关于禽类冷冻加工技术的探讨

禽肉类是天然食物中最优良的动物食品之一。因其具有较高的营养价值和鲜美的口味，本文仅对禽肉类的禽类冷冻加工技术作一介绍。     

远程光通信设备的供电方案探讨

光缆物理网作为最贴近用户的战略性资源,是争夺业务的关键性基础物理网络。如何为光通信设备提供安全、经济和便利的供电,是通信运营商和建设者非常关心的课题。本文简要介绍了远程光通信设备的供电方式及需要考虑的相关问题。     

Fuel model development for the Greek East‐Mediterranean forest litter layer

In order to develop fuel models used as input in wildland fire propagation models, it is necessary to determine relevant vegetation properties concerned with the prediction of the combustion process. This research considers property measurements of two biomass species, namely Pinus halepensis and Pinus brutia. Both species are commonly found in Greece and other Eastern Mediterranean countries. The physical application of the biomass properties relates to the structure of pine forest litter. Measurements have been recorded of the characteristics of the litter layer in situ, and common fuel properties have been determined in the laboratory using samples of the two litter species. In addition, DTA, TG and DTG analysis were performed of the two litter species. The results of the measurements are presented in a format suitable for input in fire propagation models. Comparisons of data have been made with those from other literature sources. Copyright © 2012 John Wiley & Sons, Ltd.     

Male-Produced Aggregation Pheromone of the Lesser Mealworm Beetle, <Emphasis Type="Italic">Alphitobius diaperinus</Emphasis>

The lesser mealworm beetle, Alphitobius diaperinus (Panzer), is a widespread serious pest in poultry production facilities and is difficult to control by conventional means. Although pheromone-based tools have become useful in the management of other beetle pests, no pheromone was known for A. diaperinus, and this study sought to develop basic pheromone information. Volatiles were collected in the laboratory from groups of male and female A. diaperinus maintained on poultry food (chick starter mash). Gas chromatographic–mass spectrometric analysis of volatiles collected from feeding males and females revealed five male-specific compounds that were identified as (R)-(+)-limonene, (E)-β-ocimene, (S)-(+)-linalool, (R)-(+)-daucene, and 2-nonanone. Emission of these began 1–2 weeks after adult emergence and could continue for at least 1 year, ceasing and resuming in response to changes in food availability and quality and other factors. No female-specific compounds were discovered. A synthetic blend of the five male compounds was attractive to both sexes in poultry production facilities in Illinois and Arkansas, indicating that the blend functions as an aggregation pheromone, but it is not yet known whether all five compounds are required for activity. A new pitfall trap is described for field use.     

Effect of chitosan and thyme oil on a ready to cook chicken product

The present study examined the effect of natural antimicrobials: chitosan, thyme and their combination, on the shelf-life of a Ready to Cook (RTC) chicken-pepper kebab (skewer) stored under aerobic conditions at 4 ± 0.5 °C for a period of 12 days. Treatments examined in the present study were the following: A (control samples, untreated), A–CH (chitosan; 1.5% v/w), A–T (thyme essential oil; 0.2% v/w) and A–CH–T (chitosan; 1.5% v/w and thyme essential oil; 0.2% v/w). The shelf-life of the samples was determined using both microbiological and sensory analyses. Among the microorganisms examined, pseudomonads were the most resistant group towards the combined application of chitosan and thyme oil (ca. 1.5 log cycle reduction) while Lactic acid bacteria (LAB), Brochothrix thermosphacta and Enterobacteriaceae were the most sensitive to the combined action of these two agents (2–3 log cycle reduction). Yeasts-moulds were also part of the natural microbial association of the RTC product, with A–CH–T treatment suppressing effectively their growth during the entire period of storage. Treatments A–CH and A–CH–T resulted in lower pH values as compared to the control (A) samples. Of the treatments examined in the present study, A–CH–T, gave a “spicy”, desirable and pleasant (organoleptically acceptable) RTC product. Based primarily on sensory data (taste attribute) A–CH, A–T and A–CH–T treatments extended the product's shelf-life by ca. 4 and 6 days, respectively, as compared to the control sample.     

深圳市部分市售禽类制品二噁英污染水平研究

目的了解深圳市部分市售禽类制品(鸡肉、鸭肉、鸡蛋、鸭蛋)中17种二噁英污染情况。方法于2004年12月至2008年10月期间,随机采集深圳市市售的26份禽类样品,参照美国国家环保局EPA1613方法,采用索式抽提装置和FMS自动纯化系统分别对样品进行提取和净化,采用同位素稀释技术,用高分辨气相色谱/高分辨双聚焦磁式质谱联用(HRGC/HRMS)的超痕量有机分析技术平台,对样品中的二噁英进行定量分析检测。结果禽肉中PCDD/Fs含量(pgWHO-TEQ/g脂肪)范围是0.03～1.61,平均含量为0.50;禽蛋中PCDD/Fs含量范围是0.22～5.66,平均含量为1.43。其中有1份鸡肉和1份鸡蛋中二噁英含量超过欧盟执行标准,含量分别为1.61和5.66。结论本次调查的禽类制品中二噁英平均含量低于欧洲标准,但个别样品存在二噁英污染现象。     

Fate of Tannins in Corsican Pine Litter

Tannins are ubiquitous in higher plants and also in litter and soils where they affect many biogeochemical processes. Despite this well-recognized role, their fate in litter and mineral soils is hardly known, as often only trace amounts, if any, are measured. In this study, we conducted an incubation experiment with Corsican pine litter to which known amounts of tannic acid (TA) or condensed tannins (CTs) from Corsican pine were added. Using Folin–Ciocalteu as a measure for total phenolics and HCl–butanol as an assay specific for CTs, acetone/water extractable phenolics and tannins decreased with time towards very low levels. Application of thermally assisted hydrolysis and methylation to litter before and after acetone/water extraction revealed that TA concentration decreased. By contrast, CTs remained to a great extent in the litter and could not be extracted suggesting that they were tightly bound.     

Geographic origin of meat—elements of an analytical approach to its authentication

This review article discusses recent analytical developments with respect to the determination of the geographic origin of raw meat. The main emphasis is laid on lamb, beef and poultry. So far, some methods have shown quite promising potential (e.g. stable isotope ratios, trace elements), others have remained unsatisfactory in their discriminating power to authenticate the geographic origin of meat (e.g. microbiological profile, sensory traits, volatile compounds). Other methods (e.g. animal genotype, gross chemical composition) could be auxiliary criteria as they help to determine related indicators such as feeding or housing conditions but not directly the origin. The complexity of this question is large. An integrated approach simultaneously addressing various species and production characteristics such as environment, animal husbandry conditions, breed, feeding and drinking water has to be developed. Strategies have to be different for global and micro-regional scales.     

Nutritional composition and condensed tannin concentration changes as browse leaves become litter

BACKGROUND: The role of condensed tannins (CT) in ruminant nutrition and health makes changes in leaf litter (LL) after abscission of interest. This study compared the effect of different drying methods of green leaves (GL) with that of natural drying of LL on CT, fibre, crude protein (CP) and phosphorus (P) concentrations in nine Texas browse species. Leaves harvested before autumn shedding were oven‐dried (OD) or freeze‐dried (FD). RESULTS: Where different (P < 0.05), extractable CT concentrations were higher while protein‐ and fibre‐bound CT concentrations were lower in GL‐FD than in LL. Drying method changed total CT concentration in three species. Where different, fibre fraction concentrations were greater in LL than in GL, regardless of drying method. In some species, CP and P concentrations were lower in LL than in GL, but in five species they did not change (P > 0.05) from GL to LL, with CP concentrations ranging from 63 to 151 g kg^?1 in the latter. CONCLUSION: Browse LL had high nutritive value and CT concentrations, explaining why browsing ruminants utilise this feed resource. However, changes in nutrient and CT concentrations as leaves become litter in some species mean that information on one is not necessarily applicable to the other. Copyright © 2010 Society of Chemical Industry