Effect of calcium propionate on the microstructure and pectin methy‐ lesterase activity in the parenchyma of fresh‐cut Fuji apples

Abstract

AbstractThere is an increasing demand for fresh‐cut fruits. One of the main problems with these products is their short shelf life. The use of additives such as calcium propionate may increase their shelf life, because calcium preserves the structural integrity of the cells and propionate acts as food preservative. This work analyses the microstructure of Fuji apple parenchyma treated with calcium propionate immediately after treatment and after storage for 1 and 2 weeks at 4 °C by using light microscopy (LM) and low‐temperature scanning electron microscopy (cryo‐SEM). This work also studies the effects of treatment and storage time on the enzymatic activity of pectin methylesterase (PME) by measuring the amount of acid released per unit of time at pH 7 and at 63 °C. The results show that calcium propionate treatment has consolidating and structuring effects on the parenchyma and partially minimises the degrading effects of fresh‐cut apples. In addition, treatment with calcium propionate decreases the activity of the PME both in non‐stored apples and in those stored for 1 and 2 weeks probably due to the inhibiting effect of propionate. Copyright © 2006 Society of Chemical Industry