The Reduction of Glucosinolate and Sinapine Contents under Industrial Processing of Rapeseed

The glucosinolate and sinapine contents in industrially processed samples including seed, conditioned flakes, expeller press cake, solvent extracted meal and toasted meal of high glucosionlate (HG) and double low (DL) rapeseed were determined. Technological unit processes including flaking, conditioning, expeller pressing and solvent extraction had a little effect on the content of glucosinolate (with exception of DL when one-fifth of glucosionolate was lost) and sinapine contents while toasting stage reduced contents of both compounds by 62 to 74% of original level in the seeds. Overall industrial process reduced glucosinolate content by 64 to 79% of seed value in HG and DL rapeseed, respectively, whereas sinapine was decreased by 26% in both types of rapeseed.     

Primary Metabolites and Polyphenols in Rapeseed (Brassica napus L.) Cultivars in China

Defatted meals of 10 rapeseed (Brassica napus L.) varieties were investigated for their total phenolic, phenolic acid (free, esterified, and insoluble-bound forms), and tannin contents. The antioxidant capacities (AC) of methanol extracts from samples were assessed using the 2,2′-diphenyl-1-picrylhydrazyl radical (DPPH•), Folin–Ciocalteu method and ferric reducing antioxidant power (FRAP), and β-carotene–linoleic acid tests. In the fraction of free phenolic acids, sinapic, caffeic, ferulic, syringic, gallic, and p-coumaric acids were identified. In the fraction of esterified phenolic acids, sinapine, sinapoyl glucoside, and disinapoyl gentiobiose were identified. After basic hydrolysis, sinapic, ferulic, cinnamic, and 4-hydroxybenzoic acids were identified, and sinapic acid (SA) constituted 98.3% to 99.6% of the total esterified phenolic acids. Eleven components (sinapic, protocatechuic, p-coumaric, syringic, vanillic, gallic, caffeic, ferulic, salicylic, cinnamic, and 4-hydroxybenzoic acids) in the fraction of insoluble-bound phenolic acids were identified. The AC of the samples correlated with the total phenolic content. Overall, the total phenolics showed a better correlation with AC than the individual phenolic compounds. Moreover, SA, sinapoyl glucoside, and disinapoyl gentiobiose showed a highly significant and strong positive correlation with the AC of rapeseed meals, and the derivatives of cinnamic acid showed a higher correlation with AC than the derivatives of benzoic acid. The change in the canolol content in rapeseeds under microwave irradiation is discussed. The correlation of the canolol formed with SA and its derivatives is discussed.     

Production of Canolol from Canola Meal Phenolics via Hydrolysis and Microwave-Induced Decarboxylation

A potent antioxidant, anti-inflammatory and anti-mutagenic agent; 4-vinyl-2,6-dimethoxyphenol (canolol) was obtained from canola meal in a significant yield via alkaline (NaOH)/enzymatic (ferulic acid esterase) hydrolysis followed by microwave-assisted decarboxylation. The hydrolysis was carried out either through using canola meal directly as a substrate or by using the 70 % aqueous methanolic extract filtrates. The hydrolyzed extracts underwent RP-HPLC analysis which showed that 81.0 and 94.8 % of the total phenolics were hydrolyzed to sinapic acid after the alkaline hydrolysis of the meal and the methanolic extracts, respectively. The enzymatic hydrolysis showed lower conversion rates (49.5 and 58.3 %). The hydrolyzed extracts were consequently decarboxylated using 8-diazabicyclo[5.4.0]undec-7-ene under microwave irradiation at different conditions. The HPLC profiling of decarboxylated extracts showed that using microwave at 300 W of microwave power for 12 min brought the highest sinapic acid conversion to canolol (58.3 %) yielding 4.2 mg canolol from each gram of canola meal suggesting that the process could be commercially economical.     

Antioxidant activity of rapeseed phenolics and their interactions with tocopherols during lipid oxidation

Commercial rapeseed press cakes are rich sources of phenolic compounds, namely, sinapic acid derivatives, which can be extracted as free sinapic acid and its bound forms (such as sinapine, the choline ester of sinapic acid). Fractionated rapeseed extracts rich in sinapic acid and sinapine were compared for their capacity to inhibit the formation of lipid oxidation products. Oxidation at 40°C was monitored by the formation of hydroperoxides (indicating primary oxidation products) and propanal (secondary oxidation products). The 70% methanolic extract of rapeseed meal, added as an equivalent of 500 μmol/kg oil (based on sinapic acid equivalent for sinapic acid-rich extracts or sinapine equivalent for sinapinerich extracts) showed good antioxidative activity compared with the addition of 500 μmol/kg oil sinapic acid. Apart from this, the interaction between a mixture of α-/γ-tocopherol and sinapic acid was investigated using response surface methodology for the experimental design. The experiments indicated that the addition of sinapic acid (concentration dependent) caused inhibition of peroxide formation, complementing further lower endogenous tocopherol concentration in oils. This paper was initially presented at the 95th AOCS Annual Meeting and Expo in Cincinnati, Ohio, May 1–4, 2004.     

Antioxidative effect of the main sinapic acid derivatives from rapeseed and mustard oil by‐products

Amongst oilseeds, rapeseed and mustard are rich sources of phenolic compounds, which also prominent in the by‐products of their respective oil processing or in commercial rapeseed and mustard press cakes. These cakes are rich sources of sinapic acid derivatives, which could be extracted as free sinapic acid or sinapine, the choline ester of sinapic acid. Sinapic acid is a widely investigated antioxidative compound. However, the main compound in the press cakes is present as sinapine. Investigations on the free‐radical‐scavenging activity of sinapic acid and sinapine indicate that sinapine had a significant but lower activity as compared to sinapic acid. Apart from this, sinapic acid, sinapine and different tocopherols were compared as antioxidants for inhibition of the formation of lipid oxidation products in purified rapeseed oils. The oxidation at 40 °C was monitored by the formation of hydroperoxides and propanal. The experiments indicate that in contrast to tocopherol mixtures addition of sinapic acid causes increasing inhibition of hydroperoxide formation when enhancing the concentration from 50 to 500 μmol/kg oil. Sinapine was not able to inhibit the formation of hydroperoxides, compared to sinapic acid. This indicates that sinapic acid‐rich extracts, as compared to sinapine‐rich fractions, could better inhibit the lipid oxidation in bulk lipid systems.     

Antioxidant capacity of rapeseed meal and rapeseed oils enriched with meal extract

Response surface methodology (RSM) was used to evaluate the quantitative effects of two independent variables: solvent polarity and temperature of the extraction process on the antioxidant capacity (AC) and total phenolics content (TPC) in meal rapeseed extracts. The mean AC and TPC results for meal ranged between 1181–9974 µmol TE/100 g and 73.8–814 mg sinapic acid/100 g of meal. The experimental results of AC and TPC were close to the predicted values calculated from the polynomial response surface models equations (R² = 0.9758 and 0.9603, respectively). The effect of solvent polarity on AC and TPC in the examined extracts was about 3.6 and 2.6 times greater, respectively, than the effect of processing temperature. The predicted optimum solvent polarity of ε = 78.3 and 63.8, and temperature of 89.4 and 74.2°C resulted in an AC of 10 014 µmol TE/100 g and TPC of 863 mg SAE/100 g meal, respectively. The phenolic profile of rapeseed meal was determined by an HPLC method. The main phenolics in rapeseed meal were sinapine and sinapic acid. Refined rapeseed oils were fortified with an extract – rich in polyphenols – obtained from rapeseed meal. The supplemented rapeseed oil had higher AC and TPC than the refined oil without addition of meal extracts. However, AC and TPC in the enriched oils decreased during storage. The TPC in the studied meal extracts and rapeseed oils correlated significantly (p<0.0000001) positively with their AC (R² = 0.9387). Practical applications: Many bioactive compounds extracted from rapeseed meal provide health benefits and have antioxidative properties. Therefore, it seems worth to consider the application of antioxidants extracted from the rapeseed meal for the production of rapeseed oils with potent AC. Moreover, antioxidants extracted from the rapeseed meal were added to refined rapeseed oil in order to enhance its AC. AC was then tested by FRAP assay. FRAP method is based on the reduction of the ferric tripyridyltriazine (Fe³⁺‐TPTZ) complex to the ferrous tripyridyltriazine (Fe²⁺‐TPTZ), and it is simple, fast, low cost, and robust method. FRAP method does not require specialized equipment and can be performed using automated, semi‐automatic, or manual methods. Therefore the proposed FRAP method can be employed by the fat industry laboratories to asses the AC of rapeseed oils and meal.     

Effect of Operating Parameters on Oil and Phenolic Extraction Using Supercritical CO<Subscript>2</Subscript>

Supercritical fluid extraction (SFE) with carbon dioxide was used to extract oil from canola press cake. Different operating conditions, e.g. pressure, temperature, and co-solvent % were investigated to optimize extraction parameters to yield canola meal with <4% oil. The residual oil content in the extracted canola meal reduced to 2.1–2.9% in our experimental trials. Residues of the optimum conditions based on oil yield were compared for the total phenolic content and the main phenolic compounds. Sinapine (the choline ester of sinapic acid) was the major phenolic constituent in both the SFE and n-hexane extracted canola meals and press cakes. n-Hexane extracted residues showed the retention of the highest sinapic acid, sinapine, sinapoyl glucose and total phenolic contents (mg/g) while the SF-extracted residues showed the lowest values for these compounds.     

Transformation of 3,5-dimethoxy-4-hydroxy cinnamic acid and its derivatives using enzyme from white-rot fungus Trametes versicolor: Enzyme characteristics and its application

Transformation of 3,5-dimethoxy-4-hydroxy cinnamic acid (sinapic acid), sinapaldehyde, sinapine and sinapoyl in the model system containing an enzyme secreted by the fungus Trametes versicolor was investigated. The affinity of this enzyme was highest for sinapic acid followed by sinapaldehyde and sinapine. The optimum temperature and pH for these transformations were 50°C and pH 3·3, 50°C and pH 4·5, 60°C and pH 4·0 for sinapaldehyde, sinapine, and sinapic acid, respectively. The apparent heat of the enzyme-sinapic acid complex formation is −2557·6 J mol⁻¹. Higher concentrations of sinapine and sinapic acid caused enzyme inhibition. When canola meal was treated with this enzyme the phenolics content in this commodity was decreased by 90%.     

Quality of Rapeseed Oil Produced by Conditioning Seeds at Modest Temperatures

Conditioning rapeseed can significantly increase the amount of bioactive compounds in the crude oil, but if the conditioning temperatures are too high, they can cause unwanted side effects such as darker color and sensory defects. Modest conditioning temperatures may be more suitable, but little is known about the effects on the quality and bioactive composition of the resulting oil. Oil was recovered from five rapeseed cultivars by cold pressing (CP) or by pressing seeds conditioned at 80 °C for 30 min (HP). Conditioning rapeseed increased oil yield without changing fatty acid composition and increased the amount of total sterols by 16 %, total tocopherols by 20 %, and the levels of polyphenols. Levels of the polyphenol canolol were up to 55-fold higher in HP oil than in CP oil. These higher levels of bioactive compounds gave HP oil higher radical scavenging activity. Although HP oil also had higher free fatty acid contents, peroxide levels, and specific UV extinctions (K values). The quality parameters of HP and CP oils were within codex limits indicating high quality. Modest conditioning temperatures can be used to produce rapeseed oil with high quality and radical scavenging activity.     

Attenuation of sinapic acid and sinapine-derived flavor-active compounds using a factorial-based pressurized high-temperature processing

De-oiled canola meals are sources of protein-containing flavor-active phenolic compounds. Conventional canola oil processing utilizes an excess amount of solvents and is associated with the release of high-intensity bitter flavor-active phenolic compounds, limiting the use of the canola meal. Recent advances in the extraction and isolation of the bitter favor-active phenolic compounds from canola by-products produce protein isolates, however, would benefit the industry by producing a side-stream ingredient rich in phenolics. High temperature and pressure-aided processing, namely the accelerated solvent extraction (ASE) was investigated to extract the flavor-active bitter molecules from the canola meal. The extractability of flavor-active phenolic compounds including the major sinapates, kaempferol derivatives, and other thermo-generative compounds including thomasidioc acid (TA) was evaluated. The effects of temperature, solvent extractant and concentration, and the particle size of the meal were examined on the extraction efficiency of these phenolic compounds. Extraction temperature (180°C) was the primary determinant (p < 0.05) for the attenuation of major sinapates including sinapine and sinapic acid. Both ethanol and methanol extractants at a concentration of 70% (v/v) significantly (p < 0.05) extracted the flavor-active phenolic compounds. The pressurized high temperature through optimized ASE conditions attenuated the bitter undesirable flavor-active phenolic molecules from canola meal, thereby facilitating a potential value-added phenolic-rich by-product.     

A rapid high-performance liquid chromatographic method for the determination of sinapine and sinapic acid in canola seed and meal

A high-performance liquid chromatographic (HPLC) method has been developed to separate sinapine and sinapic acid from other phenolics in canola seed and meal in a single run. The separation was achieved with a reverse-phase C18 column. Owing to the higher recovery of phenolics and ease of use, refluxing with 100% methanol for 20 min was selected as the extraction method for HPLC analysis and determination of total phenolics using Folin-Ciocalteu reagent. A 10-min isocratic/linear/concave gradient and a 15-min isocratic/linear gradient were selected as the best gradients for the separation of these phenolic compounds. Peak identities for sinapine and sinapic acid were verified with ion exchange separation followed by HPLC analysis. The method was calibrated using sinapine bisulfate and sinapic acid standards; correlation coefficients (R ²) for the calibration curves were 0.997 and 0.999 for sinapine bisulfate and sinapic acid, respectively. The extinction coefficient of sinapine was determined to be 1.16 times that of sinapic acid at the detector wavelength (330 nm). Applying this method to routine canola phenolic analyses can greatly reduce the cost by simplifying the procedures and reducing the time required for each determination.     

Fatty Rapeseed Products for Dairy Cows

In the present investigation (3 experiments) the effects of fatty rapeseed products were studied on both straw-based and hay-based rations for lactating cows. Compared rapeseed products, used as ingredients of concentrate mixtures, were full-fat rapeseed (43% oil), partially defatted rapeseed expellercake (19% oil) and fully defatted rapeseed meal (2% oil). The rapeseed and rapeseed expellercake compared to the defatted rapeseed meal resulted in significantly higher yields of milk and 4% fat-corrected milk, when barley straw was the dominating roughage. In the hay-based diet the positive effects of added fat were not as much expressed. The iodine number of the milk fat increased about 4 units, when feeding the high-fat rations, i.e. the softness of the butter was improved. The results indicate that supplementation of straw with fatty rapeseed products will improve the possibility of a biologically and economically beneficial use of cereal straw in dairy cow rations.     

Pilot plant extraction of oil fromVernonia galamensis seed

Vernonia galamensis seed containing 40–42% oil and 30–34% epoxy acid, (cis-12,13-epoxy-cis-9-octadecenoic) was processed to oil and meal. Seed conditioning, pressing and solvent extraction research were conducted in pilot facilities at the French Oil Mill Machinery Co. (Piqua, OH). The robust lipase system was successfully inactivated by treating 200 lb. batches ofV. galamensis seed in a cooker/conditioner at 195–200°F and >10% moisture. Conditioned seed was mechanically pressed and the press discharge cone setting was varied during operation from 1/32″ to 3/32″ to demonstrate the feasibility of both full pressing and prepressing. Prepressing successfully reduced oil level in the press cake to ca. 20%. Press cake was extracted with hexane in a 1.5-ft³ batch-type, four-stage percolation unit with a 6″ square extraction cross section. Solvent extraction reduced oil level in the defatted meal to 1–2%. The defatted meal was desolventized and toasted. Excessive foaming of the vernonia oil extract made complete solvent stripping in the oil stripping unit difficult.     

Recovery of Oil,Erucic Acid,and Phenolic Compounds from Rapeseed and Rocket Seeds

Erucic acid‐enriched oil, sought for industrial purposes, from rapeseed (agronomic plant) and rocket seeds (non‐agronomic plant) was extracted by three different processes: supercritical CO₂, mechanical expression, and hexane extraction. Oil extraction yields were determined and the extracted oils were characterized for their fatty acid and phenolic compound compositions. Higher oil yields were achieved using hexane compared to mechanical expression and supercritical CO₂ extractions. Fatty acid analysis indicated a higher content of erucic acid in rapeseed oil than in rocket oil. In addition, supercritical CO₂ extraction allowed better recovery of phenolic compounds with high antioxidant activities. The most prominent identified polyphenols were vanillin, sinapic acid, syringic acid, and apigenin.     

乙醇提取油茶饼残油的研究

探讨了乙醇为溶剂热回流提取油茶饼中残油的方法。通过单因素实验及正交实验考察了乙醇体积分数、液料比、浸提温度、浸提时间及提取次数对油茶饼中残油收率的影响,确定了优化的提取条件为：乙醇体积分数95%、液料比10∶1（mL∶g）、浸提温度92℃、浸提时间3h、提取次数2次。在此优化条件下,油茶饼中平均残油收率达到残油含量的96.04%。研究结果表明,乙醇具有替代6号溶剂油提取油茶饼中残油的前景。     

Thermal Stability of Rapeseed Oil Fortified with Unsaturated Fatty Acid Sterol Esters

The thermal stability of rapeseed oil fortified with 3 % sterol linolenate, sterol linoleate, and sterol oleate was investigated using the Rancimat accelerated oxidation method. The results indicated that the sterol ester content in fortified oil displayed positive correlations (P < 0.05) with total phenols and tocopherols and significant negative correlations (P < 0.05) with acid value (AV), peroxide value (POV), conjugated diene value, \(\varDelta E\) value, viscosity, and polyphenols and γ-tocopherol levels. The sterol ester content in fortified oil was found to significantly decrease when the oil was heated at 110 °C. The rate of increase of the AV, POV, \(\varDelta E\) value, and viscosity, and the rate of decrease of polyunsaturated fatty acid, tocopherol, and polyphenol contents were accelerated with the increase of the degree of unsaturation of fatty acid sterol esters in rapeseed oil during heating. Therefore, the oxidative stability is further reduced by increasing the degree of unsaturation, as the instability of fortified oil is mainly due to the decomposition of unsaturated fatty acid sterol esters. The addition of lipid-soluble polyphenols is an effective method to improve the stability of rapeseed oil fortified with unsaturated fatty acid sterol esters.     

Antioxidant (Tocopherol and Canolol) Content in Rapeseed Oil Obtained from Roasted Yellow-Seeded <Emphasis Type="Italic">Brassica napus</Emphasis>

In this study, the effect of temperature (140, 160, 180 °C) and roasting time (5, 10, 15 min) on the bioactive compound content (canolol, tocopherol and plastochromanol‐8) of cold‐pressed oil from yellow‐seeded rapeseed lines of different colors was investigated. Roasting increased the peroxide value in the seed oils compared to the oils from the control samples. However, roasting did not affect the acid values of the oils, which were 1.15–1.47 and 1.30–1.40 mg KOH/g, for line PN1 03/1i/14 (yellow seeds) and line PN1 563/1i/14 (brown seeds), respectively. In this study, the seeds of line PN1 03/1i/14 were characterized by different changes in canolol content during roasting than the seeds of PN1 563/1i/14. There was a 90‐fold increase in canolol for the line PN1 03/1i/14 (768.26 µg/g) and a 46‐fold increase for the line PN1 563/1i/14 (576.43 µg/g). Changes in tocopherol and PC‐8 contents were also observed. There was an increase in the contents of γ‐T and PC‐8 in the oils obtained from the seeds roasted at 180 °C for 10 and 15 min. γ‐T content increased by 17–18% after 15 min of roasting, whereas the PC‐8 content increased twofold.     

Amygdalin Contents of Oil and Meal from Wild Almond: Effect of Different Heat Pretreatment and Extraction Methods

The effects of different heat treatment methods on the extraction yield of oil and the amygdalin contents of the wild almond meal and oil were investigated. When using hexane as a solvent for the extraction, oil yield and amygdalin contents of the extracted oils increased by increasing the applied temperature as the pretreatment (46.1–51.6%, w/w, for oil yield and 26–49 mg/100 mL oil for the amygdalin content). When using mechanical oil extraction, hot-press resulted in higher oil yield (23.2%) than did the cold-press (15.6%) but the amygdalin levels of the extracted oils were not significantly different (12.8–12.9 mg/100 mL oil). Autoclaving ground wild almond and hot-press resulted in a significant increase in the peroxide and acid values of the oils. Investigation of fatty acid profiles of different samples showed that heat treatment and extraction method in this study did not impact the fatty acid profiles of the extracted oils.     

微波萃取除虫菊的研究

本研究使用经改造的家用微波炉作为主要设备,对微波萃取除虫菊干花做了L9（3^4）正交实验。考察了四个因素：微波辐射时间、微波功率、 溶剂用量、洗涤滤饼的溶剂量对三个指标：提取率、 溶剂回收率、除虫菊酯总含量的影响。实验结果表明：辐射时间200 s、微波功率750w、溶剂用量240ml、洗涤滤饼的溶剂量20ml可提高最高的提取率; 辐射时间200s、微波功率．750w、溶剂用量240ml、洗涤滤饼的溶剂量30ml可得到最高的溶剂回收率;辐射时间200s、微波功率850w、溶剂用量240ml、洗涤滤饼的溶剂量30ml可得到最高的除虫菊酯总含量。综合考虑提取率、溶剂回收率和除虫菊酯总含量,最佳组合为辐射时间200s、微波功率750w、溶剂用量240ml、洗涤滤饼的溶剂量30ml。     

Optimization of Microwave-Assisted Extraction of Tea Saponin and Its Application on Cleaning of Historic Silks

Microwave-assisted extraction (MAE) was utilized to extract tea saponin from oil-tea camellia seed cake. The factors influencing the extraction efficiency were studied, including the effects of microwave power, irradiation duration, temperature, ratio of solvent to material and aqueous ethanol concentration. By systematic orthogonal experiments, the optimal extraction technology was determined. Compared with a conventional extraction method, MAE shows great advantages with the extraction time reduced from 6 h to 4 min, 50 % organic solvent saved and about 14 % extraction yield enhanced. Fourier transform infrared spectroscopy testing and high performance liquid chromatography analysis proved that the extracted resultants were tea saponin with similar compounds as a standard tea saponin. The extracted tea saponin was applied on the cleaning of historic silks and showed good removal effect on the stains. This work provides useful information for fully use of oil-tea camellia seed cake and new applications of tea saponin at the protection of historic textiles.