Effect of cold storage on physiology and quality of Sudanell peach

Firm-ripe (R) and firm-breaker (B) Sudanell and Sudanell-1 peach cultivars were stored at 0 degrees C and 90-95% relative humidity (RH) for 40 days plus a subsequent ripening period of 3 days at 20 degrees C. For one batch thermal pretreatment at 30 degrees C for 84 h was also applied. In Sudanell peaches after 2 weeks of cold storage plus subsequent ripening, radiating internal flesh browning (IB) was marked. In Sudanell-1 cv, a short delay in the appearance of IB was detected. The latency period of IB was 2 weeks for Sudanell R, and 3 weeks for Sudanell B and Sudanell-1. In Sudanell-1 R ethylene emission decreased to a minimum after 12 days of storage, probably related to the latency period of IB. Concomitantly with IB development, flesh firmness decreased, remaining relatively high after subsequent ripening, when abnormal and astringent flavors appeared. When the latency period was surpassed ethylene emission and respiration increased slightly. After 48 h of thermal pretreatment, these emissions were reduced and remained constant until the end of treatment. This effect persisted throughout cold storage and IB development was reduced. After 2 weeks of storage fungal attacks appeared and were widespread after 4 weeks (mainly Alternaria sp. alone or associated to IB). Sudanell-1 showed the highest weight losses due to fungal attacks and dehydration.