Functional Improvement of Starches
by Conjugation with Proteins, Peptides and Amino Acids
The high energy value and useful physical properties
of starch have made it widely used in food and industrial applications
as a thickener, water retention agent, colloidal stabilizer, gelling agent,
bulking agent , adhesive, and so on. These functions of starch are brought
about by its gelatinization and retrogradation behavior. This behavior
is influenced by the kind of starch, the granule size and the presence
of coexisting substance. Hence, the function of starch is thought to be
controllable by the choice of starch and granule size, and changeable by
physical treatment (heating under dry or wet conditions) and chemical modification
(starch ester, starch ether, cross linking, etc.).
However, the recent increase in demand for functionality and application
has made the characteristics of native starch and modified starch insufficient
when considered from the viewpoint of material science. We considered that
the conjugation of non-starchy substances with starch would be important
and effective for achieving significant functional changes of starch. Among
the likely substances, protein is quite different from starch since it
is a charged polymer.
We thus attempted to improve the functions of potato starch by conjugating
starch and protein with a covalent bond. We chose whey protein isolate
(WPI) for conjugation. In our work, the carboxymethyl groups required for
conjugating with proteins were slightly introduced to potato starch as
the first step. The resulting slightly modified carboxymethyl starch (CMS)
was conjugated with proteins by water-soluble carbodiimide, and the functional
changes in the conjugated potato starch were investigated in detail.
We could achive the multiple improvements in starch by conjugation with
WPI as follows:
1) enhancement of the thermal stability of starch
2) depression of retrogradation of starch
3) reduction of digestibility with amylase
4) provision of some biological functions with starch.
We could also prepare the amino acids-CMS conjugates and achieved similar
improvement of starch by conjugation with amino acids.
REFERENCES
Ito, A.; Hattori, M.; Yoshida, T.; Watanabe, A.; Sato, R.; Takahashi, K., Regulatory Effect of Amino Acids on the Pasting Behavior of Potato Starch Is Attributable to Its Binding to the Starch Chain. J. Agric. Food Chem. 2006, 54 (26), 10191 - 10196. [Abstract]
Ito, A.; Hattori, M.; Yoshida, T.; Takahashi, K., Contribution of the Net Charge to the Regulatory Effects of Amino Acids and epsilon-Poly(L-lysine) on the Gelatinization Behavior of Potato Starch Granules. Biosci. Biotechnol. Biochem. 2006, 70 (1), 76-85.[Abstract]
Yang, W.; Komine, N.; Hattori, M.; Ishii, Y.; Takahashi, K., Improvement of patato starch by conjugation with e-poly(L-lysine) through the Maillard reaction. J. Appl. Glycosci. 2005, 52, 253-259.
Yamagishi, Y.; Hattori, M.; Yoshida, T.; Takahashi, K. Improvement of the functional properties of sucrose stearate by phosophorylation. J. Agric. Food Chem. 2004, 52, 8039-8045. [Abstract]
Ito, A.; Hattori, M.; Yoshida, T.; Takahashi, K. Reversible Regulation of Gelatinization of Potato Starch with Poly( e-lysine) and Amino Acids. Starch
2004, 56, 570-575. [Abstract]
Yang, W.; Hattori, M.; Kawaguchi, T.; Takahashi, K. Properties of Starches
Conjugated with Lysine and Poly-lysine by the Maillard Reaction. J. Agric.
Food Chem. 1998, 46, 442-445.
[Abstract]
Hattori, M.; Aiba, Y.; Nagasawa, K.; Takahashi, K. Functional Improvements
in Alginic Acid by Conjugating with beta-Lactoglobulin. J. Food Sci.
1996, 61, 1171-1176. [Abstract]
Yang, W.; Hattori, M.; Takahashi, K. Functional Changes of Carboxymethyl
Potato Starch by Conjugation with Amino Acids. Biosci. Biotech. Biochem.
1995, 59, 2203-2206. [Abstract]
Hattori, M.; Yang, W.; Takahashi, K. Functional Changes of Carboxymethyl
Potato Starch by Conjugation with Whey Proteins. J. Agric. Food Chem.
1995, 43, 2007-2011. [Abstract]
Takahashi, K.; Hattori, M.; Features of Protein-Starch Granule Conjugates.
In Food Hydrocolloids: Structures Properties, and Functions; Nishinari,
K. and Doi, E. Ed. ; Plenum Press: New York, 1994; Vol. pp 467-472.
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