Journal of Food Processing & Technology

Critical variants increasing the sweetness of sweet-tasting protein, brazzein

4^th International Conference and Exhibition on Food Processing & Technology

August 10-12, 2015 London, UK

Kwang-Hoon Kong, Jin-Kyung Lim and Mi-Ki Kim

Posters-Accepted Abstracts: J Food Process Technol

Abstract:

The demand for non-calorigenic protein-based sweeteners with favorable taste properties is high. Brazzein, a sweet-tasting protein
with a molecular mass of 6.4 kDa, was originally isolated from the fruit of the West African plant Pentadiplandra brazzeana
Baillon. Brazzein is the smallest naturally occurring sweet-tasting protein described to date and provides an optimal system for
investigating the chemical and structural requirements of the sweet-taste response. Particularly, brazzein is an ideal candidate for a
low-calorie sweetener because of its natural origin and favorable physical properties. Brazzein is also the most heat-stable and pH
stable member of the set of proteins known to have intrinsic sweetness. Brazzein is approximately 2,000 times sweeter than sucrose.
To develop highly sweet protein, in this study, we constructed several brazzein variants by site-directed mutagenesis. The brazzein
variants were expressed in E. coli BL21 and yeast Kluyveromyces lactis which is recognized as GRAS. Some of brazzein variants were
not sweeter than the wild-type brazzein. The variants of the residues that located in the loop between β-strand III and β-strand III
showed similar sweetness to the wild-type brazzein. On the other hand, the variants of the residues that located in the β-strand III
in loop between α-helix and β-strand and the residues in N- and C- termini increased sweetness. Moreover, the introduction of
multiple variants results in stronger sweetness, showing approximately 5,000-22,500 times sweeter than sucrose (g/g).The increasing
order of their sweetness were triple variants>double variants>single variants. This study offers information on the precise interaction
mechanism of brazzein with human sweet taste receptor responsible for the sweetness of brazzein and will be of great value in future
design of brazzein sweeter variants.

Biography :

Kwang-Hoon Kong is from Chung-Ang University in Korea.