不同饱和度的三酰甘油酯的共存对胆固醇氧化的影响

为了评价三酰甘油酯的不同饱和程度对胆固醇氧化的影响,将精制的沙丁鱼油三酰甘油酯(碘价IV=182.6)、部分氢化沙丁鱼油三酰甘油酯(IV=174.5)、全氢化沙丁鱼油三酰甘油酯(IV=92.0)分别与胆固醇混合,制成CST、CTPH和CTFH三组试样,在25℃避光处诱导其氧化。研究结果表明:试样的氧化稳定性随着上述各试样的不饱和程度的增加而降低。CST的过氧化物诱导期比CTPH的短,并且在较短的诱导期内CST中组成沙丁鱼油三酰甘油酯的高度不饱和脂肪酸(PUFA)比CTPH的明显减少。各试样中生成的主要胆固醇氧化物有7-β-羟基胆固醇、7-酮基胆固醇、β-环氧化胆固醇和胆甾烷三醇。胆固醇氧化物的生成量随着过氧化物价(POV)的变化和PUFA的减少而增加。胆固醇的氧化与共存的鱼油三酰甘油酯的自动氧化有关。尽管在胆固醇氧化物生成阶段,降低鱼油三酰甘油酯的不饱和度可有效地延缓胆固醇的氧化,但是在诱导期以后胆固醇的氧化速率与CST和CTPH中PUFA的比例无关。     

Physicochemical and Microbiological Changes Associated with Bakasang Processing—A Traditional Indonesian Fermented Fish Sauce

The production of ‘Bakasang’, an Indonesian fermented fish sauce, was replicated in the laboratory in order to study the physicochemical and microbiological changes associated with the process. Bakasang samples were produced by incubating mixtures of small sardine ( Engraulis japonicus ) at different concentrations of sodium chloride and glucose at 37°C for 40 days. Changes in pH, total soluble nitrogen, total free amino nitrogen, amino acid composition and total plate counts were observed. The isolation and identification of microflora were also performed. In general, the pH decreased throughout the incubation period, irrespective of NaCl and glucose concentrations. Increases in the amounts of total soluble nitrogen and total free amino nitrogen were noticed during the 40 days of fermentation. The amino acids, glutamic acid, alanine, isoleucine, and lysine were prominent at the end of the process. The total plate count increased during the first 10 days and then decreased gradually for both total microbial population and lactic acid bacteria population. Micrococcus , Streptococcus and Pediococcus spp were predominantly present during Bakasang fermentation.     

ɛ-(γ-Glutamyl)lysine Crosslink Formation in Sardine Myofibril Sol during Setting at 25°C

The quantitative change of ?-(y-glutamyl)lysine (EGL) crosslink and relationship between crosslink content and gel-strength were examined on salt-ground myofibril sol from sardine (Sardinops melanostictus) during incubation at 25°C. In the presence of EGTA, no EGL crosslinks were detected in myofibril sol and gelation did not occur. The EGL crosslink content and breaking strength of gels increased in proportion to incubation time. High correlation was observed between the logarithm of breaking strength and logarithm of EGL crosslink content (r=0.987). The EGL crosslinks formed by transglutaminase are important in the setting of sardine meat sol at < 30°C.     

Acceptability of diets containing olive oil fried sardines (Sardina pilchardus) in the prevention of dietary hypercholesterolaemia in rats

Garlic (Allium sativum L) bulb explants produced undifferentiated white globular callus when grown on MS medium having 2,4-dichlorophenoxy-acetic acid (2,4-D) and Kinetin (Kn). Such callus when grown on medium having indole-3-yl-acetic acid (IAA) and/or Kn developed into the differentiating callus which had comparatively more allicin than that of undifferentiated callus. The effect of sucrose, NH/NO ratios and hormone concentrations on growth and allicin development in the callus was investigated. There was a significant increase in allicin development in callus when grown for up to 4 weeks on medium (a) having sucrose at 3% and 5% levels; (b) having NH and NO ratios at 2:1 and 1;1; and (c) with Kn alone at a concentration of 0.5 mg litre^?1, which produced a tenfold increase in allicin content.     

黄酒对高血脂大鼠血清总胆固醇含量的影响

通过动物实验,对黄酒的降血清胆固醇功能进行了初步研究。给雄性SD成年大鼠喂高胆固醇饲料,造成高血脂动物模型,再给模型鼠按不同剂量灌喂浓缩的黄酒。结果显示,黄酒浓缩物具有降血清胆固醇的作用。     

磷脂保健饮料的研制及功效研究

以大豆磷脂、维生素Ｃ、维生素Ｅ、不饱和脂肪酸、乳酸锌为主要成份,经过高压均质控制ｐＨ（大于６）,低温（７０￣９０℃）长时（９０￣１２０ｍｉｎ）灭菌等主要工艺及添加稳定剂的方法,成功的制得了稳定性良好的磷脂保健饮料。经ＷＩＳＴＡＲ大鼠和人体临床试验证明,它对降低血液中的胆固醇和甘油三酯有明显效果。     

精制鱼油胆固醇测定在国标GB 5009.128-2016的应用与优化

目的依据GB 5009.128-2016 《食品安全国家标准食品中胆固醇的测定》,建立适用于精制鱼油胆固醇测定的分析方法。方法以国标所述为依据,对样品皂化加热方式及冷却放置时间进行了优化,对比了不同测定方法的专属性,最终利用气相色谱法进行测定。结果该方法专属性好,胆固醇含量在2.4993～199.9404μg/mL范围内线性关系好,线性方程为Y=0.2649X-0.2498,r~2为1.0000,定量限达到0.8 ppm,含量精密度的相对标准偏差为2.7%(n=12),回收率在101.5%～106.5%之间。结论该方法快捷、高效、专属性强,适用于精制鱼油的胆固醇含量测定。     

脱乙酰魔芋葡甘聚糖性质及其脂类结合能力研究

采用红外及X-衍射等分析手段表征魔芋葡甘聚糖(KGM)与脱乙酰魔芋葡甘聚糖(Da-KGM)结构并比较其持水性和粘度,以纤维素为对照,采用体外模拟人体胃及肠道的pH环境,对比分析KGM及Da-KGM对脂肪及胆固醇的吸附能力。结果显示KGM脱乙酰基后1733 cm~(-1)处的乙酰基的特征吸收峰消失,结晶度增加,持水性下降83.7%,高粘度特性丧失;相比纤维素,KGM具有良好的脂肪及胆固醇吸附能力,其吸附总量随样品质量、吸附时间和胆固醇浓度的增加而增大,与天然KGM相比,Da-KGM的脂肪及胆固醇吸附能力降低,可能是因为KGM脱除乙酰基后KGM分子链间氢键作用加强致使与脂类结合位点减少,以及高粘度特性消失致使对脂类的直接包裹能力下降,提示KGM经脱乙酰加工成魔芋食品后在肠道与脂类的结合能力下降,其减肥降脂的生理功效可能受到影响。     

Characteristics of low‐fat beefburgers as influenced by various types of wheat fibres

Hydrated wheat fibres (bran and white and red beeswings) were added at three levels (50, 100 and 150 g kg⁻¹ ) to beefburger as replacement for fat and evaluated for chemical and physical properties, energy content and sensory traits. Uncooked and cooked beefburgers formulated with wheat fibres had higher (P⩽0.05) moisture, protein and carbohydrate contents and lower (P⩽0.05) fat contents than that of the control. However, ash content was increased (P>0.05) by the addition of wheat fibres. The cholesterol content of uncooked and cooked beefburgers decreased as level of wheat fibres increased or fat content decreased. The addition of wheat fibres reduced the cholesterol content from 6 to 45% for uncooked and cooked beefburgers. The energy content of uncooked and cooked beefburgers was lower (P ⩽0.05) than that of control by between and 6 and 41%. The cooking yield and reduction in diameter of beefburgers were significantly (P⩽0.05) improved by the addition of wheat fibres. The addition of red and white beeswings showed an improvement in the texture trait. Colour traits, tenderness, juiciness, connective tissue amount, beef flavour intensity and overall palatability were not affected by the addition of wheat fibres to beefburgers. Hydrated wheat fibres can be used successfully as a fat substitute in ground meat products. © 1999 Society of Chemical Industry     

精制鱼油三甘油酯时与之共存下的胆固醇的氧化分解

使用鳕鱼肝脏抽出的 ,经精制的鱼油三甘油酯、胆固醇和三油酸甘油酯纯品 ,分别组成 4组试样 :胆固醇与精制鱼油三甘油酯 (CFT) ;胆固醇与三油酸甘油酯 (CT) ;三油酸甘油酯 (TO) ;胆固醇 (CHOL) ,放置在 2 5℃干燥空气中贮存 ,定期对各组的氧吸收量进行测定 ,并对其中三甘油酯和胆固醇的氧化分解产物进行定性、定量分析。经 10 4d的贮存 ,只有CFT组的氧吸收量增加 ,并生成游离脂肪酸和胆固醇氧化物。而且胆固醇氧化物的数量 ,随着高度不饱和脂肪酸 (PUFA)和油酸的减少而增加。研究结果表明 ,水产制品中胆固醇的氧化与共存的油脂中的PUFA的氧化分解有关。     

Adsorption and Desorption of Cholesterol in Continuous Supercritical Fluid Processing of Anhydrous Milk Fat

The adsorption breakthrough volume of adsorbent for cholesterol reduction of anhydrous milk fat (AMF) was determined by passing supercritical carbon dioxide (SC-CO₂) phase through an adsorption column with magnesium silicate at 40°C/241 bar. The breakthrough quantity for 76% cholesterol reduction was 2.0g fat/g adsorbent. With in-line adsorption on magnesium silicate, the cholesterol reduction in the extracts was 80 to 86%. Magnesium silicates saturated with cholesterol were regenerated with 10% ethanol in CO₂ at 40°C and 64°C/241 bar. The adsorption capacity of the magnesium silicate regenerated with 10% ethanol in SC-CO₂ at 40°C/241 bar was close to its original value. Its behavior was described by the Langmuir isotherm.     

Seasonal Changes in Lipid Composition of Sardine (Sardina pilchardus)

Sardine (Sardina pilchardus) lipids have important nutritional characteristics because of their high level of ω3 fatty acids. Studies of the lipid composition of this pelagic species, studies were carried out monthly during one year. Total lipids ranged between 1.2% and 18.4% (w/w). The nonpolar lipids were dominant, mainly composed of triacylglycerols and highest in the fatty season. Phosphatidylcholine (PC), and phosphatidylethanolamine (PE) were the principal polar lipids. They were both high in ω3 polyenoic fatty acids mainly 20:5ω3 and 22:6ω3. PC and PE were isolated and their fatty acid profiles determined; PE was higher in 22:6ω3 than PC.     

基于图像纹理分析技术检测食用植物油中动物油的掺伪

采用纹理频谱法、分形维数、改进的Hu不变矩和小波共生矩阵技术提取图像纹理特征,通过最小二乘法对图像纹理特征参数和混合油中胆固醇含量进行分析并建立多元线性回归方程。研究结果表明两者之间显著相关,相关系数R2大于0.95。图像纹理分析技术可以检测出掺入猪油含量为8.5%以上的大豆油,该方法计算的胆固醇含量与国标方法(GB/T 15206—1994)测定值之间的最大相对误差为5.75%。说明在误差允许范围内图像纹理分析技术可用于检测植物油掺伪。     

Identification of ABCA1 and ABCG1 in milk fat globules and mammary cells--implications for milk cholesterol secretion

The ATP-binding cassette (ABC) transporters ABCA1 and ABCG1 play an important role in cellular cholesterol homeostasis, but their function in mammary gland (MG) tissue remains elusive. A bovine MG model that allows repeated MG sampling in identical animals at different functional stages was used to test whether 1) ABCA1 and ABCG1 protein expression and subcellular localization in mammary epithelial cells (MEC) change during the pregnancy-lactation cycle, and 2) these 2 proteins were present in milk fat globules (MFG). Expression and localization in MEC were investigated in bovine MG tissues at the end of lactation, during the dry period (DP), and early lactation using immunohistochemical and immunofluorescence approaches. The presence of ABCA1 and ABCG1 in MFG isolated from fresh milk was determined by immunofluorescence. The ABCA1 protein expression in MEC, expressed as arbitrary units, was higher during the end of lactation (12.2 ± 0.24) and the DP (12.5 ± 0.22) as compared with during early lactation (10.2 ± 0.65). In contrast, no significant change in ABCG1 expression existed between the stages. Throughout the cycle, ABCA1 and ABCG1 were detected in the apical (41.9 ± 24.8 and 49.0 ± 4.96% of cows, respectively), basal (56.2 ± 28.1 and 54.6 ± 7.78% of cows, respectively), or entire cytoplasm (56.8 ± 13.4 and 61.6 ± 14.4% of cows, respectively) of MEC, or showed combined localization. Unlike ABCG1, ABCA1 was absent at the apical aspect of MEC during early lactation. Immunolabeling experiments revealed the presence of ABCA1 and ABCG1 in MFG membranes. Findings suggest a differential, functional stage-dependent role of ABCA1 and ABCG1 in cholesterol homeostasis of the MG epithelium. The presence of ABCA1 and ABCG1 in MFG membranes suggests that these proteins are involved in cholesterol exchange between MEC and alveolar milk.