Studies on the effects of gamma irradiation on the chemical and microbial parameters of chilled minced beef meat

ABSTRACT

Changes in quality parameters of minced beef meat samples treated with different doses of gamma irradiation [0, 3, 5, 7 and 9 KiloGray [KGy]] were followed to assess acceptability during refrigeration storage at 4°C. The obtained results indicated that irradiation improved the organoleptic quality and delayed deterioration of chilled minced meat. Application of irradiation resulted in development of off flavour which was more pronounced at high doses specially at 7 and 9 kGy but slightly dissipated after exposure to air. Application of gamma irradiation reduced the rate of development of all deteriorative changes. Irradiation with different doses had a slight significant changes in chemical analysis. Moisture content was decreased. Protein content slightly increased by increasing the irradiation doses and decreased with the progress of storage, while fat% and ash% increased with storage and irradiation doses. pH values of irradiated samples were lower than those of unirradiated samples. Application of ionizing radiation resulted in a remarkable increase in thiobarbituric acid [T.B.A.] content in chilled minced meat samples followed by a proportional increase during refrigeration storage. Total volatile basic nitrogen was decreased specially at doses of 7 and 9 KGy. The microbial load of chilled minced meat was affected by the exposure to different doses of irradiation as well as the reduction of bacterial counts were observed by increasing the irradiation doses. In conclusion, irradiation of minced meat can be effectively used as a supplement to refrigeration process and for increasing the acceptability, safety of the products and shelf life of chilled minced meat