Effect of storage conditions on the textural properties and in vitro digestibility of wheat bread containing whole quinoa flour

This research aimed to clarify the evolution of textural characteristics and in vitro digestibility under different storage conditions. Quickly increasing hardness and decreasing resilience was observed in quinoa bread after 5d cold (4 degrees C) storage. However, when stored at-18 degrees C for 5d, bread crumb still maintains a dense alveographic with 52.33% of cell density and 33.76% area fractions. In addition, the starch digestion rate decreased with increasing retrogradation degree. Scanning electron microscope (SEM) characterizations illustrated that the chunky matrix gradually disappeared with digestion. However, quinoa starch (QS) granules were the most difficult to digest owing to the relative intactness and wrapping in the protein-starch bulk. Meanwhile, X-ray diffraction (XRD) showed that the crystal structure of starch remained 21.09% stored in frozen conditions, and wheat type-A (WA) starch was mainly involved in gelatinization. The results of water migration proved that water participated in the retrogradation of starch and affected the quality of quinoa bread. Overall, bread stored in frozen conditions can maintain good texture characteristics and slow starch digestion rate. This study indicates that quinoa flour fortified bread has the potential to be developed as staple food with both low glycemic index values and storage stability.

Automated summary

This study found that quinoa bread stored under frozen conditions can maintain good texture characteristics and slow starch digestion rate, indicating the potential of quinoa flour fortified bread to be developed as staple food.