Thermal Degradation of Three Nutrients in Foods

choose a nonisothermal temperature profile

isothermal

T

1

T

2

T

3

T (°C)

15.

t

40.

degradation curve 1

n

1

0.

T

ref

1

(°C)

15.

k

T

ref

1

0.015

c

1

0.1

degradation curve 2

n

2

0.5

T

ref

2

(°C)

20.

k

T

ref

2

0.015

c

2

0.075

degradation curve 3

n

3

1.

T

ref

3

(°C)

20.

k

T

ref

3

0.03

c

3

0.05

axes limits

t

max

60.

T

min

(°C)

0.

T

max

(°C)

40.

T

2

(t) =

T

0

+(

a

1

-

T

0

) (1-exp(-0.02 t))+

a

2

sin(

a

3

t)

Foods, especially fortified ones, contain several nutrients—for example, vitamins, whose thermal degradation during storage follows different kinetics. This implies that different constant storage temperatures or nonisothermal temperature histories would result in different absolute and relative retention levels at different times. This Demonstration simulates isothermal and nonisothermal degradation curves of three hypothetical nutrients following the same or different kinetic orders. The temperature dependence of their rate constants is assumed to follow an exponential model, which can be used interchangeably with the traditional Arrhenius equation.