# Ultrasonicated brine: implications for polyphosphate functionality and beef quality

## TL;DR

Ultrasonication of brine improves the effectiveness of polyphosphate in enhancing beef quality, potentially reducing the need for high phosphate levels.

## Contribution

Ultrasonication of brine before adding polyphosphate enhances meat quality more effectively than traditional methods.

## Key findings

- Ultrasonicated brine before polyphosphate addition improved water-holding capacity and reduced cooking loss.
- Ultrasonication promoted protein unfolding and a denser protein network, enhancing thermal stability.
- Lower phosphate levels achieved comparable functionality when brine was ultrasonicated prior to phosphate addition.

## Abstract

This study evaluated whether ultrasonication of brining solutions can enhance the functional effectiveness of polyphosphate in beef systems, thereby providing a technological basis for reducing phosphate dependency. A 1.5% (w/v) NaCl brine was ultrasonicated using probe ultrasound (20 kHz, 300 W) for 0, 15, or 30 min either before polyphosphate addition (UBP) or after polyphosphate addition (UAP). Sodium tripolyphosphate was incorporated at 0, 0.1, or 0.2% (w/v), and brines were mixed with ground Longissimus lumborum at a 1:1 (w/v) ratio. Brine pH and redox potential were measured, and meat pH, water-holding capacity (WHC), cooking loss, emulsifying activity and stability, interfacial protein concentration, and color parameters were evaluated. Polyphosphate concentration was the dominant factor influencing meat pH, WHC, cooking loss, and emulsifying properties. Brine ultrasonication significantly modulated these effects, particularly through interactions with polyphosphate concentration. Pre-sonication of brine followed by polyphosphate addition (UBP) consistently resulted in higher WHC, lower cooking loss, and improved emulsifying activity compared with non-sonicated brine at the same phosphate levels. In contrast, ultrasonication of phosphate-containing brine (UAP) showed limited or inconsistent benefits at low phosphate concentrations. Structural and spectroscopic analyses (FESEM and FTIR) revealed that ultrasonicated brine promoted protein unfolding and formation of a denser, more cohesive protein network, consistent with improved water retention and thermal stability. Overall, the results demonstrate that ultrasonicated brine acts as a process-level enhancer that intensifies the functional performance of polyphosphate. While increasing phosphate concentration continuously improved meat quality, brine ultrasonication—particularly when applied prior to phosphate addition—amplified these effects, supporting the feasibility of achieving comparable functionality at lower phosphate inputs.