In this study, effects of eugenol and thymol at 100 ppm concentration on chemical, microbiological and sensory attributes of pasteurized butter samples produced experimentally were investigated during storage period at different storage temperatures. Results indicated that there was no significant difference between control and other groups containing terpenes in terms of pH levels, thiobarbituric acid (TBA) and diacetyl values at both storage temperatures (4 ±1 and -20±1 ºC) (p>0.05). However, a significant difference was found between groups stored at 4±1ºC in terms of free fatty acid levels (p<0.05) while no significant difference was observed between groups stored at -20±1ºC (p>0.05). Peroxide value was below the detection limit in all samples.

Numbers of total mesophilic aerobic bacteria, lactic Streptococcus spp. and lipolytic bacteria showed insignificant changes in all groups stored at 4±1ºC (p>0.05). In groups stored at -20±1ºC, however, there were significant differences between the storage days in terms of the numbers of bacteria mentioned above (p<0.05). No significant difference were observed between groups stored at both storage temperatures in terms of the numbers of mold, coliform and Lactobacillus spp. (p>0.05).

In sensory attributes, between groups or within groups, no changes were observed in appearance and consistency of the samples during storage period (p>0.05). Significant difference was also not found between groups in terms of taste and odor (p>0.05).

As a result, it was concluded that 100 ppm of eugenol and thymol added into the samples did not show the expected significant effects on some chemical and microbiological parameters, and their effects on sensory attributes of the butter samples were insignificant during the storage period.