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ABSTRACT
The present investigation aims at understanding the role of chemically modified starch on the firmness of fresh or stale bread. Bread was prepared from wheat flour or substituted wheat flour that contained 18% chemically modified tapioca starch and 2% vital gluten. Hydroxypropylated tapioca starch (HTS), acetylated tapioca starch (ATS), phosphorylated cross-linked tapioca starch (PTS), and native tapioca starch (NTS) were tested. Bread prepared from the substituted flour with PTS showed a firmer texture on the day of baking compared with bread prepared from NTS, HTS, and ATS. PTS retained its granular structure in the gluten network after baking and seemed to play the role of filler particles in the gluten matrix, thereby increasing firmness of fresh bread crumb. Bread prepared from the substituted flour with HTS or ATS firmed at a lower rate and showed a lower endothermic melting enthalpy of amylopectin after three days of storage compared with NTS or PTS. These findings suggest that the staling of bread containing chemically modified tapioca starch involves recrystallization of amylopectin.
Cereal Chem. 82(6):639-644
Bread is a bakery product that contains large amounts of starch, and therefore the characteristics of starch significantly influence the quality of bread. We previously studied the quality of bread using three kinds of chemically modified tapioca starches: hydroxypropylated tapioca starch (HTS), acetylated tapioca starch (ATS), and phosphorylated cross-linked tapioca starch (PTS) (Miyazaki et al, in press). The results were that bread prepared from 20% substitution of HTS for wheat flour was softer than that with 20% native tapioca starch and 100% wheat flour during storage, whereas bread prepared from the wheat flour substituted with ATS or PTS at the same level was firmer than that with native tapioca starch.
Bread staling involves organoleptic and physicochemical changes such as firming of crumb, declining flavor, increasing opacity of crumb, toughening of crust, and decreasing starch solubility (WiIlhoft 1973; Maga 1975; Knightly 1977; KuIp and Ponte 1981). Perhaps the most important change is firming of bread crumb. Firming of bread with chemically modified starch has been studied by several investigators (Inagaki and Seib 1992; Toufeili et al 1999; Takasaki and Mineki 2001; Hung and Monta 2004). Bread staling with cross-linked waxy barley has been precisely studied and the consistent result was that...