脂肪代谢重要基因网络对呼伦贝尔羊脂肪分布和脂肪酸组成的影响

选择5 月龄圈养呼伦贝尔羊巴尔虎品系与短尾品系为实验材料（n=20）,通过测定其脂肪分布、脂肪酸组成、FTO和METTL3等基因的相对表达量,研究不同品系呼伦贝尔羊脂肪代谢重要基因网络对脂肪分布和脂肪酸组成的影响。结果表明：巴尔虎羊背最长肌和臂三头肌FTO和METTL3,臂三头肌、股二头肌及皮脂AMPK,背最长肌、皮脂及尾脂CPT1 mRNA相对表达量显著高于短尾羊（P＜0.05）,背最长肌和股二头肌饱和脂肪酸、皮脂和尾脂多不饱和脂肪酸、尾脂单不饱和脂肪酸的占比显著大于短尾羊（P＜0.05）;巴尔虎羊肌肉部位ACC,皮脂FTO、METTL3、PPARγ和ACC mRNA相对表达量显著低于短尾羊（P＜0.05）,肌内脂肪含量和质量、胴体总脂肪质量和胴体脂率、背最长肌多不饱和脂肪酸和尾脂饱和脂肪酸占比显著小于短尾羊（P＜0.05）。综上,该基因网络的差异表达在一定程度上影响了不同品系呼伦贝尔羊脂肪代谢和能量代谢,进而影响了脂肪分布和脂肪酸组成。     

Effect of Temperature on the Crystalline Form and Fat Crystal Network of Two Model Palm Oil-Based Shortenings During Storage

Fat products experienced undesirable microstructural property changes due to the temperatures during transportation and storage. In this study, the lipid composition and solid fat content (SFC) of two model palm oil-based shortenings, which are denoted as shortening A (melting point of 35.1°C) and shortening B (melting point of 51.2°C), were evaluated, and their crystallization behavior and polymorphism during storage at various temperatures (?10 °C to 30 °C) was examined by X-ray diffraction (XRD) and polarized light microscopy (PLM). The fractal dimension (D _b) was calculated to qualify the change in the crystal network during storage. The aggregation of high-melting triacylglycerols (TAGs) nanostructure and the formation of the most stable β polymorph were observed in shortening at higher temperatures (≥0 °C) during storage. At the same temperature, the intensity of β crystals in the two samples increased as the storage time increased, and this trend was obvious at high temperatures (≥10 °C). In addition, the intensity of the β crystals in the two samples gradually increased as the temperature increased, and the size of the crystalline particles became larger. The crystal size in shortening A was larger than that in shortening B at high temperatures (≥10 °C). The crystal network of shortening B was denser than that of shortening A. The D _b value reached a maximum at 10 °C and 30 °C for shortening A and B, respectively. These findings have important implications on the storage stability and functional properties of palm oil-based shortenings.     

微波熬炼制取鸡油的条件研究

微波功率密度增加、熬炼时间延长可提高鸡油的得率,降低其水分含量,但当微波功率密度超过2.75W/g、时间超过10min后,鸡油得率及水分含量变化不显著。经响应面分析法优化得到微波熬炼鸡板油的最佳条件为:功率密度2.7325W/g,提取时间11.3min。回归模型预测最优条件下鸡油得率为:84.279%,验证值为:84.2%,与预测值误差为0.09%。与湿法熬煮相比,微波熬炼所得鸡油得率高,POV值较低,而AV值较高,颜色稍暗且偏红,黄色较浅。经GC-MS分析,不同熬制方法得到的鸡油的脂肪酸组成显著不同,微波熬炼所得鸡油中脂肪酸相对含量为月桂酸0.675%,肉豆蔻酸0.816%,棕榈酸27.05%,硬脂酸5.05%,棕榈油酸6.322%,油酸45.927%,亚油酸13.86%,亚麻酸0.30%。     

Relationships of Ether-Extractable Fat vs Folch Fat and Fat Content vs Cholesterol Content for Beef Longissimus Muscles

The relation between ether-extractable fat and chloroform-methanol (2:1)-extractable fat (or Folch fat) and that between fat and cholesterol were evaluated for raw and cooked beef longissimus muscles. Folch fat values were, on average, 6.2% higher than ether-extractable fat values for raw samples and 13.4% higher for cooked samples. Cholesterol was correlated (P<0.05) with fat for both raw and cooked samples, but correlation coefficients were very low (0.37 or lower). The relation between moisture and fat values also was determined.     

乳脂制品和奶油——脂肪酸度的测定

<正> 1 范围 此方法适用于乳脂制品中脂肪酸度的测定。 2 参考标准 IDF 50B:1985——乳与乳制品-取样方法 IDF 68A:1977——无水乳脂肪、无水奶油、乳脂肪、半流体黄油——鉴别标准 FAO/WHO A-2:乳脂制品 ISO2446——乳-脂肪含量的测定(常规法)     

利用籼米为基质的脂肪替代品制备低脂火腿肠

用籼米为基质的脂肪替代品替代高脂火腿肠中50%脂肪制得了低脂火腿肠;通过全质构分析和感官评定相结合的方式对低脂火腿肠进行了评价。结果表明,用DE2～3的脂肪替代品替代脂肪制备的低脂火腿肠具有良好的质构和口感,能为广大消费者所接受。DE4的麦芽糊精不适合作为脂肪替代品。     

Role of Milk Fat Globule Membrane in Autoxidation of Milk Fat

The influence of the milk fat globule membrane (MFGM) on oxidation of milk fat under various conditions was monitored by fatty acid analysis and oxygen consumption at 50°C. The rate of copper-catalyzed oxidation of cream containing the membrane was faster than when the membrane was removed. In the dry state, the isolated MFGM, membrane lipids (ML) and the nonlipid membrane solids (NLMS) inhibited oxidation at 50°C and 95°C. In the presence of water, however, all membrane components enhanced oxidation at 50°C. The balance between the accelerating effects of membrane components and the inhibiting influence of other factors appeared to depend on processing conditions.     

以多糖为基质的脂肪模拟物替代动物脂肪在法兰克福香肠中的应用

将以多糖(魔芋粉、κ-卡拉胶和大麦β-葡聚糖)为基质的脂肪模拟物分别以20％、40％、60％和80％的比例替代猪脂肪用于法兰克福香肠生产中,探讨猪脂肪的不同替代比例对法兰克福香肠品质特性和感官特性的影响.结果表明,随着脂肪模拟物替代比例的增加,香肠的水分含量和碳水化合物含量显著增加(P<0.05),而总脂质含量、蛋白含...     

乳脂的功能

简要介绍了乳脂的营养功能、对胆固醇代谢的影响及某睦非常性功能。这些研究成果对乳及乳品的生产和消费有一定参考价值。     

Fat Content of Milk and Cream and Effects on Fat Globule Stability

Milk fat globules with crystalline fat content were sheared in defined flow conditions in order to ascertain the critical strain rate, which led to destabilization of the fat globules. Based on a fluid-mechanical model which considered the influence of the dispersed phase, a critical shear rate was defined. The model predicted a linear decrease in destabilization shear rate coupled with an increase in fat volume concentration. This interrelationship was confirmed in experiments. Fat globule stability, as related to shear strain rate, increased at decreasing temperatures. Critical shear rates for milk and cream should be calculated at a fat content not exceeding 45% for temperatures between 5 and 20°C. Any motion at higher fat content had a destabilizing effect on fat globules.     

亲水胶体类脂肪代用品在低脂肉糜制品中的应用

本文将几种不同的亲水胶体进行复配后应用于低脂肉糜制品中，通过肉糜制品的热稳定性和全质构分析以及感官特性的评定，筛选出一种复配型亲水胶体作为脂肪代用品，具有与高脂参照样（含脂肪３０％）相似的可接受性。本文还通过几种低脂肉制品配方的比较，详细阐述了复配胶对低脂肉制品的凝胶强度、弹性、持水率、感官评分以及超微结构等方面所起的作用。     

粉末油脂的研制

本课题对猪油粉末化乳化液的配制，喷雾干燥的条件进行了研究。着重探讨了乳化剂的ＨＬＢ值、乳化剂的添加量、乳化的温度及水份的添加量对乳化液稳定性和粘度的影响，从而筛选出较为理想的工艺条件。     

The Contribution of Modern Margarine and Fat Spreads to Dietary Fat Intake

The study of dietary fat consumption and its resultant effects on human health has been one of the most investigated topics in the field of human nutrition. Based on the results obtained from such studies, specific dietary recommendations on fat intake (both in terms of quantity and quality) have been established by health organizations around the globe. Among the various food industry sectors, the margarine manufacturers have also responded to these guidelines and now offer improved formulations with a desirable balance of fat contents and fat types. The main aim of this article is to provide an overview on how these modern margarines can contribute towards reaching the dietary guidelines relating to fat intake. In particular, the dietary recommendations with respect to the specific fatty acid types are comprehensively detailed along with an emphasis on the role of modern margarines in providing balanced fat types (more polyunsaturated fats, less saturated fats and a near‐complete absence of trans fats) in the daily diet.     

漫淡脂肪的作用

在讲究营养与健康的今天,人们在“健康食谱”中都严格控制对脂肪的摄入量,甚至有人拒绝脂肪的摄入,过度夸大了脂肪的危害性,大有“谈脂色变”之势。其实大可不必,无论是人体内的脂肪组织,还是膳食中的脂肪都对维持人体正常生理功能起到作用,在膳食中适当地摄入一定量的脂肪不仅对人体无害,且更有益于健康。一、脂肪是人体重要的组成部分我国正常成年男子体内脂肪含量占体重的10%～20%,女性高于男性约占体重的15%～25%,但人体脂肪含量常因人体自身的营养状况及活动量而有较大的变动。体内脂肪大多以甘油三酯形式储存在脂肪细胞内,分布于皮下…     

Emulsifying Properties of Bovine Milk Fat Globule Membrane in Milk Fat Emulsion: Conditions for the Reconstitution of Milk Fat Globules

A procedure for the reconstitution of milk fat globules (MFG) stabilized with milk fat globule membrane (MFGM) was developed. MFG was reconstituted by homogenizing a mixture of 1% MFGM and 25% milk fat at 45°C and at pH 7.0 for 1 min. The emulsifying properties of MFGM were evaluated by emulsifying activity (EA), emulsion stability (ES), whippability and foam stability. Of the variables affecting the reconstitution of MFG, prolonged homogenization decreased EA and ES. About 25% milk fat gave maximal EA and ES, increasing the MFGM concentration increased both EA and ES, which were also influenced by the pH level. Foam disappeared at >30°C.     

Physicochemical Properties of Milk Fat Emulsions Stabilized with Bovine Milk Fat Globule Membrane

Milk fat globules (MFG) were reconstituted with milk fat globule membrane (MFGM) and milk fat (MF). Viscosity of the reconstituted MFG was highest at pH 5.0 and 4 min emulsifying, and rose with an increase of MFGM between 40–80 mg/g fat. Adsorbed protein/unit fat increased at acid pH with increase of MFGM. The composition of proteins adsorbed on the surface of MFG was not influenced by factors of reconstitution. The size and specific surface area of globules were influenced by emulsifying time, MFGM and MF concentrations, and pH. The size range of MFG prepared by standard method was 0.9–17 μm in diameter. Median diameter was 5 μm and specific surface area was 15,600 cm²/cm³ of emulsion.     

Antioxidative Fat Replacer and High-Monounsaturated Oil Used for Pork Fat in Precooked Sausage

One high-fat and four low-fat pork sausage formulations were made: P30 with 30% pork fat (P); P11-W with 11% P and 10% added water (W); P11-WC with 11% P, 9.5% W and 0.5% carrageenan (C); Pso11-WC with 6% P plus 5% high-oleic sunflower oil (So), 9.5% W and 0.5% C; and Pso11-WGcf with 6% P plus 5% So, 7.0% W and 3% defatted glandless cottonseed flour (Gcf). Sausage patty cooking yield was highest for P11-WC and Pso11-WGcf. TBA values for refrigerated precooked patties were lowest for Pso11-WGcf, whereas carrageenan had a prooxidant effect in low-fat patties made with all-pork fat. The oil had no adverse effects on lipid oxidation and sensory properties of low-fat patties with C. The monounsaturated to saturated fatty acid ratio increased by 53–71% in the So-containing low-fat patties when compared to P11-W and P11-WC patties.     

微粒淀粉糊精于低脂贡丸中的代脂研究

微粒淀粉适用于脂肪替代,而天然的微粒淀粉价格高、且难以分离。研究了以精制玉米淀粉为原料,在不同条件下对其进行酸处理,结合球磨,获得粒径与天然微粒淀粉相近的微粒玉米淀粉糊精。将各微粒玉米淀粉糊精应用于低脂贡丸的脂肪替代,通过对低脂贡丸的质构分析及感官评定,结果表明:以722(70%EtOH-2%HCl-2h)糊精制备的低脂贡丸具有与高脂参照样相似的可接受性,糊精的水分散液可替代贡丸中一半以上的脂肪。     

脂肪颗粒大小及添加量对中式香肠品质的影响

采用析因设计研究脂肪颗粒大小(5、8、10 mm)与脂肪添加量(30%、20%和10%)对中式香肠品质的影响。结果表明:脂肪颗粒大小对香肠成品率、烘烤时间、口感、色泽、多汁性和组织状态有显著影响(P<0.05);脂肪添加量对成品率、烘烤时间、嫩度、硬度、咀嚼度、亮度值(L~*)和口感、香味、色泽、多汁性及组织状态有显著影响(P<0.05);脂肪颗粒大小和脂肪添加量对香肠香味、色泽及整体接受度有显著交互作用(P<0.05)。通过对4组香肠的质构特性及感官品质进行评价,发现4组香肠的咀嚼度、风味、多汁性和整体接受度无显著差异(P>0.05),但在减少香肠配方中脂肪添加量时,减小脂肪颗粒有利于改善香肠的硬度和组织状态,且当香肠中的脂肪颗粒大小为5 mm、脂肪添加量为20%时,其总体品质最好。