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Reduction of off-flavor generation in soybean homogenates: a mathematical model.

Mellor N, Bligh F, Chandler I, Hodgman C - J. Food Sci. (2010)

Bottom Line: Time-course simulations of LOX- beans were run and compared with experimental results.Model L(2), L(3), and L(12) beans were within the range relative to the wild type found experimentally, with L(13) and L(23) beans close to the experimental range.Sensitivity analysis indicates that reducing the estimated K(m) parameter for LOX isozyme 3 (L-3) would improve the fit between model predictions and experimental results found in the literature.

View Article: PubMed Central - PubMed

Affiliation: CPIB, Multidisciplinary Centre for Integrative Biology, School of Biosciences, the Univ. of Nottingham, Sutton Bonington Campus, LE12 5RD, UK.

ABSTRACT

Unlabelled: The generation of off-flavors in soybean homogenates such as n-hexanal via the lipoxygenase (LOX) pathway can be a problem in the processed food industry. Previous studies have examined the effect of using soybean varieties missing one or more of the 3 LOX isozymes on n-hexanal generation. A dynamic mathematical model of the soybean LOX pathway using ordinary differential equations was constructed using parameters estimated from existing data with the aim of predicting how n-hexanal generation could be reduced. Time-course simulations of LOX- beans were run and compared with experimental results. Model L(2), L(3), and L(12) beans were within the range relative to the wild type found experimentally, with L(13) and L(23) beans close to the experimental range. Model L(1) beans produced much more n-hexanal relative to the wild type than those in experiments. Sensitivity analysis indicates that reducing the estimated K(m) parameter for LOX isozyme 3 (L-3) would improve the fit between model predictions and experimental results found in the literature. The model also predicts that increasing L-3 or reducing L-2 levels within beans may reduce n-hexanal generation.

Practical application: This work describes the use of mathematics to attempt to quantify the enzyme-catalyzed conversions of compounds in soybean homogenates into undesirable flavors, primarily from the compound n-hexanal. The effect of different soybean genotypes and enzyme kinetic constants was also studied, leading to recommendations on which combinations might minimize off-flavor levels and what further work might be carried out to substantiate these conclusions.

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Comparison by individual -bean type between model predictions and experimental results (Matoba and others 1985a).
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fig04: Comparison by individual -bean type between model predictions and experimental results (Matoba and others 1985a).

Mentions: Figure 4 shows the same data but with a direct comparison between model and experimental values for each type of bean. Again there appears to be a rough correlation, with the exception of the L2 beans, and the presence of initial concentrations of n-hexanal observed experimentally in all bean types. In the present model, 13HOD-S(Z,E) and 13HOD-R(Z,E) concentrations are only depleted by the activity of HPL. In reality, these molecules may by degraded or metabolized by other pathways, and the rates of these pathways will have an effect on n-hexanal concentration. An experiment in which 13HOD-S(Z,E) and 13HOD-R(Z,E) levels are recorded while HPL activity is blocked or otherwise inhibited would enable an estimation of these rates, and enable their inclusion in the model. If we assume that these parameters and those relating to HPL remain the same regardless of the presence or absence of the 3 LOX isozymes, then while varying them will have an effect on the absolute concentrations of n-hexanal, they should have little or no effect on the relative concentrations obtained for the different bean simulations.


Reduction of off-flavor generation in soybean homogenates: a mathematical model.

Mellor N, Bligh F, Chandler I, Hodgman C - J. Food Sci. (2010)

Comparison by individual -bean type between model predictions and experimental results (Matoba and others 1985a).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2992688&req=5

fig04: Comparison by individual -bean type between model predictions and experimental results (Matoba and others 1985a).
Mentions: Figure 4 shows the same data but with a direct comparison between model and experimental values for each type of bean. Again there appears to be a rough correlation, with the exception of the L2 beans, and the presence of initial concentrations of n-hexanal observed experimentally in all bean types. In the present model, 13HOD-S(Z,E) and 13HOD-R(Z,E) concentrations are only depleted by the activity of HPL. In reality, these molecules may by degraded or metabolized by other pathways, and the rates of these pathways will have an effect on n-hexanal concentration. An experiment in which 13HOD-S(Z,E) and 13HOD-R(Z,E) levels are recorded while HPL activity is blocked or otherwise inhibited would enable an estimation of these rates, and enable their inclusion in the model. If we assume that these parameters and those relating to HPL remain the same regardless of the presence or absence of the 3 LOX isozymes, then while varying them will have an effect on the absolute concentrations of n-hexanal, they should have little or no effect on the relative concentrations obtained for the different bean simulations.

Bottom Line: Time-course simulations of LOX- beans were run and compared with experimental results.Model L(2), L(3), and L(12) beans were within the range relative to the wild type found experimentally, with L(13) and L(23) beans close to the experimental range.Sensitivity analysis indicates that reducing the estimated K(m) parameter for LOX isozyme 3 (L-3) would improve the fit between model predictions and experimental results found in the literature.

View Article: PubMed Central - PubMed

Affiliation: CPIB, Multidisciplinary Centre for Integrative Biology, School of Biosciences, the Univ. of Nottingham, Sutton Bonington Campus, LE12 5RD, UK.

ABSTRACT

Unlabelled: The generation of off-flavors in soybean homogenates such as n-hexanal via the lipoxygenase (LOX) pathway can be a problem in the processed food industry. Previous studies have examined the effect of using soybean varieties missing one or more of the 3 LOX isozymes on n-hexanal generation. A dynamic mathematical model of the soybean LOX pathway using ordinary differential equations was constructed using parameters estimated from existing data with the aim of predicting how n-hexanal generation could be reduced. Time-course simulations of LOX- beans were run and compared with experimental results. Model L(2), L(3), and L(12) beans were within the range relative to the wild type found experimentally, with L(13) and L(23) beans close to the experimental range. Model L(1) beans produced much more n-hexanal relative to the wild type than those in experiments. Sensitivity analysis indicates that reducing the estimated K(m) parameter for LOX isozyme 3 (L-3) would improve the fit between model predictions and experimental results found in the literature. The model also predicts that increasing L-3 or reducing L-2 levels within beans may reduce n-hexanal generation.

Practical application: This work describes the use of mathematics to attempt to quantify the enzyme-catalyzed conversions of compounds in soybean homogenates into undesirable flavors, primarily from the compound n-hexanal. The effect of different soybean genotypes and enzyme kinetic constants was also studied, leading to recommendations on which combinations might minimize off-flavor levels and what further work might be carried out to substantiate these conclusions.

Show MeSH