Impact of SmartFresh^TM on Apple Quality and its Interaction with Current Industry Practices

There are two major objectives to this work:

Within a specific CA regime, apples treated with 1-MCP were firmer (0.5-1 kg) than comparable apples after mid- or long-term storage (120 or 240 days, respectively). Lowering the O₂ did not consistently improve firmness, as many apples treated with 1-MCP exhibited the highest firmness regardless of gas concentrations during storage. Firmness of certain cultivars in specific CA regimes was influenced by 1-MCP, gas concentrations, and storage temperature. Ethylene, CO₂, and volatile production were generally lower in apples treated with 1-MCP, held at lower temperatures, and in lower O₂, although there were some interactions of these factors. Overall, 1-MCP had variable effects on physiological disorders and interacted with the CA regimes.

More specifically for ‘Gala’, 1-MCP treatment resulted in reduced rates of respiration, ethylene and volatile production, regardless of storage regime, and resulted in a reduced production rate of all the major volatile compounds, including esters, alcohols, acids, aldehydes, and ketones. 1-MCP treatment inhibited post-storage volatile production in CA- and air-stored fruit by as much as 95%. However, recovery of aroma was delayed significantly in fruit that had been held at 0^oC compared to 2.5^oC, suggesting aroma volatile synthesis in ‘Gala’ is chilling sensitive.

In general, there was no beneficial interaction or apparent effects of ReTain on firmness retention, or respiration, ethylene and volatile production. The incidence of physiological disorders was extremely variable, depending on storage duration, 1-MCP concentration, and postharvest application of ReTain.

When apples of proper maturity at harvest were put into storage, there was a positive response to post-storage 1-MCP applications. This response was better in fruit from CA storage than from air, and within CA the response was better in low oxygen than in standard CA.

^* This project is funded in part by the Apple Marketers’ Association of Ontario, Canadian Horticultural Council, AgroFresh Inc. (Rohm & Haas), and the Agricultural Adaptation Council.