Selected freshness indices of skin and wings from organic chicken packaged in modified atmosphere

This study is part of a project aiming to optimize storage conditions for organic chicken meat. Selected indices of skin and wings from organic chicken were evaluated. A total of 24 samples were packaged in MAP-O2 (80% O2/20% CO2), 24 samples in MAP-N2 (70% N2/30% CO2) and 48 samples as a control. The samples were analysed on days 2, 7, 10 and 14 of storage during a 14-day storage period at 2 ± 2 °C. The surface colour of skin (L*a*b*), ammonia content, thiobarbituric acid reactive substances content (TBARS) and antioxidant capacity were assessed. The lightness values (L*) for chicken skin in MAP-O2were increased on days 7 and 10 of the storage period, and were significantly (P< 0.05) higher than in the samples in MAP-N2 and the control. Significant increases of TBARS were observed in the samples in MAP-O2 from day7 and these values continued to increase until the end of the storage period. The antioxidant capacities of the samples in MAP-O2 were mostly lower than those of the samples in MAP-N2. Our results indicate that MAP-O2only had a positive effect on skin colour, whereas MAP-N2 maybe preferable for shelf-life prolongation. Organic system, broiler chicken, shelf life, colour The skin constitutes around 15% of the broiler carcass (Hayse and Marion 1973), while the yield of the wings is approximately 10% (Kokoszynski et al. 2013). The percentage of fat in the skin of broilers without adipose tissue is about 20–30%. The fat of poultry is characterized by a high proportion of unsaturated fatty acids and less cholesterol than fats from red meat, for which reason the market in edible chicken fat should thrive (Sheu and Chen 2002). The wings are usually consumed as muscle together with the skin. The proportion of skin in the wings is the highest of all culinary chicken meat portions, representing around 22%, i.e. twice the amount in the thighs (Tomaszewska-Gras and Konieczny 2010). The effect of organic rearing systems on the colour indices and chemical composition of chicken skin and wings has been reported. The skin of organic chicken is more yellow and has a higher lipid content than the skin of conventional chicken (Abdullah and Buchtova 2017). The higher lipid content is reflected in the thickness and yellowish colour (higher b*) of skin from organic production systems (Sirri et al. 2010). The nutrition of organic poultry, consisting of high consumption of plant material rich in carotenoid pigments, is the main factor contributing to the yellowish colour of the skin (Fanatico et al. 2005). Our previous study (Abdullah and Buchtova 2016) indicated that the qualitative and quantitative properties of wings from organic broilers are different from those in conventional chickens. Although the shelf life of fresh chicken is limited primarily by bacterial growth (Hulanková et al. 2018), it has been indicated that organic chicken meat contains a larger amount of free radicals and has a shorter shel flife. Excessive carcass processing should, therefore, be avoided and a reduced storage period is recommended (Castellini et al. 2006). ACTA VET. BRNO 2020, 89: 97–105; https://doi.org/10.2754/avb202089010097 Address for correspondence: Ing. Fouad Ali Abdullah Abdullah, Ph.D. University of Veterinary and Pharmaceutical Sciences Brno Palackeho tr. 1946/1, 612 42 Brno, Czech Republic Phone: +420 541 562 747 E-mail: abdullahf@vfu.cz http://actavet.vfu.cz/