不同制取工艺下油茶籽与油茶籽油中重金属迁移转化关系的研究

【目的】在浙江省油茶主产区抽样的185批油茶籽中随机抽取12个样品,分别对油茶籽果肉、外壳及通过压榨(热榨、冷榨)和浸提两种方式获得的油茶籽油、残渣物等进行测量并分析了六种重金属元素(Pb、Cd、Cr、As、Hg、Se)的含量及其相关性研究,了解不同制取工艺下油茶籽与油茶籽油中重金属迁移转化关系,以期为油茶籽油的安全生产等提供更多科学依据以及在制取工艺改进上提供一些参考。【方法】通过数据分析和相关性分析结合进行相关性研究。【结果】通过研究发现,浸提油和浸提残渣中Pb含量有超过国家标准GB 2716-2005《食用植物油卫生标准》0.1mg/kg的限量,此外浸提法中各重金属含量高于压榨法,且浸提油中各重金属元素之间都有强相关性,说明浸提方法容易受到浸提剂等本身有微量重金属物质的影响,引起复合污染,后续精炼需要加以控制;Cr的含量在油茶籽肉、油茶籽壳和浸提油中,大于As含量,在浸提残渣、热榨油、热榨残渣、冷榨油以及冷榨残渣中均大于Pb、As含量,应该引起注意。但是在GB 2762-2017《食品安全国家标准食品中污染物限量》中,规定了在豆类及其制品中最低1mg/kg,因此油茶籽油中的Cr含量其安全风险不高,但仍建议可进行长期监测以避免污染危险;Se作为人体必不可少的营养元素,在油茶籽及油茶籽油中均有检出,值得进一步研究利用发掘其经济价值;Hg在热榨中含量无论是油还是残渣均高于冷榨,可能是受温度的影响较大;油茶籽肉和油茶籽壳中Pb、Cd、Cr之间均存在强相关性,说明其同源性较高或受到了复合污染,可能受土壤及周边生活垃圾污染影响较大。【结论】浸提法较压榨法更容易受到浸提剂等本身含有微量重金属物质的影响,特别是对Pb的影响极大,应引起一定重视,加强后续精炼管理;Hg元素容易受到温度的影响在热榨法中含量高于冷榨法。因此在生产环节有效地选择更加适合的制取工艺,可以减少重金属的污染,为茶油品质的提升提供思路与创新。     

Heavy metal contaminants and processing effects on the composition,storage stability and fatty acid profiles of five common commercially available fish species in Oron Local Government,Nigeria

Five commercially available common fish species: catfish (Chsysichthyes nigrodigitatus), tilapia (Oreochromis nilotichus), ilisha (Ilisha africana), bonga (Ethmalosa fimbriata) and mudskipper (Periophthalmus koelreuteri) in Oron Local Government Area were evaluated for their content of heavy metals and the effects of salting on nutrient contents, oxidative stability and fatty acid profiles of smoke-dried fish cakes. Concentrations of heavy metals in edible muscle, liver and gill tissues were determined while the oxidative rancidities in unsalted and salted smoke-dried fish cakes, packed in low-density polyethylene (LDPE) bags and stored at 30 ± 1 °C were assessed using peroxide value (POV), thiobarbituric acid (TBA) value, free fatty acid (FFA) contents and sensory evaluation techniques. Generally the analytical data for Cu, Zn and Pb in the muscle, gills and liver of test samples were significantly low. Similarly, insignificant concentrations (<0.001 mg/100 g) of Hg, As, Cr and Cd were obtained in the fish tissues. The protein and lipid contents of the fish cakes ranged from 60.8–63.9% to 7.3–9.1%, respectively. Salting caused minimal reductions in the nutrient contents of the dried fish cakes. The POV, TBA, FFA and taste panel scores were highest during the first week of storage and declined thereafter. Salted smoke-dried samples had higher POV, TBA and FFA values than unsalted samples. Panel preference ratings for flavour/aroma and desirability characteristics of the fish cakes were in the order: C. nigrodigitatus > O. nilotichus > E. fimbriata > I. africana > P. keolreuteri. Palmitic acid (C16:0) was the predominant saturated fatty acid in the test samples. The eicosapentaenoic acid (EPA) contents of unsalted smoke-dried C. nigrodigitatus was 4.9%, Oreochromis niloticus 6.5%, Ilisha africana 2.6%, E. fimbriata 5.6% and P. koelreuteri 7.64%. The docosahexaenoic acid (DHA) contents of salted smoked dried fish were 1.8% (C. nigrodigitatus), 4.8% (O. niloticus), 9.5% (I. africana), 5.5% (E. fimbriata) and 12.3% (P. koelreuteri).     

溶剂对刺梨籽油脂肪酸组成及抗氧化活性的影响

以刺梨籽为原料,采用超声辅助溶剂浸提法制备刺梨籽油,探究不同提取溶剂对其理化指标、内源抗氧化物含量、脂肪酸组成成分及抗氧化活性的影响。结果表明：用极性溶剂制备的刺梨籽油品质虽不及非极性溶剂制备的,但内源抗氧化物(总酚、总黄酮)含量远高于用非极性溶剂制备的刺梨籽油。溶剂种类对脂肪酸的组成和相对含量影响较小,刺梨籽油中不饱和脂肪酸质量分数高达90.94%,主要以亚油酸(46.08%～46.78%)和亚麻酸(43.46%～44.86%)为主。不同提取溶剂制备的刺梨籽油均具有良好的抗氧化活性,且极性溶剂制备的刺梨籽油对DPPH·、ABTS⁺·、·OH清除率及还原能力均高于非极性溶剂。因此,极性溶剂制备的刺梨籽油具有更高的营养保健价值,可作为功能性油脂进行开发利用。     

薏苡仁油脂的化学成分分析

利用薄层层析、毛细管气相色谱、气相色谱一质谱技术,对薏苡仁油脂进行了定定量分析,结果表明：薏苡仁油中甘油三酯达87％以上,其主要的脂肪为油酸亚油酸。     

响应面优化微波辅助提取哈密瓜籽油的工艺研究

采用响应面优化微波辅助提取哈密瓜籽油工艺,考察了单因素溶剂种类、液料比、提取时间、提取温度、微波功率对哈密瓜籽油提取率的影响。结果表明：液料比为10:1(mL/g)、提取温度为46℃、微波功率为520W,得出哈密瓜籽油的平均提取率为81.88%,与预测值较为接近。并且通过气象质谱法分析出哈密瓜籽油中含有13种脂肪酸,其中主要的是亚油酸、油酸、棕榈酸、硬脂酸等。另外,经过与四种常见植物油对比,可以总结出哈密瓜籽油作为食用油的潜力巨大,并且含有的脂肪酸丰富,营养价值较高。     

Phenolic profiles of cherry tomatoes as influenced by hydric stress and rootstock technique

The aim of the present work was to evaluate the influence of genetic and technological factors (cultivar and grafting) combined with the abiotic stress (water stress) on the content of phenolic compounds (flavonoids and phenolic acids classes and total phenolics) in cherry tomato. The identification and contents of phenolic compounds and flavonoids were determined by HPLC-MS in fruits on reciprocal grafting between a drought-tolerant cultivar (Zarina) and drought-sensible cultivar (Josefina), compared with both self-grafted and non-grafted plants. The results show how pre-harvest factors, such as grafting and water stress, can influence the phenolic content of tomato fruits. Phenolic compounds, including rutin that belongs to the group of flavonoids, display a remarkable array of biological and pharmacological activities. So, the richness of ZarxJos under water stress conditions with these compounds confirms its nutritional value and it can be used as a potential source of phenols. The results suggest that grafting on specific rootstocks more adapted to water stress conditions may be a tool to improve crop quality under artificially imposed mild water stress.     

八角金盘籽油和果油的超声波-微波协同提取及其脂肪酸组成比较

采用微波-超声协同提取法,通过正交优化制备八角金盘籽油和果油,并比较两种油脂的理化特性和脂肪酸组成。结果表明：提取时间90 s、微波功率250 W、液料比10 mL/g 时,籽油出油率为34.43%;提取时间150 s、微波功率250 W、液料比10 mL·g-1 时,果油出油率为11.32%。籽油出油率明显比果油高。两种油脂除碘值外,其他理化指标差异不明显,其理化指标均达到GB / T 2716-2018食用植物油国家标准。籽油的主要脂肪酸为十五碳一烯酸(3.08%)、亚油酸(7.04%)、油酸(87.42%),其中不饱和脂肪酸相对含量为98.64%;果油的主要脂肪酸为花生酸(0.96%)、亚麻酸(1.71%)、硬脂酸(3.25%)、棕榈酸(5.08%)、油酸(25.96%)、亚油酸(61.61%),不饱和脂肪酸含量为89.52%。本研究为八角金盘油脂的开发利用提供了科学依据和技术参考。     

Comparison of basic nutrients, mineral and heavy metal contents of herby dairy products

The aim of this study was to determine basic nutrients, some minerals and heavy metal contents of herby cheese, cacik and lor. Herby cheese is a cheese made from cow and/or sheep milk mixed with some herb. Herby cacik is a dairy product manufactured from light yoghurt (non-fat), ayran (liquid yoghurt) and/or a small amount of cheese whey. Herby lor cheese is a product traditionally made in Turkey, produced from cheese whey and occasionally some whole milk added. These dairy products are mixed with wild herb species (Allium sp., Chaerophyllum macropodum, Antriscus nemorosa, Ferula sp., Prangos sp., Silene vulgaris, Tymus sp. and Mentha sp.). In this study, herby cacik, cheese and lor samples were analysed for some physicochemical, mineral and heavy metal contents. The dry matter, protein, fat, salt and ash contents among herby dairy products were found significantly different (P < 0.05). There were significant differences in Ca, P, Na, Mg, Fe, Cu and Mn content of herby dairy products (P < 0.05). Zn, Co, Cr, Ni and Cd contents of analysed samples were not significantly different (P > 0.05).     

产地、物种及加工工艺对油茶籽油中的微量元素及重金属含量的影响

以贵州不同产地及物种的油茶籽为原料,分别采用烘制和炒制对其进行预处理后压榨制油,并对油茶饼进行二次压榨制油,对不同预处理及不同压榨阶段油茶籽油的微量元素及重金属含量进行分析。结果表明：不同产地和物种的油茶籽油的微量元素及重金属含量存在不同程度的差异,形成不同品质特征的油茶籽油;与烘制预处理相比,炒制可以显著提升油茶籽油中锰、铁、铜含量（P＜0.05）,但同时增加油茶籽油中的重金属含量;不同压榨阶段油茶籽油的微量元素含量具有显著差异（P＜0.05）,二次压榨可使油茶籽油中的锰和铁含量显著增加（P＜0.05）,且蒸制处理可以提升二榨油茶籽油中的微量元素含量;相关性分析显示,不同微量元素及重金属含量之间具有不同程度的相关性,锰和锌、铅有极显著的负相关性,锌和铅有极显著的正相关性,镍和铬有极显著的正相关性。     

鱼油脂肪酸的自由基氧化变化研究

目的:研究鱼油脂肪酸混合体系中各脂肪酸在自由基作用下的氧化变化规律。方法:选择新鲜鱼油作为研究对象,在有、无光照条件下采用亚铁离子-抗坏血酸自由基发生体系,用GC-MS联用分析仪测定各脂肪酸在5h和5d内脂肪酸的变化。结果:在自由基作用下,多不饱和脂肪酸在反应开始后立即出现迅速下降的情况,经过10h后,其含量下降超过90%,其中DHA和EPA的下降尤为剧烈;单不饱和脂肪酸在自由基作用下其氧化速度和氧化程度相对多不饱和脂肪酸小,10h后其含量下降仅20%～30%。结论:鱼油自由基氧化体系中,脂肪酸氧化速度和程度与其不饱和程度成正相关;此反应体系中积累的环氧基饱和脂肪酸和烯醛类化合物主要是单不饱和脂肪酸的氧化反应的结果;无论是多不饱和脂肪酸还是单不饱和脂肪酸,光照对它们的氧化速度和氧化程度都有明显的促进作用。     

中国植物油料生产和贸易:现状、变化及前景

我国作为植物油料生产大国、消费大国及贸易大国,研究入世对我国油料生产和贸易影 响、进而判断未来变动趋势有着重要意义。该文首先对我国植物油料生产、贸易情况进行简单梳理; 在此基础上,重点分析入世后植物油料生产贸易变化及主要影响因素;最后对中国植物油料生产、 贸易未来发展趋势进行简单判断,并提出对策建议。     

不同产地牡丹籽油脂肪酸成分检测

不同产地牡丹籽以超声波辅助提取,氢氧化钠甲醇酯交换法甲酯化后.用气相色谱技术对牡丹籽油中不饱和脂肪酸组分进行定量分析,用气相色谱一质谱联用技术对不同产地牡丹籽油中脂肪酸成分进行定性验证     

石榴籽油脂肪酸成分的分析

石榴籽经石油醚提取、皂化和甲基化得到的总脂肪酸甲酯经GC分析,共检出9种成分。经GC-MS联机分析,确定脂肪酸成分为棕榈酸(2.47%)、亚油酸(4.85%)、油酸(4.07%)、硬脂酸(1.66%)、石榴酸(81.62%)、二十碳烯酸(0.53%)、花生酸(0.44%)及两个未鉴定的石榴酸三烯异构体(3.13%)。主要成分为共轭三烯不饱和脂肪酸石榴酸(9Z,11E,13Z-十八碳三烯酸),达81.62%。     

3种养殖淡水鱼重金属含量测定及健康风险评价

目的 了解福建省主要养殖淡水鱼中重金属含量水平及进行鱼类食用安全性评价,为福建省淡水鱼健康养殖和食用安全性提供参考依据。方法 选择草鱼、罗非鱼和鳗鱼为研究对象,测定和分析其重金属含量,运用单因子污染指数法、综合污染指数法和目标危险系数法进行污染评价。结果 3种养殖淡水鱼肌肉中重金属含量最高的是Cr。Cd与Pb和Hg呈极显著相关,与As呈极显著负相关;Cr与Hg呈显著负相关;Hg与As呈极显著负相关。5种重金属均未出现超标现象,草鱼受到As轻度污染、罗非鱼受到Pb和As轻度污染、鳗鱼受到Cd和Pb轻度污染,但3种淡水鱼未受到综合污染。结论 食用该批次生产的草鱼、罗非鱼和鳗鱼不存在潜在健康风险,今后应继续保持高压监管,并对出现的个别重金属的污染风险进行更精准的管控。     

超声波法提取猕猴桃籽油的工艺研究

对超声波技术提取猕猴桃籽油的工艺进行研究．探讨了不同提取剂，提取的剂用量、提取时间、次数及超声波功率对提取效果的影响。最后用正交法确定最佳工艺条件：在超声波功率250w的条件下，石油醚作为提取剂、物料比1：8、提取2次，每次20min.     

杨梅烧酒香气物质和重金属含量的分析

采用液-液萃取法萃取杨梅烧酒中的香气成分,用气相色谱-质谱联用(GC-MS)仪进行分析检测;采用原子吸收分光光度法,分析杨梅酒中的铁、锰、铜、锌、铅、镁重金属元素。结果表明,杨梅烧酒共检出22种香气成分,主要呈香化合物有酸类、酯类及醇类,主要香气成分为乙酸、己酸乙酯、己酸、苯乙醇、丁酸、丁酸乙酯;在杨梅烧酒中分别检测出6种重金属的含量为：Fe 0.93 mg/kg,Cu 0.07 mg/kg,Mn 1.24 mg/kg,Zn 0.41 mg/kg,Mg 21.96 mg/kg,Pb 0.15 mg/kg。而用于浸泡杨梅的酒中6种重金属含量为：Fe 0.12 mg/kg,Cu 0.02 mg/kg,Mn未检出,Zn 0.01 mg/kg,Mg 2.21 mg/kg,Pb 0.13 mg/kg。结果表明,重金属有从杨梅向酒中迁移的倾向。     

The effects of gender,age and region on macro- and micronutrient contents and fatty acid profiles in the muscles of roe deer and wild boar in Mecklenburg-Western Pomerania (Germany)

Samples of M. longissimus were collected from a total of 203 feral roe deer (n = 118) and wild boar (n = 85) in two regions of Mecklenburg-Western Pomerania (Germany). The muscle lipid saturated fatty acid proportions of roe deer and wild boar ranged between 33 and 49 g/100 g total fatty acids and 31 and 35 g/100 g total fatty acids, respectively. The total n − 3 PUFA proportions in roe deer muscle varied between 8.0 and 14 g/100 g fatty acids, and in wild boar muscle between 2.6 and 6.0 g/100 g fatty acids. The major vitamin E homologue, α-tocopherol, was determined to be between 5.8 and 13.1 mg/kg in roe deer muscles. Lower levels between 1.2 and 4.7 mg/kg were measured in wild boar muscles. The iron and zinc concentrations in roe deer and wild boar muscle ranged from 26.3 to 33.9 mg/kg and from 17.0 to 21.7 mg/kg, and from 13.6 to 39.3 mg/kg and 18.1 to 31.9 mg/kg, respectively.     

银纳米簇介导的荧光传感器在重金属离子检测中的应用

重金属离子作为一类环境污染物，常存在于空气、土壤和水体中，由于其易在生物体内富集、难以降解，严重威胁了人类健康，因而成为环境污染和食品安全等领域的重要检测指标。目前，用于检测重金属离子的方法主要有电感耦合等离子体质谱法、原子吸收光谱法等，然而这些方法需要复杂的仪器设备、较长的实验耗时，以及较高的操作要求，具有一定的局限性。因此，开发快速、灵敏、简便的重金属离子检测方法越来越受到研究人员的重视。银纳米簇（AgNCs）作为一种新型纳米材料，具有良好的荧光特性，其介导的荧光生物传感器可以应用于重金属离子的快速检测，并且具有高灵敏性和特异性。本文综述了以不同分子为模板合成的AgNCs，以及其介导的荧光生物传感器在单一和多种重金属离子检测方面的最新研究进展，阐述了AgNCs今后仍需深入研究的部分，并对其发展前景进行了展望。     

二氢杨梅素在猕猴桃籽油中的抗氧化性研究

以过氧化值(POV值)为指标,研究了二氢杨梅素对猕猴桃籽油的抗氧化性能。结果表明:二氢杨梅素对猕猴桃籽油具有较强的抗氧化作用,且具有剂量效应关系,即随着二氢杨梅素浓度的增大,抗氧化作用增强;抗坏血酸、柠檬酸、多聚磷酸钠、乙二胺四乙酸二钠对二氢杨梅素的抗氧化作用具有增效作用,乙二胺四乙酸二钠为最适增效剂;0.2μg/mL的二氢杨梅素对猕猴桃籽油的抗氧化作用强于同浓度的BHT和茶多酚。二氢杨梅素作为天然抗氧化剂可以有效地减缓猕猴桃籽油的氧化程度、推迟氧化诱导期,从而延长猕猴桃籽油的保质期。     

Mathematical relationships between the intake of n-6 and n-3 polyunsaturated fatty acids and their contents in adipose tissue of growing pigs

To establish the relationships between the fatty acid composition of adipose tissue in growing pigs and the intake of fatty acids, we performed a feeding trial and did a literature survey. Six groups of pigs were fed diets with variable combinations of corn, linseed and fish oil. After 38 days, biopsies of adipose tissue were analyzed for their contents of linoleic, -linolenic, eicosapentaenoic and docosahexaenoic acid. For the four fatty acids, intake data and adipose tissue levels were also collected from the literature. Linear correlations were computed for the intake of each polyunsaturated fatty acid and its level in adipose tissue, the data set consisting of either the original results only or combined with literature figures. The observed strong correlations between dietary and fat tissue polyunsaturated fatty acids indicate that the fatty acid composition of the diet may be used as an index of the fatty acid composition of the diet, and vice versa. The regression equations presented can be used to steer the fatty acid composition of adipose tissue of growing pigs by the fatty acid composition of their diet.