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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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LOX products by type after 100 min model time for different simulated  beans.
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fig02: LOX products by type after 100 min model time for different simulated beans.

Mentions: Figure 2 shows the concentration of products after 100 min predicted by the combined LOX model without the HPL reactions included. Also shown is the predicted concentration of the primary LOX products after 100 min for each of the possible combinations of LOX isozymes. In each case, with the exception of simulated L-3 only beans (L3, see nomenclature), the majority of the product formed is 13HOD-S(Z,E). The products formed in greatest concentrations by the simulated L3 beans are 9HOD-S(Z,E) and 9HOD-R(Z,E). The preferred substrate of HPL, 13HOD-S(Z,E), was modeled in the next step of the LOX pathway, and so the relative concentrations in which it is formed in different bean genotypes are significant. In the model, the L2 beans formed the most 13HOD-S(Z,E), closely followed by the L12, L23, and L123(wild type) beans, then at around one-third lower concentrations the L1 beans, the L13 beans, and finally the L3 beans producing by far the lowest concentration.


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

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

LOX products by type after 100 min model time for different simulated  beans.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig02: LOX products by type after 100 min model time for different simulated beans.
Mentions: Figure 2 shows the concentration of products after 100 min predicted by the combined LOX model without the HPL reactions included. Also shown is the predicted concentration of the primary LOX products after 100 min for each of the possible combinations of LOX isozymes. In each case, with the exception of simulated L-3 only beans (L3, see nomenclature), the majority of the product formed is 13HOD-S(Z,E). The products formed in greatest concentrations by the simulated L3 beans are 9HOD-S(Z,E) and 9HOD-R(Z,E). The preferred substrate of HPL, 13HOD-S(Z,E), was modeled in the next step of the LOX pathway, and so the relative concentrations in which it is formed in different bean genotypes are significant. In the model, the L2 beans formed the most 13HOD-S(Z,E), closely followed by the L12, L23, and L123(wild type) beans, then at around one-third lower concentrations the L1 beans, the L13 beans, and finally the L3 beans producing by far the lowest concentration.

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