NMR-baking and multivariate prediction of instrumental texture parameters in bread

To study the kinetics of the bread baking process, transverse relaxation (T -2) of protons was measured during a baking process performed inside the ma gnet of a pulsed low field H-1 nuclear magnetic resonance (NMR) instrument. Experimental NMR relaxation data were analysed both by chemometric data an alysis and by multi-exponential curve-fitting. Throughout the entire baking process from dough to bread three T-2-components were determined. During t he NMR-baking process significant shifts were observed in the characteristi c time constants at c. 55 degreesC (gelatinisation of starch) and at c .85 degreesC. In a second experiment staring of white bread crumb aged 0-8 days was inves tigated by texture analysis and NMR relaxation. High correlations (r > 0.9) between texture parameters and NMR relaxation data of bread crumb were fou nd by partial least squares regression (PLSR) models. Firmness and elastici ty as measured by a Texture Analyser were predicted with an estimated error (RMSECV) of 150 (range 200-2200) and 0.032 (range 0.4-0.7), respectively. Future texture of the bread samples was also predictable by use of NMR rela xation data from the early storage period (day 0 to day 3). (C) 2001 Academ ic Press.