# Effect of Freezing for up to 120 Days on the Physicochemical Characteristics of Hamburgers Made from Botucatu Rabbit Does Slaughtered at Different Ages

## TL;DR

This study shows that freezing rabbit hamburgers for up to four months does not significantly affect their quality, regardless of the rabbits' age at slaughter.

## Contribution

The study provides new insights into the stability of rabbit hamburger quality during frozen storage across different animal ages.

## Key findings

- Freezing rabbit hamburgers for up to 120 days did not degrade their quality beyond legal limits.
- Older rabbits produced hamburgers with higher protein and lower moisture, while younger rabbits showed higher lipid oxidation.
- Storage time and animal age affected tenderness and lipid content, but all samples met Brazilian legal standards.

## Abstract

Breeding rabbits, especially females, are intended for human consumption after their production cycle. However, since the quality of the meat from these older animals is different compared to that from younger rabbits, there are ways to add value, such as the preparation of processed products, such as hamburgers. In this scenario, the objective of this study was to evaluate the effect of freezing for up to 120 days on the physical, chemical, and technological characteristics of hamburgers made with meat from Botucatu rabbits, from animals raised at different ages. The quality of rabbit hamburgers produced at different ages does not change during four months of frozen storage. Based on the results, it is recommended to use meat from rabbits of different ages to prepare hamburgers.

This study evaluated the effect of freezing for up to 120 days on the physicochemical and technological properties of hamburgers made from Botucatu rabbit does slaughtered at 3, 12, and 24 months of age. The parameters were evaluated as follows: surface color (L*, a*, b*), pH using an insertion pH meter, cooking loss using a grill, storage loss based on weight differences, shear force in cooked samples using a texture analyzer, shrinkage percentage, chemical composition (moisture, protein, lipids, and ash), and lipid oxidation, determined by measuring the concentration of malondialdehyde in the burgers at different storage intervals (0, 60, and 120 days) under freezing conditions (−18 °C). The results indicated that increased storage time and animal age reduced tenderness and increased lipid content (p < 0.05). Burgers made from younger does showed higher levels of lipid oxidation. Age also influenced color (greater redness and lower lightness in older animals) and chemical composition, with older does producing burgers with higher protein and lower moisture and mineral content. However, all samples remained within the limits established by Brazilian legislation. This study recommends using meat from does of different ages for hamburger production, as all variations met the required legal standards.