Fingerprinting and Quantification of Procyanidins via LC-MS/MS and ESI In-Source Fragmentation

Area of Science:

• Analytical Chemistry
• Food Science
• Polymer Chemistry

Background:

• Procyanidins (PCs), also known as condensed tannins (CTs), are vital polyphenols in red wine and other foods, influencing mouthfeel and biological activities.
• Existing analytical methods for PCs/CTs provide simplified total phenolic or tannin values, failing to account for structural diversity and often correlating poorly with sensory and biological properties.
• Previous procyanidin in-source fragmentation (PC-ISF) methods require optimization for accurately characterizing CTs with higher degrees of polymerization (DP > 3).

Purpose of the Study:

• To develop and validate a rapid, optimized in-source fragmentation (ISF)-based method for comprehensive procyanidin (PC) fingerprinting.
• To accurately identify and quantify diverse condensed tannins (CTs) in complex matrices.
• To overcome limitations of current methods in correlating phenolic content with biological and sensory attributes.

Main Methods:

• Introduced condensed tannin fragmentation fingerprinting (C-TFF), a novel ISF-based method utilizing multiple in-source energies (30, 110, 140 V or 135, 330, 380 V) for PC depolymerization.
• Employed multiple reaction monitoring (MRM) for further fragmentation of depolymerized spectra in the collision cell.
• Utilized multiple linear regression (MLR) to correlate MRM transitions of analytical PC standards with unidentified PCs in target samples for identification and quantification.

Main Results:

• C-TFF successfully characterized nineteen mixtures of five B-type PCs (DPs 1-5) and commercial cider samples with high accuracy and precision.
• The method effectively visualizes and differentiates diverse CT structures, from smaller oligomers to larger polymers.
• Demonstrated the capability of C-TFF to provide comprehensive fingerprinting by identifying and quantifying individual PCs.

Conclusions:

• Condensed tannin fragmentation fingerprinting (C-TFF) offers a rapid and accurate approach for the detailed analysis of PCs/CTs in complex samples.
• This method advances the analytical capabilities for understanding the structural diversity of CTs, crucial for quality and health-related benefits.
• Future research will focus on extending C-TFF to characterize higher molecular weight CTs (mDP > 5) prevalent in samples like wine.