Author: Irene Frascari
Last saved by: Serena Miconi
Company: Università di Bologna

README file
Data Set Title: “Grape Seed Tannin Extract: MALDI-TOF Peak Dataset”
Data Set Authors: Arianna Ricci (https://orcid.org/0000-0002-4810-9123); Giuseppina Paola Parpinello (https://orcid.org/0000-0002-1439-8035); Andrea Versari (https://orcid.org/0000-0003-2960-0619)

Department of Agricultural and Food Sciences, Alma Mater Studiorum, University of Bologna, Piazza Gabriele Goidanich 60, 47521 Cesena, FC, Italy

Data Set Contact Person/s: Arianna Ricci arianna.ricci4@unibo.it 
Data Set License: this data set is distributed under a Creative Commons Attribution 4.0 International (CC BY 4.0) license, https://creativecommons.org/licenses/by/4.0/”

Publication Year: 2026
Data set Contents
The data set consists of:

•	1 digital image file saved in .jpg format 
“GrapeSeedTannin_MALDI-TOFspectrum_PeakAssignment.jpg”
•	1 tabular quantitative file saved in .csv format 
“GrapeSeedTannin_MALDI-TOFspectrum_PeakAssignment.csv”
•	1 README file saved in .rtf format
“GrapeSeedTannin_MALDI-TOFspectrum_PeakAssignment_README.rtf”
Data set Documentation
Abstract
MALDI-TOF mass spectrometry is an exceptional analytical tool for investigating grape seed tannins because its "soft" ionization technique allows for the precise detection of high-molecular-weight polymers without causing structural fragmentation. This capability enables researchers to accurately determine the exact degree of polymerization and easily profile complex proanthocyanidins, including their galloylation patterns. By providing rapid, highly sensitive, and detailed structural fingerprints of intact macromolecular mixtures, MALDI-TOF offers invaluable insights into the chemical composition and quality of grape seed extracts that conventional methods often fail to reach. The dataset features MALDI-TOF peaks acquired in linear positive mode (range 500–2500 Da), providing a representative example of the typical signals associated with a commercial grape seed tannin extract.

Content of the files: 
•	The graphical file [GrapeSeedTannin_MALDI-TOFspectrum_PeakAssignment.jpg] contains the MALDI-TOF spectra recorded in linear positive mode on a commercial grape seed tannin. The analyzed tannin is the one named as “TanB” in the related paper (see “Notes” section)
•	The tabular quantitative file [GrapeSeedTannin_MALDI-TOFspectrum_PeakAssignment.csv] contains the peak list from the MALDI-TOF spectra recorded in linear positive mode. 
•	The readme file [GrapeSeedTannin_MALDI-TOFspectrum_PeakAssignment_README.rtf] contains a short summary of analytical conditions.

File specifics
To create the .csv file , “Microsoft Excel” version: 2509 (build 19231.20156) was used, with the following specifics:
•Character set UTF-8 
•Field delimiter « ; » (semicolon)
•	Text delimiter: none

Methodologies 
For MALDI-TOF experiments, powder sample was dissolved in acetone/water 50/50% (v/v) at a concentration of 5 mg/mL, and then the solutions was mixed (1:1, v/v) with a standard solution of 2,5-dihydroxybenzoic acid at 10 mg/mL dissolved in the same solvent. Then, 1.5 μL of the mixed solution were spotted on a 384-well MALDI-TOF plate, followed by evaporation of the solvent at ambient temperature before analysis. The MALDI-TOF spectra were recorded using a Kratos compact MALDI Axima Performance TOF 2 (Shimadzu Biotech, Manchester, UK), with a nitrogen laser (337 nm), an ion gate for the selection of precursor ions, and a collision cell, using argon as the collision gas; NaCl was added in the sampling wells as the salt to enhance ion formation. The windows for separation of precursor ions were approximately 4 Da. Data were recorded in positive ion linear mode applying the accumulation of 441 scans per spectrum, and the calibration of the linear modes was done over a mass range up to 2500 Da using phosphorus red pigment as a reference. The spectra were subjected to a raster analysis over the target, using the Maldi-MS software for data treatment (Shimadzu Biotech, Manchester, UK).

Notes
The data included in this dataset are presented and discussed in the following publication:
Ricci A, Galaz Torres C, Parpinello GP, Pizzi A, Versari A. Precision Enology Strategies to Enhance the Quality of Red Wine Color: The Synergistic Effect of pH and Selected Exogenous Grape Seed Tannins. Foods. 2026; 15(12):2161. https://doi.org/10.3390/foods15122161