Propagation of stochastic temperature fluctuations in refrigerated fruits.

A steady state variance propagation algorithm is derived to investigate the effect of stochastic air temperature disturbances on the variability of the temperature field inside refrigerated fruits during cold storage conditions. The disturbances are modelled by continuous-time autoregressive processes of variable order. The algorithm is based on the finite element formulation of the heat conduction equation and involves the numerical solution of matrix equations of the Lyapunov and Sylvester type. As an example, the cold storage of pineapple has been considered. It is shown that disturbances of different order but with the same scale of fluctuation result in comparable centre temperature variances.