Data on lipid hydroperoxide isomers and lipoxygenase specificity in potato fruit juice

Description

This study aimed to quantify the levels and relative proportions of 9- and 13-hydroperoxyoctadecadienoic acid (HPODE) in the fruit juice of five industrial potato cultivars (Kuras, Saprodi, Cultivar X, Ydun, and Stratos), and to assess whether significant differences exist among them. The dataset consists of two sheets. The “Intensity” sheet contains the raw intensity data for 9-HPODE and 13-HPODE measured in three biological replicates for each cultivar. In addition, the total intensity has been calculated, and the mean and standard deviation (STD) of the three replicates are provided. The “Percentage” sheet presents the relative levels of 9- and 13-HPODE expressed as a percentage of the total intensity. The results indicate that the potato cultivars have similar total levels of lipid hydroperoxides but differ in the ratio of 9- to 13-HPODE. Overall, the 9-HPODE isomer predominates, suggesting a greater contribution of 9-lipoxygenase activity and oxidation at the C9 position. However, variations in the isomer ratio among cultivars point to differences in the relative activity of lipid oxidation pathways. Further details on data acquisition are provided in the “Steps to reproduce” section.

Steps to reproduce

1 Preparation of Potato Fruit Juice PFJ from each variety was prepared in three batches. The potatoes were washed thoroughly to remove dirt and sand, then processed using a twin-screw Angel Juicer 8500S, which produced juice and pulp. The juice was centrifuged at 4700 x g for 10 min at 4 °C in a Multifuge 3SR to remove starch and insoluble plant fibers. The resulting PFJ was immediately frozen using liquid nitrogen and stored at -21 °C until further analysis. 2 Lipid Hydroperoxide Isomer Analysis for Lipoxygenase Specificity PFJ was centrifuged at 15300 x g for 2 min at 4 °C in an Eppendorf 5417C High-speed benchtop centrifuge to remove any residual starch and particulate matter. Subsequently, 297 µL of the supernatant were mixed with 3 µL LA and incubated at 40 °C for 4 h in a Peltier-cooled incubator IPP30. Next, protein denaturation was achieved by adding 1200 µL of ice-cold MeOH, followed by incubation at -20 °C for 30 min. Subsequently, samples were centrifuged at 15300 x g for 5 min and filtered through a 0.45 µm PTFE filter. For each potato cultivar, one blank sample consisting of PFJ without added LA was prepared. The specificity of potato LOX toward the formation of 9-HPODE and 13-HPODE was then determined using a liquid chromatography-ultraviolet-mass spectrometry (LC-UV-MS) method with inspiration from Heshof et al. (2013) and Haeflinger et al. (2007). Chromatographic separation was performed on an Agilent 1260 Infinity II HPLC system from Agilent Technologies equipped with a reverse-phase Kinetex C18 column (2.6 µm, 100 Å, 150 × 2.1 mm) (Phenomenex, Torrance, California, United States). The mobile phase consisted of solvent A (0.1% formic acid in water) and solvent B (0.1% formic acid in acetonitrile) at a flow rate of 0.3 mL/min. The gradient settings for a 30 min run were: 0 min: 40% B; 10 min: 65% B; 17 min: 65% B; 18 min: 95% B; 23 min: 95% B; 26 min: 40% B; 30 min: 40% B. The autosampler was maintained at 10 °C, the column temperature at 30 °C, and the UV detection was carried out at 234 nm. The injection volume was 1 µL. The HPLC system was coupled to an Agilent InfinityLab CM/MSD XT single quadrupole mass spectrometer from Agilent Technologies (Santa Clara, California, USA) equipped with an API-ES source operated in negative ion mode. The drying gas temperature was set to 350 °C with a flow rate of 10 L/min and a nebulizer pressure of 50 psig. The capillary voltage was 3500 V, and the fragmentor voltage 200 V. Data acquisition was performed in SIM mode, targeting m/z 113 and 195 for 9-HPODE; m/z 123, 169, and 184 for 13-HPODE; and m/z 249 and 293 common to both isomers. Data processing was conducted using Agilent OpenLab CSD LCMS SQ software (Santa Clara, California, USA). Semi-quantification was based on the peak areas (AUC) of m/z 195 for 9-HPODE and m/z 169 for 13-HPODE. To correct for a 3.98-fold difference in ion response between the two analytes, the AUC of m/z 169 was multiplied by 3.98 prior to comparison.

Institutions

• Aarhus University

  Central Jutland, Aarhus

Categories

Funders

• REFINES project supported by Plant2Food

  Grant ID: NNF22SA0081019

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