Harvest and Post Harvest Processes for Cold Storage of Apples
Cold storage of apples there are issues to be considered during and after the harvest until the apple comes to the Cold Storage. It has to go through some processing. Apples are harvested before they reach eating death during the period defined as tree death or harvest death. Apples harvested too early are of poor quality due to a lack of flavor and aroma. It is recommended to separate very large and small fruits and to store medium-sized fruits specific to the variety. Very large fruits stored in cold storage have a shorter storage life, and very small fruits have low economic value. Before storing apples, it is necessary to classify them according to color, size, and maturity, and separate damaged, injured, bruised defective and diseased fruits.
Cold Storage of Apples Conditions
The cooling rate of apple fruit affects product quality, but its importance varies with variety, harvest maturity, nutritional status of the fruit, and storage history. It is very important to fastly cool apple varieties that mature in the early part of the harvest season (summer varieties) since they will soften more quickly than those that mature in the latter part of the harvest season. Summer apples tend to soften more quickly in the later stages of maturity than in the early stages within the species. The effects of slow cooling become greater as the storage length increases. Therefore, inadequate investment of resources at harvest to ensure rapid fruit cooling may not be apparent until late in the storage period when fruit may not meet minimum firmness standards for marketing. For example, a 1-day delay at 21 °C (70 °F) before cooling results in a 7- to 10-day loss of storage life for an apple.
Apple producers have learned that apple fruit responds dramatically to both temperature and atmosphere modification. Rapid temperature drop and proper maintenance of low temperatures near the cultivar’s cooling point can yield good results for a medium quality crop after 4 to 7 months of storage and in some cases longer storage. However, modern commercial cold stores can be made more suitable with the CA system for the long-term storage of apples.
The recommended conditions for commercial cold storage of apples are -1 °C to 4 °C (30 to 39 °F) and 90 to 95% RH, depending on the variety. The acceptable duration of cold room storage has become shorter over the last several years as quality standards in the market have increased.