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Starch Retrogradation and Firming of Bread Containing Hydroxypropylated, Acetylated, and Phosphorylated Cross-Linked Tapioca Starches for Wheat Flour

¹Laboratory of Food Chemistry, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Japan. ²Present address: Central Laboratory, Yamazaki Baking Co., Ltd., 3-15-6, Chitose, Sumida-ku, Tokyo 130-0025, Japan. ³Present address: Department of Life and Health Sciences, Hyogo University of Teacher Education, 942-1, Shimokume, Yashiro, Hyogo 673-1494, Japan. ⁴Corresponding author. Phone: +81-72-254-9459. Fax: +81-72-254-9921. E-mail: morita@biochem.osakafu-u.ac.jp

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.