Handling of Apples during Sorting-Grading Operation and Measuring the Mechanical Properties Firmness after Controlled Atmosphere Storage

Apples are very sensitive to surface damage during post-harvest operations and transportation. Any mis-handling can affect the texture and crunchiness thereby the shelf life of apples. Experiments were conducted to reduce mechanical damages during sorting-grading operations by installing a water tank at the feeding conveyer of sorting-grading machine. Four varieties of apples, Viz. Royal Delicious, Red Delicious, Rich-a-Red and Golden Delicious (of Himachal Pradesh, India) were studied for bruising effects by comparing handling techniques of manual unloading to the conveyer or to water handling system. After sorting-grading operation, apples were stored in controlled atmosphere storage (CAS) at a temperature of 10C, 90-95% RH, 1 to 2% oxygen and 0.5 to 1% carbon di-oxide levels. Conventionally apples are packed in corrugated fiber board (CFB) boxes in the orchard level. From the orchards, apples are transported to the storage points, where pre-storage operations like sorting-grading and bin filling are done. When apples are unloaded manually from CFB boxes to the sorting-grading machine conveyer, several mechanical damages, even though appear minor, cause firmness loss on post-storage. A new technique is used to unload apples from the CFB boxes into a water tank, from where the sorting-grading feeding conveyer picks the apples for further processing. This experiment resulted in better firm apples during shelf life period, i. e. after storage of apples for two months in CAS. Better apple firmness is found in all the four varieties with water unloading technique compared to manually unloaded apples.