浸出制油技术开发动向

目前,植物油脂大多采用己烷溶剂浸出法,或预榨-己烷溶剂浸出法制取;然而,从安全及环境方面而言,人们对替代己烷浸出法技术日益寄予更多期待。完全压榨法和超临界二氧化碳流体浸出法已在小规模生产中得以利用,异丙醇浸出、酶法浸出研究也在进展之中;但这些替代技术在大豆油、菜籽油等一般油脂大量生产中仍尚未实用化,为此,有必要进一步研究提高收率,降低生产成本。     

高效液相色谱法快速测定植物油中苯并(a)芘含量

采用乙腈饱和正己烷除去植物油中大部分油脂,并用正己烷饱和乙腈数次提取苯并芘,采用HPLC系统在流动相为乙腈∶水(90∶10)、荧光检测器:激发波长384 nm,发射波长406 nm下检测,用外标法峰面积定量。结果显示:苯并芘在4.0~80.0 ng/mL浓度范围内峰面积与浓度线性关系良好,加标回收率为92.7%~98.2%,方法定量限为2μg/kg。该法简便易行、准确可靠。     

THE QUALITY OF VEGETABLE OIL FROM THREE VARIETIES OF SUNFLOWER SEEDS (HELIANTHUS ANNUUS)

ABSTRACT

Vegetable oils become susceptible to oxidation during their processing. The appropriate extraction and refining conditions of oil from two experimental cultivars (Madero‐91 and Cianoc‐2) of sunflower seeds and a commercial one (Victoria) as a control, were studied. Isopropyl alcohol was used in the extraction and refining, and compared with hexane. The refining was performed by the miscella method at 40, 50, 60 and 70%. Free fatty acids (FFA) and malonaldehyde analysis of crude oils afforded no significant differences among solvents and sunflower varieties. In refined oils, differences found with the miscella concentration, the malonaldehyde content and FFA content were not significant. Cianoc‐2 was the best source for oil production because of its lower values in FFA and malonaldehyde content.

PRACTICAL APPLICATIONS

The use of hexano in refining vegetable oil in Mexico is common, lack of knowledge about the use of new solvents and their impact on the processing conditions with sunflower seed cultivars is lack. The present work describes at lab scale, the work conditions, advantages and posibilities and limitations of the use on isopropyl alcohol in comparison with hexane and the use of three Mexican cultivar with this approach, with emphasize in oxidation conditions of refined vegetable oil.

     

DEVELOPMENT OF A PROCESS FOR PREPARING A FISH PROTEIN CONCENTRATE WITH REHYDRATION AND EMULSIFYING CAPACITIES

A hot-solvent extraction process for preparing fish protein concentrate (FPC) with rehydration and emulsifying capacities is described. The process employed extraction at pH 2.5 in order to prevent protein-protein interaction. Equal volumes of ethanol and hexane at reflux temperatures were employed as the extracting medium. Gel formation was controlled by the addition of NaCl. The FPC produced by this method had an amino acid spectrum similar to that of the fish, formed gels when added to water and emulsions when the rehydrated material was blended with vegetable oils. Both emulsification and rehydration capacities of the FPC were pH dependent with minimum uptake of water and oil in the range of pH 5–8.     

ISOPROPYL ALCOHOL EXTRACTION OF COTTONSEED COLLETS: CRUDE OIL COMPOSITION

Isopropyl alcohol (IPA) is an attractive alternative solvent to hexane for use in vegetable oil extraction. The relative efficiencies of IPA and hexane extractions using both cottonseed collets and flakes were evaluated in terms of product composition. The aqueous IPA extracted crude cottonseed oils from expander pretreated collets were analyzed for their nonacylglycerol compositions. The IPA extraction (88, 93, 95 and 97% IPA) resulted in more free fatty acids in the crude oils than did hexane extraction, and the level of the free fatty acids increased as the IPA concentration increased. The phosphorus content was higher in the IPA-extracted oils compared to those of their hexane-extracted counterparts. The HPLC analysis showed that the IPA extractions increased concentrations of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylinositol (PI) in the crude cottonseed oils. More sugar and less gossypol were found in IPA-extracted oils and the level of sugar decreased as the IPA concentration increased. The oil extracted with 95% IPA from the expander-produced collets were lower in free fatty acid, sugar, and gossypol than those obtained from the flakes. The amount of phosphorus in the oil extracted from the collets was approximately 45% higher than that from the flakes. The IPA extraction, in combination with expander pretreatment, produced cottonseed meals with free gossypol of 366 ppm, making them suitable for feeding nonruminant animals.     

八角仔壳挥发油的微波提取及油脂的食用性分析

采用正交试验设计优选正己烷微波法提取八角挥发油的最佳工艺条件为固液比1:15(g/ml)、微波时间5min、微波功率640W,与常规的索氏提取法相比,该法具有快速、节能的特点。对八角油进行脂肪酸成分分析,结果表明,八角籽油和其他食用植物油的脂肪酸组成类似,按照油脂生产许可证发证检验的项目进行检测,发现稍加精炼的八角籽油可放心食用;八角壳油脂中的脂肪酸含量较低,与其他食用植物油差别大,做香料、调味料仍然是首选,而不适合做普通的食用植物油。     

固相萃取柱净化-气相色谱法定量测定食用植物油中饱和烃类矿物油

目的以自制硫酸硅胶和10%硝酸银硅胶填料分层装填的复合固相萃取柱为净化手段,建立一种测定食用植物油中饱和烃类矿物油的分析方法。方法样品经正己烷提取,固相萃取柱净化,氮吹浓缩,然后经DB-1石英毛细管色谱柱分离,采用气相色谱-火焰离子化检测器检测,外标法定量。结果考察了填料类型、填料用量、洗脱体积等因素对提取效率的影响。在优化的条件下,饱和烃类矿物油检测的线性范围为5.0~500.0mg/L,相关系数r~2=0.9991,方法检出限为3.0 mg/kg,定量限为10.0 mg/kg。样品在10.0、20.0、50.0 mg/kg 3个水平下的加标回收率为93.2%~103.7%,相对标准偏差为3.97%~5.33%(n=6)。结论该法操作简单、快速、准确度高,检出限能满足对食用植物油中饱和烃类矿物油残留的检测要求,且使用常规分析仪器、分析成本低,值得推广应用。     

醇法大豆浓缩蛋白加工工艺及实践

简述了以色列Hayes工程公司开发的醇法制取功能性大豆浓缩蛋白工艺及操作要点。以含水酒精为溶剂,采用同油脂浸出十分相似的工艺,脱除低温脱脂大豆粕(白豆片)中的可溶性碳水化合物,得到蛋白干基含量在65%以上的大豆浓缩蛋白商业化产品;而后在碱性条件下采用同提取分离蛋白相似的办法,对大豆浓缩蛋白进行高压均质、热处理及喷雾干燥,得到功能性大豆浓缩蛋白产品。另外,介绍了相关产品的质量标准和功能性检测方法,以及近几年来的工艺改进情况。     

柠檬精油提取工艺的优化及其GC-MS分析

采用溶剂浸提法通过正交试验对柠檬精油的提取工艺进行优化,并用气相色谱-质谱(GC-MS)分析检测柠檬精油成分。结果表明,适合的提取溶剂为正己烷;影响柠檬精油提取率的主要因素顺序为料液比>浸泡时间>浸泡温度;适合的工艺条件为料液比1∶14(m∶V)、温度50℃、提取时间1h,该工艺条件下提取率为2.11%。柠檬精油中共鉴定出52种化学成分,分别含有烯、醇、醛、酯类等化合物,其中柠檬烯占主导地位,其相对质量分数为29.63%。     

植物油角鲨烯含量及其影响因素

植物油是一类经植物原料提取的富含多种微量营养成分的油脂。角鲨烯是植物油中营养伴随物之一,对人体生理健康?和疾病预防有着积极作用。通常,不同种类植物油中角鲨烯含量差距明显,甚至同种植物油中角鲨烯含量因地域、提取部位、加工工艺等因素而存在显著差异。因此,了解植物油角鲨烯含量并探究影响其角鲨烯含量的因素,可有效保存其角鲨烯成分,提升植物油营养品质和健康价值。本文介绍了多种植物油角鲨烯含量,并分析比较了植物油种类,原料品种、成熟度、产地、提取部位及油脂提取工艺、精炼工艺、储藏条件对其角鲨烯含量的影响,以期为优化植物油选择及改进加工工艺提供参考,并且为进一步提升植物油营养品质和健康价值提供理论基础。     

Effect of fruit ripeness and method of fruit drying on the extractability of avocado oil with hexane and supercritical carbon dioxide

BACKGROUND: Oil yield from avocado fruit may be influenced by fruit pre‐treatment and extraction method. Unripe and ripe avocado fruit pieces were deep‐frozen at ? 20 °C and either freeze‐dried or oven‐dried (80 °C). Oil yield from these samples was determined after extraction with hexane and supercritical carbon dioxide (SC‐CO₂). The fruit samples were examined using scanning electron microscopy before and after oil extraction. RESULTS: Average oil yield from ripe fruit (freeze‐dried and oven‐dried combined) was 72 g kg^?1 higher than from unripe fruit for SC‐CO₂ extracts and 61 g kg^?1 higher for hexane extracts. This may be due to enzymatic degradation of parenchyma cell walls during ripening, thus making the oil more available for extraction. Freeze‐dried samples had a mean oil yield 55 g kg^?1 greater than oven‐dried samples for SC‐CO₂ extracts and 31 g kg^?1 higher for hexane extracts. However, oil yields from ripe fruit (freeze‐dried and oven‐dried) subjected to hexane extraction were not significantly different. All hexane extracts combined had a mean oil yield 93 g kg^?1 higher than SC‐CO₂ extracts. CONCLUSION: SC‐CO₂ may be more selective and may create paths of least resistance through the plant material. Hexane, on the other hand, is less selective and permeates the whole plant material, leading to more complete extraction and higher oil yields under the experimental conditions. Copyright © 2007 Society of Chemical Industry     

Study of Optimal Extraction Conditions for Achieving High Yield and Antioxidant Activity of Tomato Seed Oil

Value of tomato seed has not been fully recognized. The objectives of this research were to establish suitable processing conditions for extracting oil from tomato seed by using solvent, determine the impact of processing conditions on yield and antioxidant activity of extracted oil, and elucidate kinetics of the oil extraction process. Four processing parameters, including time, temperature, solvent-to-solid ratio and particle size were studied. A second order model was established to describe the oil extraction process. Based on the results, increasing temperature, solvent-to-solid ratio, and extraction time increased oil yield. In contrast, larger particle size reduced the oil yield. The recommended oil extraction conditions were 8 min of extraction time at temperature of 25 °C, solvent-to-solids ratio of 5/1 (v/w) and particle size of 0.38 mm, which gave oil yield of 20.32% with recovery rate of 78.56%. The DPPH scavenging activity of extracted oil was not significantly affected by the extraction parameters. The inhibitory concentration (IC(50) ) of tomato seed oil was 8.67 mg/mL which was notably low compared to most vegetable oils. A 2nd order model successfully described the kinetics of tomato oil extraction process and parameters of extraction kinetics including initial extraction rate (h), equilibrium concentration of oil (C(s) ), and the extraction rate constant (k) could be precisely predicted with R(2) of at least 0.957. Practical Application: The study revealed that tomato seed which is typically treated as a low value byproduct of tomato processing has great potential in producing oil with high antioxidant capability. The impact of processing conditions including time, temperature, solvent-to-solid ratio and particle size on yield, and antioxidant activity of extracted tomato seed oil are reported. Optimal conditions and models which describe the extraction process are recommended. The information is vital for determining the extraction processing conditions for industrial production of high quality tomato seed oil.     

葡萄籽油的浸提和精炼工艺

对葡萄籽油浸提和精炼工艺进行了研究。结果表明 ,在文中的试验条件下 ,葡萄籽油浸提最佳工艺条件是 :正乙烷为浸提剂 ,葡萄籽粒度 60目、含水量 7%、料液比 1g∶6mL、温度 65℃、浸提时间 3h。葡萄籽油精炼工艺条件是 :碱炼初温 45℃ ,碱液浓度 1 8 5 %,超碱用量 0 4%;水化加水量 4%,水化时间分别为 1 0、0 5h ;二次脱色工艺为活性脱色白土加量第 1次 4%,脱色时间3 0min、脱色温度 90℃ ,第 2次加量 3 %,脱色时间 1 5min ,温度 85℃ ,真空度 0 1MPa;在真空度 0 0 8MPa、温度 1 80℃、脱臭时间 1 5h条件下可以脱除葡萄籽油中的臭味成分 ,保持葡萄籽的固有香味     

正戊烷浸出大豆油工艺研究

以大豆坯片为原料,采用罐组式浸出法,正戊烷作溶剂进行浸出研究。通过改变影响因素,选择最优工艺条件,结合实际要求得到正戊烷浸出工艺条件为:浸出温度26℃,浸出次数3次,豆坯水分含量6.63%,豆坯坯厚0.231mm,在此条件下,粕中残油率为1.03%;浸出所得大豆毛油色泽Y70、R2.0,酸价1.81mgKOH/g,不皂化物含量1.73%,磷脂1.31%,并与正己烷浸出进行比较;同时测定浸出大豆粕蛋白含量为57.7%,NSI值82.7%。     

Oilseed treatment by ultrasounds and microwaves to improve oil yield and quality: An overview

Efficiency is a key point to ensure the profitability in the production of vegetable oils from oilseeds. To maximize the recovery yields of seed oils, the traditional process involves mechanical expression followed by subsequent chemical extraction using organic solvents (e.g. hexane). Besides health, environmental, and economic related issues to the use of organic solvents, thermal treatment of seeds during conventional oil extraction process inevitably leads to chemical changes (e.g. changes in macronutrients such as protein denaturation/degradation in the meal, oil oxidation, and changes in minor constituents such as fatty acids, sterols, phenolic compounds and tocols). Thus, at this stage of development there is a need for new efficient processes that can improve oil yield and its quality from an economical and environmental point of view. Several research groups have investigated the potential of ultrasounds (US) and microwaves (MW) as additional seed treatments to enhance oil yields and to reduce temperature and extraction times with promising results. The present review is devoted to critically discuss the main findings reported in the literature regarding the feasibility of using US and MW as potential tools to improve oil recovery yields as well as its nutritional, sensorial and physicochemical properties.     

超声波提取葡萄籽油的工艺优化及其抗氧化性研究

通过单因素试验选择温度、提取时间、功率为影响超声波提取葡萄籽油效率的3个主要因素,运用响应曲面法进行超声波提取葡萄籽油的最佳工艺研究,分析各因素对提取效果的影响,并采用DPPH自由基实验以对其抗氧化性进行评价。结果表明：最佳工艺条件为温度54℃、提取时间37min、超声波功率456W,在此条件下进行验证实验,每5g葡萄籽的葡萄籽油提取量为0.63314g,提取率13.31%;葡萄籽油质量浓度为1～25mg/mL时,其质量浓度变化与自由基清除率呈正相关,在25mg/mL时,清除率达到80.7%,继续增大葡萄籽油质量浓度,对自由基清除率影响不大。     

Determination of high molecular mass polycyclic aromatic hydrocarbons in refined olive pomace and other vegetable oils

A new and simple method has been developed for determining high molecular mass polycyclic aromatic hydrocarbons (PAHs) in refined olive pomace, and other vegetable oils from an initial sample of 0.25 g. The hydrocarbon fraction is isolated by solid‐phase extraction (SPE) on silica gel using hexane as eluent. The fraction is evaporated to reduced volume and cleaned‐up by SPE on an amino phase eluting with toluene. The evaporated residue, dissolved in acetonitrile, is analyzed by reverse‐phase high‐performance liquid chromatography with fluorescence detector using programmed excitation and emission wavelengths. The benzo(e)pyrene is determined together with other usual heavy PAHs. Interferences due to squalene and other hydrocarbons are minimized. Recoveries were greater than 80% and detection limits ranged from 0.01 to 0.2 µg kg^?1. The method was validated using certified oil samples and was applied to various vegetable oils. Copyright © 2004 Society of Chemical Industry     

Retaining maximum antioxidative potency of wheat germ oil refined by molecular distillation

A process of physical refining wheat germ oil using the technique of molecular distillation (MD) is presented in this work. Wheat germ oil was obtained from the germ by solvent extraction using hexane and also by cold pressing. The oil extracted with hexane was degummed and bleached before deacidification in order to modify the parameters of phosphorus and color. The goal in carrying out the stage of physical refining by MD was to preserve the maximum amount of original antioxidative potential obtained from extraction of the crude oil. The effect of evaporation temperature of one‐stage MD on the efficiency of free fatty acid elimination was studied. The antioxidant portion was followed by means of analytic determination of tocopherols by high‐performance liquid chromatography. Tocopherol retention up to 98% was achieved in the oil extracted by pressing, and yields of up to 96% were achieved in the oil extracted with hexane. Copyright © 2007 Society of Chemical Industry     

翅碱蓬籽油脂提取工艺优化及理化性质测定

以沧州沿海地区盐地翅碱蓬籽为原料,以石油醚(60~90℃)为提取剂,以提油率为指标,采用浸出法提取翅碱蓬籽油。利用正交实验法和响应面法对颗粒度、液料比、提取时间进行优化,并对两种方法进行了双样本T检验,结果表明两种实验方法的最佳工艺条件下提油率差异不显著。正交实验优化的最佳工艺条件为:颗粒度100目、液料比20:1(mL:g)、提取时间150 min,此时提油率平均达到25.13%。响应面法优化后的最佳工艺参数为:颗粒度100目、液料比21:1(mL:g)、提取时间128 min,此时提油率平均可达到25.12%。对响应面最佳条件下得到的翅碱蓬籽油进行理化性质分析,检测结果为:皂化值199.09 mg KOH/g,碘值141.58 g I/100 g,酸值2.00 mg KOH/g,过氧化值2.53 mmol/kg,均符合食用油标准,具备开发为高级保健食用油的条件。研究结果为翅碱蓬的进一步开发利用提供了理论依据。     

Hetero-azeotropic distillation: combining fungal dehydration and lipid extraction

A low-cost single-stage laboratory process combining fungal dehydration and lipid extraction was compared with a traditional two-stage method employing freeze-drying and subsequent mechanical disruption in the presence of solvent. The ability of a number of organic solvents to form hetero-azeotropes with water was exploited. Chloroform, cyclohexane and hexane were assessed in their abilities to both dry and extract lipid from the oleaginous phycomycete Mortierella alpina (ATCC 32222). Drying rate and lipid extraction were maximised under conditions that prevented fungal agglomeration. The total processing time was limited by the rate of dehydration rather than by the rate of lipid extraction. In all cases azeotropic distillation facilitated a greater rate of dehydration than was possible with freeze-drying. A consequent reduction in overall processing time was observed. Uniquely, both the solvent used and the mode of mixing employed controlled the morphology of the aggregates formed during distillation. In combination with mild mixing chloroform discouraged agglomeration whereas cyclohexane and hexane promoted aggregation. Successful lipid extraction was dependent on the use of dry biomass rather than on the application of heat to effect distillation. Neither the application of heat nor the solvent employed had any significant effect on the lipid composition of the extracted oil.