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.     

Enzymatic Demulsification of the Oil-Rich Emulsion Obtained by Aqueous Extraction of Peanut Seeds

This study details the enzymatic destabilization of the emulsion formed during aqueous extraction of peanut seeds and the quality of the resulting oil. The emulsion was exposed to enzymatic treatment and pH adjustment. The experimental results suggest that the alkaline endopeptidase Mifong^®2709 was the most effective demulsifier, while Phospholipase A2 and pH adjustment had little effect on emulsion stability. The demulsifying conditions of Mifong^®2709 were optimized by response surface methodology (RSM). The optimal conditions which produced a free oil yield of ~94 % were: 1:1 water-to-emulsion ratio, enzyme concentration of 1,600 IU/g of emulsion and 70 min hydrolysis time at 50 °C. We found that these conditions resulted in a positive relationship (R ² = 0.9671) between free oil yield and the degree of protein hydrolysis. Increased protease treatment produced a smaller number of oil droplets, but the size of these droplets increased significantly. When compared to demulsified oil products obtained by using thermal treatment, the oil obtained by Mifong^®2709 exhibited lower acid and peroxide values, contained more tocopherols and had a longer induction time as determined in the Rancimat test. The high yield and quality of peanut oil obtained by enzymatic treatment makes enzyme demulsification a promising approach to recovering free oil in aqueous extractions of peanuts.     

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.     

水酶法提取肉桂油的工艺研究

探索了肉桂油的水酶法提油工艺.研究了不同酶系以及酶解条件对肉桂油得率的影响.结果表明,果胶酶的作用效果好;酶解条件中,加酶量、酶解时间都对肉桂油得率有显著的影响,通过单因素分析及正交试验的结果,得出在固液比1∶6、酶解pH=3.5、酶解温度40℃、加酶量1.5％、酶解时间2h条件下,肉桂油得率能达到1.72％.经检测得到处理得到的肉桂油中桂皮醛含量达到83.6％.     

Aqueous enzymatic extraction of peanut oil and protein hydrolysates

The aqueous enzymatic process of simultaneously preparing oil and protein hydrolysates from peanut was investigated. The optimum parameters for hydrolysis using Alcalase 2.4L were established by the single-factor and orthogonal test. The optimal processing conditions were as follows: hydrolysis temperature 60 °C, pH 9.5, ratio of material to water 1:5 (w/w), alkaline extraction time 90 min, enzyme amount 1.5% (w/w) and hydrolysis time 5 h. Under these conditions, the free oil and protein hydrolysates yields were 79.32% and 71.38% respectively. In order to improve these yields, As1398 was chosen to hydrolyze the residue and emulsion. The total free oil and protein hydrolysates yields were increased to 91.98% and 88.21% respectively.     

Enzymatic pretreatment on rose-hip oil extraction: Hydrolysis and pressing conditions

In a previous report [Zúñiga, M.E., J. Concha, C. Soto, and R. Chamy, Effect of the Rose Hip (Rosa aff. rubiginosa) Oil Extraction Cold-Pressed Process, in Proceedings of the World Conference and Exhibition on Oilseed Processing, and Utilization, edited by R.F. Wilson, AOCS Press, Champaign, 2001, pp. 210–213], the authors showed that an enzymatic pretreatment of rose-hip seeds, prior to oil extraction by cold pressing, improves the oil yield. In this work, we studied the effects of temperature and moisture during the enzymatic hydrolysis stage using two previously selected mixtures of commercial enzymes: (i) Olivex (mainly pectinase) plus Cellubrix (mainly cellulase), and (ii) Finizym (mainly β-glucanase) plus Cellubrix (mainly cellulase) (all from Novozymes A/S, Madrid, Spain). In addition, we evaluated the effect of enzymatic hydrolysis on the oil extraction pressing rate at different operational pressures. Samples hydrolyzed enzymatically by either of the two commercial enzyme mixtures at 45°C and 30–40% moisture showed oil extraction yields up to 60%, an increase of greater than 50%, as compared with control samples in which the enzyme solutions were replaced by water. Both the oil extraction rate and yield by pressing increased when enzymatic pretreatment was applied. The oil extraction yield increased slightly when the operation pressure was elevated; however, when the sample was preheated, the oil extraction yield was greatly increased, especially for enzyme-treated samples. Results confirmed the importance of temperature and moisture as enzymatic hydrolysis parameters that improve rose-hip oil extraction yields in the cold-pressing process. When pressing was carried out after preheating enzymatically treated samples, it was possible to increase the oil extraction yield to 72% compared with the control without preheating, which resulted in a 46% oil yield.     

Effect of ultrasound- and pulsed electric field-assisted enzymatic treatment on the recovery and quality of sunflower oil

The aim of this study was to evaluate the effect of cavitation and electroporation on enzymolysis extraction of sunflower oil. The optimum extraction conditions during 2 h under enzyme-assisted extraction (EAE) with a maximum oil yield of ≈23.70 ± 0.11% were as follows: cellulase/pectinase ratio 2:1, enzyme concentration 2%, pH 4.5, liquid/solid ratio 6:1 ml/g, and extraction temperature 40°C. Under the optimized enzymatic conditions, the application of ultrasound- (250 W) and pulsed electric field- (1.2 kV/cm; 52.4 kJ/kg) assisted enzymatic extraction for 30 min significantly increased the oil extraction yield by 91.1% and 18.6%, respectively, as compared with EAE.     

Ethanol Production from Soybean Fiber,a Co-product of Aqueous Oil Extraction,Using a Soaking in Aqueous Ammonia Pretreatment

The effectiveness of soaking in aqueous ammonia (SAA) as a pretreatment method for the conversion of soybean fiber to ethanol via simultaneous saccharification and fermentation (SSF) was investigated. Insoluble fiber is a co-product from oil and protein extraction using two-stage, countercurrent, enzyme-assisted, aqueous extraction processing of full-fat soybean flakes (FFSF) and extruded FFSF. The fiber fractions were soaked in 15 wt% aqueous ammonia at 1:10 solid-to-liquid ratio. The effects of operating variables, including treatment times (6, 12, and 24 h), treatment temperatures (60 and 80 °C), and cellulase loadings (15 and 60 FPU/g-glucan) on the degree of enzymatic hydrolysis were determined. The best SAA conditions were 80 °C for 12 h followed by an enzyme loading of 15 FPU/g-glucan, which produced a 152-mg/g glucose yield after 48 h of hydrolysis. This was 8.7 times the amount produced from the same fiber not pretreated with SAA. The glucose yield increased to 381 mg/g when fiber obtained from extruded FFSF was submitted to SAA. SAA (80 °C, 12 h) on extruded fiber subjected to SSF increased ethanol yield from 0.06 g of ethanol/g [40% of theoretical yield] (for non SAA pretreated fiber) to 0.25 g of ethanol/g [92% of theoretical yield]. The combination of extrusion and SAA was an efficient means for converting the fiber-rich soybean fraction into ethanol.     

Optimization of Enzymatic Hydrolysis of Sacha Inchi Oil using Conventional and Supercritical Carbon Dioxide Processes

Sacha inchi (Plukenetia volubilis) oil has high polyunsaturated fatty acids content. The hydrolysis of this oil is an efficient way to obtain desirable free fatty acids (FFA). The optimization of parameters was carried out according to the maximum production of FFA using two enzymatic hydrolysis processes. The effect of enzyme concentration (5–40 % based on weight of oil), temperature (40–60 °C), and oil:water molar ratio (1:5–1:70) were studied for the conventional enzymatic hydrolysis process, while pressure (10–30 MPa) and oil:water molar ratio (1:5–1:30) were studied for the enzymatic hydrolysis in supercritical carbon dioxide (SC-CO₂) media. The hydrolysis in SC-CO₂ media resulted in higher production of FFA (77.98 % w/w) at 30 MPa and an oil:water molar ratio equal to 1:5 compared to the conventional process (68.40 ± 0.98 % w/w) at 60 °C, oil:water molar ratio equal to 1:70, and 26.17 % w/w, enzyme/oil. The only significant parameter on the production of FFA for conventional enzymatic hydrolysis was enzyme concentration, while for the hydrolysis in SC-CO₂ media both pressure and the molar ratio of oil:water were significant. Lipid class analyses showed that with both methods, FFA, monoglycerides, and diglycerides content in the final product increased compared to pure oil, while triglycerides content decreased. Fatty acid composition analysis showed that the content of fatty acids in the FFA form were similar to their triglyceride form.     

Optimization of the Aqueous Enzymatic Extraction of Wheat Germ Oil Using Response Surface Methodology

A process of aqueous enzymatic extraction of wheat germ was carried out by a multi-enzyme preparation consisting of cellulase, pentosanase, neutrase and fungal amylase (CPNF, 2:1:2:1 w/w/w/w). Hydro-thermal heating (at 112 °C for 60 min) was more effective than oven-drying regarding emulsified oil yield. Wheat germ was ground with a rate of 10,000 rpm for 90 s. The adding level (w/w) of multi-enzyme preparation of CPNF was 1.6%. Response surface methodology was used to obtain the desired data in the process optimization. The optimal set of variables was water to wheat germ ratio (v/wt, mL/g) of 3.46, pH of 5.24, temperature of 48.49 °C and time of 6 h. The emulsified oil yield was 86.74% at the optimal levels of the tested factors. Compared with organic solvent extracted oil, the content of free fatty acid of AEE extracted oil was higher and the color was slightly darker, while the peroxide value was lower and the oxidative stability was higher owing to high content of α-tocopherol. This technique for recovering oil from fresh wheat germ with enzymes is a significant improvement in both oil yield and quality over the traditional organic solvent process.     

Factors affecting oil extraction/water adsorption in sequential extraction processing of corn

The sequential extraction process (SEP) uses ethanol to extract oil and protein from cracked, flaked, and dried corn, and the dried corn simultaneously dehydrates the ethanol. Value-added co-products are possible, potentially making production of fuel ethanol more economical. The effects of solvent-to-corn (S/C) ratio, corn moisture content (MC), and number of extraction stages on ethanol drying, oil recovery, and protein loss during the simultaneous oil extraction/water adsorption step of SEP were evaluated. Extractions were carried out by using both aqueous ethanol and ethanol/hexane blends at 56°C. The S/C ratios tested were 3∶1, 2∶1 (control), 1.5∶1, and 1∶1 (w/w). More anhydrous ethanol, greater oil yields, and less co-extracted protein were obtained with higher S/C ratios. Less anhydrous ethanol and lower moisture adsorption capacities were obtained when the corn MC was ≥1.12%. Oil yields gradually decreased with drier corn, whereas protein loss increased when corn MC was <1.12%. Reducing the number of extraction stages from seven (original SEP) to five did not affect ethanol drying capability, oil yields, and protein co-extracted with oil. Using ethanol/hexane blends resulted in more anhydrous ethanol, higher oil yields, and less protein co-extracted with oil.     

Optimization of enzymatic pretreatment for n-hexane extraction of oil from Silybum marianum seeds using response surface methodology

An investigation on enzymatic pretreatment for n-hexane extraction of oil from the Silybum marianum seeds was conducted. The optimum combination of extraction parameters was obtained with the response surface methodology (RSM) at a four-variable and five-level central composite design (CCD). The optimum parameters of enzymatic pretreatment were as follows: enzyme concentration of 2.0% (w/w), temperature of 42.8 °C, reaction time of 5.6 h, and pH of 4.8. After enzymatic pretreatment, the oil was extracted by n-hexane for 1.5 h, and the oil yield on a dry basis was 45.70%, which well matched with the predicted value (45.86%). The results of the effects of the enzymatic pretreatment for n-hexane extraction of oil from the aspects of oil yield, microstructure and the fatty acid compositions showed that the enzymatic pretreatment had not affected on the fatty acid compositions, but could cause structure breakage of the S. marianum seeds and accelerate releasing extra oil, which increased the oil yield by 10.46% compared with n-hexane extraction for 1.5 h without enzymatic pretreatment, and confirmed the efficacy of enzymatic pretreatment for n-hexane extraction of oil from the S. marianum seeds.     

Lipase-Catalyzed Production of Biodiesel by Hydrolysis of Waste Cooking Oil Followed by Esterification of Free Fatty Acids

Biodiesel is conventionally produced by alkaline‐catalyzed transesterification, which requires high‐purity oils. However, low‐quality oils can be used as feedstocks for the production of biodiesel by enzyme‐catalyzed reactions. The use of enzymes has several advantages, such as the absence of saponification side reactions, production of high‐purity glycerol co‐product, and low‐cost downstream processing. In this work, biodiesel was produced from lipase‐catalyzed hydrolysis of waste cooking oil (WCO) followed by esterification of the hydrolyzed WCO (HWCO). The hydrolysis of acylglycerols was carried out at 30 °C in salt‐free water (WCO/water ratio of 1:4, v/v) and the esterification of HWCO was carried out at 40 °C with ethanol in a solvent‐free medium (HWCO/ethanol molar ratio of 1:7). The hydrolysis and esterification steps were carried out using immobilized Thermomyces lanuginosus lipase (TLL/WCO ratio of 1:5.6, w/w) and immobilized Candida antarctica lipase B (10 wt%, CALB/HWCO) as biocatalysts, respectively. The hydrolysis of acylglycerols was almost complete after 12 h (ca. 94 %), and in the esterification step, the conversion was around 90 % after 6 h. The purified biodiesel had 91.8 wt% of fatty acid ethyl esters, 0.53 wt% of acylglycerols, 0.003 wt% of free glycerol, viscosity of 4.59 cP, and acid value of 10.88 mg KOH/g. Reuse hydrolysis and esterification assays showed that the immobilized enzymes could be recycled five times in 10‐h batches, under the conditions described above. TLL was greatly inactivated under the assay conditions, whereas CALB remained fully active. The results showed that WCO is a promising feedstock for use in the production of biodiesel.     

Enzyme-assisted aqueous extraction of peanut oil

Enzyme-assisted aqueous extraction of oil from oilseeds is a relatively recent technique. In the present study, peanut oil was extracted under optimized aqueous extraction conditions using Protizyme^™, which is predominantly a mixture of acid, neutral, and alkaline proteases. The optimal conditions were: enzyme concentration of 2.5% (w/w) in 10 g of peanut seeds, pH 4.0, 40°C, and 18 h incubation with constant shaking at 80 rpm. Centrifuging the mixture at 18,000 × g for 20 min separated the oil with a recovery of 86–92%. The merits of this process over existing solvent extraction and/or mechanical pressing methods are discussed.     

Extraction of lipids and cholesterol from squid oil with supercritical carbon dioxide

The oil obtained from waste squid viscera consists of multi-compounds such as EPA, DHA and other valuable polyunsaturated fatty acids. The refining of this squid oil, using supercritical carbon dioxide plus ethanol, was performed in a semi-continuous flow extractor at 8 to 17 MPa and 25 to 50 °C. When 1.5% w/w ethanol was added to the solvent, the solubility of lipids was increased by up to 50% over the neat CO₂ value. The extraction curves indicated mass transfer to be solubility limited. Cholesterol was co-extracted with the lipids but, with its lower solubility, less than 54% appeared in the refined oil. The results of the carbon dioxide/multi-compound squid oil system at applied to the extraction conditions were correlated with the mole fraction of the cholesterol and the density of the pure solvent.     

Two-Stage Countercurrent Enzyme-Assisted Aqueous Extraction Processing of Oil and Protein from Soybeans

Enzyme-assisted aqueous extraction processing (EAEP) is an increasingly viable alternative to hexane extraction of soybean oil. Although considered an environmentally friendly technology where edible oil and protein can be simultaneously recovered, this process employs much water and produces a significant amount of protein-rich aqueous effluent (skim). In standard EAEP, highest oil, protein and solids yields are achieved with a single extraction stage using 1:10 solids-to-liquid ratio (extruded flakes/water), 0.5% protease (wt/g extruded flakes), pH 9.0, and 50 °C for 1 h. To reduce the amount of water used, two-stage countercurrent EAEP was evaluated for extracting oil, protein and solids from soybeans using a solids-to-liquid ratio of 1:5–1:6 (extruded flakes/water). Two-stage countercurrent EAEP achieved higher oil, protein and solids extraction yields than using standard EAEP with only one-half the usual amount of water. Oil, protein and solids yields up to 98 and 96%, 92 and 87%, and 80 and 77% were obtained when using two-stage countercurrent EAEP (1:5–1:6) and standard single-stage EAEP (1:10), respectively. Recycling the second skim obtained in two-stage countercurrent EAEP enabled reuse of the enzyme, with or without inactivation, in the first extraction stage producing protein with different degrees of hydrolysis and the same extraction efficiency. Slightly higher oil, protein and solids extraction yields were obtained using unheated skim compared to heated skim. These advances make the two-stage countercurrent EAEP attractive as the front-end of a soybean biorefinery.     

Characteristics and Composition of Watermelon Seed Oil and Solvent Extraction Parameters Effects

Watermelon seed oil characteristics were evaluated to determine whether this oil could be exploited as an edible oil. Hexane extraction of watermelon seeds produced yields of 50% (w/w) oil. The refractive index, saponification and iodine value were 1.4712 (at 25 °C), 200 mg KOH/g and 156 g I/100 g, respectively. The acid and peroxide values were 2.4 mg KOH/g and 3.24 mequiv/kg, respectively. The induction time of the oil was also 5.14 h at 110 °C, which was measured for the first time. Total unsaturation contents of the oil was 81.6%, with linoleic acid (18:2) being the dominant fatty acid (68.3%). Considering that the watermelon seed oil was highly unsaturated, the relatively high induction time might indicate the presence of natural antioxidants. In addition, the influence of extraction parameters on extraction of oil from watermelon seed with hexane as a solvent was studied at several temperatures (40, 50, and 60 °C), times (1, 2, and 3 h) and solvent/kernel ratios (1:1, 2:1, and 3:1). The oil yield was primarily affected by the solvent/kernel ratio and then time and temperature, respectively. The protein content of the oil-free residue was 47%.     

Simplex-Centroid Mixture Design Applied to the Aqueous Enzymatic Extraction of Fatty Acid-Balanced Oil from Mixed Seeds

A one-step method was developed to extract oil from a mixture of soybeans, peanuts, linseeds, and tea seeds using an aqueous enzymatic method. The proportion of the four seeds was targeted in accordance with a fatty acid ratio of 0.27 (SFA, saturated fatty acid(s)): 1 (MUFA, monounsaturated fatty acid(s)): 1 (PUFA, polyunsaturated fatty acid(s)), and the oil extraction yield was maximized by applying the simplex-centroid mixture design method. Three models were developed for describing the relationship between the proportion of the individual seeds in the mixture, the fatty acid ratio in the extracted oil, and the oil extraction yield, respectively. The developed models were then analyzed using an ANOVA and were found to fit the data quite well, with R ² values of 0.98, 0.93, and 0.93, respectively. The three models were validated experimentally. The results indicated that the ratio of fatty acids in the oil ranged between 0.98 and 1.12 (MUFA:PUFA) and between 0.26 and 0.28 (SFA:MUFA), which were quite close to the target values of 1 and 0.27, respectively. The oil extraction yield of 62.13 % was slightly higher than the predicted value (60.32 %).     

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.     

Separation of non-sulfonated oil from industrial petroleum sulfonate

Abstract

The non-sulfonated oil in industrial petroleum sulfonate was separated by centrifugal method and extraction method, respectively. The oil separation rates of each method were compared, and the effects of oil separation rates under different conditions on the purity of non-sulfonated oil were investigated. The purity information of non-sulfonated oil separated by different methods was analyzed by infrared spectroscopy. The experimental results showed that the oil separation rate of centrifugation was low, and the oil extraction rate was higher. The purity of non-sulfonated oil separated with alcohol–water solution as extractant was lower, while the purity of non-sulfonated oil separated by water extraction method was the highest, and the extractant was nontoxic and environmentally friendly. Water was preferred as extractant. Solvent ratio, temperature and pressure all had great influence on oil separation rate. The optimum conditions for SL petroleum sulfonate were: solvent ratio 1.5:1, 90?°C, atmospheric pressure, which the oil separation rate was 78.51%; and for DQ petroleum sulfonate, the optimum conditions were: solvent ratio 2:1, 90?°C, atmospheric pressure, which the oil separation rate was 79.86%. Non-sulfonated oil separated by water extraction had the least petroleum sulfonate, followed by ethanol single solvent extraction. Although the extraction efficiency of isopropanol aqueous solution and n-pentane was the highest, the content of petroleum sulfonate in non-sulfonated oil was the highest, which affected the product performance and should not be used.