动物性食品中除脱胆固醇的研究动态

动物性食品中常常含有较高的胆固醇，每百克含量如鸡蛋为６８０ｍｇ，奶油为２５０－４００ｍｇ，猪瘦肉为７７ｍｇ，猪肥肉为１０７ｍｇ，猪油为８５ｍｇ。胆固醇虽然是人体代谢不可缺少的物质，但过理的胆固醇是心血管疾病的原因之一，这就使从们对于动物性食品的消毒产生了一一的畏惧心理。     

胆固醇受热氧化产物研究

对胆醇醇受热氧化情况进行了研究。采用毛细管气相色谱法分离检测胆固醇氧化产物。胆固醇于90℃加热2h和高温下加热初期（150℃，10min以内），没有明显的氧化物生成。但高温加热时间较长（20min以上）时，自氧化反应很容易发生，共有6种氧化产物（5β、6β－环氧化胆固醇、5α、6α－环氧化胆固醇、3β，5α，6β－胆甾烷三醇、6－酮基胆固醇、7－酮基胆固醇、25－羟基胆固醇）被确定。胆固醇氧化产物组成和生成量与胆固醇的量、加热温度及加热时间有关。     

生物法降解动物性食品中胆固醇的安全性研究

生物法降解食品中的胆固醇一直被认为是目前最安全有效的方法之一，但是随着研究的深入，生物法也存在一定的不安全因素。按照降解机制的不同，分别阐述了生物法降解动物性食品中胆固醇时出现的一些不安全因素，希望对生物法的更好应用提供指导。     

胆固醇氧化酶法脱除食品中胆固醇的研究进展

综述了利用胆固醇氧化酶脱除食品胆固醇的国内外研究现状，重点评价了在不同反应条件下该酶降低蛋黄、乳、猪油等食品中的胆固醇的效果和在食品中应用的安全性，并针对这些研究的成果提出了今后这一研究领域尚需解决的主要问题。     

动物性食物胆固醇脱除研究

在广泛收集近年有关食物胆固醇研究论文和专著的基础上，综述了动物性食物胆固醇的物理脱除、化学脱除和生物脱除等方法的现状和展望，以期为低胆固醇食品的研究和开发提供可参考的依据。     

动物性食品中兽药残留检测技术的研究进展

兽药残留（residues of veterrinary drug）是指禽畜等动物用药（如抗生素类、激素类等）后蓄积或存留于机体或动物性产品（如乳制品、蛋类以及肉类等）中原型药物或其代谢产物,包含与兽药相关的杂质残留。本文综述了近年来国内外研究人员对于动物性食品中兽药残留检测的常用技术,并探讨动物性食品中兽药残留检测技术的发展前景。     

动物性食品中喹诺酮类药物残留检测方法研究进展

喹诺酮类药物是广谱抗菌药,具有良好的生物利用度和耐受性,不仅对革兰氏阳性菌和阴性菌有杀菌作用,还具有抗真菌和抗病毒活性,因此在兽医临床上广泛应用于治疗畜禽动物养殖过程中的细菌性感染.随着食品安全和兽药残留问题越来越受到大众关注,加强对动物性食品中喹诺酮类药物残留的监测十分必要.本文对喹诺酮类药物残留的主要检测方法进行了...     

动物性食品中磺胺类药物残留分析研究进展

介绍了动物性食品中磺胺类药物残留的来源和危害,着重对动物性食品中常见的磺胺类药物残留的分析方法进行了综述,为研究最有效的检测方法奠定了基础。     

动物性食品中残留盐酸克伦特罗的研究进展

介绍了盐酸克伦特罗(瘦肉精)的理化特性,分析了它在动物性食品中残留对人体和国民经济所造成的危害,同时又综述了动物肌肉组织中残留盐酸克伦特罗(瘦肉精)的各种分析检测方法并作了展望。     

动物性食品中莱克多巴胺检测方法研究进展

莱克多巴胺作为激素类添加剂,对动物机体产生副作用,同时影响消费者的健康.近年我国进出境口岸屡次在进口动物性食品中检出莱克多巴胺.本文对近几年来动物性食品中莱克多巴胺的检测方法新进展和新兴技术做了大量调查和整理,旨在为出入境口岸动物性食品中莱克多巴胺的检测提供一定的参考,为进出口动物性食品的安全控制提供理论依据.     

Inhibition of cholesterol oxidation in marinated foods as affected by antioxidants during heating

Chinese marinated foods rich in cholesterol, such as eggs and pork, can be susceptible to formation of carcinogenic cholesterol oxidation products (COPs) during prolonged heating. The objectives of this study were to compare the effects of various antioxidants on the inhibition of COPs in marinated eggs, pork and juice. The various COPs in marinated food samples were analyzed by a GC–MS technique. The incorporation of antioxidants, vitamin C, vitamin E, BHA and trolox were all effective in inhibiting COPs formation, with vitamin C being the most pronounced in marinated eggs, and BHA in marinated pork and juice. The inhibition effect increased with increasing levels of BHA and trolox. However, vitamin E was more effective at a low level (0.02%) than at a high level (0.1%), probably because of prooxidant activity of the latter. The same phenomenon also occurred for 0.1% vitamin C in marinated eggs, but a reversed trend was observed in marinated pork and juice. The residual amounts of each antioxidant in marinated eggs, pork and juice were also determined by HPLC.     

肉食品中的胆固醇氧化物

胆固醇是肌肉组织的一种组分。新鲜肉中不存在胆固醇氧化物。内在长期贮存和加热中生成胆固醇氧化物。肉食品中的胆固醇氧化物对人的健康有害。肉中胆固醇氧化物的总量与肉的脂类氧化物存在着线性相关。在饲料中添加生育酚以提高内源性生育酚，其动物的肉制品中胆固醇氧化物明显减少。     

Fatty acids and cholesterol oxidation in salted and dried shrimp

The aim of this work was to evaluate the occurrence of cholesterol oxidation products and to analyze the lipidic profile in salted–dried shrimp. Fifty samples of salted–dried shrimp were evaluated, and the cholesterol oxides (7β-OH, 7α-OH, 7-Keto and 25-OH) were quantified by high-performance liquid chromatography. The cholesterol oxides: 7β-OH (34.63–72.56 μg/g), 7α-OH (5.02–12.12μg/g), 7-Keto (7.44–32.68 μg/g) and 25-OH (2.37–22.88 μg/g) were determined in all samples analyzed. Regarding to the total cholesterol content and the average thiobarbituric acid reactive substances (TBARS) content, the results ranged from 73.88 to 247.69 mg/100 g, and 0.02 to 1.30 mgMA/kg, respectively. The fatty acids profile was: 27.48% saturated, 43.90% monounsaturated and 28.61% polyunsaturated. The presence of cholesterol oxidation products and the values of TBARS indicate the degree of oxidation of this product, which was probably initiated by inadequate conditions of processing and storage.     

Photosensitized oxidation of cholesterol and altered oxysterol levels in sour cream: Effects of addition of cucumber pickles

The aim of this research was to examine whether sour cream (18% fat) is an exogenous source of oxysterols and whether it is possible to improve its antioxidative properties and to modulate cholesterol transformation by adding cucumber. To determine whether cucumber modifies the properties of sour cream, fresh cucumber or cucumber pickle (pH 3.3; 1.5% lactic acid) was added in an amount of 20%. The sour cream samples were then stored under light (450 lx, 590 cd, 120 lm) for 3 wk. After storage, the addition of the cucumber pickle increased total mesophilic aerobic bacteria from 7.5 to 9.3 log cfu/g and increased the l-lactic acid content from 6.1 to 9.7 g/L. The total conjugated linoleic acid content in sour cream with cucumber pickle also increased to 4.5 mg/g fat after storage, whereas the cholesterol content decreased to 3.44 g/kg fat. Importantly, with the addition of cucumber pickle, the total content of cholesterol oxidization products (COP) did not change after storage (1.7 mg/kg fat). By contrast, the total COP content in the control sour cream sample increased from 1.7 to 7.3 mg/kg fat over 3 wk of storage. The dominant COP before and after storage was 7β-hydroxycholesterol. Thus, despite exposure to light, adding cucumber pickle to sour cream modulates cholesterol transformation and effectively inhibits the formation of oxysterols.     

Phytosterol oxidation products in enriched foods: Occurrence,exposure, and biological effects

Hypercholesterolemia is an important risk factor for the development of cardiovascular diseases. Dietary intake of phytosterols/phytostanols and their fatty acid esters results in a reduction of the LDL and total plasma cholesterol levels. Therefore, these constituents are added to a broad spectrum of foods. As in the case of cholesterol, thermo‐oxidative treatment of phytosterols may result in the formation of phytosterol oxidation products (POPs), i.e. keto‐, hydroxy‐, and epoxy‐derivatives. This review summarizes and evaluates the current knowledge regarding POPs in the light of the potentially increasing dietary exposure to these constituents via the consumption of foods enriched with phytosterols/phytostanols and their esters. Data on the occurrence of POPs and approaches to assess the potential intake of POPs resulting from the consumption of enriched foods are described. The knowledge on the uptake of POPs and the presently available data on the impact of the consumption of enriched foods on the levels of POPs in humans are discussed. Biological effects of POPs, such as potential proatherogenic properties or the loss of the cholesterol‐lowering effects compared to nonoxidized phytosterols, are discussed. Finally, knowledge gaps are outlined and recommendations for further research needed for a safety assessment of POPs are presented.     

动物福利壁垒对我国畜禽产品出口的影响与对策建议

阐述了动物福利壁垒的产生及其发展趋势,分析了动物福利壁垒对我国畜禽产品出口的影响。动物福利壁垒一方面抬高了国际贸易的市场准入门槛,削弱了我国产品的出口竞争力．影响我国肉、蛋、奶等动物食品以及皮毛制品的出口,并波及到水产、中药、餐饮等其他相关行业;另一方面,动物福利壁垒也会对我国畜牧业发展产生一定的积极影响。从政府、行业协会、企业3个方面提出了应对发达国家动物福利壁垒的对策建议。     

Effect of irradiation and packaging conditions after cooking on the formation of cholesterol and lipid oxidation products in meats during storage

The effect of irradiation and packaging conditions on the content of cholesterol oxidation products (COPs) and lipid oxidation in cooked turkey, beef, and pork during storage was studied. Ground turkey leg, beef, and pork were cooked, packaged either in oxygen-permeable or oxygen-impermeable bags, and irradiated at 0 or 4.5 kGy. Lipid oxidation and COPs were determined after 0 and 7 days of storage at 4°C. Packaging of cooked meat was more important than irradiation in developing COPs and lipid oxidation in cooked meats during storage. 7-Hydroxycholesterol, 7β-hydroxycholesterol, β-epoxide, and 7-ketocholesterol were among the major COPs formed in cooked turkey, beef, and pork after storage, and their amounts increased dramatically during the 7-day storage in aerobic conditions. Irradiation had no significant effect on the amounts of any of the COPs found in cooked turkey and beef, but increased (P<0.05) the amounts of - plus 7β-hydroxycholesterol, β-epoxide, 7-ketocholesterol, and total COPs in aerobically packaged cooked pork. The amounts of COPs and lipid oxidation products (TBARS) closely related to the proportion of polyunsaturated fatty acids in meat. The results indicated that the composition of fats in meat is important on the oxidation rates of lipids and cholesterol, and packaging is far more important than irradiation in the formation of COPs and lipid oxidation in cooked meat.     

Effect of Maillard reaction products on oxidation products in ground chicken breast

Three amino acid-sugar solutions were adjusted to pH 8.0, heated and lyophilized prior to addition to ground chicken breast (GCB). GCB with no additives, GCB with 0.01% BHT, GCB with 0.1 or 0.2 mg/g glucose heated with arginine, valine, or histidine were prepared. Thiobarbituric acid reactive substances (TBARS), volatiles determined by gas chromatography, and Hunter L*, a* and b* values were monitored over nine days. Multiple linear regression models were used to determine the effects of the studied factors on the corresponding outcome variables. a* values of GCB ranged from 1.60 to 4.90 over nine days of storage. While Maillard reaction products (MRP) lowered oxidation compared to control, no significant difference in TBARS between MRP solutions heated for 8 or 24 h was found. Further, 0.1 mg/g heated glucose-valine mixture decreased aldehydes up to 72.87%. Therefore, shelf-life of GCB could be extended using 0.1 or 0.2 mg/g MRP.     

Effect of electron-beam irradiation on cholesterol oxide formation in different ready-to-eat foods

A study of the formation of ¹cholesterol oxidation products (COPs) has been carried out in four ²ready-to-eat (RTE) foods (cooked ham, Spanish Serrano ham, minced beef, and soft cheese). The samples were previously treated with electron-beam irradiation between 1 and 8 kGy. Three COPs, 25-hydroxycholesterol, 7-ketocholesterol and 6-ketocholestanol, were extracted together with the lipid fraction using chloroform. Then, COPs were isolated by sample clean up using ³solid phase extraction (SPE) and were analyzed by ⁴high performance liquid chromatography with ultraviolet detection (HPLC-UV). Method validation was established by precision and recovery studies. Results showed that non-irradiated cheese and cooked ham samples did not contain COPs. In general, an increase in COP content was observed in all cases when the irradiation dose increased, although this increase was not linear. The 6-keto COP was not detected in any of the RTE food samples studied regardless of the irradiation dose.

Industrial relevance

Nowadays, changes in dietary habits have produced an important increase in consumption of prepared foods thus increasing microbiological contamination risks; consequently, it is necessary to apply easy methods, able to be implanted in industrial production lines, and which eliminate potential contaminants and enhance shelf life. The application of E-beam irradiation to vacuum packed ready-to-eat (RTE) food of animal origin could be a useful technique for sanitization purposes; besides, it is a clean, rapid and environmentally friendly treatment. During this treatment cholesterol oxide products (COPs) may be formed. They have received considerable attention in recent years because of their biological activity which has been associated with human diseases, such as the inhibition of cholesterol biosynthesis, atherosclerosis, changes in membrane properties, cytotoxicity, mutagenesis and carcinogenesis. Therefore, COP analysis in food samples of animal origin is of great interest.In this work, an increase in the 25-OH and 7-keto COP content has been detected after E-beam irradiation with doses from 1 to 8 kGy, which is in the upper accepted limit in other foods, but final COP concentrations found in the foodstuffs studied here were at least one order of magnitude lower than those which produce toxic effects in in vivo and in vitro experiments. Analysis was made by HPLC with UV detection; so, two COPs with absorption properties were used as targets.