Monday, January 21, 2013

Freeze-Drying Good Alternative Thermal Drying of Bee Pollen

Influence of the Industrial Processing and the Floral Origin Into the Volatile Constituents of Honeybee-Collected Pollen
Honeybee-collected pollen constitutes a potential source of energy and proteins for human consumption. The aim of this study was to determinate if the volatile fraction of pollen is affected by the application of industrial treatment processes and by the floral origin.
Two process (thermal and freeze-drying) were compared with the fresh product. The volatile composition was investigated by a suitable analytical procedure based on dynamic headspace followed by thermal desorption gas chromatography mass spectrometry. Using this methodology more than 60 volatile compounds were separated in a phenyl-methyl-siloxane 50 m chromatographic column and identified according to their mass spectra, Kovats retention indices and comparison with those of authenticated reference standards. The differences among the studied honeybee pollens, in terms on volatile profile, were studied by means of the analysis of variance and principal component analysis. The volatile profile of fresh pollen is influenced by the floral origin and altered when it is processed, either by thermal and freeze-drying process, but when thermal process was used, compounds as dimethyl sulphyde and furfural, which affect negatively the functional quality, are found.
As conclusion, the freeze-drying system could be a good alternative to the traditional thermal drying process.

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