Use of cinnamon, wheat germ, and eucalyptus oils to improve quality and shelf life of concentrated yogurt (Labneh)

Abstract

Three essential oils, namely cinnamon, eucalyptus, and wheat germ were added to concentrated yogurt (Labneh) at a concentration of 600 μL\kg. The chemical, microbiological and organoleptic properties of freshly prepared and stored Labneh at 5°C ± 1 for 6 weeks were determined. Addition of essential oils affected slightly the pH, acidity, total solids, and dry matter values of concentrated yogurt. Total viable counts, as well as counts of Streptococcus aureus, molds, and yeast in the treated Labneh were affected during storage period. The most acceptable organoleptic properties of treated Labneh were those samples treated with cinnamon, and eucalyptus oils, and to a lesser extent wheat germ oil. Cinnamon and eucalyptus oils were also found to inhibit yeast and mold count. It has been also found that cinnamon and eucalyptus essential oils decreased significantly the growth of S. aureus. No Coliforms or E. coli bacteria were detected in the treated Labneh, as well as in the positive control. This study showed that wheat germ oil had lesser effect compared to cinnamon, and eucalyptus. This study concluded that, addition of cinnamon and eucalyptus essential oils at 600 μL\kg could increase the shelf life of Labneh up to 6 weeks at 5 ± 1°C with acceptable taste, flavor and texture without addition of any chemical preservative.