Abstract

Buttermilk is an important dairy by-product from production of butter. It contains bioactive components besides its high content of phospholipid and milk fat globule membrane protein. In recent years, consumers pay more attention to their food and so their interest in health friendly probiotic products has increased considerably. This study was aimed to bring a different perspective to the sector and to present the database in order to re-evaluate the buttermilk as fermented food.

Buttermilk powder (10% solution) and raw milk was mixed in five different proportions (100, 75, 50, 25, 0) and pasteurized. After pasteurization, probiotic cultures were inoculated to the mixture and incubated until pH 4.8.  Probiotic beverages stored at +4°C for 15 days. L. acidophilus (LA-5) and mixed of L. acidophilus-B. bifidum-S. thermophilus (ABT-2) cultures were used for fermentation of the products. The stored samples were examined for quality changes at 15 days interval. pH, titratable acidity, counts of probiotic microorganisms and viscosity measurements of the probiotic beverages were determined during storage. Volatile compounds were isolated by using solid phase microextraction and identified by gas chromatography mass spectrometry. Sensory properties of the products were also evaluated by expert judges using descriptive analysis technique.

The results indicated that the total probiotic strains and pH values of samples decreased as storage time progressed. For all that each sample retained its probiotic properties during storage. A total of 18 volatile compounds were identified in fermented beverages including ketones, aldehydes, hydrocarbons and alcohols. Some acidic compounds acetic acid, butanoic acid, butanoic acid, 3-methyl, hexanoic acid, sorbic acid, benzoic acid and octanoic acid were also determined. The results of this study will provide some basic knowledge on possible use of buttermilk in probiotic dairy products.  

Keywords: buttermilk, probiotic, dairy by-product