Application of polyuronides for removing heavy metals from vegetable oils

Summary Laboratory experiments have been carried out for the removal of heavy metals from hydrogenated vegetable oils using hydrated polyuronides (degree of swelling from 4 to 12.8 ml/g) such as alginic acid, pectic and pectinic acids. The effect of the type of polyuronide, degree of esterification and oil treatment on the degree of demetalization has been studied. It has been shown that with increase in the degree of esterification of the polyuronide the efficiency of demetalization decreases. The second and third treatment of the hydrogenated oil with pectinic acid resulted in a high degree of heavy metal removal. The possibility of efficient demetalization of hydrogenated oils by treatment with water solutions of pectinic acids has also been demonstrated. The degree of metal ion removal increases with decreasing concentration of pectinic acids in the water solution.

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Einsatz von Polyuroniden zur Entfernung von SchwermtaUen aus pflanzlichen Ölen III. Einsatz von Alginsäure, Pecto- und Pectinsäuren zur Entmetallisierung von hydriertem Sonnenblumenöl

Zusammenfassung Es wurden Laboruntersuchungen zur Entfernung von Schwermetallen aus hydrierten pflanzlichen Ölen mit hydratisierten Polyuroniden (Quellungsgrad von 4 bis 12,8 ml/g) wie z. B. Alginsäure, Pecto- und Pectinsäuren durchgeführt. Es wurde der Einfluß des Polyuronids, des Veresterungsgrades und der Bearbeitungsart des Öles auf den Entmetallisierungsgrad verfolgt. Es wurde gezeigt, daß mit dem Veresterungsgrad des Polyuronids die Entmetallisierung herabgesetzt wird. Bei einer zwei- und dreifachen Bearbeitung des hydrierten Öles mit Pectinsäure wird die Entferung der Schwermetalle weitgehend erreicht. Es wurde auch die Möglichkeit für eine effektive Entmetallisierung von hydrierten Ölen durch Bearbeitung mit wäßrigen Lösungen von Pectinsäuren bewiesen. Der Grad der Entfernung der Metallionen erhöht sich mit einer Verringerung der Konzentration der Pectinsäuren im Wasser.

     

Application of pectic acid for removing heavy metals from vegetable oils

Summary Comparative studies on removing the metal complex from hydrogenated vegetable oils with the help of synthetic ion exchangers (Dowex 50 WX4, Wofatit KPS-200, KY-2, Amberlyst-15) and polyuronides, have shown pectic acid to be the most efficient in this respect. The removal of copper, iron, zinc and nickel from the oils ranged over 87 to 94%. The treatment has been carried out under static conditions. Pectic acid is known to be completely insoluble in vegetable oils and also completely harmless, which favours its application for this particular purpose. A practical method for removing metals on vegetable oils, applicable under production conditions, has been developed.

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Einsatz von Pectinsäure zur Entfernung von Schwermetallen aus pflanzlichen Ölen

Zusammenfassung Durch vergleichende Untersuchungen zur Entfernung des Metallkomplexes aus hydrogenierten pflanzlichen Ölen mit synthetischen Ionenaustauschern Dowex 50 WX4, Wolfatit KPS-200, KY-2, Amberlyst-15) und Polyuroniden wird festgestellt, daß die Pectinsäure die höchste Wirksamkeit aufweist. Es werden 87 bis 94% der Ionen von Kupfer, Eisen, Zink und Nickel entfernt. Die Behandlung erfolgt unter statischen Bedingungen. Wie bekannt, ist die Pectinsäure in pflanzlichen Ölen völlig unlösbar, so daß ihre Anwendung zum obengenannten Zweck stark begünstigt wird. Es wird ein leicht einsetzbares Entmetallisierungsverfahren entwikkelt, das unter Produktionsbedingungen durchführbar ist.

     

食用植物油中重金属分析方法的研究进展

对近十年来食用植物油重金属分析中样品预处理技术及仪器分析方法进行了综述。目前,植物油中所含重金属分析的预处理方法主要包括干法灰化、湿法消解、微波消解、液液微萃取等。其中湿法消解和微波消解是常用的预处理方法,液液微萃取法是近年来重金属萃取方面的一种预处理新方法。重金属仪器分析方法主要有原子吸收光谱法、原子荧光光谱法、电感耦合等离子体质谱法、共振光散射法、电化学分析法等,其中电感耦合等离子体质谱法具有多元素同时分析特点,是未来发展的趋势。     

植物油物理精炼中的脱胶工艺

脱胶是植物油物理精炼中一步非常重要的工序,脱胶效果的好坏直接影响到物理精炼的效率和产品的质量.为了建立一种高效稳定、经济环保的脱胶方法,各国学者不断推陈出新,发展了多种各有特色的脱胶工艺,尤其是引入磷脂酶发展起来的酶法脱胶,提供了国际领先水平的脱胶工艺.     

不同前处理方法测定植物油中重金属的研究

考察了湿法消解、干法灰化、微波消解3种不同前处理方法对植物油中重金属含量测定结果的影响。结果表明,硝酸-过氧化氢-高氯酸湿法消解为植物油前处理的最佳方法。采用石墨炉原子吸收光谱法测定植物油中的铅、镉、铬,线性范围内相关性良好,相关系数大于0.99,加标回收率分别为88.2%、94.5%、84.9%,RSD分别为8.5%、5.3%、9.1%,检出限分别为6.21、0.89、1.99μg/kg。该方法耗时短、操作简单,应用于植物油中重金属含量的测定,结果令人满意。     

植物油中生育酚与生育三烯酚测定方法比较

比较AOCS中两种测定生育酚与生育三烯酚的方法,即高效液相色谱紫外法和高效液相色谱荧光法。结果表明:高效液相色谱荧光法具有更好的回收率和准确性、更低的检出限和良好的抗杂质干扰能力,使用高效液相色谱荧光法测定12种植物油中生育酚与生育三烯酚的含量,其结果均在文献参考范围之内。     

高效液相色谱-荧光检测法快速测定植物油中的α-生育酚

建立了快速测定植物油中α-生育酚含量的高效液相色谱法。采用VP-ODS C18色谱柱,流动相为甲醇/水(体积比为98∶2),流速为1 mL/min,柱温为35℃,荧光检测激发波长为290nm,发射波长为340 nm。在上述实验条件下,α-生育酚的线性范围为0.1-25 mg/kg,检出限为2.7×10-2mg/kg,回收率为87.2%-97.3%,RSD为2.6%。该法测定样品,快速准确,重复性好。     

植物油中甾醇的高温稳定性研究

研究了6种植物油(玉米油、甾醇强化玉米油、大豆油、花生油、葵花籽油、橄榄油)中甾醇在高温条件下的热稳定性。使用气相色谱-质谱联用技术检测了植物油中3种主要甾醇(菜油甾醇、豆甾醇、β-谷甾醇)含量,并测定了油脂酸值随加热时间的变化。结果表明:总甾醇含量最高的是甾醇强化玉米油,达到7.82 mg/g,橄榄油中甾醇含量最低,为0.63 mg/g,β-谷甾醇在总甾醇中比例最高;高温加热(180℃)条件下,植物油中甾醇稳定性较强,但加热时间过长,仍会导致部分甾醇降解;加热过程中,植物油的酸值均呈上升趋势。因此,植物油中甾醇在高温条件下的降解应引起重视。     

食用植物油中生育酚和生育三烯酚检测方法的研究进展

维生素E是食用植物油中天然存在的抗氧化剂,主要包括α-、β-、γ-、δ-生育酚和相应的生育三烯酚等8种化合物。食用植物油中生育酚和生育三烯酚的组成及含量信息不仅可反映食用植物油的品质,还可用于鉴别其真伪。因此,建立食用植物油中生育酚和生育三烯酚的检测方法具有十分重要的意义。本文对食用植物油中生育酚和生育三烯酚检测方法的研究现状进行了综述,重点介绍了溶剂稀释、皂化和固相萃取等样品前处理技术,以及液相色谱、气相色谱和非水毛细管电泳等分析方法在食用植物油中维生素E测定中的应用。     

Storage stability of cooked sausages containing vegetable oils

Comminuted cooked sausages were produced using standard industrial practices, by substituting corn oil, sunflower oil, cotton seed oil, soybean oil and hydrogenated vegetable fat for animal fat. When processed, products were assessed for their stability with respect to autoxidation and change in organoleptic properties during vacuum-packed storage in a domestic refrigerator at 4 °C. Data obtained indicated that changes in thiobarbituric acid (TBA) values and organoleptic properties of products produced using corn oil, sunflower oil and hydrogenated vegetable fat were similar to those observed for reference material produced using lard. In the case of samples produced using soybean and cotton seed oil, TBA value changes were more pronounced, but did not exceed acceptable limits. A more rapid deterioration of organoleptic characteristics was also observed for the same samples, which showed flavour problems after 3 months of storage at 4 °C. Substitution of plant oils for lard considerably reduced the cholesterol content and increased the ratio of unsaturated to saturated fatty acids of cooked sausages.

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Lagerungsstabilität von Brühwürsten, die mit verschiedenen pflanzlichen Ölen hergestellt wurden

Zusammenfassung Es wurden feinzerkleinerte Brühwürste unter Praxisbedingungen gefertigt, die anstelle des tierischen Fettes (Schweinespeck), pflanzliche Öle, wie Sonnenblumenöl, Maiskornöl, Sojabohnenöl, Baumwollsamenöl und Kokosnußsfett enthielten. Die Untersuchungen der fertigen Produkte erstreckten sich vor allem auf sensorische Eigenschaften und autoxidative Stabilität während der Kühllagerung bei 4 °C unter Vakuum. Die Ergebnisse haben gezeigt, daß die Änderungen der TBA-Werte und der organoleptischen Eigenschaften der Chargen mit Maiskornöl, Sonnenblumenöl und Kokosnußfett fast ähnlich wie die der Kontrollcharge (Schweinespeck) waren. Bei der Verwendung von Sojabohnenöl und Baumwoll-samenöl waren die Änderungen der TBA-Werte dagegen intensiver, ohne jedoch die obersterlaubte Grenze zu überschreiten. Hier wurde ebenfalls, nach einer dreimonatigen Lagerung bei 4 °C, eine unerwünschte Änderung ihrer organoleptischen Eigenschaften, vor allem des Aromas, beobachtet.

     

Variation in some heavy metals during the production of white cheese

The lead, cadmium, arsenic and mercury contents in samples of milk, curd and white cheese taken from a production line were investigated. The lead, cadmium and arsenic levels were found to be 12.07±0.06 ng/ml , 1.82±0.01 ng/ml and 0.64±0.03 ng/ml in milk, 219.85±0.46 ng/g , 19.58±0.34 ng/g and 8.80±0.41 ng/g in cheese curd, 250.63±0.53 ng/g , 21.19±0.16 ng/g and 10.85±0.34 ng/g in fresh white cheese preripened in brine salted to 16%, and 260.25±0.51 ng/g , 22.87±0.17 ng/g and 11.35±0.29 ng/g in ripened white cheese, respectively. No detectable levels of mercury were found in any of the samples. Variation in the heavy metal contents of samples taken during the production stages was significant (p <.05). The heavy metal concentrations of the samples were compared with those obtained by other investigators in different countries.     

Interaction of packaging materials and vegetable oils: oil stability

The effects of different plastic films (polyethyleneterephthalate, polyvinylchloride, polypropylene and polystyrene) on the stability of olive, sunflower and palm oils were studied at 24 and 37°C during 60 days of storage. The changes in peroxide value (PV) and thiobarbituric acid value (TBA) were significantly higher (p≤0.05) in the plastic bottles than in glass. Our study indicates that the plastic permeability has played a major role in oil stability. However, both butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) were found to leach out from plastics films into vegetable oils during storage. The rate of oxidation was not reduced by antioxidant migration from plastic films to oils. Natural antioxidant (vitamin E) retarded the oxidation rate, and this was dependent on its concentration in oils examined. The results showed that the ranking of stability of oil samples is PVC≥PET>PP≥PS. Further, the stability was dependent on the type of oil. Palm oil exibited high stability properties while the highest oxidation rate was observed in sunflower oil. In addition, increasing storage temperature accelerated the oxidation and limited the stability of vegetable oils.     

Composition, stability and acceptability of different vegetable oils used for frying peanuts

The purpose of this work was to determine the chemical stability of vegetable oils in the frying process and the consumer acceptance of fried-salted peanuts prepared in different vegetable oils. Fatty acids composition was determined in sunflower, corn, soybean, peanut and olive oils. A chemical study (free fatty acid and p-anisidine values) of these oils at frying temperature (170 °C) was developed during 96 h. Consumer test of fresh products was performed on fried-salted peanuts prepared in the different oils. Peanut oil and virgin olive oil presented oleic acid as predominant fatty acid (44.8% and 64.2%, respectively), making it more resistant to lipid oxidation at frying temperature than the other refined vegetable oils (sunflower, corn and soybean oils). Virgin olive and peanut oils showed less increment of free fatty acids and p-anisidine value than the other oils along the heating essay. In addition, fried-salted peanuts prepared with refined peanut oil showed higher consumer acceptance than those prepared with other vegetable oils such as sunflower, corn, soybean and olive oils. Peanut oil could be used to fry peanuts obtaining products with higher consumer acceptance and shelf-life, thus preventing loss of their sensory and nutritional quality.     

膜分离技术在植物油脂精炼中应用进展

目前,植物油精炼一般采用传统化学精炼或物理精炼方法,二者都存在一定局限性;而膜分离技术是一种有效、低成本工艺技术,其在油脂加工业应用已日益受到人们重视。该文综述膜分离技术在植物油精炼中应用研究进展。     

Application of polyuronides for removing heavy metals from vegetable oils II. Application of chemically modified polyuronides for demetalization of hydrogenated sunflower oil

Summary The possibility of heavy metal removal from hydrogenated vegetable oils with the help of chemically modified pectins was studied. These included pectic acids of different origin, sunflower, apple and celery, crosslinked with epichlorohydrin, as well as amidated pectins with different degrees of amidation. The degree of oil demetalization obtained was high- from 78% to 94%. It was found that the removal of the heavy metals Cu, Fe, Zn and Ni depended on the type of chemical modification of the pectin. The best results were obtained with amidated pectic acid.

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Einsatz von Polyuroniden zur Entfernung von Schwermetallen aus pflanzlichen Ölen II. Einsatz von chemisch modifizierten Polyuroniden zur Entmetallisierung von hydriertem Sonnenblumenöl

Zusammenfassung Es wurde die Möglichkeit untersucht, Schwermetalle aus hydrierten pflanzlichen Ölen mit chemisch modifizierten Pectinen zu entfernen und zwar mit Epichlorhydrin vernetzten Pectinsäuren unterschiedlicher Herkunft (aus Sonnenblumenkernen, Äpfeln, Sellerie und amidierten Pectinen mit verschiedenem Amidierungsgrad). Es wurde eine hohe Entmetallisierung von 78 bis 94% erreicht. Dabei wurde festgestellt, daß die Entfernung der Schwermetalle Cu, Fe, Zn und Ni von der Art der chemischen Modifizierung des Pectins abhängig ist. Die besten Ergebnisse wurden mit amidierter Pectinsäure erzielt.

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First communication: Ivanov K, Popova M, Kratchanov C, Maneva D (1990) Z Lebensm Unters Forsch 191:210–213     

Enhancement of the oxidative stability of some vegetable oils by blending with Moringa oleifera oil

Blends (20%, 40%, 60%, 80% w/w) of Moringa oleifera oil (MOO) with sunflower oil (SFO) and soybean oil (SBO) were prepared to evaluate the changes in fatty acid (FA) composition, oxidative and thermal stability of SFO and SBO. The blending of MOO with SFO and SBO in proportions of 0–80% resulted in the reduction of linoleic acid (C_18:2) content of SFO and SBO from 67.0% to 17.2% and 56.2% to 14.6% and increase in the contents of oleic acid (C_18:1) from 26.2% to 68.3% and 21.4% to 65.9%, factors of 0.72, 0.72 and 1.27, 1.33, respectively. A storage ability test (180 days; ambient conditions) showed an appreciable improvement in the oxidative stability of substrate oils with increase of MOO concentration, as depicted by the least oxidative alterations in PV, IV and highest increase in induction period, IP, of the MOO:SBO (80: 20 w/w) blend. Each 20% addition of MOO resulted in decreases of PV and IV by factors of 0.84, 0.85 and 0.89, 0.88, respectively, and increases in IP by factors of 1.45 and 1.37 of SFO and SBO, respectively.     

Tocopherols and tocotrienols as free radical-scavengers in refined vegetable oils and their stability during deep-fat frying

The aim of this study was to assess the effect of total tocopherols and tocotrienols of refined vegetable oils on oil radical-scavenging activity and to investigate the stability of the various homologues during the deep-fat frying of French fries. Eight different refined vegetable oils were investigated, having variable levels of natural tocopherols and tocotrienols. A direct correlation between the radical-scavenging capacity of the oils, measured by the DPPH test, and the total content of natural tocopherols and tocotrienols was found. Frying experiments showed that the stability of the different tocopherols and tocotrienols present in the refined vegetable oils basically depend on two factors: the fatty acid composition of the oil, in particular polyunsaturated fatty acid content, and the kind of tocopherol and tocotrienol homologues present. The more oxidizable the oil, on the basis of fatty acid composition, the more stable were the tocopherolic antioxidants. Among the different homologues, γ-tocotrienol in palm super olein proved to be the least stable during the deep-fat frying, thus preserving the other homologues.     

植物油作为食用油和工业润滑油氧化稳定性评价的研究进展

植物油因较高的营养价值和良好的润滑性可作为食用油和工业润滑油。旨在为评价不同使用功能的植物油的氧化稳定性提供参考,从食用油和工业润滑油两方面综述了植物油氧化稳定性的检测方法,讨论比较检测方法的适用性、优缺点以及植物油在不同行业中氧化稳定性的评价指标和改善方式的差异。作为食用油,过氧化值、酸值和茴香胺值等理化指标以及氧化诱导时间是常用的评价指标;而对于工业润滑油,酸值、运动黏度和起始氧化温度是常用的评价指标。植物油的使用功能不同,其氧化稳定性研究的侧重点不同。针对指标要求的差异性选择合适的研究方法或者联合应用多个方法,对于最大程度发挥植物油的价值有重要意义。