Fruit Maturity and Storage Temperature Influence Response of Strawberries to Controlled Atmospheres

Abstract

`Chandler' strawberries (Fragaria ×ananassa Duch.) harvested three-quarter colored or fully red were stored in air or a controlled atmosphere (CA) of 5% O2 + 15% CO2 at 4 or 10 °C to evaluate the influence of fruit maturity and storage temperature on the response to CA. Quality evaluations were made after 1 and 2 weeks in air or CA, and also after 1 and 2 weeks in air or CA plus 1 day in air at 20 °C. By 2 weeks, strawberries of both maturities stored in air at 10 °C were decayed, however, strawberries stored in CA at 4 or 10 °C or air at 4 °C had no decay even after 2 weeks plus 1 day at 20 °C. Three-quarter colored fruit stored in either air or CA remained firmer, lighter (higher L* value) and purer red (higher hue and chroma values) than fully red fruit, with the most pronounced effect being on CA-stored fruit at 4 °C. CA was more effective than air storage in maintaining initial anthocyanin and soluble solids contents (SSC) of three-quarter colored fruit and fruit stored at 10 °C. Strawberries harvested three-quarter colored maintained initial hue and chroma values for 2 weeks in CA at 4 °C, becoming fully red only when transferred to air at 20 °C. Although three-quarter colored fruit darkened and softened in 10 °C storage, the CA-stored fruit remained lighter colored and as firm as the at-harvest values of fully red fruit. After 1 or 2 weeks in CA at either 4 or 10 °C plus 1 day at 20 °C, three-quarter colored fruit also had similar SSC levels but lower total anthocyanin contents than the initial levels in fully red fruit. CA maintained better strawberry quality than air storage even at an above optimum storage temperature of 10 °C, but CA was more effective at the lower temperature of 4 °C. Three-quarter colored fruit responded better to CA than fully red fruit, maintaining better appearance, firmness, and color over 2 weeks storage, while achieving similar acidity and SSC with minimal decay development.