POSTHARVEST CaCl2 DIPS INCREASE HIGHBUSH BLUEBERRY FIRMNESS
Deformed or damaged berries reduce the grade of frozen highbush blueberries (Vaccinium corymbosum L.). Before berries are frozen, immature fruit are commonly removed by density sorting in water tanks. Three studies were conducted to determine if the firmness or quality of highbush blueberries could be improved by the addition of CaCl2 to sorting tank water. `Bluecrop' and `Jersey' berries were dipped in CaCl2 solutions (0.0-4.0%) for periods of 0.5-8.0 minutes. The effect of rinsing the fruit after treatment was also studied. Berries were held at 2C for several days before evaluation. A 61.5 cm length of PVC pipe (4.0 cm. I.D.) was filled to a depth of 50 cm. with berries and dropped 4 times on to a hard surface from a height of 10 cm. The compression of the column of berries was measured and berries were removed and visually sorted according to the degree of damage. The amount of compression and number of damaged berries were inversely related to the CaCl2 concentration. Rinsing berries immediately after dips negated the effects of CaCl2. Treatment with CaCl2 may result in objectionable flavors.