Abstract SCHIRACK, ANDRIANA VAIS. The Effect of Microwave ...

treatment was over 100 °C, similar to the 11NF treatment and the peanuts in Set 2
which ranged from 119 – 139 °C. In temperatures under 100 °C, Datta and Liu
(1992) found that temperature profiles became increasingly non-uniform over longer
heating times during microwave processing. However, Ni et al. (1999) found that the
non-uniformity in temperatures is lessened when the food temperature reaches the
boiling point of water. The same study (Ni et al, 1999) also found that the key
variable which controls moisture loss during the microwave heating of solid foods
was achieving an average temperature uniformly. By evaluating the maximum
temperatures reached during processing, it was seen that the internal temperatures
during the 8NF treatment exceeded 100 °C, and perhaps reached a more uniform
temperature profile, leading to greater moisture loss and acceptable blanchability.
CONCLUSIONS
The use of microwave technology for peanut blanching provides a significant
decrease in processing time and can result in cost savings. In this study, the
relationships between temperature, moisture content, and blanchability using a
continuous belt processing method have been demonstrated. Effective blanchability
was correlated to high process temperatures and corresponding low moisture
content. All peanuts with internal temperatures exceeding 110 °C and reaching a
final moisture content of 5.5 % or below yielded acceptable blanchability. Even
peanuts varying in initial moisture content resulted in a low final moisture content
and acceptable blanchability. This study demonstrated that peanuts heated by
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