Oxygen diffusivities of apple flesh and skin

This research was part of a project which was developed on the hypotheses t hat edible coatings can be formulated to give the same effect as modified a tmosphere storage in terms of controlling the internal gas composition in f ruits and vegetables. To accomplish controlled gas exchange, knowledge of g as diffusivities through fruits and vegetables is needed to determine the o ptimal edible coating formulation and thickness. Oxygen diffusivities of th e skin and flesh of three varieties of apples (Red Delicious, Rome Beauty, and Granny Smith) were tested using a specially designed cell. Skin or fles h samples of apples were retained in the cell in such a way that gas could flow across both faces of a sample. initially nitrogen was flushed across b oth sides of a sample until an oxygen free condition around the sample was ensured. Then oxygen was used to replace the nitrogen stream on one side of the sample and the amount of oxygen diffusing through a sample measured. F ick's first and second diffusion theories were applied to the darn. Results indicate storage had a different effect on different varieties and the gas diffusivity of skin was much less than of flesh.