Changes in contents of phenolic compounds (sinapic acid derivatives) in seeds of Brassica napus L.under adverse storage conditions (original) (raw)
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Acta Scientiarum Polonorum, 2018
Background. The quality of rapeseed oil depends to a considerable degree on raw material quality. Negligence in maintaining the appropriate conditions during long-term rapeseed storage (excessively high humidity and temperature) may contribute to a deterioration of seed quality, as a result of microbial growth and changes in native antioxidant contents. The aim of this study was to investigate the effect of inappropriate storage conditions on changes in sinapic acid derivative content, which is the main phenolic compound in rapeseeds. Material and methods. The material used for tests was canola cv. PR 46 W14. Seeds with a 13.5% moisture content were stored for 21 days in a thermo-hygrostat chamber, ensuring rapeseed storage under constant humidity and temperature conditions. In this study, the level of mould fungi was analysed using the plate method, while those of sinapic acid derivatives were determined using the HPLC-DAD method. Results. Intensive growth of mould fungi in the rapeseeds was observed after 6 days of storage. Changes were recorded in sinapic acid derivative contents, which are the main phenolic compounds in rapeseed. The level of phenolic compounds found in the bound form (sinapin; sinapic acid methyl ester; 1,2-disinapoyldihexoside; 1,2-disinapoyl-hexoside and 1,2,2'-trisinapoyl-dihexoside) decreased. At the same time, an increase was recorded in trans-sinapic acid content (by 63%). Conclusion. Both qualitative and quantitative changes in phenolic compounds may be connected with the development of fungal microflora in stored rapeseeds. Only adequate storage conditions for the oil raw material, such as rapeseeds, may ensure good quality in the final product, in this case, rapeseed oil.
Processing of rapeseed oil: effects on sinapic acid derivative content and oxidative stability
European Food Research and Technology, 2003
Rapeseed oil is usually expelled from the seed at high temperatures. Refining removes most of the non-triacylglycerol components, including many sinapic acid derivatives typical for rapeseed. The effect of these phenolic constituents on the oxidative stability of the oil was studied using rapeseed and turnip rapeseed oil samples resulting from different expelling conditions and refinement steps. The polar fraction was isolated, analyzed and tested for antioxidative activity in various lipid oxidation models. The amount of phenols was greatest in the post-expelled crude rapeseed oil, decreasing with an increasing degree of refining. The polar phenol content correlated with oxidative stability. The most active antioxidant component of the polar fraction was identified as vinylsyringol, a decarboxylation product of sinapic acid. This is the first report of vinylsyringol in rapeseed oil. It was abundant in the post-expelled crude oils and apparently responsible for their high phenol content and oxidative stability. Some vinylsyringol was present in the superdegummed oil but not in the fully refined oils.
European Journal of Lipid Science and Technology, 2014
This study was conducted to evaluate the variation in chemical composition and oxidative stability of 21 different commercial rapeseed oils. Their composition was estimated immediately after opening the packaging and for the same oils at the end of their induction period. The oxidation of oils was conducted at 110°C in an oven test, while the induction time was determined in a Rancimat test at the same temperature. It was found that the initial ratio of n-6 to n-3 fatty acids was close to 2.2 to 1. These oils differed mainly in minor acids, such as C16:0 and C20:1. At the end of their shelf life, a reduction of C18:2 and C18:3 acids shares was found, which was accompanied by a slight increase of n-6 to n-3 ratio. The most variable oil-soluble compounds of oils were carotenoids, chlorophylls, and phenolics, while the tocopherols were the most stable. Induction time was the most positively correlated with the oil-soluble phenolics (r ¼ 0.76 for all samples) and chlorophylls (r ¼ 0.77 for refined oils), while carotenoids generally acted as pro-oxidants (r ¼ À 0.66 for all oils). The degradation degree of tested compounds during oxidation (on average) was as follows: phytosterols > tocopherols > carotenoids > phenolic compounds > chlorophylls.
Characterization of Rapeseed Germplasm for Various Quality Parameters
2016
Pakistan is facing with a chronic deficit in edible oil production with better quality characteristics for value added products. Biochemical characterization was evaluated in 20 rapeseed (10 entries each of Brassica napus and Brassica campestris) genotypes. These lines were characterized for major long-chain fatty acids, protein contents, glucosinolates, moisture % age, oil contents using NIRS, Spectrophotometer and NMR respectively. The biochemical assessment of Brassica napus genotypes revealed the range of 6.5 to 7.8% moisture, 43.3 to 47.4 % oil contents, 23.2 to 30.4 % protein contents, 49.0 to 53.8 % oleic acid and 7.9 to 9.6 % linolenic acid, while that of Brassica campestris genotypes showed the range of 5.5 to 7.6 % moisture, 44.1 to 48.1 % oil contents, 22.8 to 26.0 % protein contents, 38.5 to 47.9 % oleic acid and 8.0 to 10.2 % linolenic acid. Most of the lines were found to have a high percentage of oil and protein contents and oleic acid that can further be utilized in ...
European Food Research and Technology, 2003
Rapeseed meal is the dry residue of the rapeseed de-oiling process. It contains more phenolic compounds than any other oilseed meal. In analysis, rapeseed phenolic esters, mainly sinapine, are usually hydrolyzed to free phenolic acids, because sinapine is not available as a commercial standard. In this study, the efficiencies of different enzymes and enzyme preparations in hydrolyzing sinapine to sinapic acid were explored. The main phenolics in rapeseed meal were sinapine and sinapic acid. In rapeseed oil, the main phenolics were vinylsyringol, sinapine and sinapic acid. In hydrolyzing rapeseed meal, ferulic acid esterase and Ultraflo L were as effective in hydrolyzing sinapine as sodium hydroxide. Over 90% of sinapic acid derivatives were hydrolyzed to yield sinapic acid. Compared to base hydrolysis, enzyme treatment was not only as efficient but also less destructive to the liberated phenolics. Thus, enzymatic hydrolysis is a recommended procedure for optimal analysis of rapeseed phenolics. In rapeseed oils, hydrolysis was best applied in crude post-expelled rapeseed oils with high phenolic content.
European Food Research and Technology, 2009
De-oiled rapeseed is a rich source of proteins and phenolic compounds. The phenolic compounds, namely sinapic acid derivatives (SAD), could occur as free sinapic acid, esterified (as sinapine, the choline ester of sinapic acid) and decarboxylated (as canolol) forms. Rapeseed protein preparations containing very low phenolic compounds have been the focus of our ongoing research. A precipitated rapeseed protein isolate is investigated for SAD such as sinapine, sinapoyl glucose, canolol using HPLC–DAD and LC–MS. Profile of the phenolic compounds of de-oiled rapeseed, press cakes and the precipitated protein isolate are compared. HPLC–DAD analysis indicated SAD; particularly sinapine is the main phenolic compound of all the substrates. The protein derivation process did not remarkably alter the profile of the investigated protein isolate.
Journal of Stored Products Research, 2019
Improper rapeseed preservation and storage after harvest may contribute to a reduction of phytosterol contents in the seeds. The aim of the study was to investigate the dynamics of phytosterol degradation in bulks of rapeseed stored under various temperature and water activity conditions. In the experiments a hazardous level of fungal infestation was considered to reflect the population of fungi colonizing seeds during vegetation and harvest at adverse weather conditions. Changes in phytosterol contents intensified with the increase in storage temperature and water activity in seeds. The temperature in the range of 12 e24 C and water activity in seeds a w ¼ 0.75e0.76 significantly limited phytosterol degradation (6.5% and 8% after 48 and 72 days of storage), whereas in seeds with a w ¼ 0.90 stored at 30 C major phytosterol losses were observed (61% after 48 days of storage). Among the identified phytosterols the pattern of changes in campesterol content was similar to that for b-sitosterol, whereas brassicasterol degradation proceeded similarly as the reduction in avenasterol and stigmasterol levels. The degradation of stigmasterol, brassicasterol and avenasterol was more rapid than that of campesterol and b-sitosterol. Correlation analysis showed that acid value and seed germination may be used as predictive factors for phytosterol degradation. The correlation between the fungal population and phytosterol concentration was found only in seed samples, in which a substantial mould activity was observed (a w ! 0.80 at t ¼ 24-30 C and a w ! 0.86 at t ¼ 12-18 C). The results provide useful quality control points, which may be used to improve the existing postharvest management systems of rapeseed preservation and storage.
Journal of the American Oil Chemists' Society, 2012
The effect of temperature (25 or 35°C) and moisture content (10, 12.5, 15.5 %) on rapeseed phytosterol degradation was examined for 18 days. Statistical analysis showed that temperature, moisture and time of storage have a significant effect on phytosterol degradation. After 18 days of seed storage at a temperature of 25 and 30°C losses of these compounds amounted to 11 and 13 % in seeds with moisture contents of 10, 12 and 16 % in seeds with a moisture content of 12.5 %, while they were 24 and 58 % in seeds with a moisture content of 15.5 %. Among all the identified sterols the greatest degradation rate was observed for stigmasterol and brassicasterol. Losses of stigmasterol and brassicasterol during storage of seeds with a 12.5 % moisture content at a temperature of 30°C were 17 and 28 %, respectively, while in seeds with a moisture content of 15.5 % these losses increased to 73 and 63 %.
Abstract: Objective: The main target of this study was to raise stability, quality and functional properties of rapeseed oil by mixing with non-conventional oils, namely apricot kernels, grape seed, tomato seed and wheat germ containing high levels of phytonutrients. Methodology: These components such as tocopherols, tocotrienols and phytosterols as well as fatty acid composition were determined by HPLC and GLC. Rancimat was used for detecting oxidative stability. Results: Admix rapeseed oil (95, 90 and 80% v/v) with four non-conventional oils resulted in a decrease in the ratio of polyunsaturated/saturated fatty acids which have a positive influence on oxidative stability. The ratio of omega-6 to omega-3 in mixed oils was attained to desirable ratios having positive effects in decrease the risk of some diseases. Oxidative stability of rapeseed oil blended with wheat germ oil was highest. The amount of β-sitosterol was increased by increasing the ratios of non-conventional oils. Adding wheat germ oil to rapeseed oil leads to an increase in total tocopherols and α-tocopherol. Conclusion: Admixed rapeseed oil with non-conventional oil at a level of 20% v/v is more satisfactory and superior to other blends in terms of stability which is an important indicator the oil quality and shelf life of edible oils.