71A-21 |
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A. E. Ozen, I. Iri, and M. KILIC. Dept. of Food Engineering, Istanbul Technical Univ., Faculty of Chemical & Metallurgical Engineering, Maslak, Istanbul, 34469, Turkey Ropy starter cultures producing exopolysaccharides were used in fermented dairy products such as yogurt to increase viscosity and to prevent serum separation. However, a recent study showed that a ropy culture did not result in high apparent viscosity and reduce serum separation in a salted fermented milk drink. This study was undertaken to investigate the effect of different ropy starter cultures on the apparent viscosity and serum separation of a salted fermented milk drink. Effect of salt addition was also investigated to explore its impact on the performance of the ropy cultures. Nonfat milk powder and four different starter cultures, one nonropy and three ropy, were used in the preparation of drinks. Salt was added with water after the fermentation for salted drinks. The apparent viscosity was determined at a shear rate of 60 s-1 at a temperature of 10 °C. Serum separation was measured after 10 days of refrigerated storage. Apparent viscosities of the drinks produced with different ropy cultures were different. In some cases, samples prepared with the ropy cultures had lower apparent viscosities compared to that of the sample prepared with the nonropy culture. Type of culture did not affect serum separation in the drinks. Salt decreased the viscosity and increased the serum separation of samples. Effect of salt on apparent viscosity of drinks was dependent on the culture used. Differences in the apparent viscosities of the samples prepared with the ropy cultures were possibly related to different amounts and/or physicochemical properties of exopolysaccharides produced by the cultures. Influence of salt on the culture performance can be explained by interactions of exopolysaccharides with the salt.
Session 71A, Dairy Foods: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |