Laboratory-Scale Optimization of Roasting Conditions Followed by Aqueous Extraction of Oil from Wild Almond

The effects of roasting and aqueous extraction conditions for oil recovery from wild almond were optimized using response surface methodology (RSM). Optimum conditions for oil extraction were obtained at 142 °C roasting temperature, 16.5 min roasting time, 5.67 extraction pH and 4.6 h extraction time. Under these conditions, the extraction yield of 34.5% (w/w, based on the original weight of the sample) was obtained, which is equivalent to 80.0% of the total oil in the kernel. This was lower than that obtained by hexane Soxhlet (HS) extraction (43.1%, w/w, considered as 100% of total oil) but higher than that of cold pressing (CP) (18.5%, w/w; i.e., 42.9% of total oil). The refractive indices and saponification values of the oils were not affected by the extraction method. However, fatty acid and tocopherol compositions and DPPH radical scavenging capacities as well as unsaponifiable matter, iodine, peroxide and acid values of the obtained oils were impacted by the extraction method. The results showed that the quality attributes (omega-6 fatty acid content, peroxide and acid values, total tocopherol contents and antioxidant activity) of the oil obtained by AEP were somewhat similar to those of the oil extracted by CP and much superior to those of the oil obtained by HS.     

Optimization of the Aqueous Enzymatic Extraction of Rapeseed Oil and Protein Hydrolysates

An aqueous enzymatic extraction method was developed to obtain free oil and protein hydrolysates from dehulled rapeseeds. The rapeseed slurry was treated by the chosen combination of pectinase, cellulase, and β-glucanase (4:1:1, v/v/v) at concentration of 2.5% (v/w) for 4 h. This was followed by sequential treatments consisting of alkaline extraction and an alkaline protease (Alcalase 2.4L) hydrolysis to both produce a protein hydrolysate product and demulsify the oil. Response surface methodology (RSM) was used to study and optimize the effects of the pH of the alkaline extraction (9.0, 10.0 and 11.0), the concentration of the Alcalase 2.4L (0.5, 1.0 and 1.5%, v/w), and the duration of the hydrolysis (60, 120, and 180 min). Increasing the concentration of Alcalase 2.4L and the duration of the hydrolysis time significantly increased the yields of free oil and protein hydrolysates and the degree of protein hydrolysis (DH), while the alkaline extraction pH had a significant effect only on the yield of the protein hydrolysates. Following an alkaline extraction at pH 10 for 30 min, we defined a practical optimum protocol consisting of a concentration of 1.25–1.5% Alcalase 2.4L and a hydrolysis time between 150 and 180 min. Under these conditions, the yields of free oil and protein hydrolysates were 73–76% and 80–83%, respectively. The hydrolysates consisted of approximately 96% of peptides with a MW less than 1500, of which about 81% had a MW less than 600 Da.     

Separating Oil from Aqueous Extraction Fractions of Soybean

Previous research has shown that enzyme-assisted aqueous extraction processing (EAEP) extracts 88–90% of the total soybean oil from extruded full-fat soy flakes into the aqueous media, which is distributed as cream (oil-in-water emulsion), skim, and free oil. In the present work, a simple separatory funnel procedure was effective in separating aqueous skim, cream and free oil fractions allowing mass balances and extraction and recovery efficiencies to be determined. The procedure was used to separate and compare liquid fractions extracted from full-fat soy flour and extruded full-fat soy flakes. EAEP extracted more oil from the extruded full-fat soy flakes, and yielded more free oil from the resulting cream compared to unextruded full-fat soy flour. Dry matter partitioning between fractions was similar for the two procedures. Mean oil droplet sizes in the cream and skim fractions were larger for EAEP of extruded flakes compared to non-enzymatic AEP of unextruded flour (45 vs. 20 μm for cream; 13 vs. 5 μm for skim) making the emulsions from EAEP of extruded flakes less stable. All major soy protein subunits were present in the cream fractions, as well as other fractions, from both processes. The cream could be broken using phospholipase treatments and 70–80% of total oil in the extruded full-fat flakes was recovered using EAEP and a phospholipase de-emulsification procedure.     

超临界二氧化碳萃取葡萄籽油的研究

葡萄籽油中富含亚油酸和其它不饱和脂肪酸,具有较高的食用和药用价值。传统的葡萄籽油提取方法存在着收率低和溶剂残留的问题。今基于对酿酒过程中废弃葡萄籽的开发利用,探讨了采用绿色洁净分离技术——超临界流体萃取技术从废弃葡萄籽中萃取葡萄籽油的可行性,重点考察了萃取温度、萃取压力、CO2用量及不同原料对葡萄籽油产率的影响。研究表明萃取压力对产率的影响较温度显著,实验确定适宜工艺条件为萃取温度55C,萃取压力30MPa。此条件下以张裕酒厂提供的籽为原料所得产率为9.71%,同时气相色谱分析表明,葡萄籽油产品中含有72.05%的亚油酸。另外,分别以三种不同来源的葡萄籽为原料进行实验,研究显示,葡萄籽油产率随原料不同而存在一定差异,产率较高者可达13.51%。     

Extraction of Essential Oils From the Seeds of Pomegranate Using Organic Solvents and Supercritical CO2

In this study, essential oils from pomegranate seeds of the Malas variety from Shahreza, Iran, were extracted using hexane and petroleum benzene applying four extraction methods: normal stirring, soxhlet, microwave irradiation, and ultrasonic irradiation. Also, supercritical fluid extraction (SFE) using CO₂ under different conditions was used for comparison. Different methods of extraction with organic solvents (normal stirring, soxhlet, microwave irradiation, and ultrasonic irradiation) showed significant differences in the extraction yields. However, no differences were found when a given method (e.g., microwave irradiation) was applied using different organic solvents. On the other hand, different extraction conditions from the various runs of SFE resulted in different extraction yields, all of which were lower than those of the other extraction methods using organic solvents. No significant differences were observed in the fatty acid compositions of the extracted oils using organic solvents. However, the fatty acid compositions of the oils extracted under different conditions of the SFE system indicated significant differences among several fatty acids including unsaturated fatty acids.     

Pilot Scale Study of Vegetable Oil Extraction by Surfactant-Assisted Aqueous Extraction Process

A number of aqueous extraction processes (AEP) have been studied as substitutes for hexane in oilseed extraction. In our previous batch-scale work, we have shown that the aqueous surfactant-based method could effectively extract up to 95% peanut and canola oils at 25°C. The goal of this work is to perform a semi-continuous pilot-scale study of the aqueous surfactant-based method for peanut and canola oil extraction. Two extraction strategies were evaluated including (1 N- Hexane Substance Technical Guidelines (accessed in May 2008). <http://ehs.ucsc.edu/lab_research_safety/pubs/facts/Hexane.pdf>  [Google Scholar]) a single extraction stage by aqueous surfactant solution and (2 Juliano , B.O. ( 1985 ) Rice: Chemistry and Technology, . , 2nd Edn ; The American Association of Cereal Chemists , Minnesota . pp. 647 – 687 . [Google Scholar]) two extraction stages, consisting of one aqueous surfactant wash and one de-ionized water wash. At optimum conditions, 90.6% and 88.1% oil extraction efficiencies of peanut and canola oil, respectively, were achieved in a single-stage extraction, while 94.5% and 92.6% were achieved in the two-stage extraction. At the highest solid/liquid centrifuge speed, the moisture level in the extracted meal was 48%. At the optimum liquid/liquid centrifuge condition, more than 90% of the oil was recovered as free oil from the extracted-oil and surfactant-wash mixture and 39–44% of the oil was recovered from the extracted oil and DI wash mixture. Total free oil recovered after the two-stage extraction was 87.1% and 85.6% for peanut and canola, respectively.     

Efficient and Response Surface Optimized Aqueous Enzymatic Extraction of Camellia oleifera (Tea Seed) Oil Facilitated by Concurrent Calcium Chloride Addition

This paper reports an efficient aqueous enzymatic extraction (AEE) method for Camellia oleifera seed oil with the aid of response surface analysis. A maximum oil recovery of ~93.5% was obtained when a 2‐step AEE process was performed using 0.80% cellulase (v/w) solution at pH 6.0 maintained at 50 °C for 1 h followed by a solution of 0.70% Alcalase® with pH 9.2 at 57 °C for 4.1 h. It was found that the addition of Ca²⁺ during the proteolysis stage improved the free oil yield from ~62.1 to ~86.6%. This was attributed to the removal of tea saponins, cross‐linkage of anionic polysaccharides, and destabilization of cream emulsion by Ca²⁺. This was verified by decreased tea saponin and polysaccharide levels in the cream emulsion and bulk solution as well as lowering of the emulsion fraction. It was determined that addition of CaCl₂ solution in continuous flow to the proteolysate is superior to one‐time or batch addition in inhibiting emulsion formation. The addition of CaCl₂ may provide a means of replacing the more laborious, time‐consuming demulsification process otherwise required.     

Extraction and Demulsification of Oil From Wheat Germ,Barley Germ,and Rice Bran Using an Aqueous Enzymatic Method

An aqueous enzymatic method was developed to extract oil from wheat germ. Wheat germ pretreatment, effect of various industrial enzymes, pH, wheat germ to water ratio, reaction time and effect of various methods of demulsification, were investigated. Pretreatment at 180 °C in a conventional oven for 4 min reduced the moisture 12.8–2.2 % and significantly increased the oil yield. Adding a combination of protease (Fermgen) and cellulase (Spezyme CP) resulted in a 72 % yield of emulsified oil from wheat germ (both commercial and laboratory milled wheat germ). Using the same oil extraction conditions optimized for wheat germ, yields of 51 and 39 % emulsified oil were obtained from barley germ (laboratory milled), and rice bran, respectively. Three physical demulsification methods (heating, freeze-thawing, and pH adjustment) and enzymatic methods (Protex 6L, Protex 7L, Alcalase, Fermgen, Lysomax and G-zyme 999) were compared. After demulsification with Protex 6L, free oil yields of 63.8 and 59.5 % were obtained with commercial wheat germ and with laboratory milled wheat germ, respectively. Using the same demulsification conditions optimized for wheat germ, yields of 45.7 % emulsified oil and 35 % free oil were obtained for barley germ and rice bran, respectively.     

微波法提取薏苡仁油的研究

以薏苡仁油的提取率为指标,考察了微波法提取薏苡仁油的主要影响因素微波辐射功率、微波辐射时间、料液比和药材粒度;采用气相色谱法考察微波对薏苡仁油成分的影响,并与加热回流法进行了比较.结果表明,微波法提取薏苡仁油的优化工艺条件为:采用无水乙醇作溶剂、药材粒度60目、微波辐射功率300 W、微波辐射时间7 min、料液比1∶5,在此条件下薏苡仁油的提取率为6.87%;气相色谱分析表明,微波法与加热回流法提取的薏苡仁油的主要化学成分基本相同,微波辐射对薏苡仁油成分无影响.     

Destabilization of the Emulsion Formed during Aqueous Extraction of Soybean Oil

Characterization and destabilization of the emulsion formed during aqueous extraction of oil from soybean flour were investigated. This emulsion was collected as a cream layer and was subjected to various single and combined treatments, including thermal treatments and enzymatic treatments, aimed at recovery of free oil. The soybean oil emulsion formed during the aqueous extraction processing of full fat flour contains high molecular weight glycinin and β-conglycinin proteins and smaller oleosin proteins, which form a multilayer interface. Heat treatment alone did not modify the free oil recovery but freeze–thaw treatment increased the oil yield from 3 to 22%. After enzymatic treatment of the emulsion, its mean droplet size changed from 5 to 14 μm and the oil recovery increased to 23%. This increase could be attributed to the removal (due to enzymatic hydrolysis) of large molecular weight polypeptides from the emulsion interface, resulting in partial emulsion destabilization. When enzymatic treatment was followed by a freeze–thaw step, the oil recovery increased to 46%. This result can be attributed to the thinner interfacial membrane after enzymatic hydrolysis, partial coalescence during freeze–thaw, and coalescence during centrifugation. Despite the reduction in emulsion stability achieved, additional demulsification approaches need to be pursued to obtain an acceptably high conversion to free oil.     

Downstream Processes for Aqueous Enzymatic Extraction of Rapeseed Oil and Protein Hydrolysates

Downstream processes following aqueous enzymatic extraction (AEE) of rapeseed oil and protein hydrolysates were developed to enhance the oil and protein yields as well as to purify the protein hydrolysates. The wet precipitate (meal residue) from the AEE was washed with twofold water at 60 °C, pH 11 for 1 h. Emulsions from the AEE and the washing step were pooled and submitted to a stepwise demulsification procedure consisting of storage-centrifugation and freezing–thawing followed by centrifugation. Aqueous phases were pooled and adsorbed onto macroporous adsorption resins (MAR) to remove salts and sugars. Following extensive rinsing with deionized water (pH 4), desorption was achieved by washing with 85% ethanol (v/v) to obtain crude rapeseed peptides (CRPs). In a separate experiment, stepwise desorption was carried out with 25, 55, and 85% ethanol to separate the bitter peptides from the other peptides. Using a combination of the AEE process, washing and demulsification steps, the yields of the total free oil and protein hydrolysates were 88–90% and 94–97%, respectively. The protein recovery was 66.7% and the protein content was enriched from 47.04 to 73.51% in the CRPs. No glucosinolates and phytic acid were detected in the CRPs. From the stepwise desorption, a non-bitter fraction RP25 (containing 64–66% of total desorbed protein) had a bland color and significantly higher protein content (81.04%) and hence was the more desirable product.     

葡萄籽油浸提工艺的研究

以葡萄酒厂副产品葡萄籽为原料,石油醚（30～60℃）为浸提剂,利用索氏提取器提取葡萄籽油。考察了粉碎粒度、料液比、浸提浴温、浸提时间对葡萄籽油提取率的影响。结果表明：葡萄籽粉碎粒度为60目,料液比（g/mL）1∶6,浸提浴温80℃,浸提时间120 min时葡萄籽精油提取率为14.86%。实验制得葡萄籽油理化指标均符合国家食用油标准。     

Evaluation of the Triglyceride Composition of Pomegranate Seed Oil by RP‐HPLC Followed by GC‐MS

Triglyceride composition and fatty acid profiles of pomegranate seed oil were evaluated by newly developed methods in reverse‐phase‐high performance liquid chromatography (RP‐HPLC) and gas chromatography (GC), respectively. Different compositions of the mobile phase (acetone and acetonitrile) and flow rates for the HPLC system were used to obtain better separation for accurate quantitative analysis. Triglycerides with conjugated fatty acids (CLnAs) were eluted in order of the polarity of their geometrical isomers (c, t, c < t, t, c < t, t, t). The dominant triglyceride was found to be PuPuPu (32.99 %) in pomegranate seed oil, followed by PuPuCa and PuCaCa containing punicic acid and catalpic acid with total triglyceridelevels of 27.72 and 10.11 %, respectively. For fatty acid composition analysis, triglyceride fractions were derivatized into their respective methylesters which were injected into gas chromatography‐mass spectrometry (GC‐MS) to identify and gas chromatography‐flame ionization detector (GC‐FID) to quantify the conjugated fatty acids of each fraction of triglycerides. Punicic acid was found to be dominant (76.57 %) followed by catalpic acid (6.47 %) and β‐eleotearic acid (1.45 %). Pomegranate seed contained greater amounts of conjugated linolenic acids. These results showed that the present study provides more information about the composition of the triglyceride and fatty acid profiles of pomegranate seed oil compared to the reported studies. Therefore, the developed methods in this study can be used for the identification of the triglyceride and fatty acid composition for pomegranate seed oils and some such specials edible oils including CLnA isomers.     

超声波辅助提取石榴皮中熊果酸工艺研究

以石榴皮为原料,以熊果酸得率为指标,采用超声波辅助提取了石榴皮中熊果酸。分别研究了提取剂乙醇浓度、料液比、超声时间、超声温度对熊果酸提取的影响,通过正交试验优化了提取工艺。结果表明,熊果酸提取的最佳工艺条件是:乙醇体积分数50%、固液比1∶20、超声时间30 min、超声温度60℃,在最佳条件下,熊果酸得率可达1.1142%。     

超临界二氧化碳流体萃取油茶籽油及其GC／MS分析

采用环境友好的超临界二氧化碳流体萃取技术制备油茶籽油,考察了压力、时间、温度和二氧化碳流量等因素对茶籽油萃取率的影响,得到优化的工艺参数：当萃取压力30MPa、萃取温度35℃、CO2流量30L／h、萃取时间为3h时茶籽油萃取率可高达44．4％。根据中华人民共和国国家标准进行检测的结果表明：超临界二氧化碳流体萃取出的茶籽油,无需进一步精制即可达到国家食用植物油卫生标准GB／T2716—2005,而除含皂量、水分及挥发物外的指标均达到国家一级茶油标准GB11765—2003;GC／MS分析结果表明油茶籽油富含73．6％不饱和脂肪酸。实验结果表明：超临界二氧化碳流体技术萃取茶籽油具有操作简便、萃取率高、无溶剂残留、绿色环保等优点,萃取出的茶籽油具有较高的品质和良好的应用前景。     

Optimization of the Aqueous Enzymatic Extraction of Oil from Iranian Wild Almond

The seeds of wild almond, Amygdalus scoparia, contain a relatively high quantity of oil. In the current study, aqueous enzymatic extraction of the oil from Iranian wild almond was investigated using a protease and a cellulase to assist the extraction process. The effects of temperature, incubation time and pH on the oil recovery were evaluated using Box?Behnken design from response surface methodology (RSM). A 77.3 % recovery was predicted for oil using aqueous enzymatic extraction procedure at the optimized conditions of RSM (pH 5.76; 50 °C/5 h) when both enzymes were used at 1.0 % level (v/w). In practice, when both enzymes were used, a maximum of 77.8 % oil recovery was achieved at pH 5; 50 °C/4 h. Fatty acid profile, refractive index and saponification value of the aqueous enzymatic extracted oil in the current study were similar to those of the oil extracted with hexane. However, acid value, unsaponifiable matter and p‐anisidine value were higher when compared to those with hexane extracted oil. Peroxide value of the aqueous enzymatic oil was lower than that of oil extracted by hexane. Aqueous enzymatic extraction can be suggested as an environmentally‐friendly method to obtain oil from wild almond.     

从山苍子核仁油中提取各种脂肪酸的研究

山苍子核仁油是由山苍子核经生胚直接浸出法制得。其经酸炼、皂化、酸化、水解、水洗、真空精馏等工序即得系列中碳脂肪酸。C_(10)得率为3.0％～7.5％,C_(12)得率为3.5％～12.7％,产品质量好,环境污染小。指出在制取癸酸、月桂酸、C_(16)～C_(18)皂用酸等时,山苍子核仁油可以替代椰子油,既利用了野生资源,又减少了环境污染。     

植物油抽提溶剂油萃取工艺参数的优化

分析植物油抽提溶剂油萃取生产中系统结焦的原因,在现有的工艺和设备条件下对运行参数进行优化调整,延缓了装置运行的结焦速率,提高了装置的加工能力。     

超临界CO_2萃取葡萄籽油的研究

本文对超临界二氧化碳萃取葡萄籽油进行了研究。以物料的粒度、萃取温度、压力、静态萃取时间、动态萃取时间为考察指标,通过正交实验研究了不同的萃取条件对葡萄籽油产率的影响,确立了最佳的工艺条件为:物料粒度40目,在35℃,50 MP,静态萃取0 min,动态萃取60 min。