EVALUATION OF OLD ITALIAN APPLE CULTIVARS BY MEANS OF SENSORY ANALYSIS

Abstract

Sensory analysis has been applied to characterize and to evaluate old/local germplasm with the aim to obtain information on fruit quality and to explore the cultivar acceptability. In 1999, thirty-six old Italian cultivars were analysed for their sensory profile and qualitative characteristics in comparison with four cultivars presently widely grown in Italy. The fruits were tasted by 15-17 partially trained panelists, and the following descriptors were assessed by means of a non-structured scale: sweetness, acidity, flavour, astringency, crispness, firmness, mealiness, juiciness; a global preference was also expressed. Soluble solid content, titratable acidity, pH and penetrometric index were measured. The coefficients of multiple regression among global preference and sensory attributes show that sweetness and crispness were the most important determinants, sweet, crispy and aromatic apples being the most appreciated by the panelists. Positive relationship, with flavour and juiciness, and negative with astringency and mealiness were observed. Some local cultivars (Zuccherina, Iaccia) were appreciated at the same level of the old and always highly estimated Annurca and more than Golden Delicious, Red Delicious and Ozark Gold. INTRODUCTION In the last twenty years attention has been devoted in Italy to the collection, conservation and evaluation of fruit tree diversity, with two main purposes: to guarantee the availability of a wide genetic variability for breeding programs and to extend the possibility of diversification of fruit offer. The potential of exploitation of old varieties is dependent on the interest of consumers for a wider range of fruit traits and for intrinsic quality and to the tendency to the application of organic or integrated fruit growing processes. The old apple cultivars are generally characterized by quite unusual pomological traits and have sometimes a lower external appeal with respect to the standard apples. As a consequence, the success of their introduction into commercial production for niche markets is highly dependent on the intrinsic quality of the fruits and on the capacity of the consumer to distinguish the peculiar characteristics in comparison with the conventional cultivars. The hypothesis of a re-proposal of old local cultivars for fruit growing may be then supported by the evaluation of the level of acceptability and of the capacity of the consumer to perceive peculiar qualitative traits. Sensory analysis has been applied in the last years to the classification of fruit cultivars and to the evaluation of the effect of provenance, harvesting time and storage conditions on sensory profile (Durner et al., 1992; Daillant-Spinnler et al., 1996; Bernalte et al., 1999; Eccher Zerbini et al., 1999; Stainer et al., 2000). The results of a panel test could help to the exploitation of old local germplasm, integrating the characterization and evaluation work and giving supplementary information on fruit quality. In that way, the hypothesis of introduction of old varieties may be better supported by the evaluation of the level of acceptance and of the perception capacity of the distinctive traits of the fruit by the consumer. The aim of this work was to evaluate old apple cultivars individuated in central Italy and collected at the experimental farm of Tuscia University on the basis of their acceptability, qualitative traits and sensory profile, in comparison with well known and Proc. IS on Sust. Use Of Plant Biodiv. Eds. E. Duzyaman Y they had previously received some training on sensory evaluation of apple for the understanding of the meaning of the attributes and for the assessment of sweet and sour taste and aroma intensity, according to Eccher Zerbini et al. (1999). At each sensory test 8 varieties were evaluated. The evaluation was conducted in a room equipped with individual sites and with white incandescent light. Two slices of anonymous samples were submitted to the panelists. They were invited to drink a sip of water and eat some saltless crackers between samples, in order to avoid tiring effects. The most important descriptors of apple taste and quality were assessed: sweetness, acidity, flavour, astringency, crispness, firmness, mealiness, juiciness; a global appreciation was also expressed. A sensory score sheet with a 11 cm unstructured line scale, each with anchored terms at both ends was used for descriptive terms. The judjes were requested to indicate the intensity of each attribute by placing a vertical line on the unstructured scale line. Sensory data were then quantified as the distance from the origin and the vertical line. Statistical Analysis Analysis of variance was performed on all the collected data, using the procedure SYSTAT MGLH (Wilkinson, 1998). The agreement among panelists was checked by ANOVA, considering cultivar, panelist and the interaction cultivar x panelist. Multiple regression analysis between global preference and the tested attributes was then applied. The coefficient of correlation among sensory variables was also calculated.