Storage Methods and Technical Key Points for Peaches, Plums, and Apricots

(1) Room-temperature storage: Peaches are not suitable for room-temperature storage, but due to the needs of transportation and shelf-life preservation, certain measures can be taken to extend the room-temperature freshness life of peaches.

1. Calcium treatment: Soak peach fruit in a 0.2%-1.5% CaCl2 solution for 2 min or vacuum-soak for several minutes, drain the liquid, and leave bare indoors; for mid- and late-maturing cultivars this can improve storability.

2. Heat treatment: Soak fruit in constant-temperature water at 52°C for 2 min, or hold in steam at 54°C for 15 min, which can kill pathogen spores and prevent rotting.

3. Film packaging: One method is to wrap each fruit individually in a 0.02-0.03 mm thick polyvinyl chloride bag, which can also be used in combination with calcium treatment or heat treatment for better results. Another method is to pack the fruit in specially made freshness-retaining bags. The HA series peach freshness-retaining bags successfully developed by the Tianjin Fruit Preservation Research Center are 0.03 mm thick; by adding ion-exchange freshness-retaining raw materials during film production, this bag can prevent CO2 injury during storage, among which HA-16 has a significant effect for room-temperature freshness retention of peaches.

(2) Cold storage: Under conditions of 0°C and 90% relative humidity, peaches can be stored for 15-30 d. Intermittent warming treatment during cold storage can avoid or reduce chilling injury and extend storage life. For fruit stored at low temperature at -0.5-0°C, warm to room temperature (18-20°C) for 1-3 d about every 2 weeks, then resume low-temperature storage.

(3) Controlled atmosphere storage: Foreign recommendations use conditions of 0°C, 1% O2 + 5% CO2 to store nectarines, with a storage period of up to 45 d, double that of ordinary cold storage. In China, however, the controlled atmosphere standard for the honey peach group is still under study; for some cultivars, cold storage plus modified atmosphere has achieved results of storage for more than 60 d without fruit deterioration, with a maximum storage of 4 months. When conditions for standard controlled atmosphere (CA) are unavailable, peach freshness-retaining bags plus a controlled atmosphere preservative can be used for simple modified atmosphere storage (MA). The specific method is: after harvest and precooling, put peaches into special freshness-retaining bags for cold storage, add the controlled atmosphere agent, and tie the bag mouth tightly; maintain the gas composition inside the bag at 0.8%-2% oxygen and 3%-8% carbon dioxide. Okubo, Yanhong, and Zhongqiu can be stored for 40 d, 55-60 d, and 60-70 d respectively, and the fruit maintains normal ripening ability and commercial quality.