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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 0.02mM 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.)

An HPLC method for the determination of phenylalanine ammonia-lyase, flavanone 3β-hydroxylase and flavonol synthase enzyme activity is proposed. This method is based on the determination of the compounds produced and consumed on the enzymatic reaction in just one chromatographic analysis. Optimisation of the method considered kinetic studies to establish the incubation time to perform the assay. The method here described proved to be an interesting approach to measure the activities of the three enzymes simultaneously increasing the rapidity, selectivity and sensitivity over other exiting methods. The enzyme activity method developed was applied to strawberry, raspberry, blackberry, redcurrant and blackcurrant fruits., (Copyright © 2013 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.)

The usefulness of solid phase microextraction (SPME) to detect the occurrence of the irradiation markers 2-dodecylcyclobutanone (2-DCB) and 1,3-bis(1,1-dimethylethyl)benzene in irradiated ground beef was evaluated. To that aim, beef samples were irradiated with different irradiation doses and subsequently examined together with non-irradiated beef samples used as control samples. The SPME conditions applied were selected as a result of performing an optimization process including different fibers (PDMS, DVB/CAR/PDMS, polyacrylate and PDMS/DVB), as well as extraction times (10, 25 and 40min) and temperatures (40 and 60°C). For comparison, 2-DCB and 1,3-bis(1,1-dimethylethyl)benzene were additionally identified in some of the samples by steam distillation-solvent extraction (SDE). Although this study is a preliminary work, from the results obtained SPME seemed to be a rapid and valuable technique to determine 2-DCB and 1,3-bis(1,1-dimethylethyl)benzene in ground beef subjected to irradiation, offering advantages over other methods reported in the literature. In addition, SPME allowed to confirm the validity of 2-DCB as an useful marker to distinguish non-irradiated from irradiated ground beef. On the contrary, the occurrence of 1,3-bis(1,1-dimethylethyl)benzene was however established in both types of samples by SPME and SDE., (Copyright © 2008 Elsevier Ltd. All rights reserved.)