investigation of metabonomics technique by analyze of nmr data, which method is better? mean center or auto scale?

the factors such as disease can disrupt homeostasis, resulting in perturbations of endogenous biochemicals that are involved in key metabolic profiles. metabonomics is useful technique to quantitative description of endogenous metabolites present in a biological sample such as urine, plasma and tissue. high resolution 1 h nuclear magnetic resonance (nmr)-based metabonomics is a technique used to analyze and interpret multivariate metabolic data that correlate with changes of physiological conditions. before any explanation for metabolite data, preprocessing the spectroscopic data is essential. in this paper, we show scaling effects in metabonomics investigation of patients diagnosed with crohn's and celiac disease. two techniques of scaling were applied as follows: mean centering and auto scaling. results reveal that the mean centering is more useful to segregate patients from healthy subjects in the data set of crohn's and celiac disease.