Effects of low oxygen short-term exposure at 15°C on postharvest physiology and quality of apricots harvested at two ripening stages

Apricots of two harvests (9-10 degrees Brix and 13-14 degrees Brix) were treated for 6 d at 15 degrees C with 1%, 2% and 4% O-2 (low oxygen = LO) and then kept for 7 d and 5 d (respectively for the first and the second harvest) in air at 15 degrees C (shelf Life = s.l.). Control fruit were held continuously in air at 15 degrees C or for 6 d at 5 degrees C then moved to 15 degrees C. In early harvest fruit, low O-2 (1% and 2%) for 6 d controlled ethylene production even after the transfer and consequently the fruit had lower SCC and were firmer. In fruit from the second harvest, only 1% O-2 atmosphere or control fruits at 5 degrees C were able to control the rise of ethylene in s.l. and to reduce the increase of soluble solids content (SSC). A 1% O-2 atmosphere maintained acceptable firmness even during s.l. in fruit of both harvests. Respiration rate was better restricted by low temperature during the treatment but at the end of experiment no difference was observed among the samples. Colour of apricots was maintained only by 1% O-2 atmosphere or 5 degrees C temperature both in the first and in the second harvest. Sensory evaluation of fruit of the first harvest revealed that only apricots kept at 15 degrees C or in 4% O-2 were considered saleable. In the second harvest, apricots treated with 5 degrees C and 1% O-2 were judged saleable. In conclusion, early harvest fruit does not benefit from low oxygen (1% and 2% O-2) because fruit does not reach the optimal SSC whereas for late harvest apricots the use of 1% O-2 at a higher temperature than that used commercially can be an alternative to low temperature as shipping treatment or short term storage.