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Background: Chemical elicitation is one of the most effective methods currently used to enrich plant foods in bioactive compounds. Methyl jasmonate (MJ) has been described as a very useful elicitor of some plant compounds, polyphenols among them. The objective of this study was to determine the effects of pre-harvest MJ application on the increase in the main flavonoids and the antioxidant properties of black currant (Ribes nigrum) cultivars., Results: Significant enhancement of individual and total anthocyanins was measured after elicitation with MJ, particularly when a concentration of 0.2 mmol L(-1) was used. Total anthocyanins increased from 28288.74 ± 253.65 to 43561.08 ± 145.87 mg kg(-1) in Ben Hope black currants after elicitation with 0.2 mmol L(-1) MJ. Similarly, an increase from 35986.04 ± 287.98 to 41320.22 ± 109.38 mg kg(-1) was estimated in Ben Alder cultivar. Black currant flavonols were not individually affected by the treatment; however, total flavonols increased from 3115.21 ± 12.11 to 3268.41 ± 8.91 mg kg(-1) in Ben Hope and from 3016.38 ± 10.07 to 3110.95 ± 8.57 mg kg(-1) in Ben Alder. Antioxidant properties of black currants as measured by DPPH and ABTS assays improved proportionally to the increase in flavonoid content after MJ elicitation., Conclusion: Pre-harvest elicitation with MJ is proposed as a useful tool to enhance contents of anthocyanins and flavonols as well as free radical-scavenging activity of black currants. The functional black currants obtained here can be interesting for industry, for consumption as fresh fruits and for production of juice and jam. © 2015 Society of Chemical Industry., (© 2015 Society of Chemical Industry.)

Black currant seeds are obtained as a residue during juice production. Black currant seed oil contains high amounts of nutritionally desirable constituents such as γ-linolenic acid (GLA), α-linolenic acid (ALA) and stearidonic acid (SA), as well as certain phenolic acids, which act as natural antioxidants. Fatty acids and phenolic acids of seeds from black currant cultivars after elicitation with methyl jasmonate (MJ) were examined. GLA contents around 25% with respect to total fatty acid content were measured in seeds after pre-harvest treatment of black currants with 0.02mM MJ in 0.05% Tween-20. High GLA samples also exhibited high SA content (higher than 10% with respect to total fatty acid content); however, ALA dropped (from 16% to 10%). High GLA content seeds also showed increased contents of gallic, caffeic, p-coumaric and ferulic acids. In particular, seeds from 0.02mM MJ treated Ben Hope black currants exerted contents of gallic, caffeic, p-coumaric and ferulic acids of 201.4, 125.9, 201.3 and 112.5μgg(-1)vs 124.3, 58.6, 165.4 and 95.8μgg(-1) measured in seeds from untreated Ben Hope black currants. Comparable results were obtained for Ben Alder and Ben Gairn berries. Chemical elicitation with 0.02 MJ is proposed as an industrial practice in such a way that, after consideration of quality issues, it would be obtained high added value black currant seeds., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

The four stereoisomers present in a commercial sample of methyl jasmonate (MJ) were isolated at semi-preparative scale by HPLC, using a permethylated β-cyclodextrin column. This allowed the baseline resolution and collection of both major (methyl jasmonates) and minor (epi-methyl jasmonates) stereoisomers. When 1.5 mL of a 5mg per mL MJ solution were injected, isolated amounts were 3.56 mg for (-) and (+)-methyl jasmonates, with respective purities of 96.1% and 99.9%, and 0.18 mg for (-)- and (+)-epi-methyl jasmonates, with 98.6% and 91.6% respective purities. The post-harvest treatment of red raspberry fruits with the pure methyl jasmonate stereoisomers isolated proved that (-)-epi-MJ either promotes the bioformation of (+)-limonene or inhibits that of (-)-limonene to a greater extent than the other three MJ stereoisomers, while the biosynthesis of the (+)-enantiomer of α-ionone is favoured equally, whichever MJ stereoisomer used. The results obtained in the present study might be used to obtain food products with improved sensory characteristics., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Background: During potato storage the tubers tend to develop off-flavours, mainly due to lipid-derived aldehydes, whose formation is increased after boiling or processing. This may become a problem when boiled or precooked potatoes are used. Methyl jasmonate (MJ) is a phytohormone capable of modifying plant and food composition. The aim of this work was to control the formation of off-flavours in different cultivars of raw potato during storage by MJ treatment., Results: The use of Carbowax 20M as support in MJ emulsion resulted in significantly (P < 0.05) lower levels of lipid-derived compounds than the use of lanolin. Levels of the lipid-derived aldehydes propanal, hep-2-enal, nonanal, oct-2-enal and hexanal, although dependent on variety, generally decreased significantly (P < 0.05) after treatment with MJ/Carbowax 20M emulsion. Sugar-derived compounds such as pyridine and furfural, however, were not affected by this treatment., Conclusion: Treatment with MJ/Carbowax 20M can be used to diminish the formation of off-flavours in boiled potato. However, this treatment is not useful to avoid the sweetening caused by sugar-derived products. Additional advantages of exogenous MJ are a delay in the appearance of sprouting and aging and hence prolongation of the storage life of potato tubers., (Copyright © 2010 Society of Chemical Industry.)

Background: Although strawberry aroma is very complex, certain compounds have been described as main contributors, i.e. furanones, aldehydes, alcohols, sulfur compounds and particularly methyl and ethyl esters. In addition, strawberries possess potent antioxidant activity because of their high content of phenolic compounds. Among them, flavonols are highlighted as important antioxidant compounds in strawberry. The objective of this study was to assess the effect of methyl jasmonate (MJ) on the composition of the major contributors to aroma and on the content of certain flavonols in strawberry fruits., Results: The levels of all studied volatile compounds were significantly affected by MJ treatment, though the individual effect differed according to the specific compound considered. Most of them increased significantly (P < 0.05), except methyl butanoate, which always showed higher levels in untreated strawberries. In contrast to aroma compounds, the change in the concentration of flavonols (i.e. myricetin, quercetin and kaempferol) was not significant in MJ-treated strawberries. Considering the health-promoting activity of these compounds, further investigations on the experimental conditions related to the treatment are required to control flavonol bioformation by means of MJ., Conclusion: The exogenous application of MJ vapour to strawberry enhances, in general, the production of the most relevant aroma-active compounds. On the contrary, MJ treatment does not appear to influence the levels of myricetin, quercetin and kaempferol. Thus postharvest MJ treatment is proposed as an approach to obtain improved strawberry fruits in terms of sensory quality and health-promoting properties.

A method based on the use of the through oven transfer adsorption-desorption (TOTAD) interface in on-line coupling between reversed phase liquid chromatography and gas chromatography (RPLC-GC) for the determination of chiral volatile compounds was developed. In particular, the method was applied to the study of the influence of methyl jasmonate (MJ) treatment on the production and enantiomeric composition of selected aroma compounds in strawberry. The compounds studied were ethyl 2-methylbutanoate, linalool and 4-hydroxy-2,5-dimethyl-3(2H)-furanone (i.e. furaneol), which were examined on days 3, 6 and 9 after treatment. The method developed resulted in relative standard deviations (RSDs) of 21.6%, 8.1% and 9.8% and limits of detection (LD) of 0.04, 0.07 and 0.02mg/l for ethyl 2-methylbutanoate, linalool and furaneol, respectively. The application of the RPLC-TOTAD-GC method allowed higher levels of ethyl 2-methylbutanoate, linalool and furaneol to be detected, particularly after 9 days of treatment. Besides, MJ demonstrated to affect the enantiomeric distribution of ethyl 2-methylbutanoate. On the contrary, the enantiomeric composition of linalool and furaneol kept constant in both control and MJ-treated strawberries throughout the study. These results are discussed., (Copyright 2009 Elsevier B.V. All rights reserved.)

Introduction: Methyl jasmonate (MJ) contains two chiral centres at C-3 and C-7 in its chemical structure, which implies that it can exist in four possible stereoisomeric forms, namely (+)-MJ, (-)-MJ, (+)-epiMJ and (-)-epiMJ. The absolute configuration of the two side chains of MJ affects the biological activity associated with this compound., Objective: To isolate pure (-)-MJ from a natural source, Jasminum polyanthum Franch., with the intention of increasing the knowledge about its biological properties, including its effect on the biosynthesis of plant metabolites., Methodology: The method used was based on steam distillation extraction (SDE) as an extraction technique followed by high-performance liquid chromatography (HPLC) as a purification procedure. The HPLC flow-rate as well as the number of fractions accumulated were optimised to achieve the concentration and purity required., Results: The employment of 0.3 mL/min as HPLC flow-rate and the accumulation of three HPLC fractions allowed the required enantiomeric purity (95%) and concentration (0.36 mg/L in each HPLC fraction) to efficiently obtain (-)-methyl jasmonate from Jasminum polyanthum Franch. to be achieved., Conclusion: The approach proposed may enable the properties and effect of pure (-)-MJ on plant responses to be studied. The use of a natural source to obtain (-)-MJ is presented as an alternative to the enantioselective synthesis and enantiomeric resolution from the standard racaemic mixture.

A method based on the use of HPLC for the enantioselective resolution of the four stereoisomers of methyl jasmonate (MJ) with no need for the previous formation of the diastereoisomers is developed. To that end, a Nucleodex-beta-PM column as well as an optimization process considering different flow rates and mobile phase compositions were required. As a result, 0.8 mL/min and 55:45 methanol/water composition were the conditions selected to carry out the separation of the stereoisomers. Isolation of pure (-)- and (+)-MJ was accomplished by collecting the HPLC fractions corresponding to their elution time. SPE was subsequently used to concentrate and change the solvent of the HPLC fractions collected. Chiral GC and polarimetry were additionally employed to evaluate the purity and optical rotation, respectively, of the enantiomers separated. The results found in this study are particularly relevant considering that MJ stereoisomers are not commercially available.