Evaluation of Addition Peppermint Oil on the Microbial and Sensory Properties of a Soft Milk Drink (Shenina)

Abstract

The study aimed to manufacture a diluted milk drink (Al-Shenina) flavored with mint oil at concentrations (0, 0.5, 0.75, 1) µl/L. the used oil wa s extracted by cold distillation using a clevenger device, the active compounds in peppermint oil were measured by GC/MS device technology. The most important of these compounds that appeared are Menthol, Methone, Pulegone and Limonene D- and their quantities were 28.5), 19.20, 18.26, (10.46%, respectively). The diluted milk drink manufactured above was stored under refrigeration for 30 days, and the effect of cold storage was observed on the total number of bacteria, the total number of lactic acid bacteria, % of total acidity, and the peroxide number. The readings were taken every ten days, where there was a non-significant increase in the total number of bacteria Until 10 days of storage, the highest numbers for the comparison sample were 1.72 x 108 C.F.U/g, after which the numbers gradually decreased until the end of the storage period. The total number of lactic acid bacteria also had a non-significant increase in numbers up to 10 days of storage, and the highest numbers for the comparison sample were 1.5 x 106 C.F.U/gm. The % value of acidity such as lactic acid in the milk drink increased insignificantly during the storage period, and the highest values were for the comparison treatment up to 10 days of storage and amounted to 0.25% compared to other treatments in which the acidity value was (0.21%, 0.22%, 0.32%) for the quantities of oil added 0.50, 0.75, 1 microliter/liter of milk. Also, the values of the peroxide number during storage had a significant increase in periods and insignificant in other periods, and the highest values were for the comparison treatment at the end of storage and amounted to 4.25 meq O2 / kg oil and the lowest at the beginning of the storage period for the treatments containing mint oil, and it reached meq3.52 O2 / kg oil. The results of the sensory evaluation of the milk drink with added concentrations of peppermint oil showed the preference for the treatment containing 1 microliter oil/liter of milk, which obtained a total score of 94% at the beginning of storage to become 83% at the end. This means that this sample was not affected by its sensory characteristics such as taste, texture and flavor Significantly during the storage period, and it was the preferred sample for the residents compared to the comparison sample, which obtained an evaluation of 87 degrees at the beginning of storage, and which decreased at the end of storage to 37 degrees after losing many of its sensory properties during storage.