Temperature and relative humidity effects on quality, total ascorbic acid, phenolics and flavonoid concentrations, and antioxidant activity of strawberry

The physical qualities and antioxidant components of 'Jewel' strawberry fruit stored in 75, 85 or 95% relative humidity (RH) at 0.5, 10 and 20 degrees C for 4 days were studied. Overall fruit quality declined more rapidly at 20 degrees C, especially at 95% RH. Weight loss of fruit was negligible for 2 days at all temperatures but it increased at 10 degrees C in the lowest RH and increased rapidly from day 3 at 20'C especially with lower RH. Firmness was maintained, or even increased, at 0.5 or 10 degrees C, while soluble solids concentrations (SSC) decreased at higher storage temperatures. Red color, assessed using chroma, hue and lightness, and anthocyanin concentrations were relatively unchanged at 0.5 or 10 degrees C but increased rapidly at 20 degrees C as fruit ripened. Firmness, SSC and color were not affected by RH. Total phenolic compounds were slightly higher at 20 degrees C than at other temperatures at all RHs. Total ascorbic acid concentrations of the fruit remained similar for the first 2 days of storage, then declined in fruit stored at 0.5 and 20 degrees C, but remained unchanged at 10 degrees C at all RHs. Total flavonoid content of fruit did not change over time at all temperatures. The total antioxidant activity of fruit was higher at 10'C than at 0.5 and 20 degrees C on day 3, and no effect of RH was detected. In conclusion, while the best temperature for long-term storage is 0.5 degrees C, quality could be maintained at 10 degrees C for acceptable periods of time for marketing and may be associated with better nutritional quality. (c) 2007 Elsevier B.V. All rights reserved.