Rheological behaviour of sheares jams. Relation with fruit content
Eight samples of jam were sheared to destroy gel structure and their flow behaviour was analysed in a concentric cylinder viscometer. Jams were prepared from 4 different fruits—strawberry, peach, plum, and apricot—at 50% and 30% fruit content approximately. Flow of sheared jam showed time dependence, which could be quantified by the Weltmann model and which was eliminated by shearing samples for 8 min at 300 rpm. Casson's yield stress values were obtained at two ranges of shear rates: 0.08–1.01 s (O) and 2.58–387.30 s (o). o values were about double the o values. Flow was adequately described by the Herschel and Bulkley model, introducing either of the yield stress values (o or o). Significant differences were found for some of the rheological parameters studied (Weltmann A and B constants, o, o, K, and n) between samples containing 50% and 30% fruit. These results demonstrate the role played by fruit particles in the rheological behaviour of this type of product and suggest the possibility of using rheological parameters as indices of fruit content in jams.
| Main Authors: | , , |
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| Format: | artículo biblioteca |
| Published: |
Wiley-Blackwell
1991-04
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| Online Access: | http://hdl.handle.net/10261/332317 |
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