Quality attributes of gamma irradiated green and red thyme meal

Irradiation with dose of 15 kGy has been recognized as a new and alternative method for decontamination of spices and herpes in Syria. The effects of irradiation with 15 kGy and storage up to 12 months on quality characteristics of green thyme meal (GThM) and red thyme meal (RThM) were investigated.

Microbial aspects including total viable count (TVC), total mold and yeast count (TMYC), and total coliform count (TCC) were investigated. Proximate compositions percentage (moisture, protein, fat, ash, total sugar, and reducing sugar contents), and quality characteristics (total acidity (TA), pH value, and volatile basic nitrogen (VBN)) as well as sensory properties (aroma, taste color, and texture) were evaluated.

Gamma irradiation treatment with 15 kGy resulted in 100% reduction in TAC, TMYC, and TCC. The studied qualitative indicators namely, TA, and pH value, and quantities' characteristics, namely moisture, fat, and ash of GThM and RThM were significantly influenced by gamma irradiation and storage time. Sensorial properties of irradiated GThM and RThM were accepted by the panelist. The analytical parameters studied for irradiated and stored GThM and RThM were within the limits established by the national standards.

Radiation at 15 kGy had an excellent response to the microbial profile, with only minimal changes in quality attributes, after 12 months of storage.