Thermal stability and long-chain fatty acid positional distribution on glycerol of argan oil

The primary aim of this study was to determine the oxidative stability of argan oils by using peroxides and conjugated diene hydroperoxides measurements as analytical indicators. Both food and cosmetic argan oils were investigated. Their oxidative stability was also determined by monitoring the relative changes of their fatty acid profiles by ¹H NMR. In addition, valuable information regarding minor components as well as the acyl positional distribution, were obtained for both grades by high field ¹H and ¹³C NMR, respectively. Given that the cosmetic and food grades have a similar profile and content of phenolic antioxidants, vitamers, and squalene, it appears that the ratio of fatty acid aliphatic to bisallylic CH₂ groups, much higher in argan oils than in other vegetable oils, is responsible for their higher thermal stability.     

松籽油脂肪酸组成及分布特征分析

通过气相色谱法分析了松仁油的总脂肪酸组成及其上位置分布特点。结果表明,松仁油主要含有亚油酸（46.29%）、油酸（26.68%）和松籽油酸（13.84%）。sn2位置上的亚油酸（66.84%）和油酸（28.33%）含量高于sn1,3上的含量,但是Δ5系列多不饱和脂肪酸（Δ5-PUFA）主要分布在sn1,3位置上。Δ5-PUFA的存在和它们选择性地分布在sn1,3位等特点是包括红松籽油在内主要松属植物果实油脂的特点。松籽油主要由12种甘油三酯组成,其中含量比较多的是LLPi（24.13%）,OLL/LOL（17.87%）和LOPi（14.32%）。我们还对植物甾醇和维生素进行分析,结果显示松籽油含有141.64mg/100g的总植物甾醇和23.63mg/100g的总生育酚。      

紫苏子油中游离脂肪酸的动态分析

采用毛细管气相色谱的方法,以十五碳烷酸为内标,对紫苏子油中的五种游离脂肪酸:棕榈酸(C16:0)、硬脂酸(C18:0)、油酸(C18:1)、亚油酸(C18:2)、亚麻酸(C18:3)进行分析,研究紫苏子油中五种游离脂肪酸在储藏期间的变化.此分析方法无需进行甲基化,直接分析游离脂肪酸的变化.研究中对每种脂肪酸都作了方法学研究,脂肪酸的线性范围在147～922 ppm之内,12值≤0.9997.精密度≤2.43%(n=5).最后用此法测定了不同储藏期间的样品,结果显示随储藏时间的延长,游离脂肪酸的总量增加,但各脂肪酸的变化情况不同.     

大头菜油中亚油酸和亚麻酸测定与研究

通过对5份大头菜油进行脂肪酸甲酯的制备,应用配备FID的Agilent 6890A型气相色谱仪,对大头菜油中的亚油酸和亚麻酸含量进行测定。将结果与其它6种日常饮食中常用的植物油进行分析比较。结果表明:大头菜油中亚油酸含量为17.84%¹8.69%,亚麻酸含量为16.15%18.69%,亚麻酸含量为16.15%¹6.81%,二者呈正相关。与其它植物油相比,大头菜油中的亚麻酸含量远远高于大豆油、菜籽油、芝麻油、玉米油、棕榈油和葵花籽油,亚油酸含量处于中等水平。通过测定与研究,对大头菜油有一定的了解,为其推广使用提供一定的参考依据。     

紫苏提取物对紫苏油抗氧化作用的研究

采用不同溶剂从紫苏叶及紫苏籽皮中提取抗氧化成分,比较它们在紫苏油中的抗氧化活性。实验结果表明,紫苏籽皮乙醇提取物显示出较高的抗氧化活性,其合适的添加量为0.09%,如果与柠檬酸或甘氨酸配制成复合抗氧化剂,能显著提高抗氧化活性。     

被孢霉中脂肪酶对γ-亚麻酸油脂的影响

被孢霉332中含有胞内脂肪酶,菌体在外部碳源饥饿的情况下其可被诱导产生,该类脂肪酶可在大于80℃的条件下迅速失活.菌体在常温干燥过程中油脂大量消耗,同时造成酸值和过氧化值增加,高温灭酶干燥可以有效避免对油脂的破坏,菌体油脂酸值和过氧化值均较低.     

Effects of monoacylglycerols on the oil oxidation of acidic water/perilla oil emulsion under light in the presence of chlorophyll

Monoacylglycerol (MAG) effects on the oil photooxidation of an emulsion containing chlorophyll were studied. The emulsion consisted of equal weights of hexaneextracted perilla oil and 0.5% acetic acid, and 4 ppm chlorophyll b and MAG at 0, 1, or 1.5% were added. The oxidation was performed under 1,700 lx light at 25°C for 48 h. Singlet oxygen was involved in the oil oxidation of the emulsion containing chlorophyll under light. MAG protected chlorophyll and polyphenol compounds from degradation during the oxidation of the emulsion under light. MAG significantly decreased and decelerated headspace oxygen consumption and hydroperoxide production in the emulsion, and thus acted as antioxidant in photooxidation of the acidic water/perilla oil emulsion containing chlorophyll. Antioxidant activity of MAG in the photooxidation of the emulsion could be due to combined results of increased retention of polyphenols and decreased oxygen diffusion by forming a physical barrier.     

硝酸银-硅胶柱层析法分离纯化核桃油中亚麻酸工艺研究

先采用尿素包合法对核桃油中脂肪酸进行初步分离,在此基础上利用硝酸银-硅胶柱层析法对核桃油中亚麻酸进一步纯化,20g硅胶中与2g Ag NO3配制成硝酸银硅胶柱中,加入与吸附剂比例为1∶15的经尿素包合后富集得到的脂肪酸,洗脱剂流速为0.6m L/min,丙酮-石油醚浓度为8%时,核桃油中亚麻酸由原来的8.7%洗脱后提高到95.9%,以上结果表明硝酸银-硅胶柱层析法是一种高效分离亚麻酸的方法。      

Utilization of interesterified oil blends in the production of frankfurters

Ten treatments of frankfurters were produced with interesterified oil and oil blends (palm oil, palm stearin, cottonseed oil, hazelnut oil and their mixtures) and were compared to control, produced with all animal fat. Addition of interesterified oil and oil blends affected (p < 0.05) the moisture and fat content and pH values of frankfurters. According to the colour measurements, the brightness value (L^∗) of most of the samples with interesterified oil and oil blends were higher (p < 0.05) than the control. The fatty acid composition of frankfurters was modified. The PUFA/SFA values of frankfurters were increased due to the presence of interesterified oil and oil blends in the formulation. Frankfurters with 100% interesterified cottonseed oil or with interesterified oil blends with 66.6% and 83.4% cottonseed oil had PUFA/SFA ratio higher than 0.4 and are considered better than all others from the health point of view. Frankfurters produced with 100% interesterified cottonseed and hazelnut oil or with interesterified hazelnut oil blends had the same (p > 0.05) scores for sensory attributes with the control, while all other treatments were also acceptable.     

Enrichment of gamma‐linolenic acid from fungal oil by lipases

Abstract

Two microbial lipases from Geotrichum spp and Rhizopus spp isolated previously in this laboratory and a commercial lipase from Candida cylindracea were evaluated as biocatalysts for the enrichment of gamma‐linolenic acid (GLA, 18:3 n‐6) from a fungal oil derived from Mucor spp. Lipase from Geotrichum spp, as compared to lipases from Candida cylindracea and Rhizopus spp was found to be most effective in the enrichment of GLA in unesterified fatty acids upon esterification of the fungal oil fatty acids with n‐butanol. The level of GLA in the unesterified fatty acid could be raised from 10.9 % in the starting material to about 30 % in the unesterified fatty acids after a reaction period of 4 h. Selective hydrolysis of the fungal oil using lipase from Rhizopus spp resulted in about 1.5‐fold enrichment of gamma‐linolenic acid in the unhydrolysed acylglycerols. The other Upases tested were ineffective in the enrichment of GLA by selective hydrolysis of the fungal oil triacylglycerols.     

核桃油中亚麻酸对小鼠血脂和肝功能的影响

以纯度为97.2%的冷榨核桃油亚麻酸为原料,研究其对小鼠血脂和肝功能的影响。将110只雄性昆明小鼠随机分为11组,分别灌胃核桃油、亚麻酸、花生油30 d,测定小鼠血脂和肝脏指标。结果表明:亚麻酸可降低高脂血症小鼠体重、血清总胆固醇(TC)、低密度脂蛋白胆固醇(LDL-C)、甘油三酯(TG)、肝脏质量和肝脏系数,可提高小鼠血液高密度脂蛋白胆固醇(HDL-C)水平。研究表明核桃油中亚麻酸防治小鼠高脂血症和动脉粥样硬化症作用显著,且优于核桃油和花生油。     

紫苏油对益生菌的增殖作用研究

通过体外厌氧培养的方法,研究了紫苏油对嗜酸乳杆菌、双歧杆菌两种益生菌的体外增殖作用。结果表明:紫苏油添加量为3%时,嗜酸乳杆菌的增殖数达到最大值,为1.292;当紫苏油添加量为1%时,双歧杆菌的增殖数达到最大值,为1.352。紫苏油具有一定的促进益生菌增殖作用。     

紫苏芳香油含量的研究

采用水蒸气蒸馏法研究了中国和日本各地的33份紫苏试材芳香油的含量。实验结果表明,在紫苏芳香油积累的高峰期,紫苏试材芳香油的差异性大,气味呈现多样性。结合芳香油含量和香气程度,目前栽培的大叶紫苏和大叶皱白苏品种较适合生产繁殖,亚热带气候较易培育紫苏优良品种。     

氧化分解过程中亚油酸组成成分及挥发性物质的变化

利用GC—MS技术研究避光条件下亚油酸在60℃下加速氧化分解过程中组成成分及挥发性物质的变化规律。研究表明:亚油酸经60h的氧化,初始氧化的非挥发性产物不断分解成挥发性的醛、酮、醇、呋喃等,其中己醛、(E)-2-庚烯醛、(E)-2-壬烯醛、(E)-3-壬烯-2-酮、2-戊基呋喃等在12h前变化明显,可作为亚油酸自动氧化初期氧化程度的评价指标;(E,E)-2,4-壬二烯醛、(E,E)-2,4-癸二烯醛、(E)-1-辛烯-3-醇等在24h后变化明显,可作为亚油酸自动氧化后期氧化程度的评价指标。该研究确定了各阶段亚油酸氧化分解产生的主要特征挥发性物质的种类及其相对含量,对其可能的产生原因进行了剖析,确定了各阶段亚油酸氧化分解程度评价指标,为不饱和脂肪酸特征挥发性物质产生的具体途径及其机理研究提供了理论依据。     

α-亚麻酸保健功效及苏子油研究进展

本文阐述了国内外α－亚麻酸的保健功效及苏子油研究的有关报道，并对我国今后苏子油产品的研究和开发提出了建议。     

吸附脱色条件对紫苏油POV影响的研究

紫苏油含有大量的不饱和脂肪酸,是迄今发现的α-亚麻酸含量最高的植物油,极具药用价值和保健功效,但也极易氧化变质.采用单因子试验和正交试验,研究了吸附脱色时吸附温度、吸附剂用量、吸附时间对紫苏油POV的影响.确定最佳吸附脱色条件为:100℃、20min、活性炭添加量为油重的2%,活性白土添加量为油重的5%.     

Determination of thermal oxidation and oxidation products of β-carotene in corn oil triacylglycerols

A reversed phase HPLC-DAD coupled to APCI-MS method is reported for the determination of the degradation of β-carotene and characterization of the oxidation products in corn oil. Corn oil containing β-carotene was oxidized in the Rancimat at 110 °C from 1 to 14 h. A significant degradation of β-carotene was observed in corn oil during accelerated thermal oxidation. A total of eight different oxidized products of β-carotene were identified, which includes 8′-apo-β-carotenal, 6′-apo-β-carotenal, 5,6-epoxy-8′-apo-β-carotenal, β-carotene-2,2′-dione, 13-Z-5,6,5′,6′-diepoxy-β-carotene, all-E-5,8-epoxy-β-carotene, all-E-5,6-epoxy-β-carotene, and 15-Z-5,6-epoxy-β-carotene. Corn oil triacylglycerols (TAGs) oxidation products were also identified using isocratic HPLC–ESI-MS. It was found that β-carotene promoted oxidation of TAGs especially at longer exposure times. For the first time two new classes of oxidized TAGs have been identified in corn oil, which were epidioxy bis-hydroperoxides and hydroxy bis-hydroperoxides. Other oxidation products of TAGs were mono-epoxides, mono-hydroperoxides, and epoxy hydroperoxides. It was found that complementing the HPLC-DAD method for β-carotene with ESI-MS method for TAGs oxidation provides a comprehensive set of analytical tools to characterize carotenoids and triacylglycerols oxidation and degradation in edible oils.     

紫苏油微胶囊的性质与体外模拟消化研究

为提高紫苏油在人体胃肠道内的有效消化吸收能力,以明胶和海藻酸钠为壁材,采用复凝聚法制备紫苏油微胶囊,并对微胶囊的理化特性、抗潮性、耐热性、模拟胃肠道条件下的消化吸收能力以及微胶囊化前后紫苏油的脂肪酸成分进行分析。结果表明：紫苏油微胶囊水分含量为3.91%,堆积密度为0.31 g/mL,休止角为44.47°,包埋率为87.747%。微胶囊产品应尽量置于阴凉干燥的环境中保存,在食品加工中,加工温度应控制200℃以下,且尽可能缩短加工时间。在模拟消化吸收过程中,胃液内累积释放率为 13.25%;肠液内累积释放率33.02%;释放机理符合Ritger-Peppas模型,释放机制为非Fick 扩散过程。微胶囊化前后紫苏油的脂肪酸含量基本无变化。     

超临界CO2从松子仁中萃取亚麻酸油的工艺研究

探讨超临界CO_2从松子仁中萃取亚麻酸油的萃取压力和温度、精馏柱温度以及萃取时间对亚麻酸油产率的影响,通过正交实验方案摸索出超临界CO_2从松子仁中萃取亚麻酸油的最佳条件。并与精榨方法提取的亚麻酸油比较,表明超临界流体萃取的亚麻酸油收率高,活性成分保存好。