RELATIONSHIP OF SOLUBLE SOLIDS, ACIDITY AND AROMA VOLATILES TO FLAVOR IN LATE-SEASON NAVEL ORANGES

Late-season navel oranges in California sometimes have poor flavor even though they have high soluble solids content (SSC) and are very sweet. The reasons for this low flavor quality were investigated by evaluating individual late-season navel oranges for sensory attributes and then measuring SSC, titratable acidity (TA) and aroma volatiles from juice taken from the same oranges. A wide range in hedonic scores from below a rating of 4 (dislike slightly) to above 8 (like very much) was obtained for the 95 fruit evaluated, although 78% of the fruit were above a rating of 6 (like slightly). Correlation coefficients calculated between the sensory and chemical (SSC, TA and flavor volatiles) attributes were mostly non-significant and, in every case, very low, indicating that there were no clearly identifiable reasons for the flavor differences observed among the individual fruit. Partial least squares analysis using the combined chemical data as a dependent variable came to a similar conclusion and was able to account for only 25% of the variation in the sensory data by using the chemical data. It is possible that components other than those that were evaluated were responsible for the flavor differences or that the fruit were too similar in taste for our sensory panel to accurately categorize on an individual fruit basis.