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Saturday, April 29, 2017

WSU-TFREC/Postharvest Information Network/Packing Gala Apples in Washington State



Packing Gala Apples in Washington State


Sampling

The 1992 WSDA Washington Fruit Survey reports that there are 5,900 acres of Gala planted at 649 trees per acre. This indicates that Gala will become one of Washington State's major varieties. However, this variety is one of the first in modern times to be a "summer" apple whose quality declines rapidly in storage and one that requires multiple picking.

Sampling of Gala apples began in August 1992 and continued through March 1994 (1992 and 1993 crops). Gala apples were sampled repeatedly from 8 packinglines in 8 packinghouses in 1992 and from 14 packinglines in 12 packinghouses in 1993. Forty Gala apple samples were obtained from August 17 to December 7 from the 1992 crop. Fifty Gala samples were obtain from August 3 to March 1 from the 1993 crop.


Fruit Firmness

The firmness of Gala apples declines rapidly in regular storage (Figure 1). This calculated to a loss of 0.3 lb. per week in fruit firmness at time of packing as the season progressed. Fruit sampled in 1993 were firmer than those sampled in 1992. Gala apples sampled over the two years averaged 17.0 lbs. (2.2).

When Galas were held for seven days at 70°F the decline in firmness of Gala apples held was rapid (Figure 2). Most likely it is this firmness which the consumer experiences. Galas should be stored in CA rather than regular storage even for only a short period of time since CA will retain firmness.

 

 


Soluble Solids

The average soluble solids levels of regular storage Galas at time of packing rose slightly as the season progressed due to the conversion of starch to soluble solids (Figure 3). The average soluble solids level of Galas was 13.0% (0.8) over the two years.

 

 


Acidity

The level of acidity of Gala apples packed in August-September of 1992 was significantly higher than that sampled later in 1992 or in 1993 (Figure 4). Acidity at time of packing over the two years averaged 0.476% (0.1).

 

 


Quality Changes

Gala apple quality changes rapidly in storage and after warm room treatment. Sugar acid ratios, one measure of flavor, did not develop a pattern of change during the season, possibly due to our sampling fruit from a number of packers rather than following a single lot of fruit through the season.


Temperature

Temperature regimes followed by warehouses packing Galas are similar to that of Red Delicious (Tables 1 and 2). The average rise in flesh temperature for Galas during packing in 1993 was 17°F. Temperature management on Gala apples should be reconsidered in view of the tendency toward very rapid decline in firmness of this variety. When packing fruit whose flesh temperature (0.5" under the skin) averages 64°F, one cannot assume that Gala apples on arrival will be as firm as they could be if the fruit were colder.

 

Table 1. Average temperatures of fruit, water, and air in packinglines in 1992.

PackinglineFruit before dumpingDump tank waterFruit before waxingDryer airFruit at tray filler
A341895213059
B146835511265
C155986913674
H138464211849
K245875211057
N136544512560
R153857013074
S154875910661
Avg.46795612062

 

Table 2. Average temperatures of fruit, water, and air in packinglines in 1993.

PackinglineFruit before dumpingDump tank waterFruit before waxingDryer airFruit at tray filler
A1528569--71
B146916211667
C150776512667
C242946913575
D140485014156
E1608576--77
G153717013071
I14396----61
K147786512552
K2447868--71
L23848499055
N3566466--70
P148776612570
R147545510752
S14676599361
Avg.46756111263

Summary of Gala Quality and Temperature Management

Gala quality declines rapidly in regular storage and less so in CA. Soluble solids levels remained at acceptable levels during the two years. Acid levels were quite high in the fall of 1992 and less in 1993.

Temperature management during packing is an area which needs attention of the industry. Apple quality deteriorates rapidly when fruit temperatures at time of packing are high.

Dr. Eugene Kupferman, Postharvest Specialist

WSU Tree Fruit Research and Extension Center
1100 N. Western Ave., Wenatchee, WA 98801
Kupfer@wsu.edu

Tree Fruit Postharvest Journal 5(2):19-22
August 1994

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