TITLE:
The Principles of Starch Gelatinization and Retrogradation
AUTHORS:
Masakuni Tako, Yukihiro Tamaki, Takeshi Teruya, Yasuhito Takeda
KEYWORDS:
Principles; Starch; Amylose; Amylopectin; Hydrogen Bonding; Gelatinization and Retrogradation Mechanism
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.5 No.3,
January
22,
2014
ABSTRACT:
The polysaccharides, such as κ-carrageenan, ι-carrageenan, agarose (agar), gellan
gum, amylose, curdlan, alginate, and deacetylated rhamsan gum, in water changed
into an ice-like structure with hydrogen bonding between polymer and water
molecules, and between water-water molecules even at a concentration range of
0.1% - 1.0% (W/V) at room
temperature, resulting in gelation. Such dramatic changes from liquid into gels
have been understood at the molecular level in principles. In this
review, we describe the structure-function relationship of starch on the view
point of rheological aspects and discuss gelatinization and retrogradation
mechanism including water molecules at molecular level. The starch molecules
(amylose and amylopectin) play a dominant role in the center of the tetrahedral
cavities occupied by water molecules, and the arrangement is partially similar
to a tetrahedral structure in a gelatinization process. The arrangement should
lead to a cooperative effect stabilizing extended regions of ice-like water
with hydrogen bonding on the surface of the polymer molecules, where hemiacetal
oxygen and hydroxyl groups might participate in hydrogen bonding with water
molecules. Thus, a more extended ice-like hydrogen bonding within water
molecules might be achieved in a retrogradation process. Though many
investigations not only include starch gelatinization and retrogradaion, but
also the gelling properties of the polysaccharides have been undertaken to
elucidate the structure-function relationship, no other researchers have
established mechanism at the molecular level. There is reasonable consistency
in our investigations.