Investigation of stress relaxation parameters during the storage of gingerbread cookies made from spelt wheat

Abstract

Relaxation test in uniaxial compression mode was performed on gingerbread cookies made from spelt wheat. Relaxation data were modeled by Peleg and Normand. The aim was to calculate stress relaxation parameters (percent stress relaxation, k1 (initial rate of relaxation), k2 (extent of relaxation) and relaxation time) for this type of product and to observe the changes in these parametrs during their storage. At 10-80% strains tested, the measured stress relaxation parameters (k1, k2, % SR, RT) varied little up to 60% strain. In general, gingerbread cookies had little elastic character. During storage, solid character of the samples increased in all samples. Relaxation time was the parameter that was unable to observe changes in the textural properties of the cookies during storage at high relative humidity whereas in the dried out sample, all parameters changed significantly.