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Postharvest Information Network

Friday, June 23, 2017

WSU-TFREC/Postharvest Information Network/Retail Quality of Washington Apples



Retail Quality of Washington Apples


Introduction

A study by Richard Bartram, Jim Fountain, Ken Olsen, Des O'Rourke and other cooperating USDA scientists was recently brought to my attention. The study was funded by a grant from the Tree Fruit Research Commission. The goal of the study was to investigate the actual quality of Washington Red and Golden Delicious apples in the domestic retail marketplace. Apple samples were purchased in five major marketplaces during the 1983 marketing season.

Exeperimental Procedure

Apples were obtained from cooperating warehouses in Washington State before shipment. Washington preshipment apples were obtained once in January, which correlates with the fruit arriving in the stores in February. Apple samples were also purchased in 1) the Philadelphia/Richmond, Virginia corridor, 2) New York/New Jersey, 3) Chicago, 4) Los Angeles, and 5) Texas. Each area was sampled twice, once in February and again in April of 1983.

The apples were taken to a laboratory located near the retail store where in-depth analyses were performed. The apples were not special "experimental" fruit, rather the samples were obtained from cooperating shippers before shipment from Washington, and were purchased from stores as they received the fruit. The apples were not taken from the store display areas. By using this procedure, the apples were identified as to source without being exposed to retail display temperatures or handling.

Each sample consisted of 10 apples. All of the samples were taken from tray packs, no bagged apples were included. Firmness, soluble solids, and acidity were tested on all samples. In addition, disorders such as bruises, scald, bitter pit and decay were noted. Watercore was also recorded. The person taking the sample also noted the retail price.


In-state Tests

Twenty shippers cooperated by providing apple samples to the project for the January in-state testing. The result was a total of 80 different lots of fruit; two-thirds of them were Red Delicious. The fruit was 70% from regular storage and 30% from controlled atmosphere (CA). The apple grades were 70% Extra Fancy, and 30% Fancy. The range of sizes represented a cross section of sizes being shipped at the time.


Results of In-state Tests

Firmness--In 41 % of the samples from regular storage, average firmness levels were less than 11 pounds. CA stored Red Delicious samples had only 4% of the fruit less than 11 pounds. For more details see Table 1.

Table 1. Average Pressure Tests.

Pounds Pressure
Red Delicious--All Grades and Sizes
FOB
February
April
Less than 11
(% of all Samples)
30%
30%
15%
11 to 11.9
21
14
12
12 to 12.9
27
12
12
13 to 13.9
14
10
16
14 and higher
8
33
44
Less than 11
(% of Refrigerated Storage Samples)
41%
44%
NA
11 to 11.9
27
16
NA
12 to 12.9
23
12
NA
13 to 13.9
7
11
NA
14 and higher
2
18
NA
Less than 11
(% of CA Storage Samples)
4%
14%
13%
11 to 11.9
8
12
12
12 to 12.9
38
13
12
13 to 13.9
29
10
17
14 and higher
21
51
45

Acidity--Red Delicious sampled at this time had low acidity; 80% of all apples tested below 0.200% acidity (combination or regular storage and CA). This indicated that the fruit were lacking in flavor and had poor shelf life.

Flesh browning--Both the regular storage and the CA storage fruit had almost no internal browning (see Table 2).

Table 2. Percent of Red Delicious Apple Samples of All Grades and Sizes Having One or More Apples Affected with Internal Browning.

Browning
FOB
February
April
None
94%
69%
96%
Slight
0
7
3
Moderate
0
7
3
Severe
6
17
0

Bruising--Bruising was relatively rare on Red Delicious; 82% of the fruit had none or less than one ¼-inch bruise (see Table 3).

Table 3. Percent of Bruised Red Delicious Apple Samples of All Grades by the Largest Bruise in a Sample.

Bruise size
FOB
February
April
None
6%
2%
18%
1/4-inch or less
76
7
29
1/4- to 1/2-inch
14
36
33
1/2- to 3/4-inch
3
24
15
3/4- to 1-inch
0
19
3
Larger than 1 inch
1
11
1

There were samples from 278 lots of Red Delicious purchased in mid-February from the five market areas, representing fruit from 76 Washington warehouses. At this sampling date, slightly over half of the fruit (55%) came from regular storage, and almost all of it (94%) was Extra Fancy grade.

Firmness--Red Delicious delivered to stores in mid-February out of regular storage had 44% of the fruit testing less than 11 pounds. Apples out of CA storage had only 14% of the fruit testing less than 11 pounds.

Acidity--Again, 80% of the fruit tested below 0.200% acids.

Flesh browning--Internal flesh browning, which could be classified as moderate or severe, developed in 28% of the lots of the regular storage fruits and in 19% of the lots of CA-stored apples.

Bruising--By the time the apples had reached the marketplace, 99% of the lots showed at least one apple with a bruise larger than -inch.


Results of the April In-store Sampling

At this sampling date, samples from 313 lots of fruit were purchased, which represented fruit from 75 shippers. Most (95%) of the fruit had been CA stored, and most (97%) were graded Extra Fancy.

Firmness--Only 15% of the fruit purchased tested less than 11 pounds, quite an improvement from the previous date. Remember that most of this fruit came from CA storage.

Acidity--Unfortunately, 86% of the Reds contained less than 0.200% acids.

Flesh browning--Internal flesh browning classified as moderate or severe was found in only 1% of the lots sampled.

Bruising--Red Delicious in the marketplace in April showed a great reduction in the amount of bruising over those sampled in February. Only 47% of the lots had one apple or more with a bruise larger than -inch.


Summary of the Condition of Red Delicious

Problems such as storage scald, decay and bitter pit did not prove to be significant during any of the marketing periods sampled.

In February, the primary adverse condition factors found in about one-third of the Red Delicious sampled were firmness (below 11 pounds), low acidity (below 0.200%) and a great number of bruises. In addition, many of the lots showed moderate to severe flesh browning.

In April, the samples showed that the fruit was in far better condition, except for acid levels. Fruit firmness had improved significantly and bruises were reduced. Only a few samples showed internal browning.


Implications of Fruit Condition on Price

Regular storage fruit which appeared in the marketplace was the source of poor condition of the apples in February. This may be due to any of three reasons. First, fruit placed in regular storage for marketing during the late regular storage period may have had lower than optimum quality, if the best fruit at that specific harvest period was selected for early CA. Second, the difference in fruit condition out of storage demonstrates the effectiveness of CA in the retention of fruit firmness and condition. Third, quality differences could also have been due to placement of late harvested fruit, which failed to qualify as CA quality, in early CA, and later sale of this fruit as regular storage fruit. I personally feel that the truth is a combination of factors.

The authors of the study conclude with the following statement about prices. Grower returns are affected by fruit condition, which influences market movement. An analysis of historical apple prices by O'Rourke and McGary, which took into account the effects of crop size, United States disposable income, and inflation, suggested that for the 1982-83 season, the Washington apple industry should have averaged FOB $11.83 per box. The actual average reported by the Washington Growers Clearinghouse Association was $9.78 per box. Undoubtedly, the poor condition of many lots of fruit in the mid-marketing period contributed to prices being an average of $2.00 per box less than they could have been.


Apple Commission and Fruit Quality

In 1985, the Washington State Apple Commission embarked on a program to help the industry continue to improve the quality and condition of Washington apples in the marketplace. Tom Hale reported that the amount of fresh produce available nationally will increase dramatically over the next 5 years. Also, imports are on the increase. Washington has been taking markets away from competing states. Any future expansion must come from increased consumption, that is, repeat sales. Buyers are becoming much more discriminating in their apple purchases, so in order to maintain and strengthen the state's leadership role in the marketplace, Washington must supply markets with apples of the highest quality.

Various industry committees have been discussing methods by which improvements in grade standards can be implemented. One improvement, which has been included in the 1986 crop, is testing prerelease date shipments for soluble solids content. This certainly is a step in the right direction.


Monitoring the Quality ofApples in Storage

Although it is important for a shipment to meet the grade standards, it is also useful to anticipate the quality and condition of apples by testing fruit while it is still in storage.

Dr. Ken Olsen and I described (Postharvest Pomology Newsletter 2(4):34) a simple technique which warehouses can use to determine the condition of Reds and Goldens in storage. It is useful in determining lots suitable for export or other long distance shipment, as opposed to local sales. It can also assist in determining the sequence of rooms to be opened.

The most reliable method of checking fruit condition after storage is to test fruit firmness. Unfortunately, testing the fruit immediately upon removal from the storage room only provides a rough indication of the actual condition of the apples. It does not indicate how long the fruit will last in the market (shelf life). To determine the comparative shelf life of the fruit, allow the fruit to remain at room temperature under conditions which do not promote shriveling. Testing the firmness of apples after they have remained at room temperature for 7 to 10 days will give a better indication of shelf life. The best method is to combine the two approaches--test fruit immediately upon removal from storage, and test it again several times during a week or more at room temperature. The recommended procedure follows:

  1. At harvest: Select uniform fruit of an average size for that lot. Using fruit of the same size will minimize the effect of size on firmness. Place about 80 fruit per lot in a polyliner, leaving a 2-inch opening on top. The polyliner will prevent shrivel but may increase the amount of storage scald in a sample. Sample each lot of fruit in the room. Place the samples close to the door. Plastic cherry lugs are ideal.

    If the warehouse manager has not taken samples at harvest, one option would be to take samples from the top bins by opening the room after it qualifies, airing it out and going in to pull the samples from the top bins. Several warehouse managers use this technique on a monthly basis during the season.

    Persons entering a closed CA room must wear an approved breathing apparatus. Entering a closed CA room is extremely dangerous. You can easily lose consciousness in less than 30 seconds. Dr. Dave Blanpied described steps to take if you must enter a sealed CA room (Postharvest Pomology Newsletter 2(1):12-14). It is far more sensible to enter an aired out room.

  2. During the storage season: Test apples in storage at least twice during the storage season if the maturity of the fruit selected for that room is matched with the planned length of storage. In other words, fruit selected for long-term storage while on the tree, using internal maturity indicators in order to time harvest, should be tested in February and again in April. Test fruit of questionable maturity each month.

  3. At each testing date: Remove half of the fruit in the sample kept by the door (40 fruit from each lot). Place 30 fruit in a box with a polyliner which has a 2-inch opening on top. Set this box at room temperature. Test the other 10 fruit for firmness on the day the fruit is taken from the CA. Check for external and internal defects and condition. Test each apple twice with a well calibrated pressure tester, avoiding the sunny and shady sides. Repeat these tests at 3 to 4-day intervals. Remember that an export delivery may take as long as 21 days. Testing fruit kept at room temperature for 14 days simulates export delivery far better than does testing for a shorter length of time.

  4. Graph the average firmness values for each lot of fruit as shown in Figure 1. It will become immediately obvious which lots of fruit have shelf life and which lots will lose condition rapidly.


Watercored Fruit in Storage

Apples with moderate or severe watercore are not suited for long-term CA storage. Watercored apples are postclimacteric and can easily go into anaerobic respiration in which a winey flavor and odor will be generated. Watercored apples give off ethylene, which can ripen apples in the same storage room - especially under regular storage conditions. Internal breakdown and internal browning may occur when seriously watercored fruit are stored.

The Apple Maturity Program has been cooperating on a project to determine the relationship of fruit mineral content to fruit quality and condition. Fruit from commercial orchards was left on the tree for 1 and 2 weeks past long-term CA maturity (1985). When harvested, a portion of the fruit was examined for quality and condition. Most of the fruit was placed in long-term CA. In many cases there was slight watercore in most of the fruit before storage. Few apples developed internal breakdown in storage, nor did they show signs of watercore after storage. However, after being held at room temperature for 10 days, a significant number of the apples developed internal breakdown. In other words, in a commercial packing system, the fruit would have looked very good. Unfortunately, by the time the fruit arrived in the hands of the consumer in a distant market, internal browning would have developed. Watercored apples are sweet and tasty if marketed early in the season.

Dr. Eugene Kupferman, Postharvest Specialist

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

Post Harvest Pomology Newsletter, Vol 4. No. 3
November-December 1986

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