Enzymatic saccharification of canola meal

For the enzymatic saccharification of canola meal by enzyme preparations from Trichoderma reesei as well as by commercially available hemicellulase and multienzyme preparations, a pretreatment consisting of autoclaving is necessary. These enzyme preparations hydrolysed over 20% (w/w) of pretreated canola meal, which constitutes over 70% saccharification of the total polysaccharides present in canola meal. The results show that saccharification of canola meal is mainly brought about by hemicellulases capable of degrading arabinogalactan, arabinoglucan, galactan and galactomannan, while cellulases and xylanases play a minor role. These hemicellulases were found to be more stable at 50°C than cellulases or xylanases. This pretreatment also released water-soluble polysaccharides consisting mainly of arabinose and glucose. Trichoderma reesei was unable to produce enzymes capable of hydrolysing this polysaccharide when cultivated on canola meal as substrate.     

Processing of canola meal for incorporation in trout and salmon diets

Canola meals (two commercial meals and one low-heat meal) were processed to reduce fiber content, then washed with selected solvents to reduce the content of antinutritional substances and further concentrate protein. The meals, fiber-reduced meals, and washed meals were used to provide 40% of total protein (26–38% of feed) in the diets of 6-g rainbow trout for 3 weeks or 25% of total protein (21–31% of feed) in the diets of 23-g chinook salmon for 11 weeks. Air-desolventized (low-heat) canola meal, as compared to commercial meal, provided no protein quality advantage in trout feeds. Fiber reduction processing of commercial meal increased meal protein content by 11–16% and reduced crude fiber by 23–50%, but did not have any effect on the quality of protein for trout or salmon. Solvent-washing of fiber-reduced meal improved fish response to canola meal, probably due to reduced glucosinolate content, but possibly also due to reduced sinapine content and alterations in protein availability. Protein concentration was increased by 25–40% by washing, and glucosinolate concentration was reduced by 40–90%.     

Radical scavenging activity of canola hull phenolics

Possible use of canola hulls as a source of natural anti-oxidants was explored. Cyclone canola hulls were extracted with methanol (30 to 80%, vol/vol) and acetone (30 to 80%, vol/vol). The free radical-scavenging activity of phenolic extracts so prepared was evaluated using the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) radical ion (ABTS^o−), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, and chemiluminescence assays. The total content of phenolics in prepared extracts from canola hulls ranged from 15 to 136 mg sinapic acid equivalents per gram of extract. Higher levels of condensed tannins were detected in the acetone extracts than in the corresponding methanolic counterparts. Seventy and 80% (vol/vol) acetone extracts displayed markedly stronger antioxidant activity than any of the other extracts investigated. Statistically significant linear correlations were found between TEAC (Trolox equivalent antioxidant capacity) values (expressed in mM of Trolox equivalents per gram of extract) and total pehnolics, TEAC and total condensed tannins (i.e., determined using the modified vanillin and pronthocyanidin assays), as well as TEAC and protein precipitation activity of phenolic extracts (i.e., measured using the dye-labeled assay). The antioxidant activities of extracts as determined by the ABTS^o− radical ion assay correlated highly with those of the chemiluminescence and DPPH radical assays.     

Characterization of chlorophyll pigments present in canola seed,meal and oil

Chlorophyll pigments present in canola seed, meal and crude and degummed oils were analyzed by high-performance liquid chromatography (HPLC) with a fluorescence detector. Chlorophylls a and b, low levels of pheophytin a, and occasionally traces of pheophorbide and its methyl ester were present in canola seed. Meals and oils contained magnesium-deficient chlorophyll pigments such as pheophorbide a, methylpheophorbide a, pheophytins a and b, and pyropheophytins a and b but not chlorophyll a or b. The amounts of chlorophyll pigments were oil > seed >> meal. Both crude and degummed oils contained pheophytin a and pyropheophytin a as main components, but the ratio of pyropheophytin a to pheophytin a was markedly higher in degummed oils. No pheophorbides were detected in degummed oils. These results suggest that oil processing steps such as extraction and degumming affect the composition of chlorophyll pigments. Publication No. 678 Canadian Grain Commission.     

Isolation and identification of galactinol from castor oilseed meal

Galactinol, 1-O-α-D-galactopyranosyl-D-myo-inositol, is an essential intermediate in the biosynthesis of raffinose saccharides in plant tissues. The unavailability of a commercial source for this metabolite has hindered research on raffinose saccharide metabolism to date. The objective of this study was to develop a facile method for obtaining highly purified galactinol from a readily available source. Defatted castor oilseed meal was found to exhibit a simple soluble carbohydrate profile that included galactinol. Purification of galactinol from castor meal was achieved by enzymatic treatment and a series of liquid chromatography steps, including ion-exchange and carbon adsorption. The isolation procedure was reliable with a yield of 278 mg of galactinol from 150 g of defatted meal. The purity of galactinol was estimated at 96.4% by high-performance liquid chromatography. The identity of the purified galactinol was confirmed by enzymatic analysis, identical relative retention times on high-performance liquid chromatography and gas chromatography, and comparison of its mass spectrum to that of authentic galactinol. Presented at the AOCS Annual Meeting in Chicago in May 1991 [INFORM 2:334 (1991)].     

Separation and characterization of pigments from bleached and deodorized canola oil

An analysis of pigments responsible for color formation during bleaching and deodorization of canola oils treated with activated bleaching earth (ABE) or novel mineral-acid/silica (AS) adsorbents is presented. The chromophores are trace glycerides and were concentrated by silica column chromatography. The concentrated color bodies were hydrolyzed and analyzed as free acids or methyl esters by reversed-phase high-performance liquid chromatography with photodiode array and mass spectrometry detection,¹H and¹³C nuclear magnetic resonance and infrared spectroscopies. Absorbance in deodorized oils is mostly from oxygenated C18 and C20 fatty acids with 1 to 4 double bonds. High-wavelength absorbance in AS-bleached oils is from conjugated pentane fatty acids that are not observed for ABE-bleached oils. Thus, both the bleaching agent and the deodorization treatment affect the distribution and concentration of such stable chromophores.     

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.     

Optimization of ultrasound-assisted extraction for the maximum quantity and quality of phenolics from Stachys lavandulifolia

The response surface methodology was used to evaluate the effects of extraction time, power of ultrasound, liquid to solid ratio, and solvent composition on the quantity and quality (from aspect of antioxidant activity) phenolics of Stachys lavandulifolia. The best extraction time, power of ultrasound, liquid to solid ratio, and solvent composition for both the quality and quantity of phenolics were 14 min, 300 W, 40 (v/w), and 57% methanol, respectively. Only the liquid to solid ratio was effective on the quality of phenolics. Also, the comparison between the ultrasound-assisted extraction and maceration methods showed the suitability of ultrasound-assisted extraction for extracting phenolics from this plant.     

Detection of olive oil adulteration with canola oil from triacylglycerol analysis by reversed-phase high-performance liquid chromatography

The objective of this study was to explore the use of reversed-phase high-performance liquid chromatography (RP-HPLC) as a means to detect adulteration of olive oil with less expensive canola oil. Previously this method has been shown to be useful in the detection of some other added seed oils; however, the detection of adulteration with canola oil might be more difficult due to similarities in fatty acid composition between canola oil and olive oil. Various mixtures of canola oil with olive oils were prepared, and RP-HPLC profiles were obtained. Adulteration of olive oil samples with less than 7.5% (w/w) canola oil could not be detected.     

Optimization of extraction parameters of bioactive components from defatted marigold (Tagetes erecta L.) residue using response surface methodology

Response surface methodology (RSM) was used to estimate the optimum extraction parameters, in which the antioxidant activity (AA) of the extract from the defatted marigold residue was the strongest. The AA of marigold extracts was investigated by the radical scavenging activity assays ((2,2-azinobis-(3-ethylbenzothiazolin-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH)). Results demonstrated that AA was significantly affected by the content of total phenolics (TP) and total flavonoids (TFA) (p < 0.0001). The optimal extraction parameters of marigold extracts for the highest AA by ABTS method were ethanol concentration of 79.7%, extraction temperature of 74.2 °C and time of 8.1 h, and by DPPH assay with 89.3% of ethanol concentration at 81.5 °C for 11.1 h, AA values were 2.42 and 1.86 mmol TE/g, respectively.     

Review of the treatment of seafood processing wastewaters and recovery of proteins therein by membrane separation processes — prospects of the ultrafiltration of wastewaters from the fish meal industry

The wastewaters generated in fish meal production (average flow rates of 1100 m³/h for a plant capacity of 100 ton fish/h) contain a high organic load, and therefore they should not be discharged directly into the sea without effective treatment in order to prevent a negative impact on the environment. On the other hand, these effluents contain a large amount of potentially valuable proteins. These proteins can be concentrated by means of ultrafiltration (UF) and recycled into the fish meal process, improving its quality and the economic benefits from the raw material, whereas the treated water can be discharged into the sea or reused in the plant. Due to the high concentration of suspended matter in these effluents, microfiltration (MF) pre-treatment is required. An extensive review of the application of pressure-driven membrane separation processes in the treatment of seafood processing effluents and recovery of proteins therein is presented. Two effluents from a fish meal plant located in Talcahuano, Chile, were characterised and microfiltrated with a Whatman filter No. 1. A mineral tubular membrane, Carbosep M2 (MWCO = 15 kDa, ID = 6 mm and L = 1.2 m) was used in the UF experiments. The operating conditions were optimised in total recirculation mode, and the subsequent concentration experiments were carried out at 4 bar, 4 m/s, ambient temperature and natural pH. The results show that UF reduces the organic load from the fish meal wastewaters and allows the recovery of valuable raw materials comprising proteins. Moreover, they point out that further investigation should be dedicated to the use of UF membranes of lower molecular weight cut-off — or even NF membranes — in order to achieve complete recovery of the proteins contained in these effluents. Although the membrane undergoes severe fouling, it can easily be cleaned through a caustic washing.     

Identification and Quantitation of Allelochemicals from the Lichen Lethariella canariensis: Phytotoxicity and Antioxidative Activity

Phytotoxicity-based extraction and fractionation were employed to separate allelochemicals contained in an extract of Lethariella canariensis. Twelve phenolic substances were isolated from the phytotoxic fraction Letharal of the thalli. These were identified by spectroscopic methods, physicochemical constants, and HPLC chemical correlation, and determined to be atranol (2), chloroatranol (3), hematommic acid (4), chlorohematommic acid (5), methyl hematommate (6), methyl chlorohematommate (7) (new compound), ethyl hematommate (8), ethyl chlorohematommate (9), methyl -orsellinate (10), atranorin (11), chloroatranorin (12), and (+)-usnic acid (13). Further identification and quantification of these allelochemicals in the environment were conducted by HPLC. Several phenolic compounds showed moderate antimicrobial activity. The cytostatic activity of the polyphenols was investigated on U937 and HL-60 cells. All compounds were assayed, with the exception of 10. The Letharal mixture decreased cell viability in both cell lines. Protection against lipid peroxidation was investigated using brain homogenates. Compounds 2, 3, 6, 8, 11, and Letharal decreased H₂O₂/Fe⁺² induced lipid peroxidation in a concentration-dependent manner, while 10 and 13 were unable to protect tissue against oxidative stress.