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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 0.02 mM 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 0.02 mM MJ treated Ben Hope black currants exerted contents of gallic, caffeic, p -coumaric and ferulic acids of 201.4, 125.9, 201.3 and 112.5 μg g −1 vs 124.3, 58.6, 165.4 and 95.8 μg g −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. [ABSTRACT FROM AUTHOR]

Linoleic and linolenic acids are health-promoting compounds having a number of biological properties. In the present study, oxidative degradation of these fatty acids into off-flavor compounds in boiled potato was intended to be reduced. To that end, raw potatoes were treated by applying: (i) the commercial mixture (±)-methyl jasmonate, (ii) pure (+)-methyl jasmonate, and (iii) pure (−)-methyl jasmonate, respectively. Four cultivars (i.e., Cara, Inca Sun, Mayan Gold, and Maris Piper) were included in the study. As a result, the post-harvest application of (±)-methyl jasmonate and (+)-methyl jasmonate to raw potatoes during storage resulted in a significant decrease of lipid-derived volatile compounds in boiled potato. This suggests an inhibitory effect of both the commercial enantiomeric mixture and the pure (+)-methyl jasmonate on the lipoxygenase pathway. Stabilization of linoleic and linolenic acids against autoxidation is achieved by treatment with the enantiomeric mixture and pure (+)-methyl jasmonate. (−)-Methyl jasmonate however exhibited the opposite effect since it did not reduce lipid oxidation in boiled potato. The results found in the present work support earlier evidence on different effects of methyl jasmonate enantiomers on plant food composition. From a practical point of view, post-harvest treatments with (+)-methyl jasmonate can be used by the potato industry to obtain healthier and more pleasant products. Practical application The results found in the present study demonstrate that the practical applications of methyl jasmonate treatments minimize lipid oxidation in boiled potato. That allows us to obtain, on the one hand, tubers containing higher contents of linolenic and linoleic acids and, on the other, more pleasant flavor after boiling. The exogenous application of (+)-MJ to raw potato during storage enabled lipid oxidation in boiled potato to be reduced. Therefore, (+)-MJ treatment might be used by the potato industry to obtain a healthier and more pleasant product. [ABSTRACT FROM AUTHOR]

Effect of preharvest methyl jasmonate treatments on the levels of ellagic acid, quercetin and myricetin in raspberries and blackcurrants was investigated. Varietal influence on treatment effect was particularly considered. For this purpose, different cultivars of raspberry (Glen Lyon, Glen Ample and Tumaleen) and blackcurrant (Ben Hope, Ben Alder and Gairn) were studied. The treatments were carried out by spraying two distinct concentrations of methyl jasmonate (0.01 and 0.1 mM) on berry plants. Cultivar to cultivar variations in the contents of ellagic acid and myricetin were observed in untreated berries. No varietal differences were however found in quercetin content. The effect of preharvest methyl jasmonate treatments was also cultivar independent. Preharvest methyl jasmonate always resulted in a general increase of the flavonoids studied, particularly, ellagic acid and quercetin. For instance, the content of ellagic acid increased approximately from 10 to 22 mg 100 g −1 and quercetin increased from 6 to 16 mg 100 g −1 in Glen Lyon raspberries. Similarly, ellagic acid increased from 6 to 11 mg 100 g −1 and quercetin from 4 to 9 mg 100 g −1 in Ben Hope blackcurrants. Preharvest methyl jasmonate treatment can be useful to food industry to obtain berries with enhanced health promoting properties. [ABSTRACT FROM AUTHOR]

The effect of preharvest and postharvest treatments with methyl jasmonate on the concentrations of myricetin, ellagic acid and quercetin in red raspberry was investigated. Different raspberry varieties and different MJ concentrations were included in the study. The preharvest MJ application to raspberry plants resulted in a significant increase of the flavonoids in all varieties. Increases from 90.32 to 336.95 μg/g of myricetin, from 103.15 to 218.91 μg/g of ellagic acid and from 65.22 to 163.15 μg/g of quercetin were obtained in Glen Lyon variety after pre-harvest treatment with 0.1 mM MJ. Postharvest MJ treatment did not lead to such a significant increase in the concentrations but enabled natural decline during storage to be avoided. Contents of myricetin, ellagic acid and quercetin were maintained. Concentrations in postharvest MJ treated raspberries were constant between 60 and 100 μg/g. Enzyme studies reflected increase in PAL activity after preharvest MJ treatment. No MJ promoting effect and even an inhibitory effect was however observed in FHT and FLS enzymes, respectively. The results found in the present work help get an insight into the mechanisms of MJ action in phenylpropanoid metabolism in raspberries. Preharvest MJ treatment of raspberries can be useful for obtaining fruit with enhanced healthy promoting properties. [ABSTRACT FROM AUTHOR]

Highlights: [•] An enantioselective HPLC method permits the resolution of methyl jasmonate stereoisomers. [•] It is the first time that the four stereoisomers have been isolated by semi-preparative chiral HPLC. [•] The effect of the stereoisomers on the changes in raspberries’ chiral volatiles was studied. [•] Bioformation of (+)-limonene was promoted to a greater extent by (−)-epi-methyl jasmonate. [•] The other chiral flavours were produced in the same amounts with the four stereoisomers. [Copyright &y& Elsevier]

Highlights: [•] MJ treatment of strawberry increases DPPH antioxidant activity. [•] MJ treatment of strawberry increases the anti-inflammatory activity. [•] Antioxidant and anti-inflammatory activities of MJ-strawberry fractions were evaluated. [•] EtOAc and n-butanol fractions displayed the highest activity. [•] Identification of polyphenols in these fractions were carried out by LC–MS. [Copyright &y& Elsevier]

Abstract: The effect of methyl jasmonate in combination with ethanol on the formation of aroma constituents in berryfruit belonging to the Rosaceae was investigated. Postharvest treatments of raspberries, strawberries and blackberries were carried out. After evaluating the aromatic fractions of the berries, esters and terpenes were the most abundant compounds. There were different effects of the treatment according to the berry species. In contrast to raspberries, which exhibited a significant decline (p <0.05) in the total amount of volatiles after treatment, a significant (p <0.05) enhancement of total volatile compounds was observed in strawberries, while no significant effect was found in blackberries. Esters and terpene compounds responded similarly in strawberries and blackberries suggesting similarity in the biochemistry of their aroma synthesis. In contrast, raspberry volatile compounds showed a different pattern, reflecting different biosynthetic pathways for aroma formation in raspberry. The natural volatile compounds, methyl jasmonate and ethanol, seemed to have either promoting effects on the formation of the (−)-enantiomers of chiral terpenes and ionones or inhibitory effects on the synthesis of the corresponding (+)-enantiomers. [Copyright &y& Elsevier]

Abstract: 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 &y& Elsevier]