Cell Wall Modifications Following Cold Storage of Calcium-Treated 'Golden Reinders' Apples

'Golden Reinders' apples harvested at commercial maturity were dipped in 2% (w/v) CaCl2 and stored for 4 or 7 months at 1 degrees C and 92% RH under air. Cell wall composition and some related enzyme activities were determined thereafter in order to assess the effects of calcium treatment on fruit firmness and cell wall metabolism throughout the commercial life of produce. Multivariate analysis of data showed that firmness was strongly related to the yield of pectin-enriched fractions isolated from cell wall materials. Reduced pectin degradation was observed in calcium-treated apples, probably in relation to inhibited activity of some pectolytic enzymes, possibly in response to suppressed ethylene production. Data suggests enhanced establishment of ionic interactions between pectic polymers in treated fruit, leading to higher firmness levels at the end of shelf life.