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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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Simulated peak n-hexanal concentration against varying Km parameter values for L-1, L-2, and L-3 isoenzymes in “wild type” beans. Peak n-hexanal is given relative to the value at default Km (0.49 mM).
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fig05: Simulated peak n-hexanal concentration against varying Km parameter values for L-1, L-2, and L-3 isoenzymes in “wild type” beans. Peak n-hexanal is given relative to the value at default Km (0.49 mM).

Mentions: Changing the kinetic parameters of each of the 3 LOX isozymes in the model affects the peak n-hexanal concentration for simulated beans to varying degrees (Figure 5). Most of the variation was seen by reducing L-3 Km (increasing Vmax), with peak n-hexanal of around one-fifth that predicted using the default value following a 1000-fold decrease. Increasing L-3 Km 1000-fold only results in a very slightly higher peak n-hexanal concentration. Increasing L-2 Km (reducing Vmax) 1000-fold reduces peak n-hexanal concentration to around 0.6 times the value for the default parameter, while decreasing 1000-fold has relatively little effect. Increasing or decreasing L-1 Km (decreasing or increasing Vmax) has the least effect relatively of the 3 isozymes, with peak n-hexanal remaining in a similar range for all the parameter values tested. Reducing or decreasing Vmax values of the 3 LOX isozymes in the model should have a similar effect as changing individual LOX protein concentration and so more precise data for the concentration of the different LOX isozymes in the different bean types would be useful in testing the model further. The analysis would suggest that increasing levels of L-3 or reducing L-2 would have the greatest effect on reducing n-hexanal generation.


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

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

Simulated peak n-hexanal concentration against varying Km parameter values for L-1, L-2, and L-3 isoenzymes in “wild type” beans. Peak n-hexanal is given relative to the value at default Km (0.49 mM).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig05: Simulated peak n-hexanal concentration against varying Km parameter values for L-1, L-2, and L-3 isoenzymes in “wild type” beans. Peak n-hexanal is given relative to the value at default Km (0.49 mM).
Mentions: Changing the kinetic parameters of each of the 3 LOX isozymes in the model affects the peak n-hexanal concentration for simulated beans to varying degrees (Figure 5). Most of the variation was seen by reducing L-3 Km (increasing Vmax), with peak n-hexanal of around one-fifth that predicted using the default value following a 1000-fold decrease. Increasing L-3 Km 1000-fold only results in a very slightly higher peak n-hexanal concentration. Increasing L-2 Km (reducing Vmax) 1000-fold reduces peak n-hexanal concentration to around 0.6 times the value for the default parameter, while decreasing 1000-fold has relatively little effect. Increasing or decreasing L-1 Km (decreasing or increasing Vmax) has the least effect relatively of the 3 isozymes, with peak n-hexanal remaining in a similar range for all the parameter values tested. Reducing or decreasing Vmax values of the 3 LOX isozymes in the model should have a similar effect as changing individual LOX protein concentration and so more precise data for the concentration of the different LOX isozymes in the different bean types would be useful in testing the model further. The analysis would suggest that increasing levels of L-3 or reducing L-2 would have the greatest effect on reducing n-hexanal generation.

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