Relationships between sensory and instrumental quality characteristics of 'Fuji' apples by multivariate analysis

Standard quality parameters and sensory characteristics (sensory acceptability and sensory acidity) of 'Fuji' apples (Malus x domestica Borkh.) were studied in relation to storage conditions, storage duration and shelf life period. 'Fuji' apples harvested at 185 days after full bloom were analysed after 3, 5, and 7 months of cold storage in normal atmosphere (AIR: 21% O 2 + 0.03% CO 2 ) or under three different controlled atmospheres (CA), in which oxygen and carbon dioxide were held at 1% + 1% (ULO1), 2% + 2% (LO) or 1% + 3% (ULO2), respectively. During post-storage ripening, apples were kept at 20°C for 1, 5 and 10 days before analytical measurements were made.Partial least squares regression models (PLS1) were run, in an attempt to correlate sensory acceptability and sensory acidity to instrumental measurements (SSC, TA, firmness and Hue). PLS1 model for sensory acceptability, where the instrumental quality parameters were used as X-variables, showed that the quality parameters most positively influencing acceptability were SSC, TA, firmness and background colour (Hue). The predicted sensory acidity versus the measured sensory acidity plot from the PLS1 model developed for sensory acidity revealed three groups defined by sensory acidity with a correlation coefficient of r= 0.94. Thus, ULO1-stored fruit had the highest sensory acidity score, ULO2- and LO-stored fruit showed intermediate sensory acidity score, and finally AIR-stored apples had the lowest sensory acidity score.