Identification of marker components
One of the aims of project was to identify biomarkers that could indicate the degree of ripening. Two peptides (GVEEPPKGHKGNKK and QAISNNKDQGSY) identified by the LC-MS proteomics, which showed a linear response with the time of processing, are candidates for application in process and quality control, together with several of the metabolites identified by the metabolite analyses. For use in predictive modelling, the ideal biomarkers are compounds where the formation rates depend on water activity and temperature. Free amino acids generated by the action of different aminopeptidases, such as alanine/ phenylalanine and pyroglutamic acid, which responded differently to reduced water activities in the laboratory experiments, are candidates for the first 8-10 months, together with some di- and tripeptides.