Natural preservation of chicken breast meat using thyme and garlic extracts impact on physicochemical quality, microbial stability, and shelf-life during chilled storage

Abstract

The preservative efficiency of the extracts from thyme (Thymus vulgaris L.) and garlic (Allium sativum L.) in chicken breast meat stored under refrigeration conditions (4 ± 1°C, 12 days) was estimated in relation to the extent of lipid oxidation (TBARS, free fatty acids), microbiological quality (total plate count, psychrotrophs), physicochemical properties (pH) and water holding capacity (drip loss, water-holding capacity [WHC]). All combinations of treatments with extracts demonstrated significantly less oxidative spoilage and microbial growth in comparison with the control sample (p<0.05). Combination of the extracts from thyme and garlic at the level of 0.10% provided the highest preservative activity, providing TBA values remaining under the threshold of rancidity, lowering microbial count and pH, and avoiding any changes in WHC. Correlation analysis showed dependency among the parameters of lipid oxidation, microbial growth, increase in pH, and moisture losses, which means that meat degradation is based on the interaction of biochemical and microbiological processes rather than separate processes. According to the established microbiological criterion of quality in terms of log CFU/g value of 5.0, combination of thyme and garlic extracts improved preservation activity, but their number of psychrotrophs became equal to 5.12 ± 0.15 log CFU/g after 12 days of storage. In accordance with both microbiological and oxidative criteria of acceptance, shelf life of refrigerated chicken meat increased up to 12 days in comparison with about 4 days for the control sample.