Influence of Bacterial Cell Population and pH on the Color of Nonfat Milk

Author: Owens S.L.   Brewer J.L.   Rankin S.A.  

Publisher: Academic Press

ISSN: 0023-6438

Source: Lebensmittel-Wissenschaft und -Technologie, Vol.34, Iss.5, 2001-08, pp. : 329-333

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Abstract

Nonfat milk was acidified to pH values typically achieved during fermentation (AM) or inoculated with bacterial cells of Lactococcus lactis ssp. lactis (LM) or Propionibacterium freudenreichii ssp. shermanii (PM). Indices of reflectance L*, a*, b*and spectral values were obtained. Reduced fat milk (TM) and nonfat milk (NM) were included as controls. L*, a*, and b*values for AM were typically closest to TM at pH ∼4.6. The LM and PM treatments had little effect on reflectance L*values, while a*and b*indices were altered towards TM values. Reduction in pH, bacterial cell type and population influence instrumental measurements of milk appearance.

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