Coffee brew shelf life modelling by integration of acceptability and quality data

A methodology for the development of shelf life models predicting consumer acceptability of coffee brew on the basis of simple and easily detectable quality indices was proposed. Coffee brew was assessed during storage for consumer acceptability using both acceptability scoring methodology and evaluation of consumer rejection by survival analysis. Samples were also analysed for hydrogen ion concentration and intensity of sensory attributes (acid, off-flavour and bitter) by a trained sensory panel. Hydrogen ion concentration and sourness resulted to be the indices best correlating with the percentage of consumer rejecting the product during storage. Mathematical functions predicting hydrogen ion concentration and sourness as a function of the risk of consumer rejection were defined. These equations provided information to assist companies in choosing acceptance limits and were integrated with classic shelf life kinetic approach to produce shelf life models accounting for consumer response. Due to lower uncertainty of hydrogen ion concentration data as compared to sourness sensory data, only the former resulted to be a useful indicator of coffee brew shelf life.