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Rheological properties of fermented milk produced by a single exopolysaccharide producing Streptococcus thermophilus strain in the presence of added calcium and sucrose
Author(s) -
PURWANDARI UMI,
VASILJEVIC TODOR
Publication year - 2009
Publication title -
international journal of dairy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.061
H-Index - 53
eISSN - 1471-0307
pISSN - 1364-727X
DOI - 10.1111/j.1471-0307.2009.00501.x
Subject(s) - syneresis , sucrose , food science , chemistry , calcium , skimmed milk , fermentation , streptococcus thermophilus , rheology , lactobacillus , materials science , organic chemistry , composite material
The effect of calcium supplementation, presence of exopolysaccharides (EPS) and sucrose on the texture of low‐fat fermented milk was examined. Reconstituted skim milk (14%) was acidified by 2% glucono‐δ‐lactone (GDL) or a single strain, EPS‐producing Streptococcus thermophilus , and incubated at 42°C. The levels of calcium and sucrose addition ranged from 0 to 9 m m and 0 to 45 m m respectively. Compared with acidified milk (GDL), fermented milk containing EPS showed different rheological properties in the presence of added calcium and sucrose. Calcium addition reduced gel characteristics: G′, K, and the second maximum of derivative of shear rate‐shear stress; while sucrose addition also increased them but subsequently reduced syneresis. Added calcium or sucrose increased gel hysteresis and reduced apparent yield stress.