Studies
of some functional properties of thaumatin, a protein sweetener
*Elemo, B. O. and Adu,
O. B.
Biochemistry Department, Lagos State University,
P.M.B. 1087, Apapa, Lagos State, Nigeria
Abstract
Thaumatin, an intensely sweet
protein from the fruit of Thaumatococcus danielli Benth., was
isolated, purified on Sephadex G50, and some of its functional
properties studied. The functional properties studied included
protein solubility, emulsifying activity, emulsion stability,
foaming capacity and stability and the effect of pH on the sweetness
and temperature stability of thaumatin. The effect of thaumatin on
food color stability was also investigated. Gel filtration on
Sephadex G50 yielded four fractions of which three possessed
thaumatin activity. The purified, freeze-dried sample was fluffy,
light cream-colored powder. Thaumatin was soluble over a wide range
of pH (2≤ pH ≤ 10). The protein maintained sweetness at high
temperature over both acidic and basic pH, while it lost sweetness
beyond pH 9. Thaumatin resulted in high whippability (140%) and
foam stability. The protein also had relatively good emulsion
properties, and heating had little effect on its emulsion stability.
All these are suitable properties required of any novel protein for
use in food formulations.
