Using of Combined Treatment between Edible Coatings Containing Ethanolic Extract of Papaya (Carica Papaya L.) Leaves and Gamma Irradiation for Extending Shelf-Life of Minced Chicken Meat

Abstract

The objective of this work was to study the combined effect of edible coating containing ethanolic extract of papaya (Carica papaya L.) leaves at ratio 2% and gamma irradiation at dose levels of 0, 2, 4 and 6 kGy on the chemical, microbiological and sensorial qualities of minced chicken thighs meat during cold storage (4 ± 1°C). Samples of minced chicken thighs meat were divided into three groups; uncoated (control), coated with edible coating (without any additives), and irradiated coated with edible coating samples at 0, 2, 4 and 6 kGy. The obtained results showed that gamma irradiation at 2, 4 and 6 kGy with edible coating reduced the initial total bacterial count, psychrophilic bacteria and lactic acid bacteria and prolonged shelf-life of the samples under investigation. Coated samples and irradiated at 2 kGy reduced the counts of Enterobacteriaceae, Staphylococcus aureus and Bacillus cereus as well as eliminating Salmonella spp, while coated samples irradiated at 4 and 6 kGy completely eliminated these bacteria. On the other hand, combination treatments of minced chicken thighs meat samples showed slight increase in thiobarbituric acid reactive substances (TBARS) post irradiation and during cold storage, but had no effects on their total volatile nitrogen (TVN) contents, while a gradual increase in these chemical quality indexes was observed during cold storage. Finally, combination treatment had no adverse effects on the sensory properties of minced chicken thighs meat samples. Therefore the incorporation of ethanolic extract of papaya leaves in edible coating materials increases the bacterial inhibitory effect of gamma irradiation and is suitable for preservation of minced chicken thighs meat or meat and chicken products.