氟苯尼考及其代谢物氟苯尼考胺在肉鸡中残留消除规律

目的 评估氟苯尼考及其代谢物氟苯尼考胺在不同品种肉鸡中的残留消除规律。方法 选用AA肉鸡、WOD168肉鸡、雪山鸡和狼山鸡为试验对象, 于出栏前3周开始按氟苯尼考25 mg/kg体重饮水给药, 连用5 d, 于停药后1、3、5、7、10、14 d采集肌肉、肝脏、肾脏、皮脂, 检测其中的氟苯尼考和氟苯尼考胺残留量, 并利用WT1.4软件计算休药期。结果 氟苯尼考及其代谢物氟苯尼考胺可迅速残留于肉鸡肌肉、肝脏、肾脏和皮脂中, 残留物以氟苯尼考为主。停药后第1 d残留量达到峰值, 肾脏组织中的残留量最大; 停药后第3 d, 各组织中氟苯尼考和氟苯尼考胺的残留量进入快速消除期, 均低于最大残留限量值; 停药后第14 d已基本消除完全。利用WT1.4软件计算出AA肉鸡、WOD168肉鸡、雪山鸡和狼山鸡休药期分别至少为3.22、3.85、4.49和4.32 d。结论 氟苯尼考在慢速型肉鸡体内的休药期要长于快速型肉鸡, 但都小于5 d。     

The implications of point source phosphorus management to potable water treatment

The Vaal River Barrage reservoir is an important source of raw water for Rand Water which supplies at least 10 million people with drinking water daily. Return effluents from waste water treatment works, industries and informal urban settlements in the catchment has resulted in algal problems in the raw water and treatment process.In order to attempt to reduce the effect of eutrophication of South African inland water quality the Department of Water Affairs implemented in 1985 a 1 mg/l ortho-phosphate standard for waste water treatment works effluents.The amount of phosphate originating from the waste water treatment works decreased significantly over the 10 years after the standard was implemented even though 40% of the time the works do not comply to the standard. This has resulted in no significant change in the chlorophyll values at Rand Water Intake No. 1. The algal species composition has changed with blue-greens becoming more dominant which has resulted in a higher incidence of algal related problems. The stabilizing of the chlorophyll values is not only as a result of lower ortho-phosphate levels but also due to residence times, turbidity and conductivity.To further reduce the algal concentrations at Rand Water Intake No. 1 the 1 mg/l ortho-phosphate standard will have to be enforced, the standard possibly reduced and diffuse sources managed on a catchment basis.     

冰鲜黄羽肉鸡贮存过程中肉品质指标的变化规律

本试验旨在研究黄羽肉鸡冰鲜鸡贮藏7d内肉品质指标变化规律及其相关性分析。以80日龄黄羽肉鸡为试验对象,4℃冷藏,测定0、1、2、3、4、5、6、7d鸡肉的肉色、pH值、剪切力和失水率。结果表明：随贮藏时间的延长,冰鲜鸡肉的亮度值(L*)先上升后下降;红度值(a*)呈现下降趋势;黄度值(b*)和失水率长呈现上升趋势;pH值先下降后上升;剪切力没有明显的变化规律。冰鲜鸡pH值与b*呈极显著正相关(p＞0.01),相关系数达到0.795。由此可知,贮藏7d对冰鲜鸡的肉色和失水率有影响,pH值与黄度值(b*)相关性最大。     

Novel mechanisms for the decomposition of 1-(amino acid)-1-deoxy-D-fructoses (Amadori compounds): A mass spectrometric approach

A study of the mechanisms involved in unimolecular mass spectral fragmentations of 1-(amino acid)-1-deoxy-D-fructoses (Amadori rearrangement products, or ARPs) has led to proposals for a number of new mechanistic routes to Maillard reaction products. One of the proposed mechanisms involves decomposition by initial dehydration or dehydroxylation directly from the cyclic hemiketal forms of the ARPs rather than from the open chain carbonyl forms. Another proposed mechanism involves formation of the pyrylium ion which could be the key intermediate in the formation of polymeric material. A number of other important Maillard reaction heterocycles could also be formed via the reactive pyrylium ion. The effect of variation of the ARP amino acid on 1,2- and 2,3-type enolization products was demonstrated. Intramolecular nucleophilic reactions observed in the mass spectral fragmentations also gave clues to the mechanisms of formation of compounds such as β-carbolenes from the tryptophan ARP.     

NaOH溶液处理对鸡肉品质的影响

为研究NaOH溶液处理对鸡肉品质的影响,选取市售黄羽肉鸡60 只,随机分为对照组和NaOH溶液浸泡组（pH 9组、pH 11组和pH 13组,每组15 只）,并对其进行肉品质和微生物指标检测。结果表明：NaOH溶液浸泡可以显著增加鸡肉的质量和腐败指标（总挥发性盐基氮、组胺、酪胺和亚精胺）含量（P＜0.05）,显著降低剪切力、风味营养物质（蛋白质、肌内脂肪、肌苷酸和氨基酸）含量（P＜0.05）;低pH值NaOH溶液浸泡的鸡肉,其菌落总数和大肠菌群数明显升高,而高pH值NaOH溶液具有一定的杀菌效果。     

Dromedary camel milk proteins,a source of peptides having biological activities – A review

Many useful properties are assigned to camel (Camelus dromedarius) milk, which is traditionally used for the treatment of tuberculosis, gastroenteritis, and allergy in many countries. Some amino acid sequences, which are encrypted in the camel proteins, may play a beneficial role in human health once they are released from milk either in vivo during normal digestion or by proteolysis with purified enzymes or during bacterial fermentation. Similar to the bovine milk counterparts, camel milk bioactive peptides may display a variety of potential activities that were almost always unveiled from in vitro analyses: anti-microbial, anti-oxidative, anti-hypertensive, anti-inflammatory, and immunomodulatory activities. Today, there is a growing interest for bioactive peptides generated from camel milk. This paper reviews available data on the potential biological activities of the camel milk proteins and their peptides liberated either during milk fermentation with proteolytic bacterial strains or by enzyme hydrolysis with specific proteases or simulated gastro-intestinal digestion.     

不同日龄和性别舞阳鸽胸肌肉常规肉品质及主要营养成分的比较

为充分解析河南地方资源舞阳鸽肉质性状特点,本研究系统分析了不同日龄和性别舞阳鸽胸肌肉的肉品质及营养组成,并与白羽王乳鸽和市售乳鸽进行比较。随机选取健康乳鸽、成年公鸽和成年母鸽各30只,进行屠宰。取双侧胸肌,一侧立即进行常规肉品质(肉色、pH、失水率和剪切力)的测定,一侧冷冻保存,用于营养组成(常规成分、氨基酸、脂肪酸和微量元素)的测定。结果显示：舞阳乳鸽胸肌肉的肉色红度值显著高于成年母鸽(P＜0.05),成年公鸽胸肌肉的剪切力显著高于成年母鸽和乳鸽(P＜0.05),三者pH和失水率没有显著差别(P＞0.05)。与白羽王乳鸽相比,舞阳乳鸽肉色偏红偏黄,pH、剪切力和失水率都偏高。日龄对舞阳鸽胸肌肉水分、脂肪、肌苷酸含量有显著影响(P＜0.05),舞阳乳鸽水分比白羽王乳鸽高5.36%,脂肪比白羽王乳鸽低48.08%。成年母鸽胸肌肉必需氨基酸占比显著高于成年公鸽和乳鸽(P＜0.05),尤其是亮氨酸、蛋氨酸和苯丙氨酸占有显著优势(P＜0.05)。舞阳乳鸽胸肌肉鲜味氨基酸比白羽王乳鸽高出24.44%。日龄对舞阳鸽饱和脂肪酸和单不饱和脂肪酸比例影响显著(P＜0.05)。白羽王乳鸽未检出花生三烯酸(C20:3),舞阳乳鸽含量高达4.75%。不同日龄和性别舞阳鸽胸肌肉微量元素Fe、Cu、Zn、Se含量没有显著差异(P＞0.05)。与市售鸽肉相比,Fe含量较高,Cu、Zn含量较低。综上所述,日龄和性别对舞阳鸽胸肌肉的肉色、剪切力、水分、脂肪、肌苷酸、氨基酸和脂肪酸组成均有影响。舞阳鸽肉不仅具有色泽红润、嫩度小、不易酸败、风味好等地方畜禽品种肉特有品质,同时氨基酸组成更均衡,脂肪酸组成更优化,是一种高蛋白、低脂肪的理想型食用肉类。     

The protection of bovine skeletal myofibrils from proteolytic damage post mortem by small heat shock proteins

This study aimed to determine how small heat shock proteins (sHSPs) protect myofibrillar proteins from μ-calpain degradation during ageing. Immunoprecipitation experiments with M. longissimus dorsi (LD) from Angus heifers (n = 14) examined the interaction between αβ-crystallin, desmin, titin, HSP20, HSP27 and μ-calpain. Results showed that αβ-crystallin associated with desmin, titin, HSP20, HSP27 and μ-calpain. Exogenous αβ-crystallin reduced desmin and titin degradations in myofibrillar extracts and attenuated μ-calpain activity. In a second experiment, bull LD (n = 94) were aged at − 1.5 °C for up to 28 days post mortem. μ-Calpain autolysed faster in high ultimate pH (pH_u) meat (pH_u ≥ 6.2) and this was concomitant with the more rapid degradation of titin and filamin in this pH_u group. Desmin stability in intermediate pH_u meat (pH_u 5.8 to 6.19) may be due to the protection of myofibril-bound sHSPs combined with the competitive inhibition of μ-calpain by sHSPs.     

Fat spectro-colorimetric characteristics of lambs switched from a low to a high dietary carotenoid level for various durations before slaughter

This study investigated the changes in fat reflectance spectrum characteristics and color in lambs switched from a low to a high dietary carotenoid level for various durations before slaughter. Six treatments, feeding a high dietary carotenoid level for 0, 15, 30, 45, 60 or 75 days before slaughter, were compared in individually indoor penned lambs. Each treatment used 10 Romane lambs; feeding management ensured similar growth pattern and carcass weight for all the treatment groups. There was a change in reflectance spectrum characteristics and yellowness of subcutaneous fat as early as 15 days after the switch. Mean concentration of carotenoid pigments and yellowness of subcutaneous fat increased linearly with the duration of the high dietary carotenoid level. In perirenal fat, the change in reflectance spectrum characteristics was observed as early as 15 days after the switch, but the response to the duration of the high dietary carotenoid level was curvilinear.