Detection of eight genetically modified canola events using two event-specific pentaplex PCR systems

An event-specific multiplex polymerase chain reaction (PCR) detection method was developed to simultaneously detect eight genetically modified (GM) canola events (GT73, MS1, MS8, RF1, RF2, RF3, T45, and Topas 19/2). For a successful multiplex PCR assay, the eight GM canola events were divided into groups 1 and 2 in consideration of their amplicon sizes, primer efficiencies, and target sequences. In addition to the canola endogenous reference gene, FatA, the two pentaplex PCR assays targeted group 1, containing GT73, MS8, RF3, and T45, and group 2, including MS1, RF1, RF2, and Topas 19/2. Event-specific primers targeting the eight GM canola events were designed, and their specificities were confirmed using 14 GM events of maize, soybean, cotton, and canola. After optimizing the reaction conditions, the limits of detection of these two assays were approximately 0.025% for group 1 and 0.0125% for group 2. This multiplex PCR method for eight GM canola events was validated by two operators, and the data confirmed the reliability of the developed assays. The method was used to test commercially available canola seed (eight samples) and meal (one sample) produced in South Korea, China, Canada, and Australia, and the results revealed one or more GM canola events in seven of the nine samples tested. These results show that the developed multiplex system is applicable for use in the specific testing of eight commercially available GM canola events.     

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.     

Development of a method for chlorophyll removal from canola oil using mineral acids

Because of the high level of chlorophyll-type compounds found in canola oil, bleaching is an important and critical step in the canola oil refining process. In this study, a new method for reducing the chlorophyll-type impurities prior to the bleaching step was developed. This method is based on precipitating the chlorophyll compounds with mineral acids. Concentrations of chlorophyll-type compounds of up to 30 ppm could be reduced to amounts of less than 0.01 ppm by mixing the crude canola oil with a 0.4 wt% mixture of phosphoric and sulfuric acids (2:0.75, vol/vol) for 5 min at 50°C. Centrifugation and filtration also were examined as two main methods for separating the chlorophyll precipitates. The results showed that filtration by a precoated textural filter with filter-aid clay could separate the precipitates as well as the centrifugation method.     

Proportions of C18∶1n−7 and C18∶1n−9 fatty acids in canola seedcoat surface and internal lipids

Lipids of canola seedcoats (Brassica napus L. andB. rapa L.) were prepared by surface washing and by complete extraction of seed coats with toluene. The major fatty acyl-containing triacylglycerols, wax esters and free fatty acids were separated by thin-layer chromatography prior to transesterification and analysis by gas-liquid chromatography. The proportion of C18∶1n−7 to C18∶1n−9 was higher in the extracted lipids than in the surface-washed lipids for all three classes.     

Structured lipids from high-laurate canola oil and long-chain omega-3 fatty acids

The lipase-assisted acidolysis of high-laurate canola oil (HLCO; Laurical 25) with long-chain n−3 FA (DHA and EPA) was studied. Response surface methodology was used to obtain a maximal incorporation of DHA or EPA into HLCO. The studied process variables were the amount of enzyme (2–6%), reaction temperature (35–55°C), and incubation time (12–36 h). The amount of water added and the mole ratio of substrates (oil to DHA or EPA) were kept at 2% and 1∶3, respectively. All experiments were conducted according to a face-centered cube design. Under optimal conditions (4.79% of enzyme; 46.1°C; 30.1 h), the incorporation of DHA into HLCO was 37.3%. The corresponding maximal incorporation of EPA (61.6%) into Laurical 25 was obtained using 4.6% enzyme, a reaction temperature of 39.9°C, and a reaction period of 26.2 h. Examination of the positional distribution of FA on the glycerol backbone of modified HLCO with DHA showed that the DHA was primarily located in the sn-1,3 positions of the TAG molecules. However, lauric acid also remained mainly in the sn-1,3 positions of the modified oil. For EPA-modified Laurical 25, lauric acid was present mainly in the sn-1,3 positions, whereas EPA was randomly distributed over the three positions.     

Antioxidative effect of ethanol tea extracts on oxidation of canola oil

There is an increasing interest in the biological effects of natural antioxidants present in teas on formation ofin vivo free radicals, carcinogenesis, and atherogenesis. Teas are traditionally classified into six major groups, namely, green, yellow, white, black, dark-green, and oolong teas. The present study examined the antioxidative activity of ethanol extracts from these six major groups of teas against oxidation of heated canola oil. The oxidation was conducted at 100°C by monitoring oxygen consumption and changes in linoleic and linolenic acids in canola oil. The ethanol extracts of green, yellow, and white teas strongly inhibited oxidation of canola oil compared to butylated hydroxytoluene, probably due to the presence of natural polyphenols. In contrast, oolong teas examined exhibited only moderate antioxidative activity because of the partial destruction of natural polyphenols by semifermentation. The ethanol extracts of black, dark-green, and ginseng teas studied showed little or no protection to canola oil from lipid oxidation, probably due to the complete destruction of natural polyphenols by fermentation during manufacturing processes.     

Enzyme-aidedvs. two-stage processing of canola: Technology,product quality and cost evaluation

The investigation focussed on the use of carbohydrase enzymes to enhance oil extraction during pressing in a laboratory expeller. Enzyme-treated seeds at 6% moisture were pressed in the expeller set at full-press conditions. Control seeds were pressed at wider choke openings but at the same barrel pressures as enzyme-treated samples. Time of pressing and temperature and pressure inside the expeller barrel were used to calculate throughput and energy requirements per unit weight of processed material. Treatment with enzymes improved throughput of the expeller, increased oil flow rate and oil recovery. Material throughput was increased by 30–50%, depending on canola variety. The recovery of the oil was increased from 72% of the seed oil for control samples, to 90–93% for enzyme-treated samples. The average residual oil content in presscakes from enzyme-treated seeds was 7.4%. The oil quality was inferior to cold-pressed control but was much better than has been reported for solvent-extracted oil.     

牦牛酥油鞘磷脂对小鼠脂质代谢紊乱和肝脏组织炎症的调节作用

研究牦牛酥油鞘磷脂对高脂饮食小鼠脂质代谢紊乱和肝脏组织炎症的调节作用.选取30只C57BL/6J雄性小鼠随机分为5组,分别为低脂组、高脂组、鞘磷脂高剂量组(鞘磷脂添加量为1.20g/100g)、鞘磷脂中剂量组(鞘磷脂添加量为0.60g/100g)和鞘磷脂低剂量组(鞘磷脂添加量为0.30g/100g).采用酶联免疫和荧光...     

Polypeptide profile and functional properties of defatted meals and protein isolates of canola seeds

Laboratory‐defatted meals from four types of canola seeds were analysed for protein profile by reducing and non‐reducing forms of sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS‐PAGE). In the absence of a reducing agent (2‐mercaptoethanol), four major polypeptide bands (16, 18, 30 and 53 kDa) were prominent in similar ratios in all varieties. In the presence of mercaptoethanol, significant reductions in intensity of the major bands occurred, suggesting that the major polypeptides contained smaller units which were held together by disulphide bonds. Meals from Brassica napus seeds had higher protein solubilities than meals from Brassica rapa seeds. Meals with higher protein solubility values also had higher foaming capacity (FC) values. Generally, the acid‐precipitated (pH 4.0) protein isolates (APPIs) had higher FC values than the calcium‐precipitated isolates (CPPIs). On the other hand, the CPPIs formed emulsions with higher values of emulsifying activity index (EAI) when compared to the APPIs. The results indicate that variations in functional properties of protein isolates and meals between the four seed types were probably due to differences in protein conformation in aqueous solutions rather than differences in polypeptide composition. © 2001 Society of Chemical Industry