Comparison of green and synthetic silver nanoparticles in zein-based edible films: Shelf-life study of cold-stored turkey breasts

This study aimed to compare the effect of zein edible film containing silver nanoparticles produced by green tea leaf extract (Z-gAgNPs) with zein film containing synthetic silver nanoparticles (Z-AgNPs) on the shelf life of turkey breast during refrigerated storage. The produced silver nanoparticles were analyzed using dynamic light scattering (DLS), UV-Vis spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), and atomic force microscope (AFM). According to the obtained results, the green fabricated silver nanoparticles (gAgNPs) showed higher polydispersity index (PDI), stability, homogeneity, spherical shape without cavity, and lower size compared to the synthetic silver nanoparticles (AgNPs). The studied treatments were divided into four groups, including 1- control (C) (turkey breast meat without packaging), 2- Z (turkey breast meat packaged with zein film), 3- Z-AgNPs (turkey breast meat packaged with zein film containing 0.5% (w/w) of AgNPs), and 4-Z-gAgNPs (turkey breast meat packaged with zein film containing 0.5% (w/w) of gAgNPs). The treatments were analyzed for 12 days with 3-day intervals in refrigerator conditions. In general, the measurement of total viable count, total volatile basic nitrogen (TVB-N), and pH values showed that Z-gAgNPs film significantly (p ≤ .05) delayed the spoilage of the studied samples until the end of the 12th day of storage and Z-AgNPs, Z, and C treatments were in the next ranks, respectively. It is concluded that the biofabricated silver nanoparticles using green tea leaf extract have more appropriate physicochemical features and higher efficiency compared to the synthesized silver nanoparticles using chemical methods in zein edible films in improving the shelf life of the cold-stored turkey breast meat and can be introduced as a promising alternative to the plastic packaging.

The Caucasian Whortleberry Extract/Myrtle Essential Oil Loaded Active Films: Physicochemical Properties and Effects on Quality Parameters of Wrapped Turkey Breast Meat

In this research work, the effects of myrtle essential oil (MEO) and Caucasian whortleberry extract (CWE) as natural additives were investigated on mechanical, physico-mechanical and antimicrobial properties of gellan/polyvinyl alcohol (G/PVA) film. Then, optimal blend active films were used for the wrapping of turkey breast meat stored at low temperature (4 ± 1 °C) for 15 days and chemical and sensory properties of wrapped meats were evaluated. The addition of MEO and CWE decreased tensile strength and increased the strain at the break of the films (p ≤ 0.05). Additionally, with increasing the amount of MEO and CWE, the permeability to water vapor (WVP) and the moisture content (MC) of the films decreased (p ≤ 0.05). MIC test showed that MEO and CWE were effective against S. aureus, E. coli, S. typhimurium, and P. fluorescens. at the concentrations of 5-6 and 15-17 mg/mL, respectively. Different microbiological, chemical, and sensory tests indicated that active films significantly enhanced the shelf life of turkey breast meat (p ≤ 0.05). Therefore, based on our finding in this study, the use of these active and biodegradable packagings can be effective and useful for protecting the microbial and sensory quality of turkey breast meat.

Improvement of turkey breast meat quality and cooked gel functionality using hot-boning, quarter sectioning, crust-freeze-air-chilling and cold-batter-mincing technologies

The effect of rapid carcass chilling on breast meat quality was evaluated using commercial (COMM) and random-bred (RB) turkeys. Immediately after slaughter, 48 turkeys from COMM or RB line were randomly subjected to one of four chilling methods: 1) water-immersion chilling (WIC) of the carcasses at 0°C ice slurry, 2) WIC after temperature abuse (TA) of the carcasses at 40°C for 30 min (TA-WIC), 3) hot-boning, quarter sectioning, and crust-freeze-air-chilling (HB-(1)/4CFAC) of breast fillets at -12°C, and 4) HB-(1)/4CFAC of fillets after TA of carcasses (TA-HB-(1)/4CFAC). The TA increased carcass and fillet temperatures by ∼1.3 and ∼4.1°C, respectively, regardless of turkey line, whereas HB-(1)/4CFAC of fillets required 28 and 33% of carcass chilling time for COMM and RB, respectively. During chilling, COMM breast pH rapidly reduced from 6.04 to 5.82, resulting in a significantly lower pH than RB after chilling (P < 0.05), whereas COMM R-value sharply increased from 1.17 to 1.43, causing no difference from RB (P > 0.05). Significantly higher L* value and cooking yield (P < 0.05) were seen in the samples of TA and WIC than those of no TA and HB-(1)/4CFAC, respectively, with no difference observed between COMM and RB fillets (P > 0.05). Higher values of hardness, gumminess, and chewiness were found for RB, no TA, and HB-(1)/4CFAC gels than COMM, TA, and WIC, respectively. These results generally indicated that protein quality and textural properties of turkey fillets were improved, regardless of strains or temperature abuse, using HB-(1)/4CFAC technology.