Relationship between ethylene response manipulation and volatile production in Jonagold variety apples

The ripening of Jonagored Jonagold apple fruit (Malus x domestica Borkh.) d uring development was manipulated with preharvest applications of ReTain or a combination of ReTain plus Ethrel. The fruits, harvested preclimacteric at approximately the same stages of maturity, were stored in refrigerated a ir (RA) for 45 days or in controlled atmosphere (CA) for 180 days at 0 degr ees C. Volatile evolution, ethylene production, and respiration of stored f ruit were studied during poststorage holding at 22 degrees C. ReTain reduce d volatile production by 19%, but application of Ethrel to ReTain-treated f ruit increased production to control levels. The inhibition of volatile pro duction by ReTain appears to be independent of respiration but may be relat ed to the ethylene-producing capacity of the fruit. Although ReTain reduced flavor-related volatile esters, it did not affect levels of the compound r esponsible for the typical spicy flavor in Jonagored Jonagold fruit, 4-meth oxy-2-propenylbenzene. The CA-stored fruit had a much reduced production of volatile compounds compared to RA-stored fruit, with more discernible effe cts in ReTain-treated fruit. Ethrel application to ReTain-treated fruit imp roved the volatile production intermediate between the ReTain alone and con trol in CA-stored fruit. The data collectively suggest that ReTain may have some promise for better scheduling of harvest of apples with no appreciabl e loss in RA-stored fruit quality. Reduction in production of alpha-farnese ne by ReTain may also reduce the potential for scald development in CA-stor ed fruit.