the handbook of food engineering practice crc press chapter 10 ...

Figure 13.
Aspartame degradation kinetics plotted as Arrhenius relation
The obtained kinetic information allows the prediction of aspartame degradation
and thus the shelf life of the product for any keeping temperature. Thus, if one assumes
that the product is overcompensated with aspartame at 0 time to allow for acceptable
product sweetness up to the point that half of the sweetener is degraded, the shelf life at 4 o
C is approximately 4 weeks (670 hr). Remaining shelf life can also be calculated after
exposure at any known temperature conditions. As an example, it is assumed that the
aseptic milk product is exposed for ten days the temperature conditions shown in Figure
14. It is a non specific variable distribution with a mean temperature,Tm, of 7.1 o C. The
total aspartame degradation at the end of the 10 days can be calculated by integration. The
value of ratio Γ (Eq.48 and Table 5) is determined as 1.0437. At T m after 10 days, the
remaining aspartame is 71.7%. Thus the actual aspartame level is calculated as 68.7%.
This can further be translated to remaining shelf life at constant 4 o C of 307 hr (12.8 days).
Note that if the product was assumed to have remained at 4 o C at the first 10 days, the
remaining shelf life would be 18 days.
The practical value of the described approach is that it allows a systematic
approach to shelf life prediction and optimization. Indeed similar results at the other
studied pHs showed activation energies in the range of 14 to 18 kcal/mol and shelf lifes
that reached 60 days at the lower end of pH range of 6.38. This is a valuable indication of
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