Biochemical and fungal caracterization of dried pears and other fruits

The drying of pears allows their conservation due principally to the inhibition of microbial growth, making the dried pear a safe food for consumers. The knowledge of microbial flora, as well as some biochemical factors, is very important for ensuring the consumers health. In this study samples of pears of the variety S. Bartolomeu were dried under different systems: traditional open air sun drying, a solar stove, a solar drier and a drying tunnel. It was intended to isolate yeasts and moulds from dried pears subject to different drying processes, and also to some other fruits dried industrially. In this way, the following biochemical characteristics of dried fruits were evaluated: water activity and moisture content. Furthermore, the morphological characteristics of the isolates were also analyzed. Finally, as previously stated, the results obtained for dried pears were compared with the results obtained for samples of prunes and raisins, dried by industrial methods. The results of the biochemical characterization of the samples under study showed that all samples had a water activity lower than 0.60. After inoculated incubation it was only observed the grow of a mould in one sample of dried pears obtained by the traditional open air sun drying method, allowing to conclude that only this last method may induce the pears deterioration by microbial growth. The other systems tested for the drying of pears produce fruits that when dried can be conserved and consumed safely.