The degree of the texture involvement in the sensory evaluation for food varies depending upon the nature of food. So far as an apple is concerned, either sweetness as gustatory stimuli or crispness as physical characteristics is generally recognized to be the major factor affecting the sensory evaluation. Present studies were conducted to examine the relation between the physical and chemical properties and the organoleptic evaluation by panels, in order to clarify the contribution of taste sensation and texture of an apple to consumer's preference.
Three cultivars of apple fruits (Kogyoku, Alps Otome and Oregon Spur) were measured instrumentally for shage, color, sugar content, acidity and texture. In parallel with physical and chemical measurement, sensory tests were performed on the same parameters and the relation between the evaluations, instrumental and organoleptic, was investigated for each parameter. The regularity in relation to the preference for an apple was studied by comparing the results, obtained by the Scheffes paired comparison method, with data from physical and chemical measurement.
The differences in shape and color among these three cultivars were distinct visually and instrumentally. The skin color of the three cultivars was essentially red but each tone was specific. In particular, the skin color of Kogyoku and Alps Otome, which had a deep red color and high chroma, was highly evaluated by panels.
The acidity and sugar content were significantly correlated with the sensory evaluation for sweetness. The sweetness ratio was confirmed to be a good measure of the degree of sweet flavor. The result from the Scheffe's paired comparison method suggested that the acidity was specifically potent to influence the preference of sweet flavor rather than the sugar content. The strong correlation between the intensity of sweetness and the total evaluation was obtained. It was postulated that the intensity of sweetness was the most major factor affecting the acceptability of an apple.
Both firmness and crispness, determined by the texture profile method showed the remarkable correlation between the sensory evaluation and the texturometric measurement. As regards juiciness, however, no correlation between the results obtained organoleptically and instrumentally was found. Among factors influencing the palatability of an apple, the intensity of sweetness was the most influential one, and the texture could also contribute to its preference.