Articles
Viscosity of tomato-based product can be influenced by structural modification of constitutive particles as well as biochemical modification of pectins
Article number
1445_37
Pages
265 – 270
Language
English
Abstract
In order to influence the viscosity of tomato-based products, processors can choose to manufacture their products from cultivars known to provide more or less viscous products, or/and to act on key parameters of the process known to modify texture, such as break temperature and product concentration.
While these solutions are known to have an impact on texture, the underlying physicochemical mechanisms remain poorly understood and therefore poorly controlled.
Using an experimental design including two lines contrasting for the texture of their purees and both hot- and cold-break processes that also cause textural changes, the aim of our study was to identify the molecular and physical mechanisms underlying each origin of the changes.
Initially, rheological analysis of the purées did not enable us to differentiate between textural changes due to the process and those due to the change in cultivar, but sensory analysis showed that consumers did differentiate between the two causes of textural change.
A detailed physico-chemical analysis of each puree showed that ‘H1311’, which systematically exhibited purees with higher viscosity than ‘Terradou’, also exhibited 30% more insoluble solids than ‘Terradou’ within its dry matter content, identifying soluble/insoluble solid proportion as a key trait for genetic improvement of tomato cultivars dedicated to produce viscosity.
Concerning the impact of the HB/CB process, our study showed that HB purees exhibited pectins with molecular volume twice to four times higher than CB ones.
But the most unpredictable result was obtained by Fluorescence microscopy of the particles revealing that HB purees contained a higher proportion of particles exhibiting entanglement between lycopene-rich particles and cell-wall fragments, which are particles theoretically opposed for their hydrophobicity.
This study enables us to provide new hypotheses as to the molecular mechanisms that cause texture changes and opens the way to better control of this parameter for industrial tomatoes.
While these solutions are known to have an impact on texture, the underlying physicochemical mechanisms remain poorly understood and therefore poorly controlled.
Using an experimental design including two lines contrasting for the texture of their purees and both hot- and cold-break processes that also cause textural changes, the aim of our study was to identify the molecular and physical mechanisms underlying each origin of the changes.
Initially, rheological analysis of the purées did not enable us to differentiate between textural changes due to the process and those due to the change in cultivar, but sensory analysis showed that consumers did differentiate between the two causes of textural change.
A detailed physico-chemical analysis of each puree showed that ‘H1311’, which systematically exhibited purees with higher viscosity than ‘Terradou’, also exhibited 30% more insoluble solids than ‘Terradou’ within its dry matter content, identifying soluble/insoluble solid proportion as a key trait for genetic improvement of tomato cultivars dedicated to produce viscosity.
Concerning the impact of the HB/CB process, our study showed that HB purees exhibited pectins with molecular volume twice to four times higher than CB ones.
But the most unpredictable result was obtained by Fluorescence microscopy of the particles revealing that HB purees contained a higher proportion of particles exhibiting entanglement between lycopene-rich particles and cell-wall fragments, which are particles theoretically opposed for their hydrophobicity.
This study enables us to provide new hypotheses as to the molecular mechanisms that cause texture changes and opens the way to better control of this parameter for industrial tomatoes.
Authors
D. Page, M. Sinkora, A. Lecas, A. Rolland-Sabate, A.-L. Fanciullino, R. Giovinazzo, F. Zuber, N. Bertin
Keywords
tomato, processing, viscosity, soluble pectin, particle, microscopy
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