochemistry

This review describes advances in the preparation of food-relevant double emulsions (DEs) of the water-in-oil-in-water (W/O/W) and oil-in-water-in-oil (O/W/O) types with emphasis on research published within the last decade. The information is assembled and critically evaluated according to the following aspects: the food application area, the range of encapsulated components and emulsion composition, the emulsification preparation methods, the balancing of the osmotic pressure, the stabilization by increased viscosity or gelation, the role of protein-polysaccharide interactions, and the techniques used to estimate DE yield and emulsification efficiency. Particular focus is directed toward the control of encapsulation and release behavior, including strategies that have been employed to improve the retention ability of the inner phase droplets by modifying the outer oil-water interface through mixed ingredient interactions, Pickering stabilization by particles, and biopolymer gelation. We also briefly consider the incorporation of DEs into dried microcapsules and the stability of W/O/W emulsions during eating and digestion. It would appear that 2 outstanding issues are currently preventing full realization of the potential of DEs in food applications: (i) the lack of availability of large-scale production equipment to ensure efficient nondestructive 2nd-stage emulsification, and (ii) the limited range of food-grade ingredients available to successfully replace polyglycerol polyricinoleate as the primary emulsifier in W/O/W formulations.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/1541-4337.12261

Double Emulsions Relevant to Food Systems: Preparation, Stability, and Applications

Fermented foods and alcoholic beverages have long been an important part of the human diet in nearly every culture on every continent. These foods are often well-preserved and serve as stable and significant sources of proteins, vitamins, minerals, and other nutrients. Despite these common features, however, many differences exist with respect to substrates and products and the types of microbes involved in the manufacture of fermented foods and beverages produced globally. In this review, we describe these differences and consider the influence of geography and industrialization on fermented foods manufacture. Whereas fermented foods produced in Europe, North America, Australia, and New Zealand usually depend on defined starter cultures, those made in Asia and Africa often rely on spontaneous fermentation. Likewise, in developing countries, fermented foods are not often commercially produced on an industrial scale. Although many fermented products rely on autochthonous microbes present in the raw material, for other products, the introduction of starter culture technology has led to greater consistency, safety, and quality. The diversity and function of microbes present in a wide range of fermented foods can now be examined in detail using molecular and other omic approaches. The nutritional value of fermented foods is now well-appreciated, especially in resource-poor regions where yoghurt and other fermented foods can improve public health and provide opportunities for economic development. Manufacturers of fermented foods, whether small or large, should follow Good Manufacturing Practices and have sustainable development goals. Ultimately, preferences for fermented foods and beverages depend on dietary habits of consumers, as well as regional agricultural conditions and availability of resources.

https://onlinelibrary.wiley.com/doi/epdf/10.1111/1541-4337.12520

Fermented foods in a global age: East meets West

Xylanases are hydrolytic enzymes which cleave the β-1, 4 backbone of the complex plant cell wall polysaccharide xylan. Xylan is the major hemicellulosic constituent found in soft and hard food. It is the next most abundant renewable polysaccharide after cellulose. Xylanases and associated debranching enzymes produced by a variety of microorganisms including bacteria, actinomycetes, yeast and fungi bring hydrolysis of hemicelluloses. Despite thorough knowledge of microbial xylanolytic systems, further studies are required to achieve a complete understanding of the mechanism of xylan degradation by xylanases produced by microorganisms and their promising use in pulp biobleaching. Cellulase-free xylanases are important in pulp biobleaching as alternatives to the use of toxic chlorinated compounds because of the environmental hazards and diseases caused by the release of the adsorbable organic halogens. In this review, we have focused on the studies of structural composition of xylan in plants, their classification, sources of xylanases, extremophilic xylanases, modes of fermentation for the production of xylanases, factors affecting xylanase production, statistical approaches such as Plackett Burman, Response Surface Methodology to enhance xylanase production, purification, characterization, molecular cloning and expression. Besides this, review has focused on the microbial enzyme complex involved in the complete breakdown of xylan and the studies on xylanase regulation and their potential industrial applications with special reference to pulp biobleaching, which is directly related to increasing pulp brightness and reduction in environmental pollution.

/pdf/microbial-xylanases-and-their-industrial-application-in-pulp-oanprfzwyh.pdf

Microbial xylanases and their industrial application in pulp and paper biobleaching: a review.

Flavor mystery of Chinese traditional fermented baijiu: The great contribution of ester compounds.

Flavor mystery of Chinese traditional fermented baijiu: The great contribution of ester compounds

Chinese Baijiu (Chinese spirit or Chinese liquor) is one of the six major distilled spirits in the world, and is renowned overseas. Chinese Baijiu has a long history of more than 1000 years when people first begin to brew liquor using distillation. So far, Chinese Baijius have formed 12 types according to their flavour characteristics. The strong flavour Chinese spirit is regarded as one of the typical representatives, and occupies a > 70% market share in China. The liquor brewing process is under an open environment, with grains as the fermentation substrates, as well as Daqu as the saccharifying ferment. The brewing process is complex and impacted by multiple factors. Among the factors, the microorganisms have important influences on the brewing process and product quality of liquors. In the past decades, a series of research achievements have been made with strong flavour Chinese spirits. However, reviews related to this field are relatively few. In this paper, we have reviewed strong flavour Chinese spirits including the introduction, brewing process, microorganism diversity of Daqus, fermented grains and pit muds, and the application of microbes. Copyright © 2017 The Institute of Brewing & Distilling

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/jib.404

The brewing process and microbial diversity of strong flavour Chinese spirits: a review

Background Short-chain fatty acids (SCFAs) play important physiological roles in human health. Adverse effects on health are known with a low or excessive concentration of SCFAs although the optimal level of SCFAs in the body is unknown yet. The level of endogenous SCFAs is affected by many factors of which gut bacteria are the most important one. However, how gut bacteria and a dietary intervention affect SCFA balance in the gut still needs to be clarified. Scope and approach In addition to addressing the importance of a dynamic balance of SCFAs for health, we discuss the factors affecting the dynamic balance of SCFAs, especially the gut SCFA-producing bacteria, including the classification of the bacteria, their response to diet, the SCFAs metabolic pathways and the catalytic mechanisms of the main rate-limiting enzymes. Key findings and conclusions SCFAs levels can be regulated endogenously and exogenously. Exogenous regulation delivers SCFAs to gut by esterification with dietary fibres. Endogenous regulation like diet, directly or indirectly affect gut microbiota, including their abundance, fitness and SCFAs production. Until now, 74 bacterial species are reported to produce SCFAs, the metabolic pathways are classified into 4 categories, and the 4 rate-limiting enzymes in the metabolic pathways are summarized. We also propose methods for long-lasting endogenous SCFAs balancing, including identifying the minimum sets of SCFA-producing bacterial group, and possible dietary intervention to form a minimum group of gut microbiota for SCFAs synthesis. An integrated approach will help realize the rational regulation of balanced SCFAs levels to benefit human health.

Dynamic balancing of intestinal short-chain fatty acids: The crucial role of bacterial metabolism

Purification and characterization of a cellulase-free, thermostable xylanase from Streptomyces rameus L2001 and its biobleaching effect on wheat straw pulp

Xiuting Li

Papers

Flavor mystery of Chinese traditional fermented baijiu: The great contribution of ester compounds.

Flavor mystery of Chinese traditional fermented baijiu: The great contribution of ester compounds

The brewing process and microbial diversity of strong flavour Chinese spirits: a review

Dynamic balancing of intestinal short-chain fatty acids: The crucial role of bacterial metabolism

Purification and characterization of a cellulase-free, thermostable xylanase from Streptomyces rameus L2001 and its biobleaching effect on wheat straw pulp