# Adenosine Triphosphate and Adenylate Energy Charge in Ready-to-Eat Food

## TL;DR

This study examines how thermal processing and cold storage affect nucleotide content in ready-to-eat meat and fish food, revealing new insights into dietary nucleotide preservation.

## Contribution

The study reveals a new phenomenon of adenylate nucleotide reappearance after thermal processing, impacting food freshness assessment.

## Key findings

- Heating at temperatures above 65°C releases intracellular nucleotides into free form during food processing.
- Cold storage does not significantly change free nucleotide concentrations in processed ready-to-eat foods.
- Adenylate energy charge (AEC) values in processed foods show a distinct range compared to raw samples.

## Abstract

It is commonly accepted that dietary nucleotides should be considered as essential nutrients originating mainly but not exclusively from meat and fish dishes. Most research in food science related to nutrition nucleotides is focused on raw products, while the effects of thermal processing of ready-to-eat food on nucleotide content are largely overlooked by the scientific community. The aim of this study is to investigate the impact of thermal processing and cold storage on the content of dietary nucleotides in freshly prepared and canned ready-to-eat meat and fish food. The concentrations of ATP, ADP, AMP, IMP, Ino, and Hx were determined using NMR, HPLC, FPMLC, and ATP bioluminescence analytical techniques; freshness indices K and K1 and adenylate energy charge (AEC) values were estimated to assess the freshness status and confirm a newly unveiled phenomenon of the reappearance of adenylate nucleotides. It was found that in freshly prepared at 65 °C ≤ T ≤ +100 °C and canned food, the concentration of free nucleotides was in the range of 0.001–0.01 µmol/mL and remained unchanged for a long time during cold storage; the correct distribution of mole fractions of adenylates corresponding to 0 < AEC < 0.5 was observed compared to 0.2 < AEC < 1.0 in the original raw samples, with either a high or low content of residual adenylates. It could be assumed that heating at nonenzymatic temperatures T > 65 °C can rupture cell membranes and release residual intracell nucleotides in quite a meaningful concentration. These findings may lead to a conceptual change in the views on food preparation processes, taking into account the phenomenon of the free adenylates renaissance and AEC bioenergetics.