Chemometric approach for assessing the quality of olive cake pellets

Abstract

This article investigates the influence of processing parameters (conditioning and binder content), on quality of fuel agro-pellets produced from four olive cultivars (Istarska Bjelica, Buža, Pendolino, Leccino) grown in experimental filed in Croatia (Istria). Physical and chemical properties of pellets have been determined to assess their quality. Low ash and sulphur levels were detected, with elevated nitrogen levels for all samples. Analysis of variance and post-hoc Tukey's HSD test at 95% confidence limit have been utilised to show significant differences between various samples. Low coefficients of variation have been obtained for each applied assay (0.09–2.98%), which confirmed the high accuracy of the measurements. Score analysis and principal component analysis have been used for assessing the effect of process variables and variety of cultivars on final quality of pellets. For PCA modelling, experimental data for physical and chemical properties have been used. Standard score analysis revealed that equally good physical and chemical characteristics of pellets can be obtained with conditioning at 50 °C, but also without conditioning. The use of binders didn't affect the quality of pellets as much.