Uso de extrato de alho conjugado a revestimento de quitosana na estabilidade em almôndegas elaboradas à base de carne mecanicamente separada de tilápia do Nilo (Oreochromis niloticus)

Abstract

During the processing and storage of fish products, physical, chemical, and microbiological changes are a major concern due to reduced stability. This study aimed to evaluate the influence of garlic (Allium sativum L.) extract and a commercial chitosan coating on refrigerated meatballs made from mechanically separated meat (MSM) of Nile tilapia (Oreochromis niloticus). The aqueous garlic extract was characterized by in vitro antimicrobial activity analysis using scanning electron microscopy (SEM), high-performance liquid chromatography (HPLC), and Fourier transform infrared spectroscopy (FTIR). The microbiological quality of the MSM was assessed in accordance with current legislation. Five meatball treatments were prepared: three with the addition of garlic extract (1%, 3%, and 6%), in addition to the negative control group without additives and the positive control group with the synthetic additive butylhydroxytoluene (BHT). Each meatball was modeled with 50g of each. The coating was applied exclusively to the 6% garlic extract group. The meatballs were stored in the refrigerator at 4°C for 28 days to assess stability. At time zero, treatment samples were analyzed for water holding capacity (WHC) and cooking loss (CLP), as well as by SEM and determination of the fatty acid profile of the negative control group. Data were analyzed by ANOVA followed by Tukey's test, considering a significance level of p≤0.05. Garlic extract showed significant antimicrobial activity against Staphylococcus aureus and Escherichia coli. FTIR and HPLC characterized the garlic extract, confirming the presence of functional groups containing sulfur and nitrogen compounds, as well as allicin and inulin, associated with antimicrobial and antioxidant activity. A MEV revealed irregular and dispersed microstructures in the extract. The CMS met the microbiological standards of current legislation, demonstrating stability of the prepared products with a pH range of approximately 5.9 to 6.5 and TBARS ranging from 1.58 to 4.89 mg kg-1. It was observed that the garlic extract added to the meatballs did not influence (p<0.05) the WHC and PPC. The refrigerated meatballs combined with the chitosan coating revealed porous microstructures, while the coating alone presented a more continuous, homogeneous surface with little dispersion and porosity, validating the natural film when analyzed by SEM. The fatty acid analysis of the meatballs without additives detected saturated and unsaturated lipid components, as well as palmitic, linoleic, and eicosanoic acids. Therefore, we concluded that the chitosan-coated meatballs with garlic extract presented greater microbiological safety and stability under refrigeration, maintaining their physicochemical characteristics within quality standards.