Assessment of relationships between sensory and instrumental quality of controlled-atmosphere-stored 'Fuji' apples by multivariate analysis

Physicochemical parameters, sensory attributes, and total aroma emission of 'Fuji' apples (Malus x domestica Borkh.) were studied in relation to storage conditions, storage duration, and shelf life period. Commercially ripe fruit were analyzed after 3, 5, and 7 mo of cold storage in normal atmosphere (AIR) (210 L/m(3) O-2 + 0.3 L/m(3) CO2) or under 3 different controlled atmosphere (CA) treatments (10 L/m(3) O-2 + 10 L/m(3) CO2, 20 L/m(3) O-2 + 20 L/m(3) CO2) or 10 L/m(3) O-2 + 30 L/m(3) CO2), after which apples were kept at 20 degreesC for 1, 5, and 10 d. Data were subjected to partial least square regression (PLSR) analysis. Physicochemical parameters were wen preserved throughout storage, especially in CA-stored apples; however, these apples showed lower total aroma emission. Sensory acceptability was also higher for CA-stored fruit after 7 mo of storage, whereas no significant differences were found for shorter storage periods. Accordingly, greater scores in sensory firmness, sensory flavor, sensory acidity, and appearance were observed for fruit stored in 10 L/m(3) O-2 + 10 L/m(3) CO2 after long storage. Two PLSR models were established, I for relating physicochernical parameters to overall acceptability, and another for assessing the correlation between sensory acidity and instrumentally measured titratable acidity. The 1st PLSR model indicated that soluble solids concentration, titratable acidity, flesh firmness, and background color of the shaded side have a positive influence on acceptability. The 2nd model indicated that sensory acidity also showed an excellent correlation to instrumentally measured titratable acidity.