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.     

Chloronaphthalenes as food-chain contaminants: a review

Chloronaphthalenes are dioxin-like environmental and food contaminants that for many years have undergone diffusion from dispersed emission sources of various types on a global scale. When released into ambient air like many other semivolatile organohalogen compounds, chloronaphthalenes undergo various processes and pathways including sequestering by plant vegetation and biota. Recently available data indicate that sequestering rates of chloronaphthalenes by plant biomass and including edible plants as well as concentrations in food sources of plant origin can be greater than was earlier predicted. Additionally, it become known very recently that in some highly industrialized countries such as Japan, Canada and the UK, the technical chloronaphthalene mixtures are still a subject of industrial and commercial interest, even if such activities are illegal. Recent achievements in HRGC-HRMS have enabled elucidation and quantification of the chloronaphthalene congener composition in environmental matrices, food sources and technical mixtures, their persistency, environmental fate, accumulation in biota and potential for food chain biomagnification. However, at the same time this raised questions regarding human exposure to these compounds. By the late 1990s, these developments added to the relatively rapidly growing knowledge on these compounds and especially individual congener properties such as thermodynamic and physicochemical features and toxicity. Multistage fractionation has recently enabled routine congener-specific quantification of tetra- to octachloronaphthalene in various matrices. This paper reviews the literature on chloronaphthalenes as food chain contaminants and covers their origin, physicochemical properties, toxicity, environmental concentrations and persistency, and homologue group and congener composition in various matrices. The review also covers distribution in environmental compartments and subsequent fate and migration to food sources, as well as the magnitude of dietary intake and human body concentrations. Data on chloronaphthalene residues in food, however, are still scare, an exception being seafood sources and recently available data from Spain on their concentrations in staple foods and dietary intake.     

PVC as a food packaging material

Manufacture of polyvinyl chloride (PVC) in western Europe for all applications is now almost 4 m tonnes and the UK accounts for about 400 kt of this.The aim of this paper is to illustrate the relative importance of PVC as a packaging material where, in the UK for example, for food packaging it accounts for almost 40 kt (10%) of the PVC used.The different types of PVC packaging material—bottles, foil, cling film and cap sealing—and their method of manufacture are described, together with the range of food packaging applications in which they are used. The physical properties of PVC are described and, additionally, its cost and competitiveness with other materials are compared. The chemical nature of PVC compositions arising from the addition of heat stabilisers and plasticisers to achieve the desired properties is also described, with particular reference to heat stability.With the VCM toxicity issue now behind us, and PVC polymer with a maximum level of 1 ppm vinyl chloride monomer (VCM) being supplied for food packaging, PVC must be the most stringently controlled and thoroughly researched material for food packaging. Recent developments in polymerisation technology and polymer manufacture, which have enabled this level to be achieved, are briefly described.The current situation on the global migration issue, on which attention is currently focused, not only for plasticised PVC, but also other packaging materials as well, is briefly reviewed.     

废弃木质建筑材料再生循环利用的途径

每年我国建筑和装修过程中会产生大量的木质建筑废弃物,合理的利用这些废弃木质建筑物,不仅可以节省大量处理费用,而且可以变废为宝,从而部分缓解我国木材的供需矛盾.本文笔者介绍了几种常见的废弃木质建筑材料再生循环利用的途径.     

Viscosity as related to dietary fiber: a review

Viscosity is a physicochemical property associated with dietary fibers, particularly soluble dietary fibers. Viscous dietary fibers thicken when mixed with fluids and include polysaccharides such as gums, pectins, psyllium, and beta-glucans. Although insoluble fiber particles may affect viscosity measurement, viscosity is not an issue regards insoluble dietary fibers. Viscous fibers have been credited for beneficial physiological responses in human, animal, and animal-alternative in vitro models. The following article provides a review of viscosity as related to dietary fiber including definitions and instrumentation, factors affecting viscosity of solutions, and effects of viscous polysaccharides on glycemic response, blood lipid attenuation, intestinal enzymatic activity, digestibility, and laxation.     

Manure-borne estrogens as potential environmental contaminants: a review

Livestock wastes are potential sources of endocrine disrupting compounds to the environment. Steroidal estrogen hormones such as estradiol, estrone, and estriol are a particular concern because there is evidence that low nanogram per liter concentrations of estrogens in water can adversely affect the reproductive biology of fish and other aquatic vertebrate species. We performed a literature review to assess the current state of science regarding estrogen physicochemical properties, livestock excretion, and the fate of manure-borne estrogens in the environment. Unconjugated steroidal estrogens have low solubility in water (0.8-13.3 mg L(-1)) and are moderately hydrophobic (log Kow 2.6-4.0). Cattle excrete mostly 17alpha-estradiol, 17beta-estradiol, estrone, and respective sulfated and glucuronidated counterparts, whereas swine and poultry excrete mostly 17beta-estradiol, estrone, estriol, and respective sulfated and glucuronidated counterparts. The environmental fate of estrogens is not clearly known. Laboratory-based studies have found that the biological activity of these compounds is greatly reduced or eliminated within several hours to days due to degradation and sorption. On the other hand, field studies have demonstrated that estrogens are sufficiently mobile and persistent to impact surface and groundwater quality. Future research should use standardized methods for the analysis of manure, soil, and water. More information is needed about the types and amounts of estrogens that exist in livestock wastes and the fate of manure-borne estrogens applied to agricultural lands. Field and laboratory studies should work toward revealing the mechanisms of estrogen degradation, sorption, and transport so that the risk of estrogen contamination of waterways can be minimized.     

浅议如何构筑卷烟工业企业原料体系

综述了建立烟叶原料体系是发展中式卷烟和卷烟工业实现可持续发展的需要，分析了正确确立原料体系研究的工作原则、指导方针和解决的突出问题。提出了原料体系正常运转的经营模式和组织实施的措施。     

木质材料蠕变研究进展

分析了木质材料长期受力过程中产生蠕变的原因及影响因素,总结了目前常用的描述木质材料蠕变的数学模型.根据木材发生蠕变的原因,提出了几点减小木材蠕变的木材改性的方法.     

单晶CVD金刚石作为功能材料的应用

阐述单晶CVD金刚石的发展,特性及应用。分析了单晶CVD金刚石在工业与技术应用方面的优越性。目前其重要应用领域主要包括：半导体器件;微波技术;监测器件与检测系统;光纤通讯以及光信息存储技术等。     

水刺多层复合建筑覆盖材料的制备及性能

分别以2.2 dtex×51 mm(纤维A)和1.67 dtex×38 mm(纤维B)两种规格的100%疏水性涤纶为原料,经六层交叉铺网和两层直铺网复合,再经水刺加固制备了两种面密度均为100 g/m2的水刺多层复合建筑覆盖材料(样品A和样品B)。该材料兼有两种铺网结构的优势,纤维相互交缠致密。测试结果表明,样品A的基本力学性能优于样品B,其拉伸强力大,防水、防潮、防渗性能强,且耐划破强力已超过80 N的国际施工要求。     

Soyhulls as an alternative feed for lactating dairy cows: a review

Dairy producers use soyhulls, a byproduct of soybean processing, to replace either grain or forage in diets of lactating dairy cows. In view of the nutritional and economical value of soyhulls it is anticipated that this practice will continue to increase in popularity among nutritionists and producers of ruminant animals. This paper reviews information regarding the nutritional value of soyhulls and the effects of feeding this alternative feed on ruminal fermentation, nutrient digestion and utilization, and performance of dairy cows. Soyhulls can replace corn grain to supply about 30% of the dry matter (DM) in high-grain diets without negatively affecting either the fermentation or digestion of nutrients in the gastrointestinal tract or the performance of dairy cows. Additionally, data suggest that soyhulls might successfully replace forage to supply < or = 25% of the DM in diets of dairy cows when the supply of effective fiber, which includes a chemical and a physical component, remains adequate after including the hulls. However, caution should be exercised when data from different studies are extrapolated to practical situations because the response to feeding soyhulls appears to be largely affected by the type of carbohydrate being replaced by soyhulls; the amount, type, and physical form of the dietary forage; and the incidence of either negative or positive associative effects before and after the addition of soyhulls to the original diet. Unfortunately, the paucity of data from experiments in which soyhulls constituted more than 25 to 30% of the dietary DM restricts the ability to identify the maximum amount of soyhulls that can be used in diets of dairy cows. Information from studies in which > or = 25 to 30% of dietary DM supplied as either cereal grains or forages are replaced with soyhulls is needed to better understand and predict the production of dairy cows fed diets containing the hulls. This knowledge is essential for maximizing the use of soyhulls in diets for dairy cows.     

Inulin and oligofructose as dietary fiber: a review of the evidence

This critical review article examines the composition and source of inulin and oligofructose, the physiological effects of their consumption, and how these materials relate to the concept of dietary fiber. Inulin and oligofructose are fructans extracted on a commercial basis from the chicory root. Inulin has been defined as a polydisperse carbohydrate material consisting mainly, if not exclusively, of beta (2-1) fructosyl-fructose links ranging from 2 to 60 units long. Native chicory inulin has an average degree of polymerization (DP) of 10 to 20, whereas oligofructose contains chains of DP 2 to 10, with an average DP of 4. While a universally accepted definition for dietary fiber does not exist, it is generally agreed that this term includes saccharides (+ lignin) that are not hydrolyzed or absorbed in the upper part of the gastrointestinal tract. These materials reach the colon, where they may be totally fermented, partially fermented, or remain unfermented. In addition, fibers contribute to fecal bulking. Inulin and oligofructose are not digested in the upper part of the gastrointestinal tract or are they absorbed and metabolized in the glycolytic pathway, or directly stored as glycogen like 'sugars' or starches. None of the molecules of fructose and glucose that form inulin and oligofructose appear in the portal blood. These materials are quantitatively fermented by the microflora of the colon; further, it has been demonstrated that this fermentation leads to the selective stimulation of the growth of the bifidobacteria population. After reviewing their chemistry, origin, and physiological effects, it is the opinion of the authors that inulin and oligofructose are dietary fiber. They share the basic common characteristics of dietary fibers, that is, saccharides of plant origin, resistance to digestion and absorption in the small intestine, and fermentation in the colon to produce short-chain fatty acids that are absorbed and metabolized in various parts of the body. Moreover, this fermentation induces a bulking effect.     

International legislation on trace elements as contaminants in food: a review

Environmental contaminants such as trace elements may be present in all foods. Foods, raw materials and ingredients for food production are to an increasing extent traded across borders. Hence, there is a need for international legislation on trace elements as contaminants in food. In 1961, the FAO and WHO established the Codex Alimentarius to elaborate international food legislation. Contaminants in food are handled by the Codex Committee for Food Additives and Contaminants (CCFAC). The Codex Alimentarius system for developing legislation concerning trace elements as contaminants in food is based upon the Codex General Standard for Contaminants and Toxins in Food (GSCTF). By October 2001, the principles for setting maximum limits (MLs) for contaminants in food are agreed, and work is in progress on MLs for trace elements such as lead and cadmium in the various food categories. The status for the proposals is presented and discussed. The EU Regulation 466/2001 of 8 March 2001 sets MLs for lead and cadmium in various foods. This regulation will apply from 5 April 2002. The EU regulation is more detailed but similar to the Codex draft standards for lead and cadmium in food. In future, legislators and administrators in the Codex and EU and analytical chemists will discuss how to use more and better analytical data as risk-management tools to protect public health. Trace elements' speciation is an important aspect of this discussion.     

Delactosed permeate as a dairy processing co-product with major potential value: a review

Delactosed permeate (DLP) is the co-product generated during the separation of pre-crystallised lactose from milk and whey permeates. DLP production has grown with the increased production of high protein content ingredients such as whey protein concentrates and isolates. Although DLP is nutritionally rich, with approximately 0.5–1.5, 68–70, 9–10 and 8–9 g/100 g dry matter of protein, total sugars, total mineral and organic acids, respectively, it is still currently underutilised, mostly for animal feed or energy production. There are a number of novel, promising and sustainable DLP-derived food and non-food applications which are the subject of current research. Therefore, there exists the opportunity to exploit this dairy co-product in the development of new value-added ingredients. In this comprehensive review, DLP production, processing challenges and potential applications are discussed, along with identification and assessment of selected strategies for the valorisation of DLP.     

Dietary N-epsilon-carboxymethyllysine as for a major glycotoxin in foods: A review

N-epsilon-carboxymethyllysine (CML), as a potential glycotoxin and general marker for dietary advanced glycation end products (dAGEs), exists in raw food and is formed via various formation routes in food processing such as Maillard reaction between the reducing sugars and amino acids. Although comprehensive cause-effect proof is not available yet, current research suggests a potential risk of chronic diseases such as diabetes is associated with exogenous CML. Thus, CML is causing public health concerns regarding its dietary exposure, but there is a lack of explicit guidance for understanding if it is detrimental to human health. In this review, inconsistent results of dietary CML contributed to chronic disease are discussed, available concentrations of CML in consumed foods are evaluated, measurements for dietary CML and relevant analytic procedures are listed, and the possible mitigation strategies for protecting against CML formation are presented. Finally, the main challenges and future efforts are highlighted. Further studies are needed to extend the dietary CML database in a wide category of foods, apply new identifying methods, elucidate the pathogenic mechanisms, assess its detrimental role in human health, and propose standard guidelines for processed food.