Apple Cold Storage
Harvesting and Post-Harvest Transactions
Fruits are harvested in the period defined as tree or harvest death before they come to eating. Due to the lack of apple taste and aroma in the fruit harvested very early the quality is low. It is recommended to separate large and small fruits and store medium-sized fruits specific to the variety. Large fruits stored in the cold have a shorter storage life small fruits have low economic value. Before storing apples, it is necessary to classify them according to color, size and maturity levels, and to separate damaged, injured, bruised, defective and diseased fruits.
Cold Storage Features
In commercial cold storage warehouses, apples are kept at 0 ° C to 2 ° C. It is noted that many apple varieties are stored for a long time at -1 ° C to 0 ° C and in an environment with 85-90% relative humidity. The apple freezes at -2 ° C. In our country, Golden Delicious, Starking Delicious and Granny Smith apple varieties are kept cold.
The fruits of the Golden Delicious apple variety are medium and large. Flesh is white, hard, juicy and delicious. The outer skin color is green and turns yellow when maturity progresses. Cold storage conditions at 0 ° C, 90% humidity environment, storage life is considered as 5 months.
Starking Delicious apple variety is also medium size and large. Fruit meat shows characteristics similar to Golden variety. Crust outer color is yellow-red and red. Cold storage conditions at 0 ° C and 90% relative humidity, storage life is consider as 7 months.
The fruits of the Granny Smith apple variety are medium and large. The fruit is bright vivid green color. Fruit meat is white, hard, very juicy and a very high quality apple variety with a pleasant sour taste. Cold storage conditions at 9 ° C, 90% relative humidity, storage life is 9 months.
In the cold storage of the apple, the relative humidity level of the storage air is important and it should not be allowed to change the humidity. 4-6% moisture loss in apple causes pellum, while the increase in storage temperature shortens the storage life of the apple, frost damages occur in the apple at very low temperatures.
Product Freezing Storage
Apples with low tendency to browning, good taste and texture, do not crumble when dissolved, are suitable for freezing. Apples must have reached to its maturity, but it should not be softened.
Apples to be frozen are washed after classification, and subsequently they are mechanically peeled in special peelers and cleaned by removing the core houses at the same time. Then, it is watched by the workers in a sorting band and the defective parts are cutted with a knife andit is sliced , checked by the experts.
Some pretreatments are applied to ensure that the slices obtained do not lose their texture as a result of freezing and also to prevent browning of the colour. The most convenient method of preserving color is the scalding of slices in hot water or steam. Other methods can be used for the same purpose, as it causes loss of scalding, taste and water-soluble substances.Slices in a solution containing ascorbic acid (0.5-2%), SO2 (0.01-0.05%), CaCl2 (0.1-0.5%) and sugar (10-40%), especially by applying vacuum, It is stated that the color can be preserved sufficiently by keeping it and freezing after the solution is discharged with the help of drainage. Prepared apple slices are packaged, sugar syrup is added on it or mixed with 5 to 1 sugar, packaged and frozen. Frozen apple slices produced in this way are mostly used in apple bakery products such as cakes.