3.5. TA
Highbush blueberries are characterized by high citric and succinic acid contents, averaging 75% and 17%, respectively
(Ehlenfeldt et al., 1994). Therefore, acidity results are expressed as a percentage of citric acid. Changes in TA levels
of ‘Elliott’ highbush blueberries during storage are summarized in Table 1. The acidity of the fresh blueberries was
determined to be 0.84 ± 0.00%. This stayed at about the same level during 18 days of storage at 10 C for both containers. No differences (p 6 0.05) were observed through the end of storage. At 23 C, blueberry acidity was affected by the container type. Acidity decreased (p 6 0.05) in blueberries packed in PLA containers while it was constant in blueberries packed in clamshells. This is in agreement with Harb and Streif (2004) who reported an enhanced consumption of organic acids as respiration substrate because the respiratory rate of berries stored under increasing CO2 values was significantly higher than that of air-stored fruits. Kim et al. (1995) reported higher TA with higher CO2 levels
for ‘Coville’ blueberries. Temperature also affected acidity for blueberries packed into PLA containers. Results showed decreased acidity with increased temperature storage. Rosenfeld et al. (1999) reported that TA in ‘Bluecrop’ blueberries increased with increased temperature storage for the same package.