Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/8/2003
Publication Date: 3/1/2004
Citation: Xie, F., Dowell, F.E., Sun, X.S. 2004. Using visible and near-infrared reflectance spectroscopy and differential scanning calorimetry to study starch, protein, and temperature effects on bread staling. Cereal Chemistry. 81(2):249-254 Interpretive Summary: Bread staling is a complex process that occurs during bread storage. It is a progressive deterioration of quality that affects taste, firmness, etc. The mechanism of bread staling is not clear even though it has been studied for 150 years. Starch, protein, and temperature effects on bread staling were investigated in this study. The results showed that starch, protein, and moisture all contributed to the bread staling process. Bread staling was mainly due to amylopectin changes, and low temperature dramatically accelerated this process. Protein retarded bread staling, but not as much as temperature. The starch and protein interaction had less effect on staling. Protein hindered the bread staling process mainly by diluting starch and retarding the starch changes. Near-infrared spectroscopy (NIRS) measured staling accurately in different batches. The results of this study could lead to solutions for reducing bread staling that will bring economic benefit to bakers and consumers in the future. In addition, the results will be helpful in further developing NIRS applications as a means for studying bread staling or other similar phenomenon.
Technical Abstract: Starch, protein, and temperature effects on bread staling were investigated using visible and near-infrared spectroscopy (NIRS) and differential scanning calorimetry (DSC). Bread staling was mainly due to amylopectin retrogradation. NIRS measured amylopectin retrogradation accurately in different batches. Three important wavelengths, 970nm, 1155nm, and 1395nm, were associated with amylopectin retrogradation. NIRS followed moisture and starch structure changes when amylopectin retrograded. The amylose-lipid complex changed little one day after baking. The capability of NIRS to measure changes in the retrograded amylose-lipid complex was limited. Two important wavelengths, 550nm and 1465nm, were key for NIRS to successfully classify the starch-starch (SS) and starch-protein (SP) bread based on different colors and protein contents in SS and SP. Low temperature dramatically accelerated the amylopectin retrogradation process. Protein retarded bread staling, but not as much as temperature. The starch and protein interaction was less important than the starch retrogradation. Protein hindered the bread staling process mainly by diluting starch and retarding starch retrogradation.