Continuous data of Lipoxygenase activity in potato cultivars

Description

This study aimed to determine the lipoxygenase (LOX) activity in the fruit juice of five industrial potato cultivars and to assess whether significant differences exist among them. The dataset is organized into three sheets: “Standard curve” sheet: This sheet contains five data points ranging from 10 to 100 µM 13-hydroperoxyoctadecadienoic acid (13-HPODE) along with their corresponding absorbance values at 234 nm. The data demonstrate a linear relationship between 13-HPODE concentration and absorbance at 234 nm. “Raw data” sheet: This sheet includes the primary measurements of LOX activity for the five potato cultivars. Each dataset consists of a blank sample (sample + buffer, without substrate) and three biological replicates (R1, R2, and R3), each measured in technical triplicates. Absorbance was recorded every 15 seconds over a 5-minute period. Data processing was carried out as follows: 1) (Highlighted in yellow) Technical replicates were averaged for each biological replicate, and the blank value was subtracted. 2) (Highlighted in yellow) Absorbance values were converted to 13-HPODE equivalents using the standard curve from the “Standard curve” sheet. 3) (Highlighted in yellow) LOX activity (expressed as µM/min from step 2) was normalized to mM 13-HPODE/min per mg protein using the measured protein content of each juice sample. “Final result” sheet: This sheet summarizes the calculated LOX activity for each biological replicate (Rate R1, Rate R2, and Rate R3), along with the mean ± standard deviation (STD). The results indicate clear differences in LOX activity among the potato cultivars. Further details on data acquisition are provided in the “Steps to reproduce” section. Overall, the data demonstrate that potato cultivars differ significantly in lipoxygenase activity, a key factor influencing lipid oxidation.

Steps to reproduce

1 Preparation of Potato Fruit Juice Potato fruit juice (PFJ) from each variety (Kuras, Saprodi, Ydun, Stratos and a secret cultivar "Cultivar X) was prepared in three batches. The potatoes were washed thoroughly to remove dirt and sand, then processed using a twin-screw Angel Juicer 8500S (Angel® Juicer, South Korea), which produced juice and pulp. The juice was centrifuged at 4700 x g for 10 min at 4 °C in a Multifuge 3SR (Fisher Scientific™, Germany) 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 DUMATHERM® Protein Determination The protein concentration of PFJ samples (Section 1) was determined using a DUMATHERM® (Gerhardt Analytical Systems, Königswinter, Germany). The combustion was performed with 1.4 mL O_2/mg sample and the flow rate of oxygen was set to 200 mL/min. A standard curve from Trizma® base and EDTA was applied to obtain the total nitrogen. A standard nitrogen-to-protein conversion factor of 6.25 (Van Gelder, 1981; Zhang et al., 2017) was then applied to estimate the protein content of the samples from the total nitrogen. 3 Conjugated diene assay To evaluate Lipoxygenase (LOX) activity in PFJ derived from the five potato cultivars (Section 1), a model system was established using PFJ as the LOX source and linoleic acid (LA) as the substrate in a 20 mmol/L phosphate buffer at pH 7. A 4.3 mmol/L LA solution was freshly prepared according to Chrisnasari et al. (2024). In brief, the solution was prepared by mixing 13.5 μL of LA with 12.5 μL of Tween® 20 in 4 mL of MilliQ-water. Then, 0.55 mL of 0.5 mol/L NaOH was added, and the final volume was adjusted to 10 mL with MilliQ-water. Reaction mixtures were then prepared by adding 100 μL of 100-fold diluted PFJ to 117 μL of the LA solution, followed by adjusting the volume to 1 mL with 20 mmol/L phosphate buffer at pH 7, resulting in a final LA concentration of 0.5 mmol/L for the assay. The LOX activity was analyzed as follows; 100 μL of each sample was transferred to a UV-Vis 96-well plate, and the absorbance was measured continuously at 234 nm every 15 s for 5 min monitoring the development in conjugated dienes (Chen et al., 2021) using a Synergy 2 Multi-Detection Microplate Reader (BioTek Instruments Inc., Vermont, USA). A 13-HPODE standard curve (10-100 μmol/L) was prepared on the same plate and used to quantify the change in the FAHP concentration. Subsequently, LOX activity was normalized to the protein content using DUMATHERM® analysis (Section 2), and the resulting potato LOX activity was expressed as (mmol/L 13-HPODE eq.)/(min∙mg protein).

Institutions

• Aarhus University

  Central Jutland, Aarhus

Categories

Funders

• REFINES project supported by Plant2Food

  Grant ID: NNF22SA0081019

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