The effects of Eugenol and thymol on chemical, microbiological and sensory quality of pasteurized butter

In this study, effects of the some terpenes (eugenol and thymol) which are used for antioxidant properties and different storage temperatures on chemical, microbiological and sensory attributes of butter samples produced experimentally were investigated during storage period.Experimental butter samples were produced by a dairy plant which is located in Malatya. With control group, three different groups containing eugenol and thymol at 100 ppm concentration were prepared. The samples were stored at 4±1 oC or -20±1oC, and they were analyzed for chemical (pH, free fatty acidity, TBA, peroxide value, and diacetyl content), microbiological properties (total mesophilic aerobic bacteria, lactic acid bacteria, yeast and mold, coliform and lipolytic bacteria) and sensory attributes on days 0, 10, 20, 30, 60, 90, 120, 150 and 180 during the storage period. The study was composed of three replicates.Result 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 (p>0.05). However, a significant difference was found between groups stored at 4±1oC in terms of free fatty acidity (p<0.05) while no significant difference was observed between groups stored at -20±1oC (p>0.05). Peroxide value was not detected in any of the 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). However, in groups stored at -20±1oC, there were significant differences between storage days in terms of, the numbers of bacteria mentioned above (p<0.05). No significant differences was observed between groups stored at both storage temperatures in terms of the numbers of yeast-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 samples during storage period (p>0.05). It was also not found significant difference between groups in terms of taste and odor of samples (p>0.05).As a result, it was observed that eugenol and thymol have significant effect on some chemical and microbiological parameters and have not effect on sensory attributes of butter samples during storage period. It was also seen that application eugenol and thymol at 100 ppm concentration to butter was inefficient.Key words: Butter, eugenol, thymol, shelf-life, chemical, microbiological, sensory, quality.