# Mechanisms Underlying the Changes in the Digestive Properties of Chicken Breasts Induced by the Changes in Protein Structure During Frozen Storage

## TL;DR

This study shows how freezing chicken breasts at different temperatures affects their protein structure and digestibility over time.

## Contribution

The novel finding is that lower freezing temperatures (-40°C) better preserve chicken breast protein structure and digestibility compared to -18°C during storage.

## Key findings

- Protein digestibility decreases with longer frozen storage duration.
- Chicken breasts stored at -40°C have better protein structure and higher digestibility than those stored at -18°C.
- Higher freezing temperatures and longer storage cause more protein damage and aggregation.

## Abstract

This study aimed to investigate the effects of different freezing temperatures and storage durations on the digestive and structural properties of chicken meat proteins. The texture, protein digestibility, particle size, and microstructure of the digested samples were used to characterize their digestive properties. Conformational changes in the digested samples were confirmed by infrared spectroscopy, circular dichroism, and endogenous tryptophan fluorescence spectra. The results revealed that the moisture and protein contents decreased with extended storage and increased temperature. Compared to fresh chicken breasts, protein digestibility decreased as the duration of frozen storage increased. Moreover, the samples stored at −40 °C had higher digestibility than those stored at −18 °C, and the protein structure of the samples stored at −18 °C exhibited more damage and was more likely to aggregate compared to the protein of samples stored at −40 °C. Therefore, a higher freezing temperature and an extended frozen storage duration result in greater structural damage to the protein and lower protein digestibility.