| Autor: |
Mei H. Ong, Ibrahim M. Al-Ruqaie, A. Steve Whitehouse, Stefan Kasapis, Rukmal Abeysekera |
| Rok vydání: |
1998 |
| Předmět: |
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| Zdroj: |
Food Hydrocolloids. 12:273-281 |
| ISSN: |
0268-005X |
| DOI: |
10.1016/s0268-005x(98)00015-0 |
| Popis: |
The structural properties of acid pigskin gelatin/oxidised waxy maize starch/glucose syrup mixtures at a 70% total level of solids were investigated. Depending on polymer composition and pH, mixtures form phase-separated gels with a gelatin or an oxidised starch continuous matrix. It was found that the continuous phase determined the mechanical behaviour of a mixture. Thus gelatin/glucose syrup systems or gelatin continuous mixtures show a three-fold transformation in viscoelasticity, namely: from solutions at high temperature (>35°C) and rubbery solids at ambient temperature to high modulus viscoelastic liquids at subzero temperatures (e.g. >10 6 Pa at 10 Hz and −20°C). In the language of polymer physics a transition was observed from rubber-like to glass-like consistency. By contrast, oxidised starch/glucose syrup systems and oxidised starch continuous mixtures show a transformation from liquid-like to solid-like behaviour at subzero temperatures due to water crystallisation. Concentrated oxidised starch (≈31%) with glucose syrup (≈39%) systems are capable of forming intermolecular amylose-like structures at high temperatures (e.g. 80°C), which remain solid-like throughout the cooling run (down to −20°C). Therefore the development of crystallinity (water/polymeric aggregates) in starch-dominated systems prevents them from exhibiting glass-related viscoelasticity. The investigative approach in general, and this mixture in particular (with its multitude of structures) might provide guidance for development work in the confectionery industry. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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Full Text from ScienceDirect