FRUIT QUALITY EVALUATION OF FOUR LOQUAT CULTIVARS GROWN IN SICILY

Abstract

Chemical (soluble solids content, titratable acidity, pH), morphological (weight, longitudinal and transversal diameter, thickness of the flesh, number of seeds, peel colour), and sensorial characteristics of four loquat cultivars (‘Algerie’, ‘Claudia’, ‘Nespolone di Trabia’ and ‘Sanfilippara’) from mature, organically-grown trees in Sicily, were analysed. The determinations were carried out by traditional instrumental techniques, by a panel test and by an electronic olfactory system. A panel of 10 trained judges was used to determine intensity of some attributes in the sensory profile of the different cultivars, while the electronic olfactory system was used to identify possible differences in the aromatic “fingerprint”. The main differences in the analytical evaluation among the four cultivars were the higher acidity and the lower fraction of soluble solids of ‘Sanfilippara’ and ‘Nespolone di Trabia’; while the highest value of soluble solids was observed in ‘Claudia’. These chemical characteristics were in agreement with the assessment of judges. In an overall sensory evaluation, ‘Claudia’ scored highest with attributes such as sweetness and juiciness, while ‘Sanfilippara’ had the most characteristic loquat odor and ‘Nespolone di Trabia’ the most grass odour. The responses of electronic olfactory system sensors were analyzed with a Principal Component Analysis (PCA). The plot of the two main components of the PCA analysis, PC1 and PC2, showed discrimination among the aromatic pattern of the four cultivars. The results show that the perception of volatile compounds by the human nose is important to evaluate the quality of loquat fruits, but, in this research, it is unable to discriminate the cultivars as well as the electronic nose.