“Manshanu” Production: Microbiological and Biochemical

The microbiological and biochemical changes during the ripening of the milk for Manshanu (local fermented butter) production were assessed. The biochemical changes were evaluated in terms of titratable acidity, pH and diacetyl content. The flavor changes in the butter in terms of free fatty acids during the storage were also studied. The use of pure starter culture was found to improve the keeping quality of the butter compared to the butter produced by chance fermentation. The free fatty acids contents of the butter from the pure culture remained at its initial level of 0.168%, oleic acid for 16 days of frozen storage. There was an increase from 0.168% to 0.273% oleic acid after 16 days of storage under refrigeration. With the traditionally prepared butter the free fatty acids increased from 0.168% to 0.643% during 16 days of storage at refrigeration temperature. The microorganisms involved in the ripening of milk for manshanu production were isolated, identified, purified on nutrient agar slants and used as pure starter culture for the butter production. Streptococci lactis, Leuconostoccremoris and Lactobacillus lactis were isolated and identified. Lactobacillus lactiswas isolated only twice in the total of ten trials. A mixed starter culture of the dorminant organisms S. lactis and L. cremeris, when used as pure culture resulted in the butter production with better flavor and keeping quality.

Keywords: manshanu, starter culture, ripening, diacetyl.